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Network Working Group J. Collins Request for Comments: 3073 Bitstream Inc. Category: Informational March 2001

       Portable Font Resource (PFR) - application/font-tdpfr
                     MIME Sub-type Registration

Status of this Memo

 This memo provides information for the Internet community.  It does
 not specify an Internet standard of any kind.  Distribution of this
 memo is unlimited.

Copyright Notice

 Copyright (C) The Internet Society (2001).  All Rights Reserved.

Abstract

 This document describes the registration of the Multipurpose Internet
 Mail Extensions (MIME) sub-type application/font-tdpfr.  The encoding
 is defined by the PFR Specification.

 A Portable Font Resource (PFR) contains a set of glyph shapes.  Each
 glyph shape is associated with a character code.  The PFR format is
 designed to be both compact and platform-independent.  It is intended
 to facilitate accurate rendering of fonts in all environments whether
 or not they have the required fonts already installed.

1. Conventions used in this document

 The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
 document are to be interpreted as described in RFC-2119 [REQ].

2. Overview

 This document describes the registration of the MIME sub-type
 application/font-tdpfr.  The encoding is defined by [PFR].

Collins Informational [Page 1] RFC 3073 PFR March 2001

3. PFR Definition

 PFR (Portable Font Resource) is defined by Bitstream Inc. in [PFR].
 The documentation can be obtained from Bitstream at:

 Bitstream Inc.
 215 First Street
 Cambridge MA 02142 U.S.A.
 Phone: +1 617 497 6222
 Fax:   +1 617 868 0784

 A copy of this specification can also be found at:

 http://www.bitstream.com/pfrspec/index.html

 While a brief scope and feature description is provided in this
 section as background information, the reader is directed to the
 original PFR specification [PFR] to obtain complete feature and
 technical details.

3.1 PFR Scope

 A PFR contains a set of glyph shapes.  Each glyph shape is associated
 with a character code.  The PFR format is designed to be both compact
 and platform-independent.  It is intended to facilitate accurate
 rendering of fonts in environments whether or not they have the
 required fonts already installed.

 The glyph shape definitions in a PFR are resolution-independent.
 This allows glyph definitions to be displayed or printed on devices
 with a wide variety of resolutions.  It also allows glyphs to be
 rendered at any size.

3.2 PFR Features

 Some of the features of the PFR format are:

Compact representation of glyph shapes

Independent of byte order and operating system

Independent of output device resolution

Fully scalable to any glyph size

Optional inclusion of bitmap glyph images

Adopted as the font standard by DAVIC, DVB, and DTG

Collins Informational [Page 2] RFC 3073 PFR March 2001

4. Comments

 This document is submitted by J. Collins, Bitstream Inc.  All
 comments should be directed to <jcollins@bitstream.com>.

5. MIME Definition

 The PFR media type has been previously registered with IANA as
 application/vnd.truedoc.  In view of its subsequent widespread
 adoption as a standard font format by multiple standards bodies who
 have relationships with the Internet community, Bitstream has been
 asked to re-register this media type within the IETF tree.

6. IANA Registration

 To: ietf-types@iana.org
 Subject: Registration of Standard MIME Media type
     application/font-tdpfr

 MIME media type name: application

 MIME subtype name: font-tdpfr

 Required parameters: none

 Optional parameters: none

 Encoding considerations: Binary or base 64 required

 Security considerations:

    PFR uses a structure that can store glyph image data and encoding
    arrays.  The fields defined in the PFR specification are of a
    descriptive nature and provide information that is useful to
    facilitate viewing and rendering of glyph images by a recipient.
    As such, the fields currently defined in the PFR specification do
    not in themselves create additional security risks, since the
    fields are not used to induce any particular behavior by the
    recipient application.

    PFR has an extensible structure, so that it is theoretically
    possible that fields could be defined in the future which could be
    used to induce particular actions on the part of the recipient,
    thus presenting additional security risks, but this type of
    capability is not supported in the referenced PFR specification.
    Indeed, the definition of fields that would include such
    processing instructions is inconsistent with the goals and spirit
    of the PFR specification.

Collins Informational [Page 3] RFC 3073 PFR March 2001

 Interoperability considerations: none

 Published specification:

    The specification for this content type is available on request
    from:

    Bitstream Inc.
    215 First Street
    Cambridge MA 02142 U.S.A.
    Phone: +1 617 497 6222
    Fax:   +1 617 868 0784

 A copy of this specification can also be found at:

    http://www.bitstream.com/pfrspec/index.html

 Applications which use this media type:

    Netscape Communicator, Bitstream WebFont Maker, Hexmac Typograph

 Additional information: None

 Magic number(s): 50 46 52 30 hex

 File extension(s): PFR

 Macintosh File Type Code(s): Creator: 'b$pw' Type: 'PFR '

 Person to contact for further information:

    "John Collins" <jcollins@bitstream.com>

 Intended usage: common

 Author/Change controller:

    "John Collins" <jcollins@bitstream.com>

Collins Informational [Page 4] RFC 3073 PFR March 2001

7. References

 [REQ]   Bradner, S., "Key words for use in RFCs to Indicate
         Requirement Levels", BCP 14, RFC 2119, March 1997.

 [MIME1] Freed, N. and N. Borenstein,  "Multipurpose Internet Mail
         Extensions (MIME) Part One: Format of Internet Message
         Bodies", RFC 2045, November 1996.

 [MIME4] Freed, N. and N. Borenstein,  "Multipurpose Internet Mail
         Extensions (MIME) Part Four: Registration Procedