GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc1013

Network Working Group Robert W. Scheifler Request for Comments: 1013 June 1987

                X WINDOW SYSTEM PROTOCOL, VERSION 11
                               Alpha Update
                                April 1987
   Copyright (c) 1986, 1987 Massachusetts Institute of Technology
                 X Window System is a trademark of M.I.T.

Status of this Memo

 This RFC is distributed to the Internet community for information
 only.  It does not establish an Internet standard.  The X window
 system has been widely reviewed and tested.  The internet community
 is encouraged to experiment with it.  Distribution of this memo is
 unlimited (see copyright notice on page 2).

M.I.T. [Page 1] RFC 1013 June 1987

 Permission to use, copy, modify, and distribute this document for any
 purpose and without fee is hereby granted, provided that the above
 copyright notice appear in all copies and that both that copyright
 notice and this permission notice are retained, and that the name of
 M.I.T. not be used in advertising or publicity pertaining to this
 document without specific, written prior permission.  M.I.T. makes no
 representations about the suitability of this document or the
 protocol defined in this document for any purpose.  It is provided
 "as is" without express or implied warranty.
  Author: Robert W. Scheifler
         Laboratory for Computer Science
         545 Technology Square, Room 418
         Cambridge, MA 02139
  Contributors:
         Dave Carver (Digital HPW)
         Branko Gerovac (Digital HPW)
         Jim Gettys (MIT/Project Athena, Digital)
         Phil Karlton (Digital WSL)
         Scott McGregor (Digital SSG)
         Ram Rao (Digital UEG)
         David Rosenthal (Sun)
         Dave Winchell (Digital UEG)
  Implementors of initial server who provided useful input:
         Susan Angebranndt (Digital)
         Raymond Drewry (Digital)
         Todd Newman (Digital)
  Invited reviewers who provided useful input:
         Andrew Cherenson (Berkeley)
         Burns Fisher (Digital)
         Dan Garfinkel (HP)
         Leo Hourvitz (Next)
         Brock Krizan (HP)
         David Laidlaw (Stellar)
         Dave Mellinger (Interleaf)
         Ron Newman (MIT)
         John Ousterhout (Berkeley)
         Andrew Palay (ITC CMU)
         Ralph Swick (MIT)
         Craig Taylor (Sun)
         Jeffery Vroom (Stellar)
 This document does not attempt to provide the rationale or pragmatics
 required to fully understand the protocol or to place it in
 perspective within a  complete system.  Knowledge of X Version 10
 will certainly aid in understanding this document.

M.I.T. [Page 2] RFC 1013 June 1987

 The protocol contains many management mechanisms that are not
 intended for normal applications.  Not all mechanisms are needed to
 build a particular user interface.  It is important to keep in mind
 that the protocol is intended to provide mechanism, not policy.
 This document does not attempt to define precise formats or bit
 encodings.
  1. ——————————————————————

M.I.T. [Page 3] RFC 1013 June 1987

 SECTION 1.  TERMINOLOGY
 Access control list
         X maintains a list of hosts from which client programs may be
         run.  By default, only programs on the local host may use the
         display, plus any hosts specified in an initial list read by
         the server.  This "access control list" can be changed by
         clients on the local host.  Some server implementations may
         also implement other authorization mechanisms.
 Active grab
         A grab is "active" when the pointer or keyboard is actually
         owned by the single grabbing client.
 Ancestors
         If W is an inferior of A, then A is an "ancestor" of W.
 Atom
         An "atom" is a unique id corresponding to a string name.
         Atoms are used to identify properties, types, and selections.
 Backing store
         When a server maintains the contents of a window, the
         off-screen saved pixels are known as a "backing store".
 Bit gravity
         When a window is resized, the contents of the window are
         not necessarily discarded.  It is possible to request the
         server (though no guarantees are made) to relocate the
         previous contents to some region of the window.  This
         attraction of window contents for some location of a window
         is known as "bit gravity".
 Bitmap
         A "bitmap" is a pixmap of depth one.
 Button grabbing
         Buttons on the pointer may be passively "grabbed" by a
         client.  When the button is pressed, the pointer is then
         actively grabbed by the client.
 Byte order
         For image (pixmap/bitmap) data, byte order is defined by
         the server, and clients with different native byte ordering
          must swap bytes as necessary.  For all other parts of the
         protocol, the byte order is defined by the client, and the
         server swaps bytes as necessary.
 Children
         The "children" of a window are its first-level subwindows.

M.I.T. [Page 4] RFC 1013 June 1987

 Client
         An application program connects to the window system server
         by some interprocess communication (IPC) path, such as a TCP
         connection or a shared memory buffer.  This program is the
         window system server.  More precisely, the client is the IPC
         path itself; a program with multiple paths open to the server
         is viewed as multiple clients by the protocol.  Resource
         lifetimes are controlled by connection lifetimes, not by
         program lifetimes.
 Clipping regions
         In a graphics context, a bitmap or list of rectangles can
         be specified to restrict output to a particular region of
         the window.  The image defined by the bitmap or rectangles
         is called a "clipping region".
 Color cell
         An entry in a colormap is known as a "color cell".  An entry
         contains three values specifying red, green and blue
         intensities.  These values are always viewed as 16 bit
         unsigned numbers, with zero being minimum intensity.  The
         values are scaled by the server to match the display
         hardware.  The components of a cell are coincident with
         components of other cells in DirectColor and TrueColor
         colormaps.
 Colormap
         A "colormap" consists of a set of color cells.  A pixel value
         indexes the color map to produce intensities to be displayed.
         Depending on hardware limitations, one or more colormaps may
         be installed at one time, such that windows associated with
         those maps display with true colors.
 Connection
         The IPC path between the server and client program is known
         as a "connection".  A client program typically (but not
         necessarily) has one connection to the server over which
         requests and events are sent.
 Containment
         A window "contains" the pointer if the window is viewable and
         the hotspot of the cursor is within a visible region of the
         window or a visible region of one of its inferiors.  The
         border of the window is included as part of the window for
         containment.  The pointer is "in" a window if the window
         contains the pointer but no inferior contains the pointer.
 Coordinate system
         The coordinate system has X horizontal and Y vertical, with
         the origin [0, 0] at the upper left.  Coordinates are
         discrete, and in terms of pixels.  Each window and pixmap has

M.I.T. [Page 5] RFC 1013 June 1987

         its own coordinate system.  For a window, the origin is at
         the inside upper left, inside the border.
 Cursor
         A "cursor" is the visible shape of the pointer on a screen.
         It consist of a hot spot, a source bitmap, a shape bitmap,
         and a pair of colors.  The cursor defined for a window
         controls the visible appearance when the pinter is in that
         window.
 Depth
         The "depth" of a window or pixmap is number of bits per pixel
         it has. The depth of a gcontext is the depth of the root of
         the gcontext.
 Device
         Keyboards, mice, tablets, track-balls, button boxes, etc. are
         all collectively known as input "devices".  The core protocol
         only deals with two devices, "the keyboard" and "the
         pointer".
 Drawable
         Both windows and pixmaps may be used as sources and
         destinations  in graphics operations.  These are collectively
         known as "drawables". However, an InputOnly window cannot be
         used as a source or destination in a graphics operation.
 Event
         Clients are informed of information asynchronously via
         "events". These events may be either asynchronously generated
         from devices, or generated as side effects of client
         requests.  Events are grouped into types; events are never
         sent to a client by the server unless the client has
         specificially asked to be informed of that type of event,
         but other clients can force events to be sent to other
         clients. Events are typically reported relative to a window.
 Event mask
         Events are requested relative to a window.  The set of event
         types a client requests relative to a window described using
         an "event mask".
 Event sychronization
         There are certain race conditions possible when
         demultiplexing device events to clients (in particular
         deciding where pointer and keyboard events should be sent
         when in the middle of window management operations).  The
         event synchronization mechanism allows synchronous processing
         of device events.

M.I.T. [Page 6] RFC 1013 June 1987

 Event propagation
         Device-related events "propagate" from the source window to
         ancestor windows until some client has expressed interest in
         handling that type of event, or until the event is discarded
         explicitly.
 Event source
         The smallest window containing the pointer is the "source"
         of a device related event.
 Exposure event
         Servers do not guarantee to preserve the contents of windows
         when windows are obscured or reconfigur contents of regions
         of windows have been lost.
 Extension
         Named "extensions" to the core protocol can be defined to
         extend the system.  Extension to output requests, resources,
         and event types are all possible, and expected.
 Font
         A "font" is an array of glyphs (typically characters).  The
         protocol does no translation or interpretation of character
         sets.  The client simply indicates values used to index the
         glyph array.  A font contains additional metric information
         to determine inter-glyph and inter-line spacing.
 Glyph
         A "glyph" is an image, typically of a character, in a font.
 Grab
         Keyboard keys, the keyboard, pointer buttons, the pointer,
         and the server can be "grabbed" for exclusive use by a
         client.  In general, these facilities are not intended to be
         used by normal applications, but are intended for various
         input and window managers to implement various styles of
         user interfaces.
 Graphics context
         Various information for graphics output is stored in "GC"'s,
         such as foreground pixel, background pixel, line width,
         clipping region, etc.
 Hotspot
         A cursor has an associated "hot spot" which defines a point
         in the cursor that corresponds to the coordinates reported
         for the pointer.
 Identifier
         Each resource has an "identifier", a unique value associated
         with it that clients use to name the resource.  An identifier

M.I.T. [Page 7] RFC 1013 June 1987

         can be used over any connection to name the resource.
 Inferiors
         The "inferiors" of a window are all of the subwindows nested
         below it: the children, the children's children, etc.
 Input focus
         The "input focus" is nominally where keyboard input goes.
         Keyboard events are by default sent to the client expressing
         interest on the window the pointer is in.  This is said to be
         a "real estate driven" input focus.  It is also possible to
         attach the keyboard input to a  specific window; events will
         then be sent to the appropriate client independent of the
         pointer position.
 Input manager
         Control over keyboard input is typically provided by an
         "input manager" client.
 InputOnly window
         A window that cannot be used for graphics requests.
         InputOnly windows are "invisible", and can be used to control
         such things as cursors, input event generation, and grabbing.
 InputOutput window
         The "normal" kind of opaque window, used for both input
         and output.
 Key grabbing
         Keys on the keyboard may be passively "grabbed" by a client.
         When the key is pressed, the keyboard is then actively
         grabbed by the client.
 Keyboard grabbing
         A client can actively "grab" control of the keyboard, and key
         events will be sent to that client rather than the client the
         events would normally have been sent to.
 Mapping
         A window is said to be "mapped" if a map call has been
         performed on it.  Unmapped windows are never viewable or
         visible.
 Modifier keys
         Shift, Control, Meta, Super, Hyper, ALT, Compose, Apple,
         CapsLock, ShiftLock, and similar keys are called "modifier"
         keys.
 Obscures
         Window A "obscures" window B if both are viewable
         InputOutput windows and A is higher in the global stacking

M.I.T. [Page 8] RFC 1013 June 1987

         order, and the rectangle defined by the outside edges of
         intersects the rectangle defined by the outside edges of B.
         Note the (fine) distinction with "occludes". Also note that
         window borders are included in the calculation.
 Occludes
         Window A "occludes" window B if both are mapped and A is
         higher in the global stacking order, and the rectangle
         defined by the outside edges of A intersects the rectangle
         defined by the outside edges of B.  Note the (fine)
         distinction with "obscures".  Also note that window borders
         are included in the calculation.
 Padding
         Some padding bytes are inserted in the data stream to
         maintain alignment of the protocol requests on natural
         boundaries.  This increases ease of portability to some
         machine architectures.
 Parent window
         If C is a child of P, then P is the "parent" of C.
 Passive grab
         Grabbing a key or button is a "passive" grab.  The grab
         activates when the key or button is actually pressed.
 Pixel value
         A "pixel" is an N-bit value, where N is the number of bit
         planes used in a particular window or pixmap.  For a window,
         a pixel value indexes a colormap to derive an actual color
         to be displayed.
 Pixmap
         A "pixmap" is a three dimensional array of bits.  A pixmap
         is normally thought of as a two dimensional array of pixels,
         where each pixel can be a value from 0 to (2^N)-1, where N
         is the depth (z axis) of the pixmap.  A pixmap can also be
         thought of as a stack of N bitmaps.
 Plane mask
         Graphics operations can be restricted to only affect a
         subset of bit planes of a destination.  A "plane mask" is
         a bit mask describing which planes are to be modified, and
         is stored in a graphics context.
 Pointer
         The "pointer" is the pointing device attached to the cursor,
         and tracked on the screens.
 Pointer grabbing
         A client can actively "grab" control of the pointer, and

M.I.T. [Page 9] RFC 1013 June 1987

         button and motion events will be sent to that client rather
         than the client the events would normally have been sent to.
 Pointing device
         A "pointing device" is typically a mouse or tablet, or some
         other device with effective dimensional motion.  There is
         only one visible cursor is defined by the core protocol,
         and it tracks whatever pointing device is attached as the
         pointer.
 Property
         Windows may have associated "properties", consisting of a
         name, a type, a data format, and some data.  The protocol
         places no interpretation on properties, they are intended
         as a general-purpose naming mechanism for clients.  For
         example, clients might share information such as resize
         hints, program names, and icon formats with a window
         manager via properties.
 Property list
         The "property list" of a window is the list of properties
         that have been defined for the window.
 Redirecting control
         Window managers (or client programs) may wish to enforce
          window layout policy in various ways.  When a client
         attempts to change the size or position of a window, the
         operation may be "redirected" to a specified client,
         rather than the operation actually being performed.
 Reply
         Information requested by a client program is sent back to
         the client with a "reply".  Both events and replys are
         multipexed on the same connection.  Most requests do not
         generate replies.
 Request
         A command to the server is called a "request".  It is a
         single block of data sent over a connection.
 Resource
         Windows, pixmaps, cursors, fonts, graphics contexts, and
         colormaps are known as "resources".  They all have unique
         identifiers associated with them for naming purposes.  The
         lifetime of a resource is bounded by the lifetime of the
         connection over which the resource was created.
 Root
         The "root" of a pixmap or gcontext is the same as the root
         of whatever drawable was used when the pixmap or gcontext
         was created.  The "root" of a window is the root window

M.I.T. [Page 10] RFC 1013 June 1987

         under which the window was created.
 Root window
         Each screen has a "root window" covering it.  It cannot be
         reconfigured or unmapped, but otherwise acts as a full
         fledged window. A root window has no parent.
 Save set
         The "save set" of a client is a list of other client's
         windows which, if they are inferiors of one of the client's
         windows at connection close, should not be destroyed, and
         which should be remapped if it is unmapped.  Save sets are
         typically used by window managers to avoid lost windows if
         the manager should terminate abnormally.
 Screen
         A server may provide several independent "screens", which
         typically have physically independent monitors.  This would
         be the expected configuration when there is only a single
         keyboard and pointer shared among the screens.
 Server
         The "server" provides the basic windowing mechanism.  It
         handles IPC connections from clients, demultipexes graphics
         requests onto the screens, and multiplexes input back to the
         appropriate clients.
 Server grabbing
         The server can be "grabbed" by a single client for exclusive
         use. This prevents processing of any requests from other
         client connections until the grab is complete.  This is
         typically only a transient state for such things as
         rubber-banding and pop-up menus, or to execute requests
         indivisibly.
 Sibling
         Children of the same parent window are known as "sibling"
         windows.
 Stacking order
         Sibling windows may "stack" on top of each other.  Windows
         above both obscure and occlude lower windows.  This is
         similar to paper on a desk. The relationship between
         sibling windows is known as the "stacking order".
 Stipple
         A "stipple pattern" is a bitmap that is used to tile a
         region to serve as an additional clip mask for a fill
         operation with the foreground color.

M.I.T. [Page 11] RFC 1013 June 1987

 Tile
         A pixmap can be replicated in two dimensions to "tile"
         a region.  The pixmap itself is also known as a "tile".
 Timestamp
         A time value, expressed in milliseconds, typically since
         the last server reset.  Timestamp values wrap around (after
         about 49.7 days). The server, given its current time is
         represented by timestamp T, always interprets timestamps
         from clients by treating half of the timestamp space as
         being earlier in time than T, and half of the timestamp
         space as being later in time than T.  One timestamp value
         (named CurrentTime) is never generated by the server;
         this value is reserved for use in requests to represent
         the current server time.
 Type
         A type is an arbitrary atom used to identify the
         interpretation of property data.  Types are completely
         uninterpreted by the server; they are solely for the
         benefit of clients.
 Unviewable
         A window is "unviewable" if it is mapped but some ancestor is
         unmapped.
 Viewable
         A window is "viewable" if it and all of its ancestors are
         mapped.  This does not imply that any portion of the window
         is actually visible.
 Visible
         A region of a window is "visible" if someone looking at the
         screen can actually "see" it:  the window is viewable and the
         region is not occluded by any other window.
 Window gravity
         When windows are resized, subwindows may be repositioned
         automatically relative to some position in the window.  This
         attraction of a subwindow to some part of its parent is known
         as "window gravity".
 Window manager
         Manipulation of windows on the screen, and much of the user
         interface (policy) is typically provided by a "window
         manager" client.
 XYFormat
         The data for a pixmap is said to be in "XYFormat" if it is
         organized as a set of bitmaps representing individual bit
         planes.

M.I.T. [Page 12] RFC 1013 June 1987

 ZFormat
         The data for a pixmap is said to be in "ZFormat" if it is
         organized as a set of pixel values in scanline order.

SECTION 2. PROTOCOL FORMATS

Request Format

 Every request contains an 8-bit "major" opcode, and a 16-bit length
 field expressed in units of 4 bytes.  Every request consists of 4
 bytes of header containing the major opcode, the length field, and a
 data byte) followed by zero or more additional bytes of data; the
 length field defines the total length of the request, including the
 header.  The length field in a request must equal the minimum length
 required to contain the request; if the specified length is smaller
 or larger than the required length, an error is enerated.  Unused
 bytes in a request are not required to be zero.  Major opcodes 128
 through 255 are reserved for extensions.  Extensions are intended
 to contain multiple requests, so extension requests typically have
 an additional minor opcode encoded in the "spare" data byte in the
 request header, but the placement and interpretation of this minor
 opcode, and all other fields in extension requests, are not defined
 by the core protocol. Every request is implicitly assigned a sequence
 number, starting with one,used in replies, errors, and events.

Reply Format

 Every reply contains a 32-bit length field expressed in units of 4
 bytes. Every reply consists of 32 bytes, followed by zero or more
 additional bytes of data, as specified in the length field.  Unused
 bytes within a reply are not guaranteed to be zero.  Every reply
 also contains the least significant 16 bits of the sequence number
 of the corresponding request.

Error Format

 Error reports are 32 bytes long.  Every error includes an 8-bit error
 code. Error codes 128 through 255 are reserved for extensions.  Every
 error also includes the major and minor opcodes of the failed
 request, and the least significant 16 bits of the sequence number of
 the request.  For the following errors (see Section 5), the failing
 resource id is also returned: Colormap, Cursor, Drawable, Font,
 GContext, IDChoice, Pixmap, and Window.  For Atom errors, the failing
 atom is returned.  For Value errors, the failing value is returned.
 Other core errors return no additional data.  Unused bytes within
 an error are not guaranteed to be zero.

Event Format

 Events are 32 bytes long.  Unused bytes within an event are not

M.I.T. [Page 13] RFC 1013 June 1987

 guaranteed to be zero.  Every event contains an 8-bit type code.  The
 most significant bit in this code is set if the event was generated
 from a SendEvent request. Event codes 64 through 127 are reserved for
 extensions, although the core protocol does not define a mechanism
 for selecting interest in such events. Every core event (with the
 exception of KeymapNotify) also contains the least significant 16
 bits of the sequence number of the last request issued by the client
 that was (or is currently being) processed by the server.

SECTION 3. SYNTAX

 The syntax {...} encloses a set of alternatives.
 The syntax [...] encloses a set of structure components.
 In general, TYPEs are in upper case and AlternativeValues are
 capitalized.
 Requests in Section 10 are described in the following format:
     RequestName
             arg1: type1
             ...
             argN: typeN
         =>
             result1: type1
             ...
             resultM: typeM
             Errors: kind1, ..., kindK
             Description.

If no ⇒ is present in the description, then the request has no reply (it is asynchronous), although errors may still be reported.

Events in Section 12 are described in the following format:

  EventName
          value1: type1
          ...
          valueN: typeN
          Description.

M.I.T. [Page 14] RFC 1013 June 1987

SECTION 4. COMMON TYPES

LISTofFOO

 A type name of the form LISTofFOO means a counted list of elements
 of type FOO; the size of the length field may vary (it is not
 necessarily the same size as a FOO), in some cases may be implicit,
 and is not fully specified in this document.

BITMASK and LISTofVALUE

 The types BITMASK and LISTofVALUE are somewhat special.  Various
 requests contain arguments of the form:
         value-mask: BITMASK
         value-list: LISTofVALUE
 used to allow the client to specify a subset of a heterogeneous
 collection of "optional" arguments.  The value-mask specifies which
 arguments are to be provided; each such argument is assigned a unique
 bit position.  The representation of the BITMASK will typically
 contain more bits than there are defined arguments; unused bits in
 the value-mask must be zero (or the server generates a Value error).
 The value-list contains one value for each one bit in the mask, from
 least to most significant bit in the mask.  Each value is represented
 with 4 bytes, but the actual value occupies only the least
 significant bytes as required; the values of the unused bytes do not
 matter.

Or Types

 A type of the form "T1 or ... or Tn" means the union of the indicated
 types; a single-element type is given as the element without
 enclosing braces.

DEVICE: 32-bit id (<class,model,manufacturer,unit> 8 bits each) WINDOW: 32-bit id PIXMAP: 32-bit id CURSOR: 32-bit id FONT: 32-bit id GCONTEXT: 32-bit id COLORMAP: 32-bit id DRAWABLE: WINDOW or PIXMAP ATOM: 32-bit id (top 3 bits guaranteed to be zero) VISUALID: 32-bit id (top 3 bits guaranteed to be zero) VALUE: 32-bit quantity (used only in LISTofVALUE) INT8: 8-bit signed integer INT16: 16-bit signed integer INT32: 32-bit signed integer CARD8: 8-bit unsigned integer CARD16: 16-bit unsigned integer CARD32: 32-bit unsigned integer

M.I.T. [Page 15] RFC 1013 June 1987

TIMESTAMP: CARD32 BITGRAVITY: {Forget, Static,

           NorthWest, North, NorthEast,
           West, Center, East,
           SouthWest, South, SouthEast}

WINGRAVITY: {Unmap, Static,

           NorthWest, North, NorthEast,
           West, Center, East,
           SouthWest, South, SouthEast}

BOOL: {True, False} EVENT: {KeyPress, KeyRelease,

      OwnerGrabButton,
      ButtonPress, ButtonRelease, EnterWindow, LeaveWindow,
      PointerMotion, PointerMotionHint,
      Button1Motion, Button2Motion, Button3Motion,
      Button4Motion, Button5Motion, ButtonMotion
      Exposure, VisibilityChange,
      StructureNotify, ResizeRedirect,
      SubstructureNotify, SubstructureRedirect,
      FocusChange,
      PropertyChange, ColormapChange,
      KeymapState}

POINTEREVENT: {ButtonPress, ButtonRelease, EnterWindow, LeaveWindow,

             PointerMotion, PointerMotionHint,
             Button1Motion, Button2Motion, Button3Motion,
             Button4Motion, Button5Motion, ButtonMotion
             KeymapState}

DEVICEEVENT: {KeyPress, KeyRelease,

            ButtonPress, ButtonRelease,
            PointerMotion,
            Button1Motion, Button2Motion, Button3Motion,
            Button4Motion, Button5Motion, ButtonMotion}

KEYCODE: CARD8 BUTTON: CARD8 KEYMASK: {Shift, CapsLock, Control, Mod1, Mod2, Mod3, Mod4, Mod5} BUTMASK: {Button1, Button2, Button3, Button4, Button5} KEYBUTMASK: KEYMASK or BUTMASK STRING8: LISTofCARD8 STRING16: LISTofCHAR2B CHAR2B: [byte1, byte2: CARD8] POINT: [x, y: INT16] RECTANGLE: [x, y: INT16,

          width, height: CARD16]

ARC: [x, y: INT16,

    width, height: CARD16,
    angle1, angle2: INT16]

HOST: [family: {Internet, NS, ECMA, Datakit, DECnet}

     address: LISTofCARD8]
 The [x,y] coordinates of a RECTANGLE specify the upper left corner.

M.I.T. [Page 16] RFC 1013 June 1987

 The primary interpretation of "large" characters in a STRING16 is
 that they are composed of two bytes used to index a 2-D matrix;
 hence the use of CHAR2B rather than CARD16.  This corresponds to
 the JIS/ISO method of indexing two-byte characters.  It is expected
 that most "large" fonts will be defined with two-byte matrix
 indexing.  For large fonts constructed with linear indexing, a
 CHAR2B can be interpreted as a 16-bit number by treating byte1 as
 the most significant byte; this means that clients should always
 transmit such 16-bit character values most significant byte first,
 as the server will never byte-swap CHAR2B quantities.
 The length, format, and interpretation of a HOST address are specific
 to the family.

SECTION 5. ERRORS

 In general, when a request terminates with an error, the request has
 no side effects (i.e., there is no partial execution).  The only
 requests for which this is not true are ChangeWindowAttributes,
 ChangeGC, PolyText8, PolyText16, FreeColors, StoreColors, and
 ChangeKeyboardControl.
 The following error codes can be returned by the various requests:

Access

         An attempt to grab a key/button combination already grabbed
         by another client.
         An attempt to free a colormap entry not allocated by the
         client.
         An attempt to store into a read-only or an unallocated
         colormap entry.
         An attempt to modify the access control list from other than
         the local (or otherwise authorized) host.
         An attempt to select an event type, that at most one client
         can select at a time, when another client has already
         selected it.

Alloc

         The server failed to allocate the requested resource.
         Note that this only covers allocation errors at a very coarse
         level, and is not intended to (nor can it in practice hope
         to) cover all cases of a server running out of allocation
         space in the middle of service.

M.I.T. [Page 17] RFC 1013 June 1987

         The semantics when a server runs out of allocation space are
         left unspecified.

Atom

         A value for an ATOM argument does not name a defined ATOM.

Colormap

         A value for a COLORMAP argument does not name a defined
         COLORMAP.

Cursor

         A value for a CURSOR argument does not name a defined CURSOR.

Drawable

         A value for a DRAWABLE argument does not name a defined
         WINDOW or PIXMAP.

Font

         A value for a FONT or <FONT or GCONTEXT> argument does not
         name a defined FONT.

GContext

         A value for a GCONTEXT argument does not name a defined
         GCONTEXT.

IDChoice

         The value chosen for a resource identifier is either not
         included in the range assigned to the client, or is already
         in use.

Implementation

         The server does not implement some aspect of the request.  A
         server which generates this error for a core request is
         deficient.  As such, this error is not listed for any of the
         requests, but clients should be prepared to receive such
         errors, and handle or discard them.

Length

         The length of a request is shorter or longer than that
         required to minimally contain the arguments.

Match

         An InputOnly window is used as a DRAWABLE.
         Some argument (or pair of arguments) has the correct type and
         range, but fails to "match" in some other way required by the
         request.

Name

         A font or color of the specified name does not exist.

M.I.T. [Page 18] RFC 1013 June 1987

Pixmap

         A value for a PIXMAP argument does not name a defined PIXMAP.

Property

         The requested property does not exist for the specified
         window.

Request

         The major or minor opcode does not specify a valid request.

Value

         Some numeric value falls outside the range of values accepted
         by the request.  Unless a specific range is specified for an
         argument, the full range defined by the argument's type is
         accepted.  Any argument defined as a set of alternatives can
         generate this error.

Window

         A value for a WINDOW argument does not name a defined WINDOW.

Note: the Atom, Colormap, Cursor, Drawable, Font, GContext, Pixmap, and Window errors are also used when the argument type is extended by union with a set of fixed alternatives, e.g.,<Window or PointerRoot or None>.

SECTION 6. KEYBOARDS

 Keycodes are always in the inclusive range [8,255].
 For keyboards with both left-side and right-side modifier keys (e.g.,
 Shift and Control), the mask bits in the protocol always define the
 OR of the keys. If electronically distinguishable, they can have
 separate up/down events generated, and clients that want to
 distinguish can track the individual states manually.
 <As part of the core we need to define a universal association
 between keycaps and keycodes.  A keycap is the graphical information
 imprinted on a keyboard key, e.g., "$ 4", "T", "+ =".>

SECTION 7. POINTERS

 Buttons are always numbered starting with one.

SECTION 8. PREDEFINED ATOMS

 Predefined atoms are not strictly necessary, and may not be useful in
 all environments, but will eliminate many InternAtom requests in most
 applications.  The core protocol imposes no semantics on these names,

M.I.T. [Page 19] RFC 1013 June 1987

 except as they are used in FONTPROP structures (see QueryFont).  Note
 that upper/lower case matters.
    BITMAP               ICON_SIZE               RGB_GREEN_MAP
    COMMAND              ITALIC_ANGLE            RGB_RED_MAP
    COPYRIGHT            MAX_SPACE               SECONDARY
    CUT_BUFFER0          MIN_SPACE               SIZE_HINTS
    CUT_BUFFER1          NAME                    STRIKEOUT_ASCENT
    CUT_BUFFER2          NORMAL_HINTS            STRIKEOUT_DESCENT
    CUT_BUFFER3          NORM_SPACE              STRING
    CUT_BUFFER4          PIXMAP                  SUBSCRIPT_X
    CUT_BUFFER5          POINT_SIZE              SUBSCRIPT_Y
    CUT_BUFFER6          PRIMARY                 SUPERSCRIPT_X
    CUT_BUFFER7          QUAD_WIDTH              SUPERSCRIPT_Y
    DEFAULT_CHAR         RECTANGLE               UNDERLINE_POSITION
    END_SPACE            RESIZE_HINT             UNDERLINE_THICKNESS
    FACE_NAME            RESOLUTION              WEIGHT
    FAMILY_NAME          RGB_BEST_MAP            WINDOW
    FONT_ASCENT          RGB_BLUE_MAP            WM_HINTS
    FONT_DESCENT         RGB_COLOR_MAP           X_HEIGHT
    ICON                 RGB_DEFAULT_MAP         ZOOM_HINTS
    ICON_NAME

SECTION 9. CONNECTION SETUP

 For remote clients, the X protocol can be built on top of any
 reliable byte stream.  For TCP connections, displays on a given host
 a numbered starting from 0, and the server for display N listens and
 accepts connections on port 6000+N.
 The client must send an initial byte of data to identify the byte
 order to be employed.  The value of the byte must be octal 102 or
 154.  The value 102 (ASCII uppercase B) means values are transmitted
 most significant byte first, and value 154 (ASCII lowercase l) means
 values are transmitted least significant byte first.  Except where
 explicitly noted in the protocol, all 16-bit and 32-bit quantities
 sent by the client must be transmitted with this byte order, and all
 16-bit and 32-bit quantities returned by the server will be
 transmitted with this byte order.
 Following the byte-order byte, the following information is sent by
 the client at connection setup:
         protocol-major-version: CARD16
         protocol-minor-version: CARD16
         authorization-protocol-name: STRING8
         authorization-protocol-data: STRING8
         The version numbers indicate what version of the protocol the
         client expects the server to implement.  See below for an

M.I.T. [Page 20] RFC 1013 June 1987

         explanation. The authorization name indicates what
         authorization protocol the client expects the server to use,
         and the data is specific to that protocol. Specification of
         valid authorization mechanisms is not part of the core X
         protocol.  It is hoped that eventually one authorization
         protocol will be agreed upon.  In the mean time, a server
         that implements a different protocol than the client expects,
         or a server that only implements the host-based mechanism,
         will simply ignore this information.
 Received by the client at connection setup:
         success: BOOL
         protocol-major-version: CARD16
         protocol-minor-version: CARD16
         length: CARD16
         Length is the amount of additional data to follow, in units
         of 4 bytes. The version numbers are an escape hatch in case
         future revisions of the protocol are necessary.  In general,
         the major version would increment for incompatible changes,
         and the minor version would increment for small upward
         compatible changes.  Barring changes, the major version
         will be eleven, and the minor version will be zero.  The
         protocol version numbers returned indicate the protocol the
         server actually supports.  This might not equal the version
         sent by the client.  The server can (but need not) refuse
         connections from clients that offer a different version
         than the server supports.  A server can (but need not)
         support more than one version simultaneously.
 Additional data received if authorization fails:
         reason: STRING8
 Additional data received if authorization is accepted:
         vendor: STRING8
         release-number: CARD32
         resource-id-base, resource-id-mask: CARD32
         image-byte-order: {LSBFirst, MSBFirst}
         bitmap-format-scanline-unit: {8, 16, 32}
         bitmap-format-scanline-pad: {8, 16, 32}
         bitmap-format-bit-order: {LeastSignificant, MostSignificant}
         pixmap-formats: LISTofFORMAT
         roots: LISTofSCREEN
         keyboard: DEVICE
         pointer: DEVICE
         motion-buffer-size: CARD32
         maximum-request-length: CARD16
         where
           FORMAT: [depth: CARD8,

M.I.T. [Page 21] RFC 1013 June 1987

                    bits-per-pixel: {4, 8, 16, 24, 32}
                    scanline-pad: {8, 16, 32}]
           SCREEN: [root: WINDOW
                    device: DEVICE
                    width-in-pixels, height-in-pixels: CARD16
                    width-in-millimeters,height-in-millimeters:CARD16
                    allowed-depths: LISTofDEPTH
                    root-depth: CARD8
                    root-visual: VISUALID
                    default-colormap: COLORMAP
                    white-pixel, black-pixel: CARD32
                    min-installed-maps, max-installed-maps: CARD16
                    backing-stores: {Never, WhenMapped, Always}
                    save-unders: BOOL
                    current-input-masks: SETofEVENT]
          DEPTH: [depth: CARD8
                    visuals: LISTofVISUALTYPE]
          VISUALTYPE: [visual-id: VISUALID
                       class: {StaticGray, StaticColor,
                               TrueColor,GrayScale, PseudoColor,
                               DirectColor}
                               red-mask, green-mask, blue-mask: CARD32
                               bits-per-rgb-value: CARD8
                               colormap-entries: CARD16]
 Per server information:
 The vendor string gives some indentification of the owner of the
 server implementation.  The semantics of the release-number is
 controlled by the vendor.
 The resource-id-mask contains a single contiguous set of bits (at
 least 18); the client allocates resource ids by choosing a value
 with (only) some subset of these bits set, and ORing it with
 resource-id-base.  Only values constructed in this way can be
 used to name newly created resources over this connection.
 Resource ids never have the top 3 bits set.  The client is not
 restricted to linear or contiguous allocation of resource ids.
 Once an id has been freed, it can be reused, but this should not
 be necessary. An id must be unique with respect to the ids of
 all other resources, not just other resources of the same type.
 Although the server is in general responsible for byte swapping
 data to match the client, images are always transmitted and
 received in formats (including byte order) specified by the
 server.  The byte order for images is given by image-byte-order,
 and applies to each scanline unit in XYFormat (bitmap) format,
 and to each pixel value in ZFormat.
 A bitmap is represented in scanline order.  Each scanline is padded
 to a multiple of bits as given by bitmap-format-scanline-pad.  The

M.I.T. [Page 22] RFC 1013 June 1987

 pad bits are of arbitrary value.  The scanline is quantized in
 multiples of bits as given by bitmap-format-scanline-unit.  Within
 each unit, the leftmost bit in the bitmap is either the least or
 most significant bit in the unit, as given by
 bitmap-format-bit-order.  If a pixmap is represented in XYFormat,
 each plane is represented as a bitmap, and the planes appear from
 most to least significant in bit order.
 For each pixmap depth supported by some screen, pixmap-formats lists
 the ZFormat used to represent images of that depth.  In ZFormat, the
 pixels are in scanline order, left to right within a scanline.  The
 number of bits used to hold each pixel is given by bits-per-pixel,
 and may be larger than strictly required by the depth.  When the
 bits-per-pixel is 4, the order of nibbles in the byte is the same as
 the image byte-order.  Each scanline is padded to a multiple of bits
 as given by scanline-pad.
 How a pointing device roams the screens is up to the server
 implementation, and is transparent to the protocol.  No geometry
 among screens is defined.
 The server may retain the recent history of pointer motion, and to a
 finer granularity than is reported by MotionNotify events.  Such
 history is available via the GetPointerMotions request.  The
 approximate size of the history buffer is given by
 motion-buffer-size.
 Maximum-request-length specifies the maximum length of a request, in
 4-byte units, accepted by the server; i.e., this is the maximum value
 that can appear in the length field of a request.  Requests larger
 than this generate a Length error, and the server will read and
 simply discard the entire request.  Maximum-request-length will
 always be at least 4096 (i.e., requests of length up to and including
 16384 bytes will be accepted by all servers).
 Per screen information:
 The allowed-depths specifies what pixmap and window depths are
 supported.  Pixmaps are supported for each depth listed, and windows
 of that depth are supported if at least one visual type is listed for
 the depth.  A pixmap depth of one is always supported and listed, but
 windows of depth one might not be supported.  A depth of zero is
 never listed, but zero-depth InputOnly windows are always supported.
 Root-depth and root-visual specify the depth and visual type of the
 root window.  Width-in-pixels and height-in-pixels specify the size
 of the root window (which cannot be changed).  The class of the root
 window is always InputOutput.  Width-in-millimeters and
 height-in-millimeters can be used to determine the physical size and
 the aspect ratio.

M.I.T. [Page 23] RFC 1013 June 1987

 The default-colormap is the one initially associated with the root
 window.  Clients with minimal color requirements creating windows of
 the same depth as the root may want to allocate from this map by
 default.
 Black-pixel and white-pixel can be used in implementing a
 "monochrome" application.  These pixel values are for permanently
 allocated entries in the default-colormap; the actual RGB values may
 be settable on some screens.
 The border of the root window is initially a pixmap filled with the
 black-pixel.  The initial background of the root window is a pixmap
 filled with some unspecified two-color pattern using black-pixel and
 white-pixel.
 Min-installed-maps specifies the number of maps that can be
 guaranteed to installed simultaneously (with InstallColormap),
 regardless of the number of entries allocated in each map.
 Max-installed-maps specifies the maximum number of maps that might
 possibly be installed simultaneously, depending on their
 allocations. For the typical case of a single hardware colormap,
 both values will be one.
 Backing-stores indicates when the server supports backing stores for
 this screen, although it may be storage limited in the number of
 windows it can support at once.  If save-unders is True, then the a
 server can support the save-under mode in CreateWindow and
 ChangeWindowAttributes, although again it may be storage limited.
 The current-input-events is what GetWindowAttributes would return for
 the all-event-masks for the root window.
 Per visual-type information:
 A given visual type might be listed for more than one depth, or for
 more than one screen.
 For PseudoColor, a pixel value indexes a colormap to produce
 independent RGB values; the RGB values can be changed dynamically.
 GrayScale is treated the same as PseudoColor, except which primary
 drives the screen is undefined, so the client should always store
 the same value for red, green, and blue in colormaps.  For
 DirectColor, a pixel value is decomposed into separate RGB
 subfields, and each subfield separately indexes the colormap for
 the corresponding value; The RGB values can be changed dynamically.
 TrueColor is treated the same as DirectColor, except the colormap
 has predefined read-only RGB values, which are server-dependent,
 but provide (near-)linear ramps in each primary.  StaticColor is
 treated the same as PseudoColor, except the colormap has
 predefined read-only RGB values, which are server-dependent.
 StaticGray is treated the same as StaticColor, except the red,

M.I.T. [Page 24] RFC 1013 June 1987

 green, and blue values are equal for any single pixel value,
 resulting in shades of gray.  StaticGray with a two-entry colormap
 can be thought of as "monochrome".
 The red-mask, green-mask, and blue-mask are only defined for
 DirectColor and TrueColor; each has one contiguous set of bits, with
 no intersections.
 The bits-per-rgb-value specifies the log base 2 of the approximate
 number of distinct color values (individually) of red, green, and
 blue. Actual RGB values are always passed in the protocol within a
 16-bit spectrum.
 The colormap-entries defines the number of available colormap entries
 in a newly created colormap.  For DirectColor and TrueColor, this
 will usually be the size of an individual pixel subfield.

SECTION 10. REQUESTS

CreateWindow

         wid, parent: WINDOW
         class: {InputOutput, InputOnly, CopyFromParent}
         depth: CARD8
         visual: VISUALID or CopyFromParent
         x, y: INT16
         width, height, border-width: CARD16
         value-mask: BITMASK
         value-list: LISTofVALUE
         Errors: IDChoice, Window, Pixmap, Colormap, Cursor, Match,
         Value, Alloc
         Creates an unmapped window, and assigns the identifier wid
         to it.
         A class of CopyFromParent means the class is taken from the
         parent.  A depth of zero for class InputOutput or
         CopyFromParent means the depth is taken from the parent.
         A visual of CopyFromParent means the visual type is taken
         from the parent.  For class InputOutput, the visual type
         and depth must be a combination supported for the screen
         (else a Match error); the depth need not be the same as the
         parent, but the parent must not be of class InputOnly (else
         a Match error).  For class InputOnly, the depth must be
         zero (else a Match error), and the visual must be one
         supported for the screen (else a Match error), but the
         parent may have any depth and class.
         The server essentially acts as if InputOnly windows do not
         exist for the purposes of graphics requests, exposure

M.I.T. [Page 25] RFC 1013 June 1987

         processing, and VisibilityNotify events.  An InputOnly window
         cannot be used as a drawable (as a source or destination for
         graphics requests).  InputOnly and InputOutput windows act
         identically in other respects (properties, grabs, input
         control, and so on).
         The window is placed on top in the stacking order with
         respect to siblings.  The x and y coordinates are relative
         to the parent's origin, and specify the position of the upper
         left outer corner of the window (not the origin).  The width
         and height specify the inside size, not including the border,
         and must be non-zero.  The border-width for an InputOnly
         window must be zero (else a Match error).
         The value-mask and value-list specify attributes of the
         window that are to be explicitly initialized.  The possible
         values are:
             background-pixmap: PIXMAP or None or ParentRelative
             background-pixel: CARD32
             border-pixmap: PIXMAP or CopyFromParent
             border-pixel: CARD32
             bit-gravity: BITGRAVITY
             win-gravity: WINGRAVITY
             backing-store: {NotUseful, WhenMapped, Always}
             backing-bit-planes: CARD32
             backing-pixel: CARD32
             save-under: BOOL
             event-mask: SETofEVENT
             do-not-propagate-mask: SETofDEVICEEVENT
             override-redirect: BOOL
             colormap: COLORMAP or CopyFromParent
             cursor: CURSOR or None
         The default values, when attributes are not explicitly
         initialized, are:
             background-pixmap: None
             border-pixmap: CopyFromParent
             bit-gravity: Forget
             win-gravity: NorthWest
             backing-store: NotUseful
             backing-bit-planes: all ones
             backing-pixel: zero
             save-under: False
             event-mask: {} (empty set)
             do-not-propagate-mask: {} (empty set)
             override-redirect: False
             colormap: CopyFromParent
             cursor: None

M.I.T. [Page 26] RFC 1013 June 1987

         Only the following attributes are defined for InputOnly
         windows: win-gravity, event-mask, do-not-propagate-mask,
         and cursor.  It is a Match error to specify any other
         attributes for InputOnly windows.
         If background-pixmap is given, it overrides the default
         background-pixel.  The background pixmap and the window must
         have the same root and the same depth (else a Match error).
         Any size pixmap can be used, although some sizes may be
         faster than others.  If background None is specifed, the
         window has no defined background.  If background
         ParentRelative is specified, the parent's background is
         used, but the window must have the same depth as the parent
         (else a Match error); if the parent has background None,
         then the window will also have background None.  A copy
         of the parent's background is not made; the parent's
         background is reexamined each time the window background is
         required.  If background-pixel is given, it overrides the
         default and any background-pixmap given, and a pixmap of
         undefined size filled with background-pixel is used for the
         background.  For a  ParentRelative background, the
         background tile origin always aligns with the parent's
         background tile origin; otherwise the background tile
         origin is always the window origin.
         When regions of the window are exposed and the server has
         not retained the contents, the server automatically tiles
         the regions with the window's background unless the window
         has a background of None, in which case the previous screen
         contents are simply left in place. Exposure events are then
         generated for the regions, even if the  background is None.
         The border tile origin is always the same as the background
         tile origin.  If border-pixmap is given, it overrides the
         default border-pixel.  The border pixmap and the window must
         have the same root and the same depth (else a Match error).
         Any size pixmap can be used, although some sizes may faster
         than others.  If CopyFromParent is given, the parent's border
         pixmap is copied (subsequent changes to the parent do not
         affect the child), but the window must have the same depth
         as the parent (else a Match error).  If border-pixel is
         given, it overrides the default and any border-pixmap given,
         and a pixmap of undefined size filled with border-pixel is
         used for the border.
         Output to a window is always clipped to the inside of the
         window, so that the border is never affected.
         The bit-gravity defines which region of the window should be
         retained if the window is resized, and win-gravity defines
         how the window should be repositioned if the parent is

M.I.T. [Page 27] RFC 1013 June 1987

         resized; see ConfigureWindow.
         A backing-store of WhenMapped advises the server that
         maintaining contents of obscured regions when the window
         is mapped would be beneficial.  A backing-store of Always
         advises the server that maintaining contents even when the
         window is unmapped would be beneficial.  Note that, even if
         the window is larger than its parent, the server should
         maintain complete contents, not just the region within the
         parent boundaries.  If the server maintains contents,
         Exposure events will not be generated, but the server may
         stop maintaining contents at any time.  A value of NotUseful
         advises the server that maintaining contents is unnecessary,
         although a server may still choose to maintain contents.
         Backing-bit-planes indicates (with one bits) which bit
         planes of the window hold dynamic data that must be preserved
         in backing-stores. Backing-pixel specifies what value to use
         in planes not covered by backing-bit-planes.  The server is
         free to only save the specified bit planes in the
         backing-store, and regenerate the remaining planes with the
         specified pixel value.
         If save-under is True, the server is advised that, when
         this window is mapped, saving the contents of windows it
         obscures would be beneficial.
         The event-mask defines which events the client is interested
         in for this window (or, for some event types, inferiors of
         the window).  The do-not-propagate-mask defines which events
         should not be propagated to ancestor windows when no client
         has the event type selected in this window.
         Override-redirect specifies whether map and configure
         request on this window should override a SubstructureRedirect
         on the parent, typically to inform a window manager not to
         tamper with the window.
         The colormap specifies the colormap, that best reflects the
         "true" colors of the window.  Servers capable of supporting
         hardware colormaps may use this information, and window
         managers may use it for InstallColormap requests.  The
         colormap must have the same visual type as the window
         (else a match error). If CopyFromParent is specified, the
         parents's colormap is copied (subsequent changes to the
         parent do not affect the child), but the window must have
         the same visual type as the parent (else a Match error) an
         the parent must not have a colormap of None (else a Match
         error).

M.I.T. [Page 28] RFC 1013 June 1987

         If a cursor is specified, it will be used whenever the
         pointer is in the window.  If None is specified, the
         parent's cursor will be used when the pointer is in the
         window, and any change in the parent's cursor will
         cause an immediate change in the display cursor.
         This request generates a CreateNotify event.
         The background and border pixmaps and the cursor may be
         freed immediately if no further explicit references to
         them are to be made.
         Subsequent drawing into the background or border pixmap has
         an undefined effect on the window state; the server might or
         might not make a copy of the pixmap.

ChangeWindowAttributes

        window: WINDOW
        value-mask: BITMASK
        value-list: LISTofVALUE
        Errors: Window, Pixmap, Colormap, Cursor, Match, Value,
                Access
        The value-mask and value-list specify which attributes are
        to be changed.  The values and restrictions are the same
        as for CreateWindow.
        Changing the background does not cause the window contents
        to be changed.  Setting the border, or changing the
        background such that border tile origin changes, causes the
        border to be repainted. Changing the background of a root
        window to None or ParentRelative restores the default
        background pixmap. Changing the border of a root window to
        CopyFromParent restores the default border pixmap.
         Changing the back-store of an obsecured window to
         WhenMapped or Always, or changing the backing-bit-planes,
         backing-pixel, or save-under of a mapped window, may have
         no immediate effect.
         Multiple clients can select input on the same window; their
         event-masks are disjoint.  When an event is generated it
         will be reported to all interested clients.  However, at
         most one client at a time can select for
         SubstructureRedirect, at most one client at a time can
         select for ResizeRedirectr, and at most one client at a
         time can select for ButtonPress.
         There is only one do-not-propagate-mask for a window, not
         one per client.

M.I.T. [Page 29] RFC 1013 June 1987

         Changing the colormap of a window (i.e., defining a new map,
         not changing the contents of the existing map) generates a
         ColormapNorify event.  Changing the colormap os a visible
         window may have no immediate effect on the screen; see
         InstallColormap.
         Changing the cursor of a root window to None restores the
         default cursor.
         The order in which attributes are verified and altered is
         server dependent. If an error is generated, a subset of
         the attributes may have been altered.

GetWindowAttributes

         window: WINDOW
     =>
         visual: VISUALID
         class: {InputOutput, InputOnly}
         bit-gravity: BITGRAVITY
         win-gravity: WINGRAVITY
         backing-store: {NotUseful, WhenMapped, Always}
         backing-bit-planes: CARD32
         backing-pixel: CARD32
         save-under: BOOL
         colormap: COLORMAP or None
         map-is-installed: BOOL
         map-state: {Unmapped, Unviewable, Viewable}
         all-event-masks, your-event-mask: SETofEVENT
         do-not-propagate-mask: SETofDEVICEEVENT
         override-redirect: BOOL
         Errors: Window
         Returns current attributes of the window.  All-event-masks
         is the inclusive-OR of all event masks selected on the
         window by clients.  Your-event-mask is the event mask
         selected by the querying client.

DestroyWindow

         window: WINDOW
         Errors: Window
         If the argument window is mapped, an UnmapWindow request is
         performed automatically.  The window and all inferiors are
         then destroyed, and a DestroyNotify event is generated for
         each window, in order from the argument window downwards,
         with unspecified order among siblings at each level.
         Normal exposure processing on formerly obscured windows is
         performed.

M.I.T. [Page 30] RFC 1013 June 1987

         If the window is a root window, this request has no effect.

DestroySubwindows

         window: WINDOW
         Errors: Window
         Performs a DestroyWindow on all children of the window, in
         bottom to top stacking order.

ChangeSaveSet

         window: WINDOW
         mode: {Insert, Delete}
         Errors: Window, Match, Value
         Adds or removes the specified window from the client's
         "save-set".  The window must have been created by some other
         client (else a Match error).  The use of the save-set is
         described in Section 11.
         Windows are removed automatically from the save-set by the
         server when they are destroyed.

ReparentWindow

         window, parent: WINDOW
         x, y: INT16
         Errors: Window, Match
         If the window is mapped, an UnmapWindow request is
         performed automatically first.  The window is then removed
         from its current position in the hierarchy, and is inserted
         as a child of the specified parent.  The x and y coordinates
         are relative to the parent's origin, and specify the new
         position of the upper left outer corner of the window.  The
         window is placed on top in the stacking order with respect
         to siblings.  A ReparentNotify event is then generated.  The
         override-redirect attribute of the window is passed on in
         this event; a value of True indicates that a window manager
         should not tamper with this window.  Finally, if the window
         was originally mapped, a MapWindow request is performed
         automatically.
         Normal exposure processing on formerly obscured windows is
         performed. The server might not generate exposure events for
         regions from the initial unmap that are immediately obscured
         by the final map.
         A Match error is generated if the new parent is not on the
         same screen as the old parent, or if the new parent is the

M.I.T. [Page 31] RFC 1013 June 1987

         window itself or an inferior of the window, or if the window
         has a ParentRelative background and the new parent is not
         the same depth as the window.

MapWindow

         window: WINDOW
         Errors: Window
         If the window is already mapped, this request has no effect.
         If the override-redirect attribute of the window is False and
         some other client has selected SubstructureRedirect on the
         parent, then a MapRequest event is generated, but the window
         remains unmapped. Otherwise, the window is mapped and a
         MapNotify event is generated.
         If the window is now viewable and its contents had been
         discarded, then the window is tiled with its background (if
         no background is defined the existing screen contents are not
         altered) and one or more exposure events are generated.  If a
         backing-store has been maintained while the window was
         unmapped, no exposure events are generated. If a
         backing-store will now be maintained, a full-window exposure
         is always generated; otherwise only visible regions may be
         reported. Similar tiling and exposure take place for any
         newly viewable inferiors.

MapSubwindows

         window: WINDOW
         Errors: Window
         Performs a MapWindow request on all unmapped children of the
         window, in top to bottom stacking order.

UnmapWindow

         window: WINDOW
         Errors: Window
         If the window is already unmapped, this request has no
         effect. Otherwise, the window is unmapped and an UnmapNotify
         event is generated.  Normal exposure processing on formerly
         obscured windows is performed.

UnmapSubwindows

         window: WINDOW
         Errors: Window

M.I.T. [Page 32] RFC 1013 June 1987

         Performs an UnmapWindow request on all mapped children of the
         window, in bottom to top stacking order.

ConfigureWindow

         window: WINDOW
         value-mask: BITMASK
         value-list: LISTofVALUE
         Errors: Window, Match, Value
         Changes the configuration of the window.  The value-mask and
         value-list specify which values are to be given.  The
         possible values are:
             x: INT16
             y: INT16
             width: CARD16
             height: CARD16
             border-width: CARD16
             sibling: WINDOW
             stack-mode: {Above, Below, TopIf, BottomIf, Opposite}
         The x and y coordinates are relative to the parent's origin,
         and specify the position of the upper left outer corner of
         the window. The width and height specify the inside size,
         not including the border, and must be non-zero.  It is a
         Match error to attempt to make the border-width of an
         InputOnly window non-zero.
         If the override-redirect attribute of the window is False
         and some other client has selected SubstructureRedirect on
         the parent, then a ConfigureRequest event is generated, and
         no further processing is performed.  Otherwise, the following
         is performed.
         If some other client has selected ResizeRedirect on the
         window and the width or height of the window is being
         changed, then a ResizeRequest event is generated, and the
         current width and height are used instead in the following.
         The geometry of the window is changed as specified and the
         window is restacked among siblings as described below, and a
         ConfigureNotify event is generated.  If the width or height
         of the window has actually changed, then children of the
         window are affected as described below.
         Exposure processing is performed on formerly obscured
         windows.
         Changing the width or height of the window causes its
         contents to be moved or lost, depending on the bit-gravity of

M.I.T. [Page 33] RFC 1013 June 1987

         the window, and causes children to be reconfigured, depending
         on their win-gravity.  For a change of width and height of W
         and H, we define the [x, y] pairs:
             NorthWest: [0, 0]
             North: [W/2, 0]
             NorthEast: [W, 0]
             West: [0, H/2]
             Center: [W/2, H/2]
             East: [W, H/2]
             SouthWest: [0, H]
             South: [W/2, H]
             SouthEast: [W, H]
         When a window with one of these bit-gravities is resized, the
         corresponding pair defines the change in position of each
         pixel in the window.  When a window with one of these
         win-gravities has its parent window resized, the
         corresponding pair defines the change in position of the
         window within the parent.  When a window is so repositioned,
         a GravityNotify event is generated.
         A gravity of Static indicates that the contents or origin
         should not move relative to the origin of the root window. If
         the change in size of the window is coupled with a change in
         position of [X, Y], then for bit-gravity the change in
         position of each pixel is [-X, -Y], and for win-gravity the
         change in position of a child when its parent is so resized
         is [-X, -Y].  Note that Static gravity still only takes
         effect when the width or height of the window is changed, not
         when the window is simply moved.
         A bit-gravity of Forget indicates that the window contents
         are always discarded after a size change; the window is tiled
         with its background (if no background is defined, the
         existing screen contents are not altered) and one or more
         exposure events are generated.  A server may also ignore the
         specified bit-gravity and use Forget instead.
         A win-gravity of Unmap is like NorthWest, but the child is
         also unmapped when the parent is resized, and an UnmapNotify
         event is generated.
         If a sibling and a stack-mode is specified, the window is
         restacked as follows:
             Above:  window is placed just above sibling
             Below:  window is placed just below sibling
             TopIf:  if sibling occludes window, then window is placed
                     at the top of the stack
             BottomIf:  if window occludes sibling, then window is

M.I.T. [Page 34] RFC 1013 June 1987

                        placed at the bottom of the stack
             Opposite:  if sibling occludes window, then window is
                        placed at the top of the stack, else if window
                        occludes sibling, then window is placed at the
                        bottom of the stack
         If a stack-mode is specified but no sibling is specified, the
         window is restacked as follows:
             Above:  window is placed at the top of the stack
             Below:  window is placed at the bottom of the stack
             TopIf:  if any sibling occludes window, then window is
                     placed at the top of the stack
             BottomIf: if window occludes any sibling, then window is
                       placed at the bottom of the stack
             Opposite: if any sibling occludes window, then window is
                       placed at the top of the stack, else if window
                       occludes any sibling, then window is placed at
                       the bottom of the stack
         It is a Match error if a sibling is specified without a
         stack-mode, or if the window is not actually a sibling.
         Note that the computations for BottomIf, TopIf, and Opposite
         are performed with respect to the window's final geometry
         (as controlled by the other arguments to the request), not
         its initial geometry.

CirculateWindow

         window: WINDOW
         direction: {RaiseLowest, LowerHighest}
         Errors: Window, Value
         If some other client has selected SubstructureRedirect on the
         window, then a CirculateRequest event is generated, and no
         further processing is performed.  Otherwise, the following is
         performed, and then a CirculateNotify event is generated if
         the window is actually restacked.
         For RaiseLowest, raises the lowest mapped child (if any) that
         is occluded by another child to the top of the stack.  For
         LowerHighest, lowers the highest mapped child (if any) that
         occludes another child to the bottom of the stack.  Exposure
         processing is performed on formerly obscured windows.

GetGeometry

         drawable: DRAWABLE
     =>
         root: WINDOW
         depth: CARD8

M.I.T. [Page 35] RFC 1013 June 1987

         x, y: INT16
         width, height, border-width: CARD16
         Errors: Drawable
         Returns the root and (current) geometry of the drawable.
         Depth is the number of bits per pixel for the object.
         X, y, and border-width will always be zero for pixmaps.
         For a window, the x and y coordinates specify the upper
         left outer corner of the window relative to its parent's
         origin, and the width and height specify the inside size
         (not including the border).
         It is legal to pass an InputOnly window as a drawable to
         this request.

QueryTree

         window: WINDOW
     =>
         root: WINDOW
         parent: WINDOW or None
         children: LISTofWINDOW
         Errors: Window
         Returns the root, the parent, and children of the window.
         The children are listed in bottom-to-top stacking order.

InternAtom

         name: STRING8
         only-if-exists: BOOL
     =>
         atom: ATOM or None
         Errors: Value, Alloc
         Returns the atom for the given name.  If only-if-exists is
         False, then the atom is created if it does not exist.  The
         string should use the ASCII encoding, and upper/lower case
         matters.
         The lifetime of an atom is not tied to the interning client.
         Atoms remained defined until server reset (see Section 11).

GetAtomName

         atom: ATOM
     =>
         name: STRING8
         Errors: Atom

M.I.T. [Page 36] RFC 1013 June 1987

         Returns the name for the given atom.

ChangeProperty

         window: WINDOW
         property, type: ATOM
         format: {8, 16, 32}
         mode: {Replace, Prepend, Append}
         data: LISTofINT8 or LISTofINT16 or LISTofINT32
         Errors: Window, Atom, Value, Match, Alloc
         Alters the property for the specified window.  The type is
         uninterpreted by the server.  The format specifies whether
         the data should be viewed as a list of 8-bit, 16-bit, or
         32-bit quantities, so that the server can correctly
         byte-swap as necessary.
         If mode is Replace, the previous property value is discarded.
         If the mode is Prepend or Append, then the type and format
         must match the existing property value (else a Match error);
         if the property is undefined, it is treated as defined with
         the correct type and format with zero-length data.  For
         Prepend, the data is tacked on to the beginning of the
         existing data, and for Append it is tacked on to the
         end of the existing data.
         Generates a PropertyNotify event on the window.
         The lifetime of a property is not tied to the storing client.
         Properties remain until explicitly deleted, or the window is
         destroyed, or until server reset (see Section 11).
         The maximum size of a property is server dependent.

DeleteProperty

         window: WINDOW
         property: ATOM
         Errors: Window, Atom
         Deletes the property from the specified window if the
         property exists. Generates a PropertyNotify event on the
         window unless the property does not exist.

GetProperty

         window: WINDOW
         property: ATOM
         type: ATOM or AnyPropertyType
         long-offset, long-length: CARD32
         delete: BOOL
     =>

M.I.T. [Page 37] RFC 1013 June 1987

         type: ATOM
         format: {8, 16, 32}
         bytes-after: CARD32
         value: LISTofINT8 or LISTofINT16 or LISTofINT32
         Errors: Window, Atom, Property, Match, Value
         If the specified property does not exist for the specifed
         window, a Property error is generated.  Otherwise, if type
         AnyPropertyType is specified, (part of) the property is
         returned regardless of its type; if a type is specified,
         (part of) the property is returned only if its type equals
         the specified type (else a Match error).  The actual type
         and format of the property are returned.
         Define the following values:
                 N = actual length of the stored property in bytes
                     (even if the format is 16 or 32)
                 I = 4 * long-offset
                 T = N - I
                 L = MINIMUM(T, 4 * long-length)
                 A = N - (I + L)
         The returned value starts at byte index I in the property
         (indexing from 0), and its length in bytes is L.  It is a
         Value error if long-offset is given such that L is negative.
         The value of bytes-after is A, giving the number of trailing
         unread bytes in the stored property.
         If delete is True and bytes-after is zero, the property is
         also deleted from the window and a PropertyNotify event is
         generated on the window.

RotateProperties

         window: WINDOW
         delta: INT8
         properties: LISTofATOM
         Errors: Window, Atom, Match
         If the property names in the list are viewed as being
         numbered starting from zero, and there are N property names
         in the list, then the value associated with property name I
         becomes the value associated with property name (I + delta)
         mod N, for all I from zero to N - 1.  The effect is to rotate
         the states by delta places around the virtual ring of
         property names (right for positive delta, left for negative
         delta).
         A PropertyNotify event is generated for each property, in the
         order listed.

M.I.T. [Page 38] RFC 1013 June 1987

         If an atom occurs more than once in the list or no property
         with that name is defined for the window, a Match error is
         generated.  If an Atom or Match error is generated, no
         properties are changed.

ListProperties

         window: WINDOW
     =>
         atoms: LISTofATOM
         Errors: Window
         Returns the atoms of properties currently defined on the
         window.

SetSelectionOwner

         selection: ATOM
         owner: WINDOW or None
         time: TIMESTAMP or CurrentTime
         Error: Atom, Window
         Changes the owner and last-change time of the specifed
         selection.  The request has no effect if the specified time
         is earlier than the current last-change time of the specified
         selection or is later than the current server time;
         otherwise, the last-change time is set to the specified time,
         with CurrentTime replaced by the current server time.
         If the new owner is not the same as the current owner of the
         selection, and the current owner is a window, then the
         current owner is sent a SelectClear event.
         If the owner of a selection is a window, and the window is
         later destroyed, the owner of the selection automatically
         reverts to None, but the last-change time is not affected.
         The selection atom is uninterpreted by the server.
         Selections are global to the server.

GetSelectionOwner

         selection: ATOM
     =>
         owner: WINDOW or None
         Errors: Atom
         Returns the current owner of the specified selection, if any.

ConvertSelection

         selection, target: ATOM

M.I.T. [Page 39] RFC 1013 June 1987

         property: ATOM or None
         requestor: WINDOW
         time: TIMESTAMP or CurrentTime
         Error: Atom, Window
         If the specified selection is owned by a window, the server
         sends a SelectionRequest event to the owner.  If no owner for
         the specified selection exists, the server generates a
         SelectionNotify event to the requestor with property None.
         The arguments are passed on unchanged in either event.

SendEvent

         destination: WINDOW or PointerWindow or InputFocus
         propagate: BOOL
         event-mask: SETofEVENT
         event: <normal-event-format>
         Errors: Window, Value
         If PointerWindow is specified, destination is replaced with
         the window that the pointer is in.  If InputFocus is
         specified, then if the focus window contains the pointer,
         destination is replaced with the window that the pointer is
         in, and otherwise destination is replaced with the focus
         window.
         If propagate is False, then the event is sent to every client
         selecting on destination any of the event types in
         event-mask.
         If propagate is True and no clients have selected on
         destination any of the event types in event-mask, then
         destination is replaced with the closest ancestor of
         destination for which some client has selected a type in
         event-mask and no intervening window has that type in its
         do-not-propagate-mask.  If no such window exists, or if the
         window is an ancestor of the focus window and InputFocus was
         originally specified sent to any clients. Otherwise, the
         event is reported to every client selecting on the final
         destination any of the types specified in event-mask.
         The event code must be one of the core events, or one of
         the events defined by an extension, so that the server can
         correctly byte swap the contents as necessary.  The
         contents of the event are otherwise unaltered and unchecked
         by the server except to force on the most significant bit
         of the event code.

M.I.T. [Page 40] RFC 1013 June 1987

         Active grabs are ignored for this request.

GrabPointer

         grab-window: WINDOW
         owner-events: BOOL
         event-mask: SETofPOINTEREVENT
         pointer-mode, keyboard-mode: {Synchronous, Asynchronous}
         confine-to: WINDOW or None
         cursor: CURSOR or None
         time: TIMESTAMP or CurrentTime
     =>
         status: {Success, AlreadyGrabbed, Frozen, InvalidTime,
                  NotViewable}
         Errors: Cursor, Window, Value
         Actively grabs control of the pointer.  Further pointer
         events are only reported to the grabbing client.  The
         request overrides any active pointer grab by this client.
         Event-mask is always augmented to include ButtonPress and
         ButtonRelease.  If owner-events is False, all generated
         pointer events are reported with respect to grab-window,
         and are only reported if selected by event-mask.  If
         owner-events is True, then if a generated pointer event
         would normally be reported to this client, it is reported
         normally; otherwise the event is reported with respect to
         the grab-window, and is only reported if selected by
         event-mask.  For either value of owner-events, unreported
         events are simply discarded.
         Pointer-mode controls further processing of pointer events,
         and keyboard-mode controls further processing of keyboard
         events.  If the mode is Asynchronous, event processing
         continues normally; if the device is currently frozen by
         this client, then processing of events for the device is
         resumed.  If the mode is Synchronous, the device (as seen
         via the protocol) appears to freeze, and no further events
         for that device are generated by the server until the
         grabbing client issues a releasing AllowEvents request.
         Actual device changes are not lost while the device is
         frozen; they are simply queued for later processing.
         If a cursor is specified, then it is displayed regardless
         of what window the pointer is in.  If no cursor is
         specified, then when the pointer is in grab-window or one
         of its subwindows, the normal cursor for that window is
         displayed, and otherwise the cursor for grab-window is
         displayed.

M.I.T. [Page 41] RFC 1013 June 1987

         If a confine-to window is specified, then the pointer
         will be restricted to stay contained in that window.
         The confine-to  window need have no relationship to the
         grab-window.  If the pointer is not initially in the
         confine-to window, then it is warped automatically to
         the closest edge (and enter/leave events generated
         normally) just  before the grab activates.  If the
         confine-to window is subsequently reconfigured, the
         pointer will be warped automatically as necessary to keep
         it contained in the window.
         This request generates EnterNotify and LeaveNotify events.
         The request fails with status AlreadyGrabbed if the
         pointer is actively grabbed by some other client.  The
         request fails with status Frozen if the pointer is frozen
         by an active grab of another client.  The request fails
         with status NotViewable if grab-window or
         confine-to window is not viewable.  The request fails with
         status InvalidTime if the specified time is earlier than
         the last-pointer-grab time or later than the current
         server time; otherwise the last-pointer-grab time is set
         to the specified time, with CurrentTime replaced by the
         current server time.

UngrabPointer

         time: TIMESTAMP or CurrentTime
         Releases the pointer if this client has it actively
         grabbed (from either GrabPointer or GrabButton or from a
         normal button press), and releases any queued events. The
         request has no effect if the specified time is earlier
         than the last-pointer-grab time or is later than the
         current server time.
         This request generates EnterNotify and LeaveNotify events.
         An UngrabPointer is performed automatically if the event
         window or confine-to window for an active pointer grab
         becomes not viewable.

GrabButton

         modifiers: SETofKEYMASK or AnyModifier
         button: BUTTON or AnyButton
         grab-window: WINDOW
         owner-events: BOOL
         event-mask: SETofPOINTEREVENT
         pointer-mode, keyboard-mode: {Synchronous, Asynchronous}
         confine-to: WINDOW or None
         cursor: CURSOR or None

M.I.T. [Page 42] RFC 1013 June 1987

         Errors: Cursor, Window, Value, Access
         This request establishes a passive grab.  In the future,
         if the specified button is pressed when the specified
         modifier keys are down (and no other buttons or modifier
         keys are down), and grab-window contains the pointer,
         and the confine-to window (if any) is viewable, and these
         constraints are not satisfied for any ancestor, then the
         pointer is actively grabbed as described in GrabPointer,
         the last-pointer-grab time is set to the time at which
         the button was pressed (as transmitted in the ButtonPress
         event), and the ButtonPress event is reported.  The
         interpretation of the remaining arguments is as for
         GrabPointer.  The active grab is terminated automatically
         when all buttons are released (independent of the state
         of modifier keys).
         A modifiers of AnyModifier is equivalent to issuing the
         request for all possible modifier combinations.  A
         button of AnyButton is equivalent to issuing the request
         for all possible buttons.
         An Access error is generated if some other client has
         already issued a GrabButton with the same button/key
         combination on the same window. When using AnyModifier
         or AnyButton, the request fails completely (no grabs are
         established) if there is a combination.  The request has
         no effect on an active grab.

UngrabButton

         modifiers: SETofKEYMASK or AnyModifier
         button: BUTTON or AnyButton
         grab-window: WINDOW
         Errors: Window
         Releases the passive button/key combination on the
         specified window if it was grabbed by this client. A
         modifiers of AnyModifier is equivalent to issuing the
         request for all possible modifier combinations.  A
         button of AnyButton is equivalent to issuing the request
         for all possible buttons. Has no effect on an active
         grab.

ChangeActivePointerGrab

         event-mask: SETofPOINTEREVENT
         cursor: CURSOR or None
         time: TIMESTAMP or CurrentTime
         Errors: Cursor

M.I.T. [Page 43] RFC 1013 June 1987

         Changes the specified dynamic parameters if the pointer
         is actively grabbed by the client and the specified time
         is no earlier than the last-pointer-grab time and no
         later than the current server time.  The interpretation
         of event-mask and cursor are as in GrabPointer.  The
         event-mask is always augmented to include ButtonPress
         and ButtonRelease.  Has no effect on the passive
         parameters of a GrabButton.

GrabKeyboard

         grab-window: WINDOW
         owner-events: BOOL
         pointer-mode, keyboard-mode: {Synchronous, Asynchronous}
         time: TIMESTAMP or CurrentTime
     =>
         status: {Success, AlreadyGrabbed, Frozen, InvalidTime,
                  NotViewable}
         Errors: Window, Value
         Actively grabs control of the keyboard.  Further key
         events are reported only to the grabbing client.  The
         request overrides any active keyboard grab by this
         client.
         If owner-events is False, all generated key events are
         reported with respect to grab-window.  If owner-events is
         True, then if a generated key event would normally be
         reported to this client, it is reported normally;
         otherwise the event is reported with respect to the
         grab-window.  Both KeyPress and KeyRelease events are
         always reported, independent of any event selection made
         by the client.
         Pointer-mode controls further processing of pointer
         events, and keyboard-mode controls further processing of
         keyboard events.  If the mode is Asynchronous, event
         processing continues normally; if the device is currently
         frozen by this client, then processing of events for the
         device is resumed.  If the mode is Synchronous, the
         device (as seen via the protocol) appears to freeze, and
         no further events for that device are generated by the
         server until the grabbing client issues a releasing
         AllowEvents request.  Actual device changes are not lost
         while the device is frozen; they are simply queued for
         later processing.
         This request generates FocusIn and FocusOut events.
         The request fails with status AlreadyGrabbed if the
         keyboard is actively grabbed by some other client.  The

M.I.T. [Page 44] RFC 1013 June 1987

         request fails with status Frozen if the keyboard is
         frozen by an active grab of another client. The request
         fails with status NotViewable if grab-window is not
         viewable.  The request fails with status InvalidTime if
         the specified time is earlier than the last-keyboard-grab
         time or later than the current server time; otherwise the
         last-keyboard-grab time is set to the specified time,
         with CurrentTime replaced by the current server time.

UngrabKeyboard

         time: TIMESTAMP or CurrentTime
         Releases the keyboard if this client has it actively
         grabbed (from either GrabKeyboard or GrabKey), and
         releases any queued events.  The request has no effect
         if the specified time is earlier than the
         last-keyboard-grab time or is later than the current
         server time.
         This request generates FocusIn and FocusOut events.
         An UngrabKeyboard is performed automatically if the event
         window for an active keyboard grab becomes not viewable.

GrabKey

         key: KEYCODE or AnyNonModifier
         modifiers: SETofKEYMASK or AnyModifier
         grab-window: WINDOW
         owner-events: BOOL
         pointer-mode, keyboard-mode: {Synchronous, Asynchronous}
         Errors: Window, Value, Access
         This request establishes a passive grab on the keyboard.
         In the future, if the specified key (which can itself be a
         modifier key) is pressed when the specified modifier keys
         are down (and no other modifier keys are down), and the
         KeyPress event would be generated in grab-window or one of
         its inferiors, and these constraints are not satisfied for
         any ancestor, then the keyboard is actively grabbed as
         described in GrabKeyboard, the last-keyboard-grab time is
         transmitted in set to the time at which the key was
         pressed (as in the KeyPress event), and the KeyPress
         event is reported.  The interpretation of the remaining
         arguments is as for GrabKeyboard.  The active grab is
         terminated automatically when the specified key has been
         released (independent of the state of the modifier keys).
         A modifiers of AnyModifier is equivalent to issuing the
         request for all possible modifier combinations.  A key of
         AnyNonModifier is equivalent to issuing the request for

M.I.T. [Page 45] RFC 1013 June 1987

         all possible non-modifier key codes.
         An Access error is generated if some other client has
         issued a GrabKey with the same key combination on the
         same window. When using AnyModifier or AnyNonModifier,
         the request fails  completely (no grabs are established)
         if there is a conflicting grab for any combination.

UngrabKey

         key: KEYCODE or AnyNonModifier
         modifiers: SETofKEYMASK or AnyModifier
         grab-window: WINDOW
         Errors: Window
         Releases the key combination on the specified window if it
         was grabbed by this client.  A modifiers of AnyModifier is
         equivalent to issuing the request for all possible
         modifier combinations.  A key of AnyNonModifier is
         equivalent to issuing the request for all possible
         non-modifier key codes.  Has no effect on an active grab.

AllowEvents

         mode: {AsyncPointer, SyncPointer, ReplayPointer,
                AsyncKeyboard, SyncKeyboard, ReplayKeyboard}
         time: TIMESTAMP or CurrentTime
         Errors: Value
         Releases some queued events if the client has caused a
         device to freeze.  The request has no effect if the
         specified time is earlier than the last-grab time of the
         most recent active grab for the client, or if the
         specified time is later than the current server time.
         For AsyncPointer, if the pointer is frozen by the client,
         pointer event processing continues normally.  If the
         pointer is frozen twice by the client on behalf of two
         separate grabs, AsyncPointer "thaws" for both.
         AsyncPointer has no effect if the pointer is not frozen
         by the client, but the pointer need not be grabbed by
         the client.
         For SyncPointer, if the pointer is frozen and actively
         grabbed by the client, pointer event processing continues
         normally until the next ButtonPress or ButtonRelease event
         is reported to the client, at which time the pointer again
         appears to freeze.  However if the reported event causes
         the pointer grab to be released, then the pointer does not
         freeze.  SyncPointer has no effect if the pointer is not
         frozen by the client, or if the pointer is not grabbed by

M.I.T. [Page 46] RFC 1013 June 1987

         the client.
         For ReplayPointer, if the pointer is actively grabbed by
         the client and is frozen as the result of an event having
         been sent to the client (either from the activation of a
         GrabButton, or from a previous AllowEvents with mode
         SyncPointer, but not from a GrabPointer), then the pointer
         grab is released and that event is completely reprocessed,
         but this time ignoring any passive grabs at or above
         (towards the root) the grab-window of the grab just
         released.  The request has no effect if the pointer is
         not grabbed by the client, or if the pointer is not
         frozen as the result of an event.
         For AsyncKeyboard, if the keyboard is frozen by the
         client, keyboard event processing continues normally.  If
         the pointer is frozen twice by the client on behalf of
         two separate grabs, AsyncPointer "thaws" for both.
         AsyncKeyboard has no effect if the keyboard is not
         frozen by the client, but the keyboard need not be
         grabbed by the client.
         For SyncKeyboard, if the keyboard is frozen and actively
         grabbed by the client, keyboard event processing
         continues normally until the next KeyPress or KeyRelease
         event is  reported to the client, at which time the
         keyboard again appears to freeze.  However if the
         reported event causes the keyboard grab to be released,
         then the keyboard does not freeze.  SyncKeyboard has no
         effect if the keyboard is not frozen by the client, or
         if the keyboard is not grabbed by the client.
         For ReplayKeyboard, if the keyboard is actively grabbed
         by the client and is frozen as the result of an event
         having been sent to the client  (either from the
         activation of a GrabKey, or from a previous AllowEvents
         with mode SyncKeyboard, but not from a GrabKeyboard),
         then the keyboard grab is released and that event is
         completely reprocessed, but this time ignoring any passive
         grabs at or above (towards the root) the grab-window of
         the grab just released.  The request has no effect if the
         keyboard is not grabbed by the client, or if the keyboard
         is notfrozen as the result of an event.
         AsyncPointer, SyncPointer, and Replay Pointer have no
         effect on processing of keyboard events.  AsyncKeyboard,
         SyncKeyboard, and ReplayKeyboard have no effect on
         processing of pointer events.
         It is possible for both a pointer grab and a keyboard grab
         to be active simultaneously (by the same or different

M.I.T. [Page 47] RFC 1013 June 1987

         clients).  If a device is frozen on behalf of either grab,
         no event processing is performed for the device.  It is
         possible for a single device to be frozen due to both
         grabs.  In this case, the freeze must be released on
         behalf of both grabs before events can again be
         processed.

GrabServer

         Disables processing of requests and close-downs on all
         other connections (than the one this request arrived on).

UngrabServer

         Restarts processing of requests and close-downs on other
         connections.

QueryPointer

         window: WINDOW
     =>
         root: WINDOW
         child: WINDOW or None
         same-screen: BOOL
         root-x, root-y, win-x, win-y: INT16
         mask: SETofKEYBUTMASK
         Errors: Window
         The root window the pointer is currently on, and pointer
         coordinates relative to the root's origin, are returned.
         If same-screen is False, then the pointer is not on the
         same screen as the argument window, and child is None and
         win-x and win-y are zero.  If same-screen is True, then
         win-x and win-y are the pointer coordinates relative to
         the argument window's origin, and child is the child
         containing the pointer, if any.  The current state of the
         modifier keys and the buttons are also returned.

GetMotionEvents

         start, stop: TIMESTAMP or CurrentTime
         window: WINDOW
     =>
         events: LISTofTIMECOORD
         where
                 TIMECOORD: {x, y: CARD16
                             time: TIMESTAMP}
         Error: Window
         Returns all events in the motion history buffer that fall
         between the specified start and stop times (inclusive)
         and that have coordinates that lie within (including

M.I.T. [Page 48] RFC 1013 June 1987

         borders) the specified window at its present placement.
         The x and y coordinates are reported relative to the
         origin  of the window.

TranslateCoordinates

         src-window, dst-window: WINDOW
         src-x, src-y: INT16
     =>
         same-screen: BOOL
         child: WINDOW or None
         dst-x, dst-y: INT16
         Errors: Window
         The src-x and src-y coordinates are taken relative to
         src-window's origin, and returned as dst-x and dst-y
         coordinates relative to dst-window's origin.  If
         same-screen is False, then src-window and dst-window are
         on different screens, and dst-x and dst-y are zero.  If
         the coordinates are contained in a mapped child of
         dst-window, then that child is returned.

WarpPointer

         src-window: WINDOW or None
         dst-window: WINDOW
         src-x, src-y: INT16
         src-width, src-height: CARD16
         dst-x, dst-y: INT16
         Errors: Window
         Moves the pointer to [dst-x, dst-y] relative to
         dst-window's origin. If src-window is None, the move is
         independent of the current pointer position, but if a
         window is specified, the move only takes place if the
         pointer is currently contained in a visible portion of
         the specified rectangle of the src-window.
         The src-x and src-y coordinates are relative to
         src-window's origin.  If src-height is zero, it is
         replaced with the current height of src-window minus
         src-y.  If src-width is zero, it is replaced with the
         current width of src-window minus src-x.
         This request cannot be used to move the pointer outside
         the confine-to window of an active pointer grab; an
         attempt will only move the pointer as far as the closest
         edge of the confine-to window.

M.I.T. [Page 49] RFC 1013 June 1987

SetInputFocus

         focus: WINDOW or PointerRoot or None
         revert-to: {Parent, PointerRoot, None}
         time: TIMESTAMP or CurrentTime
         Errors: Window, Value
         Changes the input focus and the last-focus-change time.
         The request has no effect if the specified time is earlier
         than the current last-focus-change time or is later than
         the current server time; otherwise, the last-focus-change
         time is set to the specified time, with CurrentTime
         replaced by the current server time.
         If None is specified as the focus, all keyboard events are
         discarded until a new focus window is set.  In this case,
         therevert-to argument is ignored.
         If a window is specified as the focus, it becomes the
         keyboard's focus window.  If a generated keyboard event
         would normally be reported to this window or one of its
         inferiors, the event is reported normally; otherwise, the
         event is reported with respect to the focus window.
         If PointerRoot is specified as the focus, the focus
         window is dynamically taken to be the root window of
         whatever screen the pointer is on at each keyboard event.
         In this case, the revert-to argument is ignored.
         This request generates FocusIn and FocusOut events.
         If the focus window becomes not viewable, the new focus
         window depends on the revert-to argument.  If revert-to
         is Parent, the focus reverts to the parent (or the
         closest viewable ancestor) and the new revert-to value is
         take to be None.  If revert-to is PointerRoot or None,
         the focus reverts to that value.  When the focus reverts,
         FocusIn and FocusOut events are generated, but the
         last-focus-change time is not affected.

GetInputFocus

         =>
         focus: WINDOW or PointerRoot or None
         revert-to: {Parent, PointerRoot, None}
         Returns the current focus state.

QueryKeymap

     =>
         keys: LISTofCARD8

M.I.T. [Page 50] RFC 1013 June 1987

         Returns a bit vector for the keyboard; each one bit
         indicates that the corresponding key is currently pressed.
         The vector is represented as 32 bytes.  Byte N (from 0)
         contains the bits for keys 8N to 8N+7, with the least
         significant bit in the byte representing key 8N.

OpenFont

         fid: FONT
         name: STRING8
         Errors: IDChoice, Name, Alloc
         Loads the specified font, if necessary, and associates
         identifier fid with it.  The font can be used as a source
         for any drawable.  The font name should use the ASCII
         encoding, and upper/lower case does not matter.

CloseFont

         font: FONT
         Errors: Font
         Deletes the association between the resource id and the
         font.  The font itself will be freed when no other
         resource references it.

QueryFont

         font: FONT or GCONTEXT
     =>
         font-info: FONTINFO
         char-infos: LISTofCHARINFO
         where
                 FONTINFO: [draw-direction: {LeftToRight, RightToLeft}
                            min-char-or-byte2,max-char-or-byte2:CARD16
                            min-byte1, max-byte1: CARD8
                            all-chars-exist: BOOL
                            default-char: CARD16
                            min-bounds: CHARINFO
                            max-bounds: CHARINFO
                            font-ascent: INT16
                            font-descent: INT16
                            properties: LISTofFONTPROP]
                 FONTPROP: [name: ATOM
                            value: INT32 or CARD32]
                 CHARINFO: [left-side-bearing: INT16
                            right-side-bearing: INT16
                            character-width: INT16
                            ascent: INT16
                            descent: INT16
                            attributes: CARD16]

M.I.T. [Page 51] RFC 1013 June 1987

         Errors: Font
         Returns logical information about a font.
         The draw-direction is essentially just a hint, indicating
         whether most char-infos have a positive (LeftToRight) or a
         negative (RightToLeft)  character-width metric.  The core
         protocol defines no support for vertical text.
         If min-byte1 and max-byte1 are both zero, then
         min-char-or-byte2 specifies the linear character index
         corresponding to the first elementb of char-infos, and
         max-char-or-byte2 specifies the linear character index of
         the last element.  If either min-byte1 or max-byte1 are
         non-zero, then both min-char-or-byte2 and
         max-char-or-byte2 will be less than 256, and the two-byte
         character index values corresponding to char-infos element
         N (counting from 0) are
             byte1 = N/D + min-byte1
             byte2 = N\D + min-char-or-byte2
         where
             D = max-char-or-byte2 - min-char-or-byte2 + 1
             / = integer division
             \ = integer modulus
         If char-infos has length zero, then min-bounds and
         max-bounds will be identical, and the effective
         char-infos is one filled with this char-info, of length
             L = D * (max-byte1 - min-byte1 + 1)
         That is, all glyphs in the specified linear or matrix
         range have the same information, as given by min-bounds
         (and max-bounds). If all-chars-exist is True, then all
         characters in char-infos have non-zero bounding boxes.
         The default-char specifies the character that will be
         used when an undefined or non-existent character is used.
         Note that default-char is a CARD16 (not CHAR2B); for a
         font using two-byte matrix format, the default-char has
         byte1 in the most significant byte, and byte2 in the
         least significant byte.  If the default-char itself
         specifies an undefined or non-existent character, then
         no printing is performed for an undefined or non-existent
         character.
         The min-bounds and max-bounds contain the minimum and
         maximum values of each individual CHARINFO component over
         all char-infos (ignoring non-existent characters).  The
         bounding box of the font, i.e., the smallest rectangle
         enclosing the shape obtained  by superimposing all
         characters at the same origin [x,y], has  its upper left
         coordinate at

M.I.T. [Page 52] RFC 1013 June 1987

             [x + min-bounds.left-side-bearing, y - max-bounds.
                  ascent] with a width of
             max-bounds.right-side-bearing - min-bounds.
                  left-side-bearing and a height of
             max-bounds.ascent + max-bounds.descent
         The font-ascent is the logical extent of the font above
         the baseline, for determining line spacing.  Specific
         characters may extend beyond this.  The font-descent is
         the logical extent of the font at or below the baseline,
         for determining line spacing. Specific characters may
         extend beyond this.  If the baseline is at Y-coordinate
         y, then the logical extent of the font is inclusive
         between the Y-coordinate values (y - font-ascent) and
         (y + font-descent - 1).
         A font is not guaranteed to have any properties.  Whether
         a property value is signed or unsigned must be derived
         from a prior knowledge of the property.  When possible,
         fonts should have at least the following properties (note
         that the trailing colon is not part of the name, and that
         upper/lower case matters).
         MIN_SPACE: CARD32
            The minimum interword spacing, in pixels.
         NORM_SPACE: CARD32
             The normal interword spacing, in pixels.
         MAX_SPACE: CARD32
             The maximum interword spacing, in pixels
         SUBSCRIPT_X: INT32
         SUBSCRIPT_Y: INT32
             Offsets from the character origin where subscripts
             should begin, in pixels.  If the origin is at [x,y],
             then subscripts should begin at [x + SubscriptX,
                 y + SubscriptY].
         UNDERLINE_POSITION: INT32
             Y offset from the baseline to the top of an underline,
             in pixels. If the baseline is Y-coordinate y, then
             the top of the underline is at (y +
                  UnderlinePosition).
         UNDERLINE_THICKNESS: CARD32
             Thickness of the underline, in pixels.
         STRIKEOUT_ASCENT: INT32
         STRIKEOUT_DESCENT: INT32
             Vertical extents for boxing or voiding characters, in
             pixels.  If the baseline is at Y-coordinate y, then
             the top of the strikeout box is at (y -
             StrikeoutAscent), and the height of the box is
             (StrikeoutAscent +  StrikeoutDescent).
         ITALIC_ANGLE: INT32
             The angle of characters in the font, in degrees

M.I.T. [Page 53] RFC 1013 June 1987

             scaled by 64, relative to the three-oclock position
             from the character origin, with positive indicating
             counterclockwise motion (as in Arc requests).
         X_HEIGHT: INT32
             "1 ex" as in TeX, but expressed in units of pixels.
             Often the height of lowercase x.
         QUAD_WIDTH: INT32
             "1 em" as in TeX, but expressed in units of pixels.
             Often the width of the digits 0-9.
         WEIGHT: CARD32
             The weight or boldness of the font, expressed as a
             value between 0 and 1000.
         POINT_SIZE: CARD32
             The point size, expressed in 1/10ths, of this font at
             the ideal resolution.  There are 72.27 points to the
             inch.
         RESOLUTION: CARD32
             The number of pixels per point, expressed in 1/100ths,
             at which this font was created.
         For a character origin at [x,y], the bounding box of a
         character,i.e., the smallest rectangle enclosing the
         character's shape,  described in terms of CHARINFO
         components, is a rectangle with its upper left corner at
                 [x + left-side-bearing, y - ascent]
         with a width of
                 right-side-bearing - left-side-bearing
         and a height of
                 ascent + descent
         and the origin for the next character is defined to be
                 [x + character-width, y]
         Note that the baseline is logically viewed as being just
         below non-descending characters (when descent is zero,
         only pixels with Y-coordinates less than y are drawn),
         and that the origin is logically viewed as being
         coincident with the left edge of a non-kerned character
         (when left-side-bearing is zero, no pixels with
         X-coordinate less than x are drawn).
         Note that CHARINFO metric values can be negative.
         A non-existent character is represented with all CHARINFO
         components zero.
         The interpretation of the per-character attributes field
         is undefined by the core protocol.

QueryTextExtents

         font: FONT or GCONTEXT
         items: STRING16
     =>

M.I.T. [Page 54] RFC 1013 June 1987

         draw-direction: {LeftToRight, RightToLeft}
         font-ascent: INT16
         font-descent: INT16
         overall-ascent: INT16
         overall-descent: INT16
         overall-width: INT32
         overall-left: INT32
         overall-right: INT32
         Errors: Font
         Returns the logical extents of the specified string of
         characters in the specified font.  Draw-direction,
         font-ascent, and font-descent are as described in
         QueryFont.  Overall-ascent is the maximum of the ascent
         metrics of all characters in the string, and
         overall-descent is the maximum of the descent metrics.
         Overall-width is the sum of the character-width metrics
         of all characters in the string.  For each character in
         the string, let W be the sum of the character-width
         metrics of all characters preceding it in the string,
         let L be the left-side-bearing metric of the character
         plus W, and let R be the right-side-bearing metric of
         the character plus W.  Overall-left is the minimum L of
         all characters in the string, and overall-right is the
         maximum R.
         For fonts defined with linear indexing rather than
         two-byte matrix indexing, the server will interpret each
         CHAR2B as a 16-bit number that has been transmitted most
         significant byte first (i.e., byte1 of the CHAR2B is
         taken as the most significant byte).
         If the font has no defined default-char, then undefined
         characters in   the string are taken to have all zero
         metrics.

ListFonts

         pattern: STRING8
         max-names: CARD16
     =>
         names: LISTofSTRING8
         Returns a list of length at most max-names, of names of
         fonts matching the pattern.  The pattern should use the
         ASCII encoding, and upper/lower case does not matter.
         In the pattern, the '?' character (octal value 77) will
         match any single character, and the character '*' (octal
         value 52) will match any number of characters.  The
         returned names are in lower case.

M.I.T. [Page 55] RFC 1013 June 1987

ListFontsWithInfo

         pattern: STRING8
         max-names: CARD16
     =>
         fonts: LISTofFONTDATA
         where
                 FONTDATA: [name: STRING8
                            info: FONTINFO]
                 FONTINFO: <same type definition as in QueryFont>
         Like ListFonts, but also returns information about each
         font.  The information returned for each font is
         identical to what QueryFont would return (except that the
         per-character metrics are not returned).

SetFontPath

         path: LISTofSTRING8
         Errors: Value
         Defines the search path for font lookup.  There is only one
         search path per server, not one per client.  The
         interpretation of the strings is operating system dependent,
         but they are intended to specify directories to be
         searched in the order listed.
         Setting the path to the empty list restores the default
         path defined for the server.
         As a side-effect of executing this request, the server
         is guaranteed to flush all cached information about fonts
         for which there currently are no explicit resource ids
         allocated.
         The meaning of an error from this request is system
         specific.

GetFontPath

     =>
         path: LISTofSTRING8
         Returns the current search path for fonts.

CreatePixmap

         pid: PIXMAP
         drawable: DRAWABLE
         depth: CARD8
         width, height: CARD16
         Errors: IDChoice, Drawable, Value, Alloc

M.I.T. [Page 56] RFC 1013 June 1987

         Creates a pixmap, and assigns the identifier pid to it.
         Width and height must be non-zero.  Depth must be one of
         the depths supported by root of the specified drawable.
         The initial contents of the pixmap are undefined.
         It is legal to pass an InputOnly window as a drawable to
         this request.

FreePixmap

         pixmap: PIXMAP
         Errors: Pixmap
         Deletes the association between the resource id and the
         pixmap.  The pixmap storage will be freed when no other
         resource references it.

CreateGC

         cid: GCONTEXT
         drawable: DRAWABLE
         value-mask: BITMASK
         value-list: LISTofVALUE
         Errors: IDChoice, Drawable, Pixmap, Font, Match, Value, Alloc
         Creates a graphics context, and assigns the identifier cid to
         it.  The gcontext can be used with any destination drawable
         having the same root and depth as the specified drawable.
         The value-mask and value-list specify which components are to
         be explicitly initialized.  The context components are:
           alu-function: {Clear, And, AndReverse, Copy, AndInverted,
                          Noop, Xor, Or, Nor, Equiv, Invert,
                            OrReverse, CopyInverted, OrInverted,
                            Nand, Set}
           plane-mask: CARD32
           foreground: CARD32
           background: CARD32
           line-width: CARD16
           line-style: {Solid, OnOffDash, DoubleDash}
           cap-style: {NotLast, Butt, Round, Projecting}
           join-style: {Miter, Round, Bevel}
           fill-style: {Solid, Tiled, OpaqueStippled, Stippled}
           fill-rule: {EvenOdd, Winding}
           arc-mode: {Chord, PieSlice}
           tile: PIXMAP
           stipple: PIXMAP
           tile-stipple-x-origin: INT16
           tile-stipple-y-origin: INT16
           font: FONT

M.I.T. [Page 57] RFC 1013 June 1987

           subwindow-mode: {ClipByChildren, IncludeInferiors}
           graphics-exposures: BOOL
           clip-x-origin: INT16
           clip-y-origin: INT16
           clip-mask: PIXMAP or None
           dash-offset: CARD16
           dash-list: CARD8
         In graphics operations, given a source and destination pixel,
         the result is computed bitwise on corresponding bits of the
         pixels.  That is, a boolean operation is performed in each
         bit plane. The plane-mask restricts the operation to a subset
         of planes.  That is, the result is
         ((src FUNC dst) AND plane-mask) OR (dst AND (NOT plane-mask))
         Range checking is not performed on the values for foreground,
         background, or plane-mask; they are simply truncated to the
         appropriate number of bits.
         The meanings of the alu-functions are:
             Clear               0
             And                 src AND dst
             AndReverse          src AND (NOT dst)
             Copy                src
             AndInverted         (NOT src) AND dst
             NoOp                dst
             Xor                 src XOR dst
             Or                  src OR dst
             Nor                 (NOT src) AND (NOT dst)
             Equiv               (NOT src) XOR dst
             Invert              NOT dst
             OrReverse           src OR (NOT dst)
             CopyInverted        NOT src
             OrInverted          (NOT src) OR dst
             NAnd                (NOT src) OR (NOT dst)
             Set                 1
         Line-width is measured in pixels and can be greater than or
         equal to one (a "wide" line) or the special value zero (a
         "thin" line).
         Wide lines are drawn centered on the path described by the
         graphics request.  Unless otherwise specified by the join or
         cap style, the bounding box of a wide line with endpoints
         [x1, y1], [x2, y2], and width w is a rectangle with vertices
         at the following real coordinates:
         [x1-(w*sn/2), y1+(w*cs/2)], [x1+(w*sn/2), y1-(w*cs/2)],
         [x2-(w*sn/2), y2+(w*cs/2)], [x2+(w*sn/2), y2-(w*cs/2)]

M.I.T. [Page 58] RFC 1013 June 1987

         where sn is the sine of the angle of the line and cs is the
         cosine of the angle of the line.  A pixel is part of the line
         (and hence drawn) if the center of the pixel is fully inside
         the bounding box (which is viewed as having infinitely thin
         edges).  If the center of the pixel is exactly on the
         bounding box, it is part of the line if and only if the
         interior is immediately to its right (x increasing
         direction).  Pixels with centers on a horizontal edge are a
         special case and are part of the line if and only if the
         interior is immediately below (y increasing direction).
         Note that this description is a mathematical model
         describing the pixels that are drawn for a wide line and
         does not imply that trigonometry is required to implement
         such a model.  Real or fixed point arithmetic is
         recommended for computing the corners of the line endpoints
         for lines greater than one pixel in width.
         Thin lines (zero line-width) are "one pixel wide" lines drawn
         using an unspecified, device dependent algorithm (for
         example, Bresenham). There are only two constraints on this
         algorithm. First, if a line is drawn unclipped from [x1,y1]
         to [x2,y2] and another line is drawn unclipped from [x1+dx,
         y1+dy] to [x2+dx,y2+dy], then a point [x,y] is touched by
         drawing the first line if and only if the point [x+dx,y+dy]
         is touched by drawing the second line.  Second, the effective
         set of points comprising a line cannot be affected by
         clipping; that is, a point is touched in a clipped line if
         and only if the point lies inside the clipping region and
         the point would be touched by the line when drawn unclipped.
         Note that a wide line drawn from [x1,y1] to [x2,y2] always
         draws the same pixels as a wide line drawn from [x2,y2] to
         [x1,y1], not counting cap and join styles, but this property
         is not guaranteed for thin lines.  Also note that "jags" in
         adjacent wide lines will always line up properly, but this
         property is not guaranteed for thin lines.  A line-width of
         zero differs from a line-width of one in which pixels are
         drawn.  In general, drawing a thin line will be faster than
         drawing a wide line of width one, but thin lines may not mix
         well aesthetically desirable to obtain precise and uniform
         results across all displays, a client should always use a
         line-width of one, rather than a line-width of zero.
         The line-style defines which segments of a line are drawn:
             Solid:  the full path of the line is drawn
             DoubleDash: the full path of the line is drawn, but the
                         segments defined by the even dashes are
                         filled differently than the segments defined
                         by the odd dashes (see fill-style)
             OnOffDash: only the segments defined by the even dashes
                        are drawn, and cap-style applies to each

M.I.T. [Page 59] RFC 1013 June 1987

                        individual segment (except NotLast is treated
                        as Butt for internal caps)
         The cap-style defines how the endpoints of a path are drawn:
             NotLast: equivalent to Butt, except that for a
                      line-width of zero or one the final endpoint is
                      not drawn
             Butt: square at the endpoint, with no projection beyond
             Round: a circular arc with diameter equal to the
                    line-width, centered on the endpoint; equivalent
                    to Butt for line-width zero or one
             Projecting: square at the end, but the path continues
                         beyond the endpoint for a distance equal to
                         half the line-width; equivalent to Butt for
                         line-width zero or one
         The join-style defines how corners are drawn for wide lines:
             Miter: the outer edges of the two lines extend to meet at
                    an angle
             Round: a circular arc with diameter equal to the
                    line-width, centered on the joinpoint
             Bevel: Butt endpoint styles, and then the triangular
                    "notch" filled
         The tile/stipple and clip origins are interpreted relative to
         the origin of whatever destination drawable is specified in a
         graphics request.
         The tile pixmap must have the same root and depth as the
         gcontext (else a Match error).  The stipple pixmap must have
         depth one, and must have the same root as the gcontext (else
         a Match error).  For stipple operations, the stipple pattern
         is tiled in a  single plane, and acts as an additional clip
         mask to be ANDed with the clip-mask.  Any size pixmap can be
         used for tiling or stippling, although some sizes may be
         faster to use than others.
         The fill-style defines the contents of the source for line,
         text, and fill requests.  For all text and fill requests
         (PolyText8, PolyText16, PolyFillRectangle, FillPoly,
         PolyFillArc), for line  requests (PolyLine, PolySegment,
         PolyRectangle, PolyArc) with line-style Solid, and for the
         even dashes for line requests with line-style OnOffDash or
         DoubleDash:
             Solid: foreground
             Tiled: tile
             OpaqueStippled: a tile with the same width and height as
                             stipple, but with background everywhere
                             stipple has a zero and with foreground
                             everywhere stipple has a one
             Stippled: foreground masked by stipple

M.I.T. [Page 60] RFC 1013 June 1987

         For the odd dashes for line requests with line-style
         DoubleDash:
             Solid: background
             Tiled: same as for even dashes
             OpaqueStippled: same as for even dashes
             Stippled: background masked by stipple
         The dash-list value allowed here is actually a simplified
         form of the more general patterns that can be set with
         SetDashes.Specifying a value of N here is equivalent to
         specifying the two element list [N, N] in SetDashes.  The
         value must be non-zero.  The meaning of dash-offset and
         dash-list are explained in the SetDashes request.
         The clip-mask restricts writes to the destination drawable;
         only pixels where the clip-mask has a one bit are drawn.  It
         affects all graphics requests.  The clip-mask does not clip
         sources.  The clip-mask origin is interpreted relative to the
         origin of whatever destination drawable is specified in a
         graphics request.  If a pixmap is specified as the clip-mask,
         it must have depth one and have the same root as the gcontext
         (else a Match error).  The clip-mask can also be set with the
         SetClipRectangles request.
         For ClipByChildren, both source and destination windows are
         additionally clipped by all viewable InputOutput children.
         For IncludeInferiors, neither source nor destination window
         is clipped by inferiors; this will result in drawing through
         subwindow boundaries. The use of IncludeInferiors on a window
         of one depth with mapped inferiors of differing depth is not
         illegal, but the semantics isundefined by the core protocol.
         The fill-rule defines what pixels are inside (i.e., are
         drawn) for paths given in FillPoly requests.  EvenOdd means
         a point is inside if an infinite ray with the point as origin
         crosses the path an odd number of times.  For Winding, a
         point is inside if an infinite ray with the point as origin
         crosses an unequal number of clockwise and counterclockwise
         directed path segments.  For both rules, a "point" is
         infinitely small, and the path is an infinitely thin line.
         A pixel is inside if the center point of the pixel is inside
         and the center point is not on the boundary.  If the center
         point is on the boundary, the pixel is inside if and only if
         the polygon interior is immediately to its right (x
         increasing direction).  Pixels with centers along a
         horizontal edge are a special case and are inside if and
         only if the polygon interior is immediately below (y
         increasing direction).
         The arc-mode controls filling in the PolyFillArc request.

M.I.T. [Page 61] RFC 1013 June 1987

         The graphics-exposures flag controls GraphicsExposure event
         generation for CopyArea and CopyPlane requests (and any
         similar requests defined by extensions).
         The default component values are:
             function: Copy
             plane-mask: all ones
             foreground: 0
             background: 1
             line-width: 0
             line-style: Solid
             cap-style: Butt
             join-style: Miter
             fill-style: Solid
             full-rule: EvenOdd
             arc-mode: PieSlice
             tile: pixmap of unspecified size filled with forground
                   pixell (i.e., client specified pixel if any,
                   else 0)
             stipple: pixmap of unspecified size filled with ones
             tile-stipple-x-origin: 0
             tile-stipple-y-origin: 0
             font: <implementation dependent>
             subwindow-mode: ClipByChildren
             graphics-exposures: True
             clip-x-origin: 0
             clip-y-origin: 0
             clip-mask: None
             dash-offset: 0
             dash-list: 4 (i.e., the list [4, 4])
         Storing a pixmap in a gcontext might or might not result in a
         copy being made.  If the pixmap is later used as the
         destination for a graphics request, the change might or might
         not be reflected in the gcontext.  If the pixmap is used
         simultaneously  in a graphics request as both a destination
         and as a tile or stipple. the results are not defined.
         It is quite likely that some amount of gcontext information
         will be cached in display hardware, and that such hardware
         can only cache a small number of gcontexts.  Given the number
         and complexity of components, clients should view switching
         between gcontexts with nearly identical state as
         significantly more expensive than making minor changes to a
         single gcontext.

ChangeGC

         gc: GCONTEXT
         value-mask: BITMASK
         value-list: LISTofVALUE

M.I.T. [Page 62] RFC 1013 June 1987

         Errors: GContext, Pixmap, Font, Match, Value, Alloc
         Changes components in gc.  The value-mask and value-list
         specify which components are to be changed.  The values and
         restrictions are the same as for CreateGC.
         Changing the clip-mask also overrides any previous
         SetClipRectangles request on the context.  Changing the
         dash-offset or dash-list overrides any previous SetDashes
         request on the context.
         The order in which components are verified and altered is
         server dependent.  If an error is generated, a subset of the
         components may have been altered.

CopyGC

         src-gc, dst-gc: GCONTEXT
         value-mask: BITMASK
         Errors: GContext, Value, Match, Alloc
         Copies components from src-gc to dst-gc.  The value-mask
         specifies which components to copy, as for CreateGC.  The
         two gcontexts must have the same root and the same depth
         (else a Match error).

SetDashes

         gc: GCONTEXT
         dash-offset: CARD16
         dash-list: LISTofCARD8
         Errors: GContext, Value, Alloc
         Sets the dash-offset and dash-list in gc for dashed line
         styles.  The initial and alternating elements of the
         dash-list are the "even" dashes, the others are the
         "odd" dashes.  All of the elements must be non-zero.
         The dash-offset defines the phase of the pattern,
         specifying how many pixels into the dash-list the pattern
         should actually begin in any single graphics request.
         Dashing is continuous through path segments combined with
         a join-style, but is reset to the dash-offset each time a
         cap-style is applied.

SetClipRectangles

         gc: GCONTEXT
         clip-x-origin, clip-y-origin: INT16
         rectangles: LISTofRECTANGLE
         ordering: {UnSorted, YSorted, YXSorted, YXBanded}
         Errors: GContext, Value, Alloc, Match

M.I.T. [Page 63] RFC 1013 June 1987

         Changes clip-mask in gc to the specified list of rectangles
         and sets the clip origin.  Output will be clipped to remain
         contained within the rectangles.  The clip origin is
         interpreted relative to the origin of whatever destination
         drawable is specified in a graphics request.  The rectangle
         coordinates are interpreted relative to the clip origin.
         The rectangles should be non-intersecting, or graphics
         results will be undefined.
         If known by the client, ordering relations on the rectangles
         can be specified with the ordering argument; this may provide
         faster operation by the server.  If an incorrect ordering is
         specified, the server may generate a Match error, but is not
         required to do so; if no error is generated, the graphics
         results are undefined. UnSorted means the rectangles are in
         arbitrary order.  YSorted means that the rectangles are
         non-decreasing in their Y origin. YXSorted additionally
         constrains YSorted order in that all rectangles with an equal
         Y origin are non-decreasing in their X origin.  YXBanded
         additionally constrains YXSorted by requiring that for every
         possible Y scanline, all rectangles that include that
         scanline have identical Y origins and Y extents.

FreeGC

         gc: GCONTEXT
         Errors: GContext
         Deletes the association between the resource id and the
         gcontext, and destroys the gcontext.

ClearToBackground

         window: WINDOW
         x, y: INT16
         width, height: CARD16
         exposures: BOOL
         Errors: Window, Value, Match
         The x and y coordinates are relative to the window's origin,
         and specify the upper left corner of the rectangle.  If width
         is zero, it is replaced with the current width of the window
         minus x.  If height is zero, it is replaced with the current
         height of the window minus y.  If the window has a defined
         background tile, the rectangle is tiled with a plane-mask of
         all ones and alu-function of Copy.  If the window has
         background None, the contents of the window are not changed.
         In eithercase, if  exposures is True, then one or more
         exposure events are generated for regions of the rectangle
         that are eithervisible or are being retained in a backing
         store.

M.I.T. [Page 64] RFC 1013 June 1987

         It is a Match error to use an InputOnly window in this
         request.

CopyArea

         src-drawable, dst-drawable: DRAWABLE
         gc: GCONTEXT
         src-x, src-y: INT16
         width, height: CARD16
         dst-x, dst-y: INT16
         Errors: Drawable, GContext, Match
         Combines the specified rectangle of src-drawable with the
         specified rectangle of dst-drawable.  The src-x and src-y
         coordinates are relative to src-drawable's origin, dst-x and
         dst-y are relative to dst-drawable's origin, each pair
         specifying the  upper left corner of the rectangle.
         Src-drawable must have the same root and the same depth as
         dst-drawable (else a Match error).
         If regions of the source rectangle are obscured and have not
         been retained by the server, or if regions outside the
         boundaries of the source drawable are specified, then the
         following occurs.  If the dst-drawable is a window with a
         background of other than  None, the corresponding regions of
         the destination are tiled (with plane-mask of ones and
         alu-function Copy) with that background.  Regardless, if
         graphics-exposures in gc is True, GraphicsExposure events
         for the corresponding desitnation regions are generated.
         If graphics-exposures if True but no regions are exposed,
         then a NoExposure event is generated.
         GC components: alu-function, plane-mask, foreground,
         subwindow-mode, clip-x-origin, clip-y-origin, clip-mask

CopyPlane

         scr-drawable, dst-drawable: DRAWABLE
         GC:Gcontext
         src-x, src-y: INT16
         width, height: CARD16
         dst-x, dst-y: INT16
         bit-plane: CARD32
         Errors: Drawable, GContext, Value, Match
         Src-drawable must have the same root as dst-srawable (else
         a match error), but need not have the same depth.
         Bit-plane must have exactly one bit set.  Effectively, that
         plane of the src-drawable and the fore-ground/background
         pixels in gc are combined to form a pixmap of the same
         depth as dst-drawable, and the equivalent of a CopyArea is

M.I.T. [Page 65] RFC 1013 June 1987

         performed, with all the same exposure semantics.
         GC components: alu-function, plan-mask, foreground,
         background, subwindow-mode, graphics-exposures,
         clip-x-origin, clip-y-origin, clip-mask

PolyPoint

         drawable: DRAWABLE
         gc: GCONTEXT
         coordinate-mode: {Origin, Previous}
         points: LISTofPOINT
         Errors: Drawable, GContext, Value, Match
         Combines the foreground pixel in gc with the pixel at each
         point in the drawable.  The points are drawn in the order
         listed.
         The first point is always relative to the drawable's origin;
         the rest are relative either to that origin or the previous
         point, depending on the coordinate-mode.
         GCcomponents: alu-function, plane-mask, foreground,
         subwindow-mode, clip-x-origin, clip-y-origin, clip-mask

PolyLine

         drawable: DRAWABLE
         gc: GCONTEXT
         coordinate-mode: {Origin, Previous}
         points: LISTofPOINT
         Errors: Drawable, GContext, Value, Match
         Draws lines between each pair of points (point[i], point
         [i+1]). The lines are drawn in the order listed.  The lines
         join correctly at all intermediate points, and if the first
         and last points coincide, the first and last lines also join
         correctly.
         For any given line, no pixel is drawn more than once.  If
         thin (zero line-width) lines intersect, the intersecting
         pixels are drawn multiple times.  If wide lines intersect,
         the intersecting pixels are drawn only once, as though the
         entire PolyLine were a single filled shape.
         The first point is always relative to the drawable's origin;
         the rest are relative either to that origin or the previous
         point,  depending on the coordinate-mode.
         GC components: alu-function, plane-mask, line-width,
         line-style, cap-style, join-style, fill-style,

M.I.T. [Page 66] RFC 1013 June 1987

         subwindow-mode, clip-x-origin, clip-y-origin, clip-mask
         GC mode-dependent components: foreground, background, tile,
         stipple, tile-stipple-x-origin, tile-stipple-y-origin,
         dash-offset,dash-list

PolySegment

         drawable: DRAWABLE
         gc: GCONTEXT
         segments: LISTofSEGMENT
         where SEGMENT: [x1, y1, x2, y2: INT16]
         Errors: Drawable, GContext, Match
         For each segment, draws a line between [x1, y1] and [x2, y2].
         The lines are drawn in the order listed.  No joining is
         performed at coincident end points.  For any given line, no
         pixel is drawn more than once.  If lines intersect, the
         intersecting pixels are drawn multiple times.
         GC components: alu-function, plane-mask, line-width,
         line-style, cap-style, fill-style, subwindow-mode,
         clip-x-origin, clip-y-origin,clip-mask
         GC mode-dependent components: foreground, background, tile,
         stipple,tile-stipple-x-origin, tile-stipple-y-origin,
         dash-offset, dash-list

PolyRectangle

         drawable: DRAWABLE
         gc: GCONTEXT
         rectangles: LISTofRECTANGLE
         Errors: Drawable, GContext, Match
         Draws the outlines of the specified rectangles, as if a
         five-point PolyLine were specified for each rectangle.  The x
         and y coordinates of each rectangle are relative to the
         drawable's origin, and define the upper left corner of the
         rectangle.
         The rectangles are drawn in the order listed.  For any given
         rectangle, no pixel is drawn more than once.  If rectangles
         intersect, the intersecting pixels are drawn multiple times.
         GC components: alu-function, plane-mask, line-width,
         line-style, join-style, fill-style, subwindow-mode,
         clip-x-origin, clip-y-origin, clip-mask
         GC mode-dependent components: foreground, background, tile,

M.I.T. [Page 67] RFC 1013 June 1987

         stipple, tile-stipple-x-origin, tile-stipple-y-origin,
         dash-offset, dash-list

PolyArc

         drawable: DRAWABLE
         gc: GCONTEXT
         arcs: LISTofARC
         Errors: Drawable, GContext, Match
         Draws circular or elliptical arcs.  Each arc is specified by
         a rectangle and two angles.  The x and y coordinates are
         relative to the origin of the drawable, and define the upper
         left corner of the rectangle.  The center of the circle or
         ellipse is the center of the rectangle, and the major and
         minor axes are specified by the width and height,
         respectively.  The angles are signed integers in degrees
         scaled by 64, with positive indicating counterclockwise
         motion and negative indicating clockwise motion.  The start
         of the arc is specified by angle1 relative to the
         three-oclock position from the center, and the path and
         extent of the arc is specified by angle2 relative to the
         start of the arc.  If the magnitude of angle2 is greater
         than 360 degrees, it is truncated to 360 degrees.
         The arcs are drawn in the order listed.  If the last point in
         one arc coincides with the first point in the following arc,
         the two arcs will join correctly.  If the first point in the
         first arc coincides with the last point in the last arc, the
         two arcs will join correctly.  For any given arc, no pixel is
         drawn more than once.  If two arcs join correctly and the
         line-width is greater than zero and the arcs intersect, no
         pixel is drawn more than once.  Otherwise, the intersecting
         pixels of intersecting arcs are drawn multiple times.
         Specifying an arc with one endpoint and a clockwise extent
         draws the same pixels as specifying the other endpoint and an
         equivalent counterclockwise extent, except as it affects
         joins.
         By specifying one axis to be zero, a horizontal or vertical
         line can be drawn.
         Angles are computed based solely on the coordinate system,
         ignoring the aspect ratio.
         GC components: alu-function, plane-mask, line-width,
         line-style, cap-style, join-style, fill-style,
         subwindow-mode, clip-x-origin, clip-y-origin, clip-mask
         GC mode-dependent components: foreground, background, tile,
         stipple,tile-stipple-x-origin, tile-stipple-y-origin,

M.I.T. [Page 68] RFC 1013 June 1987

         dash-offset, dash-list

FillPoly

         drawable: DRAWABLE
         gc: GCONTEXT
         shape: {Complex, Nonconvex, Convex}
         coordinate-mode: {Origin, Previous}
         points: LISTofPOINT
         Errors: Drawable, GContext, Match, Value
         Fills the region closed by the specified path.  The path is
         closed automatically if the last point in the list does not
         coincide with the first point.  No pixel of the region is
         drawn more than once.
         The first point is always relative to the drawable's origin;
         the rest are relative either to that origin or the previous
         point, depending on the coordinate-mode.
         The shape parameter may be used by the server to improve
         performance. Complex means the path may self-intersect.
         Nonconvex means the path does not self-intersect, but the
         shape is not wholly convex.  If known by the client,
         specifying Nonconvex over Complex may improve performance. If
         Nonconvex is specified for a self-intersecting path, the
         graphics results are undefined.
         Convex means the path is wholly convex. If known by the
         client, specifying Convex can improve performance.  If Convex
         is specified for a path that is not convex, the graphics
         results are undefined.
         GC components: alu-function, plane-mask, fill-style,
         fill-rule, subwindow-mode, clip-x-origin, clip-y-origin,
         clip-mask
         GC mode-dependent components: foreground, tile, stipple,
         tile-stipple-x-origin, tile-stipple-y-origin

PolyFillRectangle

         drawable: DRAWABLE
         gc: GCONTEXT
         rectangles: LISTofRECTANGLE
         Errors: Drawable, GContext, Match
         Fills the specified rectangles.  The x and y coordinates of
         each rectangle are relative to the drawable's origin, and
         define the upper left corner of the rectangle.

M.I.T. [Page 69] RFC 1013 June 1987

         The rectangles are drawn in the order listed.  For any given
         rectangle, no pixel is drawn more than once.  If rectangles
         intersect, the intersecting pixels are drawn multiple times.
         GC components: alu-function, plane-mask, fill-style,
         fill-rule, subwindow-mode, clip-x-origin, clip-y-origin,
         clip-mask
         GC mode-dependent components: foreground, tile, stipple,
         tile-stipple-x-origin, tile-stipple-y-origin

PolyFillArc

         drawable: DRAWABLE
         gc: GCONTEXT
         arcs: LISTofARC
         Errors: Drawable, GContext, Match
         For each arc, fills the region closed by the specified arc
         and one or two line segments, depending on the arc-mode.  For
         Chord, the single line segment joining the endpoints of the
         arc is used.  For PieSlice, the two line segments joining the
         endpoints of the arc with the center point are used.  The
         arcs are as specified in the PolyArc request.
         The arcs are filled in the order listed.  For any given arc,
         no pixel is drawn more than once.  If regions intersect, the
         intersecting pixels are drawn multiple times.
         GC components: alu-function, plane-mask, fill-style,
         fill-rule, arc-mode, subwindow-mode, clip-x-origin,
         clip-y-origin, clip-mask
         GC mode-dependent components: foreground, tile, stipple,
         tile-stipple-x-origin, tile-stipple-y-origin

PutImage

         drawable: DRAWABLE
         gc: GCONTEXT
         depth: CARD8
         width, height: CARD16
         dst-x, dst-y: INT16
         left-pad: CARD8
         format: {Bitmap, XYPixmap, ZPixmap}
         bits: <bits>
         Errors: Drawable, GContext, Match, Value, Alloc
         Combines an image with a rectangle of the drawable.  The
         dst-x and dst-y coordinates are relative to the drawable's
         origin.

M.I.T. [Page 70] RFC 1013 June 1987

         If Bitmap format is used, then depth must be one (else a
         Match error) and the image must be in XYFormat. The
         foreground pixel in gc defines the source for one bits in the
         image, and the background pixel defines the source for the
         zero bits.
         For XYPixmap and ZPixmap, depth must match the depth of
         drawable (else a Match error).  For XYPixmap, the image must
         be sent in XYFormat.  For ZPixmap, the image must be sent in
         the ZFormat defined for the given depth.
         The left-pad must be zero for ZPixmap format.  For Bitmap and
         XYPixmap format, left-pad must be less than
         bitmap-format-scanline-pad (as given in the server connection
         setup info).  The first left-pad bits in every scanline are
         to be ignored by the server; the actual image begins that
         many bits into the data.  The width argument defines the width
         of the actual image, and does not include left-pad.
         GC components: alu-function, plane-mask, subwindow-mode,
         clip-x-origin, clip-y-origin, clip-mask
         GC mode-dependent components: foreground, background

GetImage

         drawable: DRAWABLE
         x, y: INT16
         width, height: CARD16
         plane-mask: CARD32
         format: {XYFormat, ZFormat}
     =>
         depth: CARD8
         visual: VISUALID or None
         bits: <bits>
         Errors: Drawable, Value, Match
         Returns the contents of the given rectangle of the drawable
         in the given format.  The x and y coordinates are relative to
         the drawable's origin, and define the upper left corner of
         the rectangle. If XYFormat is specified, only the bit planes
         specified in plane-mask are transmitted.  If ZFormat is
         specified, then bits in all planes not specified in
         plane-mask transmitted as zero.  The returned depth specifies
         the number of bits per pixel of the image.  If the drawable
         is a window,  its visual type is returned; if the drawable
         is a pixmap,the visual is None.
         If the drawable is a window, the window must be mapped, and
         it must be the case that, if there were no inferiors or
         overlapping windows, the specified rectangle of the window

M.I.T. [Page 71] RFC 1013 June 1987

         would be fully visible on the screen will include any
         visible portions of inferiors or overlapping windows
         contained in the rectangle, but if these windows are of
         different depth than the specified window, the contents
         returned for them are not defined by the core protocol.

PolyText8

         drawable: DRAWABLE
         gc: GCONTEXT
         x, y: INT16
         items: LISTofTEXTITEM8
         where
                 TEXTITEM8: TEXTELT8 or FONT
                 TEXTELT8: [delta: INT8
                            string: STRING8]
         Errors: Drawable, GContext, Match, Font
         The x and y coordinates are relative to drawable's origin,
         and specify the baseline starting position (the initial
         character origin). Each text item is processed in turn.  A
         font item causes the font to be stored in gc, and to be
         used for subsequent text; switching among fonts with
         differing draw-directions is permitted.  A text element
         delta specifies an additional change in the position along
         the x axis before the string is drawn; the delta is always
         added to the character origin (not added or subtracted based
         on the draw-direction of the current font).  Each character
         image, as defined by the a font in gc, is treated as an
         additional mask for a fill operation on the drawable.
         All contained FONTs are always transmitted most significant
         byte first.
         If a Font error is generated for an item, the previous items
         may have been drawn.
         For fonts defined with two-byte matrix indexing, each STRING8
         byte is interpreted as a byte2 value of a CHAR2B with a byte1
         value of zero.
         GC components: alu-function, plane-mask, fill-style, font,
         subwindow-mode, clip-x-origin, clip-y-origin, clip-mask
         GC mode-dependent components: foreground, tile, stipple,
         tile-stipple-x-origin, tile-stipple-y-origin

PolyText16

         drawable: DRAWABLE
         gc: GCONTEXT
         x, y: INT16

M.I.T. [Page 72] RFC 1013 June 1987

         items: LISTofTEXTITEM16
         where
                 TEXTITEM16: TEXTELT16 or FONT
                 TEXTELT16: [delta-x: INT8
                             string: STRING16]
         Errors: Drawable, GContext, Match, Font
         Just like PolyText8, except two-byte (or 16-bit) characters
         are used. For fonts defined with linear indexing rather than
         two-byte matrix indexing, the server will interpret each
         CHAR2B as a 16-bit number that has been transmitted most
         significant byte first (i.e., byte1 of the CHAR2B is taken
         as the most significant byte).

ImageText8

         drawable: DRAWABLE
         gc: GCONTEXT
         x, y: INT16
         string: STRING8
         Errors: Drawable, GContext, Match
         The x and y coordinates are relative to drawable's origin,
         and specify the baseline starting position (the initial
         character origin). The effect is to first fill a
         destination rectangle with the background pixel defined in
         gc, and then paint the text with the foreground pixel.
         The upper left corner of the filled rectangle is at
                 [x + overall-left, y - font-ascent]
         the width is
                 overall-right - overall-left
         and the height is
                 font-ascent + font-descent
         where overall-left, overall-right, font-ascent, and
         as font-descent are would be returned by a QueryTextExtents
         call using gc and string.
         The alu-function and fill-style defined in gc are ignored for
         this request; the effective alu-function is Copy and the
         effective fill-style Solid.
         For fonts defined with two-byte matrix indexing, each STRING8
         byte is interpreted as a byte2 value of a CHAR2B with a byte1
         value of zero.
         GC components: plane-mask, foreground, background, font,
         subwindow-mode, clip-x-origin, clip-y-origin, clip-mask

M.I.T. [Page 73] RFC 1013 June 1987

ImageText16

         drawable: DRAWABLE
         gc: GCONTEXT
         x, y: INT16
         string: STRING16
         Errors: Drawable, GContext, Match
         Just like ImageText8, except two-byte (or 16-bit) characters
         are used. For fonts defined with linear indexing rather than
         two-byte matrix indexing, the server will interpret each
         CHAR2B as a 16-bit number that has been transmitted most
         significant byte first (i.e., byte1 of the CHAR2B is taken as
         the most significant byte).

CreateColormap

         mid: COLORMAP
         visual: VISUALID
         window: WINDOW
         alloc: {None, All}
         Errors: IDChoice, Window, Value, Match, Alloc
         Creates a colormap of the specified visual type for the
         screen on which the window resides, and associates the
         identifier mid with it.  The visual type must be one
         supported by the screen, and cannot be of class TrueColor
         (else a Match error).  The initial values of the colormap
         entries are undefined for classes GrayScale, PseudoColor,
         and DirectColor; for StaticGray, StaticColor, and
         TrueColor, the entries will have defined values, but those
         values are specific to the visual and are not defined by
         the core protocol.  For StaticGray, StaticColor, and
         TrueColor, alloc must be specified as None (else a Match
         error). For the other classes, if alloc is None, the
         colormap initially has no allocated entries, and clients
         can allocate entries.  If alloc is All, then the entire
         colormap is "allocated" writable, but entries cannot be
         freed with FreeColors, and no relationships among entries
         is defined; the client must understand whether the colormap
         is GrayScale, PseudoColor, or DirectColor to know how to
         store into entries.

FreeColormap

         cmap: COLORMAP
         Errors: Colormap
         Deletes the association between the resource id and the
         colormap.  If the colormap is an installed map for a screen,
         it is uninstalled (see UninstallColormap).  If the colormap

M.I.T. [Page 74] RFC 1013 June 1987

         is defined as the colormap for a window (via CreateWindow or
         ChangeWindowAttributes), the colormap for the window is
         changed to None, and a ColormapNotify event is generated.The
         colors displayed for a window with a colormap of None are not
         defined by the protocol.
         Has no effect on a default colormap for a screen.

CopyColormapAndFree

         mid, src-cmap: COLORMAP
         Errors: Colormap, Alloc
         Creates a colormap for the same screen as src-cmap, and
         associates identifier mid with it.  Moves all of the client's
         existing allocations from src-cmap to the new colormap, and
         frees those entries in src-cmap. Values in other entries in
         the new colormap are undefined.

InstallColormap

         cmap: COLORMAP
         Errors: Colormap
         Makes this colormap an installed map for its screen.  All
         windows associated with this colormap immediately display
         with true colors.  As a side-effect, previously installed
         colormaps may be uninstalled, and other windows may display
         with false colors.  Which colormaps get uninstalled is
         server dependent, except that it is guaranteed that the
         M-1 most recently client-installed colormaps will not be
         uninstalled, where M is the min-installed-maps specified
         for the screen in the connection setup.
         If cmap is not already an installed map, a ColormapNotify
         event is generated on every window having cmap as an
         attribute.  If a colormap is uninstalled as a result of
         the install, a ColormapNotify event is generated on every
         window having that colormap as an attribute.
         Initially only the default colormap for a screen is
         installed.

UninstallColormap

         cmap: COLORMAP
         Errors: Colormap
         If cmap is an installed map for its screen, one or more
         colormaps are installed in its place; the choice is server

M.I.T. [Page 75] RFC 1013 June 1987

         dependent, pexcept that if the screen's default colormap is
         not installed and can be installed (without forcing other
         colormaps out), then the default colormap is used.
         If cmap is an installed map, a ColormapNotify event is
         generated on every window having this colormap as an
         attribute.  If a colormap is installed as a result of the
         uninstall, a ColormapNotify event is generated on every
         window having that colormap as an attribute.

ListInstalledColormaps

         window: WINDOW
     =>
         cmaps: LISTofCOLORMAP
         Errors: Window
         Returns a list of the currently installed colormaps for the
         screen of the specified window.

AllocColor

         cmap: COLORMAP
         red, green, blue: CARD16
     =>
         pixel: CARD32
         red, green, blue: CARD16
         Errors: Colormap, Alloc
         Allocates a read-only colormap entry corresponding to the
         closest RGB values provided by the hardware.  Returns the
         pixel and the RGB values actually used.

AllocNamedColor

         cmap: COLORMAP
         name: STRING8
     =>
         pixel: CARD32
         exact-red, exact-green, exact-blue: CARD16
         screen-red, screen-green, screen-blue: CARD16
         Errors: Colormap, Name, Alloc
         Looks up the named color with respect to the screen
         associated with the colormap, then does an AllocColor on
         cmap.  The name should use the  ASCII encoding, and
         upper/lower case does not matter. The exact RGB values
         specify the "true" values for the color, and the screen
         values specify the values actually used in the colormap.

M.I.T. [Page 76] RFC 1013 June 1987

AllocColorCells

         cmap: COLORMAP
         colors, planes: CARD16
         contiguous: BOOL
     =>
         pixels, masks: LISTofCARD32
         Errors: Colormap, Value, Alloc
         The number of colors must be positive, the number of planes
         non-negative.  If C colors and P planes are requested, then C
         pixels  and P masks are returned.  No mask will have any bits
         in common with any other mask, or with any of the pixels.  By
         ORing together masks and pixels, C*(2^P) distinct pixels can
         be produced; all of these are allocated writable by the
         request.  For GrayScale or PseudoColor, each mask will have
         exactly one bit, and for DirectColor each will have exactly
         three bits.   If contiguous is True, then if all masks are
         ORed together, a single contiguous set of bits will be formed
         for GrayScale or PseudoColor, and three contiguous sets of
         bits (one within each pixel subfield) for DirectColor.  The
         RGB values of the allocated entries are undefined.

AllocColorPlanes

         cmap: COLORMAP
         colors, reds, greens, blues: CARD16
         contiguous: BOOL
     =>
         pixels: LISTofCARD32
         red-mask, green-mask, blue-mask: CARD32
         Errors; Colormap, Value, Alloc
         The number of colors must be positive, the reds, greens, and
         blues non-negative.  If C colors, R reds, G greens, and B
         blues are requested, then C pixels are returned, and the
         masks have R, G, and B bits set respectively.  If contiguous
         is True, then each mask will have a contiguous set of bits.
         No mask will have any bits in common with any other mask, or
         with any of the pixels.  For DirectColor, each mask will lie
         within the corresponding pixel subfield.  By ORing together
         subsets of masks with pixels, C*(2^(R+G+B)) distinct pixels
         can be produced; all of these are allocated by the request.
         The initial RGB values of the allocated entries are
         undefined. In the colormap there are only C*(2^R)
         independent red entries, C*(2^G) independent green entries,
         and C*(2^B) independent blue entries.  This is true even for
         PseudoColor.  When the colormap entry for a pixel value is
         changed using StoreColors or StoreNamedColor, the pixel is
         decomposed according to the masks and the corresponding
         independent entries are updated.

M.I.T. [Page 77] RFC 1013 June 1987

FreeColors

         cmap: COLORMAP
         pixels: LISTofCARD32
         plane-mask: CARD32
         Errors: Colormap, Access, Value
         The plane-mask should not have any bits in common with any of
         the pixels.  The set of all pixels is produced by ORing
         together subsets of plane-mask with the pixels.  The request
         frees all of these pixels. Note that freeing an individual
         pixel obtained from AllocColorPlanes may not actually allow
         it to be reused until all of its "related" pixels are also
         freed.
         All specified pixels that are allocated by the client in
         cmap are freed, even if one or more pixels produce an error.
         A Value error is generated if a specified pixel is not a
         valid index into cmap, and an Access error is generated if a
         specified pixel is not allocated by the client (i.e., is
         unallocated or is only allocated by another client). If more
         than one pixel is in error, which one is reported is
         arbitrary.

StoreColors

         cmap: COLORMAP
         items: LISTofCOLORITEM
         where
                 COLORITEM: [pixel: CARD32
                             do-red, do-green, do-blue: BOOL
                             red, green, blue: CARD16]
         Errors: Colormap, Access, Value
         Changes the colormap entries of the specified pixels.  The
         do-red, do-green, and do-blue fields indicate which
         components should actually be changed.  If the colormap is an
         installed  map for its screen, the changes are visible
         immediately.
         All specified pixels that are allocated writable in cmap (by
         any client) are changed, even if one or more pixels produce
         an error.  A Value error is generated if a specified pixel is
         not a valid index into cmap, and an Access error is generated
         if a specified pixel is unallocated or is allocated
         read-only.  If more than one pixel is in error, which one is
         reported is arbitrary.

StoreNamedColor

         cmap: COLORMAP

M.I.T. [Page 78] RFC 1013 June 1987

         pixel: CARD32
         name: STRING8
         do-red, do-green, do-blue: BOOL
         Errors: Colormap, Name, Access, Value
         Looks up the named color with respect to the screen
         associated with cmap, then does a StoreColors in cmap.  The
         name should use the ASCII encoding, and upper/lower case
         does not matter.

QueryColors

         cmap: COLORMAP
         pixels: LISTofCARD32
     =>
         colors: LISTofRGB
         where
                 RGB: [red, green, blue: CARD16]
         Errors: Colormap, Value
         Returns the color values stored in cmap for the specified
         pixels.  The values returned for an unallocated entry are
         undefined. A Value error is generated if a pixel is not a
         valid index into cmap.  If more than one pixel is in error,
         which one is reported is arbitrary.

LookupColor

         cmap: COLORMAP
         name: STRING8
     =>
         exact-red, exact-green, exact-blue: CARD16
         screen-red, screen-green, screen-blue: CARD16
         Errors: Colormap, Name
         Looks up the string name of a color with respect to the
         screen associated with cmap, and returns both the exact the
         color values and the closest values provided by the hardware.
         The name should use the ASCII encoding, and upper/lower
         case does not matter.

CreateCursor

         cid: CURSOR
         source: PIXMAP
         mask: PIXMAP or None
         fore-red, fore-green, fore-blue: CARD16
         back-red, back-green, back-blue: CARD16
         x, y: CARD16

M.I.T. [Page 79] RFC 1013 June 1987

         Errors: IDChoice, Bitmap, Match, Value, Alloc
         Creates a cursor and associates identifier cid with it.
         Foreground and background RGB values must be specified, even
         if the server only has a monochrome screen.  The foreground
         is used for the one bits in the source, and the background is
         used for the zero bits.  Both source and mask (if specified)
         must have depth one (else a Match error), but can have any
         root.  The mask pixmap defines the shape of the cursor; that
         is, the one bits in the mask define which source pixels will
         be displayed.  If no mask is given, all pixels of the source
         are displayed.  The mask, if present, must be the same size
         as source (else a Match error).  The x and y coordinates
         define the hotspot, relative to the source's origin, and must
         be a point within the source (else a Match error).
         The components of the cursor may be transformed arbitrarily
         to meet display limitations.
         The pixmaps can be freed immediately if no further explicit
         references to them are to be made.
         Subsequent drawing in the source or mask pixmap has an
         undefined effect on the cursor; the server might or might
         not make a copy of the pixmap.

CreateGlyphCursor

         cid: CURSOR
         source-font: FONT
         mask-font: FONT or None
         source-char, mask-char: CARD16
         fore-red, fore-green, fore-blue: CARD16
         back-red, back-green, back-blue: CARD16
         Errors: IDChoice, Font, Value, Alloc
         Similar to CreateCursor, but the source and mask bitmaps are
         obtained from the specified font glyphs.  The mask font and
         character are optional.  The origin of the source glyph
         defines the hotspot, and the mask is positioned such that
         the origins are coincident.  The source and mask need not
         have the same bounding box metrics.  If no mask is given,
         all pixels of the source are displayed.  Note that
         source-char and mask-char are CARD16 (not CHAR2B); for
         two-byte matrix fonts, the 16-bit value should be formed
         with byte1 in the most significant byte and byte2 in the
         least significant byte.

FreeCursor

         cursor: CURSOR

M.I.T. [Page 80] RFC 1013 June 1987

         Errors: Cursor
         Deletes the association between the resource id and the
         cursor.  The cursor storage will be freed when no other
         resource references it.

RecolorCursor

         cursor: CURSOR
         fore-red, fore-green, fore-blue: CARD16
         back-red, back-green, back-blue: CARD16
         Errors: Cursor
         Changes the color of a cursor.  If the cursor is being
         displayed on a screen, the change is visible immediately.

QueryBestSize

         class: {Cursor, Tile, Stipple}
         drawable: DRAWABLE
         width, height: CARD16
     =>
         width, height: CARD16
         Errors: Drawable, Value, Match
         Returns the "best" size that is "closest" to the argument
         size.  For Cursor, this is the largest size that can be
         fully displayed.  For Tile, this is the size that can be
         tiled "fastest".  For Stipple, this is the size that can
         be stippled "fastest".
         For Cursor, the drawable indicates the desired screen.  For
         Tile and Stipple, the drawable indicates screen, and also
         possibly window class and depth; an InputOnly window cannot
         be used as the drawable for Tile or Stipple (else a Match
         error).

QueryExtension

         name: STRING8
     =>
         present: BOOL
         major-opcode: CARD8
         first-event: CARD8
         first-error: CARD8
         Determines if the named extension is present.  If so, the
         major opcode for the extension is returned, if it has one,
         otherwise zero is returned.  Any minor opcode and the request
         formats are specific to the extension.  If the extension
         involves additional event types, the base event type code is
         returned, otherwise zero is returned.  The format of the

M.I.T. [Page 81] RFC 1013 June 1987

         events is specific to the extension.  If the extension
         involves additional error codes, the base error code is
         returned, otherwise zero is returned.  The format of
         additional data in the errors is specific to the extension.
         The extension name should be in the ASCII encoding, and
         upper/lower case matters.

ListExtensions

     =>
         names: LISTofSTRING8
         Returns a list of all extensions supported by the server.

SetKeyboardMapping

         map: LISTofCARD8
     =>
         status: {Success, Busy}
         Errors: Value
         Sets the mapping of the keyboard.  Elements of the list are
         indexed starting from one.  The list must be of length 255.
         The index is a "core" keycode, and the element of the list
         defines the "effective" keycode.
         A zero element disables a key, no elements can have values 1
         through 7, and no two elements (with index larger than 7) can
         have the same non-zero value.  If the keyboard does not
         really generate a given keycode, specifying a non-zero value
         for that core keycode has no effect.
         Elements 6 and 7 of the map must always be zero.  The first
         five elements are special:  they specify the keycodes (if
         any) that correspond to the Mod1 through Mod5 modifiers.
         Setting one of these entries to zero disables use of that
         modifier bit.  No two of the firstfive elements can have the
         same non-zero value.
         A server can impose restrictions on how keyboards get
         remapped, e.g., if certain keys do not generate up
         transitions in hardware.
         If any of the keys or modifiers to be altered are currently
         in the down state, the status reply is Busy and the mapping
         is not changed.

GetKeyboardMapping

     =>
         map: LISTofCARD8

M.I.T. [Page 82] RFC 1013 June 1987

         Errors: Value
         Returns the current mapping of the keyboard.  Elements of the
         list are indexed starting from one.  The length of the list
         is 255.
         The nominal mapping for a keyboard is almost the identity
         mapping, except that map[i]=0 for keycodes that have no
         corresponding physical key, and the first five entries
         indicate the keycodes (if any) corresponding to the Mod1
         through Mod5 modifier bits.

ChangeKeyboardControl

         value-mask: BITMASK
         value-list: LISTofVALUE
         Errors: Match Value
         Controls various aspects of the keyboard.  The value-mask and
         value-list specify which controls are to be changed.  The
         possible values are:
             key-click-percent: INT8
             bell-percent: INT8
             bell-pitch: INT16
             bell-duration: INT16
             led: CARD8
             led-mode: {On, Off}
             key: KEYCODE
             auto-repeat-mode: {On, Off, Default}
         Key-click-percent sets the volume for key clicks between 0
         (off) and 100 (loud) inclusive, if possible.  Setting to -1
         restores the default. Other negative values generate a Value
         error.
         Bell-percent sets the base volume for the bell between 0
         (off) and 100 (loud) inclusive, if possible.  Setting to -1
         restores the default. Other negative values generate a Value
         error.
         Bell-pitch sets the pitch (specified in Hz) of the bell, if
         possible. Setting to -1 restores the default.  Other
         negative values generate a Value error.
         Bell-duration sets the duration (specified in milliseconds)
         of the bell, if possible.  Setting to -1 restores the
         default.  Other negative values generate a Value error.
         If both led-mode and led are specified, then the state of
         that LED is changed, if possible.  If only led-mode is

M.I.T. [Page 83] RFC 1013 June 1987

         specified, then the state of all LEDs are changed, if
         possible.  At most 32 LEDs are supported, numbered from one.
         It is a Match error if an led is specified without an
         led-mode.
         If both auto-repeat-mode and key are specified, then the
         auto-repeat mode of that key is changed, if possible.  If
         only auto-repeat-mode is specified, then the global
         auto-repeat mode for the entire keyboard is changed, if
         possible, without affecting the per-key settings.  It is
         a Match error if a key is specified without an
         auto-repeat-mode.
         A bell generator connected with the console but not directly
         on the keyboard is treated as if it were part of the
         keyboard.
         The order in which controls are verified and altered is
         server dependent.  If an error is generated, a subset of the
         controls may have been altered.

GetKeyboardControl

     =>
         key-click-percent: CARD8
         bell-percent: CARD8
         bell-pitch: CARD16
         bell-duration: CARD16
         led-mask: CARD32
         global-auto-repeat: {On, Off}
         auto-repeats: LISTofCARD8
         Errors: Match
         Returns the current control values for the keyboard.  For the
         LEDs, the least significant bit of led-mask corresponds to
         LED one, and each one bit in led-mask indicates an LED that
         is lit. Auto-repeats is a bit vector; each one bit indicates
         that auto-repeat is enabled for the corresponding key.  The
         vector is represented as 32 bytes.  Byte N (from 0) contains
         the bits for keys 8N to 8N+7, with the least significant bit
         in the byte representing key 8N.

Bell

         percent: INT8
         Errors: Match, Value
         Rings the bell on the keyboard at the specified volume
         relative to the base volume for the keyboard, if possible.
         Percent, which can range from -100 to 100 inclusive, is added
         to the base volume, and the sum limited to the range 0 to 100

M.I.T. [Page 84] RFC 1013 June 1987

         inclusive.

SetPointerMapping

         map: LISTofCARD8
     =>
         status: {Success, Busy}
         Errors: Value
         Sets the mapping of the pointer.  Elements of the list are
         indexed starting from one.  The length of the list must be
         the same as GetPointerMapping would return.  The index is a
         "core" button number, and the element of the list defines
         the "effective" number.
         A zero element disables a button, and elements are not
         restricted in   value by the number of physical buttons, but
         no two elements can have the same non-zero value.
         If any of the buttons to be altered are currently in the
         down state,the status reply is Busy and the mapping is not
         changed.

GetPointerMapping

     =>
         map: LISTofCARD8
         Errors: Value
         Returns the current mapping of the pointer.  Elements of the
         list are indexed starting from one.  The length of the list
         indicates the number of physical buttons.
         The nominal mapping for a pointer is the identity mapping;
         map[i]=i.

ChangePointerControl

         do-acceleration, do-threshold: BOOL
         acceleration-numerator, acceleration-denominator: INT16
         threshold: INT16
         Errors: Match, Value
         Defines how the pointer moves.  The acceleration is a
         multiplier for movement, expressed as a fraction.  For
         example, specifying 3/1 means the pointer moves three times
         as fast as normal. The fraction may be rounded arbitrarily
         by the server.  Acceleration only takes effect if the
         pointer moves more than threshold pixels at once, and only
         applies to the amount beyond the threshold.  Setting a
         value to -1 restores the default. Other negative values

M.I.T. [Page 85] RFC 1013 June 1987

         generate a Value error, as does a zero value for
         acceleration-denominator.

GetPointerControl

     =>
         acceleration-numerator, acceleration-denominator: CARD16
         threshold: CARD16
         Errors: Match
         Returns the current acceleration and threshold for the
         pointer.

SetScreenSaver

         timeout, interval: INT16
         prefer-blanking: {Yes, No, Default}
         allow-exposures: {Yes, No, Default}
         Errors: Value
         Timeout and interval are specified in minutes; setting a
         value to -1 restores the default.  Other negative values
         generate a Value error. If the timeout value is zero,
         screen-saver is disabled.  If the timeout value is
         non-zero, screen-saver is enabled.  Once screen-saver
         is enabled, if no input from the keyboard or pointer is
         generated for timeout minutes, screen-saver is activated.
         For each screen, if blanking is preferred and the hardware
         supports video blanking, the screen will simply go blank.
         Otherwise, if either exposures are allowed or the screen
         can be regenerated without sending exposure events to
         clients, the screen is tiled with the root window
         background tile, randomly re-origined each interval
         minutes if the interval value is non-zero.  Otherwise, the
         state of the screen does not change and screen-saver is not
         activated.  Screen-saver is deactivated, and all screen
         states are restored, at the next keyboard or pointer input
         or at the next ForceScreenSaver with mode Reset.

GetScreenSaver

     =>
         timeout, interval: CARD16
         prefer-blanking: {Yes, No}
         allow-exposures: {Yes, No}
         Returns the current screen-saver control values.

ForceScreenSaver

         mode: {Activate, Reset}
         If the mode is Activate and screen-saver is currently

M.I.T. [Page 86] RFC 1013 June 1987

         deactivated, then screen-saver is activated (even if
         screen-saver has been disabled with a timeout value of zero).
         If the mode is Reset and screen-saver is currently enabled,
         then screen-saver is deactivated (if it was activated), and
         then the activation timer is reset to its initial state, as
         if device input had just been received.

ChangeHosts

         mode: {Insert, Delete}
         host: HOST
         Errors: Access, Value
         Adds or removes the specified host from the access control
         list.  When the access control mechanism is enabled and a
         host attempts to establish a connection to the server, the
         host must be in this list or the server will refuse the
         connection.
         The client must reside on the same host as the server, and/or
         have been granted permission in the initial authorization at
         connection setup.
         An initial access control list can be specified, typically
         by naming a file that the server reads at startup and reset.

ListHosts

     =>
         mode: {Enabled, Disabled}
         hosts: LISTofHOST
         Returns the hosts on the access control list, and whether use
         of the list at connection setup is currently enabled or
         disabled.
         Each HOST is padded to a multiple of four bytes.

ChangeAccessControl

         mode: {Enable, Disable}
         Errors: Value, Access
         Enables or disables the use of the access control list at
         connection setups.
         The client must reside on the same host as the server, and/or
         have been granted permission in the initial authorization at
         connection setup.

ChangeCloseDownMode

         mode: {Destroy, RetainPermanent, RetainTemporary}

M.I.T. [Page 87] RFC 1013 June 1987

         Errors: Value
         Defines what will happen to the client's resources at
         connection close. A connection starts in Destroy mode.  The
         meaning of the close-down mode is described in Section 11.

KillClient

         resource: CARD32 or AllTemporary
         Errors: Value
         If a valid resource is specified, forces a close-down of the
         client that created the resource.  If the client has already
         terminated in either RetainPermanent or RetainTemporary mode,
         all of the client's resources are destroyed (see Section 11).
         If AllTemporary is specified, then the resources of all
         clients that have terminated in RetainTemporary are
         destroyed.

NoOperation

         This request has no arguments and no results, but the request
         length field can be non-zero, allowing the request to be any
         multiple of 4 bytes in length.  The bytes contained in the
         request are uninterpreted by the server.
         This request can be used in its minimum 4 byte form as
         "padding" where necessary by client libraries that find it
         convenient to force requests to begin on 64-bit boundaries.

SECTION 11. CONNECTION CLOSE

What happens at connection close:

         All event selections made by the client are discarded.  If
         the client has the pointer actively grabbed, an
         UngrabPointer is performed.  If the client has the keyboard
         actively grabbed,  an UngrabKeyboard is performed.  All
         passive grabs by the client are eleased.  If the client has
         the server grabbed, and UngrabServer is performed.  If
         close-down mode (see ChangeCloseDownMode) is
         RetainPermanent or RetainTemporary, then all resources
         (including colormap entries)    allocated by the client are
         marked as "permanent" or "temporary", respectively (but
         this does not prevent other clients from explicitly
         destroying them).  If the mode is Destroy, then all of the
         client's resources are destroyed as described below.

What happens when a client's resources are destroyed:

         For each window in the client's save-set, if the window

M.I.T. [Page 88] RFC 1013 June 1987

         created by the client, that save-set window is reparented to
         the closest ancestor such that the save-set window is not an
         inferior of a window created by the client.  If the save-set
         window is unmaped, a MapWindow request is performed on it.
         After save-set processing, all windows created by the client
         are destroyed.  For each non-window resource created by the
         client, the appropriate Free request is performed.  All
         colors and colormap entries allocated by the client are
         freed.

What happens when the last connection to a server closes:

         A server goes through a cycle, of having no connections and
         having some connections.  At every transition to the state
         of having no connections, the server "resets" its state, as
         if it had just been started.  This starts by destroying all
         lingering resources from clients that have terminated in
         RetainPermanent or RetainTemporary mode.  It additionally
         includes deleting all but the predefined atom identifiers,
         deleting all properties on all root windows, resetting all
         device maps and attributes (key click, bell volume,
         acceleration), resetting the access control list, restoring
         the standard root tiles and cursors, restoring the default
         font path, and restoring the input focus to state
         PointerRoot.

SECTION 12. EVENTS

    When a button is pressed with the pointer in some window W, and
    no active pointer grab is in progress, then the ancestors if W are
    searched from the root down, looking for a passive grab to
    activate.  If no matching passive grab on the button exists, then
    an active grab is started automatically for the client receiving
    the event, and the last-pointer-grab time is set to the current
    server time. The effect is essentially equivalent to a GrabButton
    with arguments:
         event-window: the event window
         event-mask: the client's selected events on the event window
         pointer-mode and keyboard-mode: Asynchronous
         owner-events: True if the client has OwnerGrabButton selected
                 on the event window, else False
         confine-to: None
         cursor: None
 The grab is terminated automatically when all buttons are released.
 UngrabPointer and ChangeActiveGrab can both be used to modify the
 active grab.
 KeyPress
   and
 KeyRelease
   and

M.I.T. [Page 89] RFC 1013 June 1987

 ButtonPress
   and
 ButtonRelease
   and
 MotionNotify
         root, event: WINDOW
         child: WINDOW or None
         same-screen: BOOL
         root-x, root-y, event-x, event-y: INT16
         detail: <see below>
         state: SETofKEYBUTMASK
         time: TIMESTAMP
         Generated when a key or button changes state, or the pointer
         moves. The "source" of the event is the window the pointer
         is in.  The window with respect to which the event is
         normally reported is found by looking up the hierarchy
         (starting with  the source window) for the first window on
         which any client has selected interest in the event,
         provided no intervening window prohibits event generation by
         including the event type in its do-not-propagate-mask.  The
         actual window used for reporting can be modified by active
         grabs and the focus window. The window the event is reported
         with respect to is called the "event" window.
         Root is the root window of the "source" window, and root-x
         and root-y are the pointer coordinates relative to root's
         origin at the time of the event.  Event is the "event"
         window.  If the event window is on the same screen as root,
         then event-x and event-y are the pointer coordinates relative
         to the event window's origin; otherwise event-x and event-y
         are zero.  If the source window is an inferior of the event
         window, then child is set to the child of the event window
         that is an ancestor of the source window.  The state
         component gives the state of the buttons and modifier keys
         just before the event.  The detailcomponent varies with
         the event type:
             KeyPress, KeyRelease:               KEYCODE
             ButtonPress, ButtonRelease:         BUTTON
             MotionNotify:                       {Normal, Hint}
         MotionNotify events are only generated when the motion
         begins and ends in the window.  The granularity of motion
         events is not guaranteed, but a client selecting for motion
         events is guaranteed to get at least one event when the
         pointer moves and comes to rest.  Selecting PointerMotion
         receives events independent of the state of the pointer
         buttons.  By selecting some subset of Button[1-5]Motion
         instead, MotionNotify events will only be received when one
         or more of the specified buttons are pressed.  By selecting
         ButtonMotion, MotionNotify events will received only when at

M.I.T. [Page 90] RFC 1013 June 1987

         least one button is pressed.  The events are always of type
         MotionNotify, independent of the selection. If
         PointerMotionHint is selected, the server is free to send
         only one MotionNotify event (with detail Hint) to the client
         for the event window, until either the key or button state
         changes, or the pointer leaves the event window, or the
         client issues a QueryPointer or GetMotionEvents request.
 EnterNotify
   and
 LeaveNotify
         root, event: WINDOW
         child: WINDOW or None
         same-screen: BOOL
         root-x, root-y, event-x, event-y: INT16
         mode: {Normal, Grab, Ungrab}
         detail: {Ancestor, Virtual, Inferior, Nonlinear,
                  NonlinearVirtual}
         focus: BOOL
         state: SETofKEYBUTMASK
         time: TIMESTAMP
         If pointer motion causes the pointer to be in a different
         window than before, EnterNotify and LeaveNotify events are
         generated instead of a  MotionNotify event.  Only clients
         selecting EnterWindow on a window receive EnterNotify events,
         and only clients selection LeaveNotifyreceive LeaveNotify
         events.  The pointer position reported in the event is always
         the "final" position, not the "initial" position of the
         pointer.  In a LeaveNotify event, if a child of the event
         window contains the "initial" position of the pointer, then
         the child component is set to that child, otherwise it is
         None.  For an EnterNotify event, if a child of the event
         window contains the "final" pointer position, then the child
         component is set to that child, otherwise it is None.  If
         the the event window is the focus window or an inferior of
         the focus window, then focus is True, and otherwisefocus is
         False.
         Normal pointer motion events have mode Normal; pseudo-motion
         events when a grab actives have mode Grab, and pseudo-motion
         events when a grab deactivates have mode Ungrab.
     Normal events are generated as follows:
     When the pointer moves from window A to window B, and A is an
     inferior of B:
         LeaveNotify with detail Ancestor is generated on A
         LeaveNotify with detail Virtual is generated on each window
         between A and B exclusive (in that order)
         EnterNotify with detail Inferior is generated on B

M.I.T. [Page 91] RFC 1013 June 1987

     When the pointer moves from window A to window B, and B is an
     inferior of A:
         LeaveNotify with detail Inferior is generated on A
         EnterNotify with detail Virtual is generated on each window
                 between A and B exclusive (in that order)
         EnterNotify with detail Ancestor is generated on B
     When the pointer moves from window A to window B, with window C
     being their least common ancestor:
         LeaveNotify with detail Nonlinear is generated on A
         LeaveNotify with detail NonlinearVirtual is generated on each
                 window between A and C exclusive (in that order)
         EnterNotify with detail NonlinearVirtual is generated on each
                 window between C and B exclusive (in that order)
         EnterNotify with detail Nonlinear is generated on B
     When the pointer moves from window A to window B, on different
     screens:
         LeaveNotify with detail Nonlinear is generated on A
         LeaveNotify with detail NonlinearVirtual is generated on each
                 window above A up to and including its root (in
                 order)
         EnterNotify with detail NonlinearVirtual is generated on each
         window
                 from B's root down to but not including B (in order)
         EnterNotify with detail Nonlinear is generated on B
     When a pointer grab activates (but after any initial warp into a
     confine-to window), with G the grab-window for the grab and P the
     window the pointer is in:
         EnterNotify and LeaveNotify events with mode Grab are
         generated (as for Normal above) as if the pointer were to
         suddenly warp from its current position in P to some position
         in G.However,  the pointer does not warp, and the pointer
         position is used as  both the "initial"and "final" positions
         for the events.
     When a pointer grab deactivates, with G the grab-window for the
     grab and P the window the pointer is in:
         EnterNotify and LeaveNotify events with mode Ungrab are
         generated (as for Normal above) as if the pointer were to
         suddenly warp from from some position in G to its current
         position in P.  However, the pointer does not warp, and the
         current pointer position is used as both the "initial" and
         "final" positions for the events.
 FocusIn
   and
 FocusOut
         event: WINDOW

M.I.T. [Page 92] RFC 1013 June 1987

         mode: {Normal, WhileGrabbed, Grab, Ungrab}
         detail: {Ancestor, Virtual, Inferior, Nonlinear,
                  NonlinearVirtual, Pointer, PointerRoot, None}
         Generated when the input focus changes.  Reported to clients
         selecting FocusChange on the window.  Events generated by
         SetInputFocus when the keyboard is not grabbed have mode
         Normal; events generated by SetInputFocus when the keyboard
         is grabbed have mode WhileGrabbed; events generated when a
         keyboard grab actives have mode Grab, and events generated
         when a keyboard grab deactivates have mode Ungrab.
     Normal and WhileGrabbed events are generated as follows:
     When the focus moves from window A to window B, and A is an
     inferior of B, with the pointer in window P:
         FocusOut with detail Ancestor is generated on A
         FocusOut with detail Virtual is generated on each window
         between A and B exclusive (in that order)
         FocusIn with detail Inferior is generated on B
         If P is an inferior of B, but P is not A or an inferior of A
                 or an ancestor of A, FocusIn with detail Pointer is
                 generated on each window below B down to and
                 including P (in order)
     When the focus moves from window A to window B, and B is an
     inferior of A, with the pointer in window P:
         If P is an inferior of A, but P is not A or an inferior of B
                 or an ancestor of B, FocusOut with detail Pointer is
                 generated on each window from P up to but not
                 including A (in order)
         FocusOut with detail Inferior is generated on A
         FocusIn with detail Virtual is generated on each window
                 between A and B exclusive (in that order)
         FocusIn with detail Ancestor is generated on B
     When the focus moves from window A to window B, with window C
     being their least common ancestor, and with the pointer in
     window P:
         If P is an inferior of A, FocusOut with detail Pointer is
                 generated on each window from P up to but not
                 including A (in order)
         FocusOut with detail Nonlinear is generated on A
         FocusOut with detail NonlinearVirtual is generated on each
                 window between A and C exclusive (in that order)
         FocusIn with detail NonlinearVirtual is generated on each
                 window between C and B exclusive (in that order)
         FocusIn with detail Nonlinear is generated on B
         If P is an inferior of B, FocusIn with detail Pointer is
                 generated on each window below B down to and
                 including P (in order)

M.I.T. [Page 93] RFC 1013 June 1987

     When the focus moves from window A to window B, on different
     screens, with the pointer in window P:
         If P is an inferior of A, FocusOut with detail Pointer is
                 generated on each window from P up to but not
                 including A (in order)
         FocusOut with detail Nonlinear is generated on A
         FocusOut with detail NonlinearVirtual is generated on each
                 window above A up to and including its root (in
                 order)
         FocusIn with detail NonlinearVirtual is generated on each
                 window from B's root down to but not including B
                 (in order)
         FocusIn with detail Nonlinear is generated on B
         If P is an inferior of B, FocusIn with detail Pointer is
                 generated on each window below B down to and
                 including P (in order)
     When the focus moves from window A to PointerRoot (or None)
         If P is an inferior of A, FocusOut with detail Pointer is
                 generated on each window from P up to but not
                 including A (in order)
         FocusOut with detail Nonlinear is generated on A
         FocusOut with detail NonlinearVirtual is generated on each
                 window above A up to and including its root (in
                 order)
         FocusIn with detail PointerRoot (or None) is generated on
                 all root windows
     When the focus moves from PointerRoot (or None) to window A:
         FocusOut with detail PointerRoot (or None) is generated on
                 all root windows
         FocusIn with detail NonlinearVirtual is generated on each
                 window from A's root down to but not including A
                 (in order)
         FocusIn with detail Nonlinear is generated on A
         If P is an inferior of A, FocusIn with detail Pointer is
                 generated on each window below A down to and
                 including P (in order)
     When the focus moves from PointerRoot to None (or vice versa):
         FocusOut with detail PointerRoot (or None) is generated on
                 all root windows
         FocusIn with detail None (or PointerRoot) is generated on
                 all root windows
     When a keyboard grab activates, with G the grab-window for the
     grab and F the current focus:
         FocusIn and FocusOut events with mode Grab are generated (as
         for Normal above) as if the focus were to change from F to G

M.I.T. [Page 94] RFC 1013 June 1987

     When a keyboard grab deactivates, with G the grab-window for the
     grab and F the current focus:
         FocusIn and FocusOut events with mode Ungrab are generated
         (as for Normal above) as if the focus were to change from G
         to F
 KeymapNotify
         keys: LISTofCARD8
         The value is a bit vector, as described in QueryKeymap.
         Reported to clients selecting KeymapState on a window.
         Generated immediately after every EnterNotify and FocusIn.
 Expose
         window: WINDOW
         x, y, width, height: CARD16
         last-in-series: BOOL
         Reported to clients selecting Exposure on the window.
         Possibly generated when a region of the window becomes
         viewable, but might only be generated when a region becomes
         visible. All of the regions exposed by a given "action" are
         guaranteed to be reported contiguously; if last-in-series is
         False then another exposure follows.
         The x and y coordinates are relative to drawable's origin,
         and  specify the upper left corner of a rectangule.  The
         width and height specify the extent of the rectangle.
         Expose events are never generated on InputOnly windows.

GraphicsExposure

         drawable: DRAWABLE
         x, y, width, height: CARD16
         last-in-series: BOOL
         major-opcode: CARD8
         minor-opcode: CARD16
         Reported to clients selecting graphics-exposures in a
         graphics context. Generated when a destination region could
         not be computed due to an obscured or out-of-bounds source
         region.  All of the regions exposed by a given graphics
         request are guaranteed to be reported contiguously; if
         last-in-series is False then another exposure follows.
         The x and y coordinates are relative to drawable's origin,
         and specify the upper left corner of a rectangule.  The width
         and height specify the extent of the rectangle.
         The major and minor opcodes identify the graphics request
         used.  For the core protocol, major-opcode is always

M.I.T. [Page 95] RFC 1013 June 1987

         CopyArea or CopyPlane and minor-opcode is always zero.

NoExposure

         drawable: DRAWABLE
         major-opcode: CARD8
         minor-opcode: CARD16
         Reported to clients selecting graphics-exposures in a
         graphics context. Generated when a graphics request that
         might produce GraphicsExposure events does not produce any.
         The drawable specifies the destination used for the
         graphics request.
         The major and minor opcodes identify the graphics request
         used.  For the core protocol, major-opcode is always CopyArea
         or CopyPlane and minor-opcode is always zero.

VisibilityNotify

         window: WINDOW
         state: {Unobscured, PartiallyObscured, FullyObscured}
         Reported to clients selecting VisibilityChange on the
         window.  In the following, the state of the window is
         calculated ignoring all of the window's subwindows.  When
         a window changes state from partially or fully obscured or
         not viewable to viewable and completely unobscured, an
         event with Unobscured  is generated.  When a window changes
         state from a) viewable and completely unobscured or b) not
         viewable, to viewable and partially obscured, an event with
         PartiallyObscured is generated.  When a window changes state
         from a) viewable and completely unobscured or b) viewable and
         partially obscured or c) not viewable, to viewable and fully
         obscured, an event with FullyObscured is generated.
         VisibilityNotify events are never generated on InputOnly
         windows.

CreateNotify

         parent, window: WINDOW
         x, y: INT16
         width, height, border-width: CARD16
         override-redirect: BOOL
         Reported to clients selecting SubstructureNotify on the
         parent. Generated when the window is created.  The arguments
         are as in the CreateWindow request.

M.I.T. [Page 96] RFC 1013 June 1987

DestroyNotify

         event, window: WINDOW
         Reported to clients selecting StructureNotify on the window,
         and to clients selecting SubstructureNotify on the parent.
         Generated when the window is destroyed.  "Event" is the
         window on which the event was   generated, and "window" is
         the window that is destroyed.

UnmapNotify

         event, window: WINDOW
         from-configure: BOOL
         Reported to clients selecting StructureNotify on the window,
         and to clients selecting SubstructureNotify on the parent.
         Generated when the window changes state from mapped to
         unmapped. "Event" is the window on which the event was
         generated, and "window" is the window that is unmapped.  The
         from-configure flag is True if the event was generated  as a
         result of the window's parent being resized when the window
         itself had a win-gravity of Unmap.

MapNotify

         event, window: WINDOW
         override-redirect: BOOL
         Reported to clients selecting StructureNotify on the window,
         and to clients selecting SubstructureNotify on the parent.
         Generated when the window changes state from unmapped to
         mapped. "Event" is the window on which the event was
         generated, and "window" is the window that is mapped.  The
         override-redirect flag is from the window's attribute.

MapRequest

         parent, window: WINDOW
         Reported to the client selecting SubstructureRedirect on the
         parent. Generated when a MapWindow request is issued on an
         unmapped window with an override-redirect attribute of False.

ReparentNotify

         event, window, parent: WINDOW
         x, y: INT16
         override-redirect: BOOL
         Reported to clients selecting SubstructureNotify on either
         the old or the new parent, and to clients selecting
         StructureNotify on the window.  Generated when the window
         is reparented.  "Event" is the window on which the event
         was generated, "window" is the window that has been
         re-rooted, and "parent" specifies the new parent.  The x

M.I.T. [Page 97] RFC 1013 June 1987

         and y coordinates are relative to the new parent's origin,
         and specify the position of the upper left outer corner of
         the window.  The override-redirect flag is from the
         window's attribute.

ConfigureNotify

         event, window: WINDOW
         x, y: INT16
         width, height, border-width: CARD16
         above-sibling: WINDOW or None
         override-redirect: BOOL
         Reported to clients selecting StructureNotify on the window,
         and to clients selecting SubstructureNotify on the parent.
         Generated when a ConfigureWindow request actually changes the
         state of the window. "Event" is the window on which the event
         was generated, and "window" is the window that is changed.
         If above-sibling is None, then the window is on the bottom of
         the stack with respect to siblings; otherwise, the window is
         immediately on top of the specified sibling.  The
         override-redirect flag is from the window's attribute.

GravityNotify

         event, window: WINDOW
         x, y: INT16
         Reported to clients selecting SubstructureNotify on the
         parent, and to clients selecting StructureNotify on the
         window.  Generated when a window is moved because of a
         change in size of the parent.  "Event" is the window on
         which the event was generated, and "window" is the
         window that is moved.

ResizeRequest

         window: WINDOW
         width, height: CARD16
         Reported to the client selecting ResizeRedirect on the
         window. Generated when a ConfigureWindow request by some
         other client on the window attempts to change the size of the
         window. The width and height are the inside size, not
         including the border.

ConfigureRequest

         parent, window: WINDOW
         x, y: INT16
         width, height, border-width: CARD16
         above-sibling: WINDOW or None
         Reported to the client selecting SubstructureRedirect on the
         parent. Generated when a ConfigureWindow request is issued on

M.I.T. [Page 98] RFC 1013 June 1987

         the window by some other client.  The geometry is as derived
         from the request.  The above-sibling is the sibling the
         window should be placed directly on top of; if None, then the
         window should be placed on the bottom.

CirculateNotify

         event, window: WINDOW
         place: {Top, Bottom}
         Reported to clients selecting StructureNotify on the window,
         and to clients selecting SubstructureNotify on the parent.
         Generated when the window is actually restacked from a
         CirculateWindow request.  "Event" is the window on which the
         event was generated, and "window" is the window that is
         restacked.  If place is Top, the window is now on top of all
         siblings; otherwise it is below all siblings.

CirculateRequest

         parent, window: WINDOW
         place: {Top, Bottom}
         Reported to the client selecting SubstructureRedirect on the
         parent. Generated when a CirculateWindow request is issued on
         the parent and a window actually needs to be restacked.  The
         window specifies the window to be restacked, and place
         specifies what the new position in the stacking order should
         be.

PropertyNotify

         window: WINDOW
         atom: ATOM
         state: {NewValue, Deleted}
         time: TIMESTAMP
         Reported to clients selecting PropertyChange on the window.
         Generated when a property of the window is changed.  The
         timestamp indicates the server time when the property was
         changed.

SelectionClear

         owner: WINDOW
         selection: ATOM
         time: TIMESTAMP
         Reported to the current owner of a selection.  Generated on
         the window losing ownership when a new owner is being
         defined.  The timestamp is the last-change time recorded for
         the selection.

SelectionRequest

         owner: WINDOW

M.I.T. [Page 99] RFC 1013 June 1987

         selection: ATOM
         target: ATOM
         property: ATOM or None
         requestor: WINDOW
         time: TIMESTAMP or CurrentTime
         Reported to the owner of a selection.  Generated when a
         client issues a ConvertSelection request. The arguments are
         as in the request.
         The owner should convert the selection based on the specified
         target type.  If a property is specified, the owner should
         store the result as that property on the requestor window,
         and then send a SelectionNotify event to the requestor using
         SendEvent.  If the selection cannot be converted as
         requested, the owner should send a SelectionNotify with the
         property set to None.

SelectionNotify

         requestor: WINDOW
         selection, target: ATOM
         property: ATOM or None
         time: TIMESTAMP or CurrentTime
         This event is only generated by clients using SendEvent.  The
         owner of a selection should send this event to a requestor
         when a selection has been converted and stored as a property,
         or when a selection conversion could not be performed
         (indicated with property None).

ColormapNotify

         window: WINDOW
         colormap: COLORMAP or None
         new: BOOL
         state: {Installed, Uninstalled}
         Reported to clients selecting ColormapChange on the window.
         Generated with value True for new when the colormap attribute
         of the window is changed.  Generated with value False for new
         when the colormap of a window is installed or uninstalled. In
         either case, state indicates whether the colormap is
         currently installed.

ClientMessage

         window: WINDOW
         type: ATOM
         format: {8, 16, 32}
         data: LISTofINT8 or LISTofINT16 or LISTofINT32
         This event is only generated by clients using SendEvent.  The
         type specifies how the data is to be interpreted by the

M.I.T. [Page 100] RFC 1013 June 1987

         receiving client; the server places no interpretation on the
         type or the data.  The format specifies whether the data
         should be viewed as a list of 8-bit, 16-bit, or 32-bit
         quantities, so that the server can correctly byte-swap as
         necessary. The data always consists of either 20 8-bit values
         or 10 16-bit values or 5 32-bit values, although particular
         message types might not make use of all of these values.

SECTION 13. FLOW CONTROL AND CONCURRENCY

  Whenever the server is writing to a given connection, it is
  permissible for the server to stop reading from that connection (but
  if the writing would block it must continue to service other
  connections).  The server is not required to buffer more than a
  single request per connection at one time.  For a given connection
  to the server, a client can block while reading from the connection,
  but should undertake to read (events and errors) when writing would
  block. Failure on the part of a client to obey this rule could
  result in a deadlocked connection, although deadlock is probably
  unlikely unless the transport layer has very little buffering, or
  unless the client attempts to send large numbers of requests without
  ever reading replies or checking for errors and events.
  If a server is implemented with internal concurrency, the overall
  effect must be as if individual requests are executed to completion
  in some serial order, and that requests from a given connection are
  executed in delivery order (i.e., the total execution order is a
  shuffle of the individual streams).  The "execution" of a request
  includes validating all arguments, collecting all data for any
  reply, and generating (and queueing) all required events, but does
  not include the actual transmission of the reply and the events.
  In addition, the   effect of any other "cause" (e.g., activation of
  a grab, pointer motion) that can generate multiple events must
  effectively generate (and queue) all required events indivisibly
  with respect to all other causes and requests.

M.I.T. [Page 101]

/data/webs/external/dokuwiki/data/pages/rfc/rfc1013.txt · Last modified: 1987/06/25 18:45 by 127.0.0.1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki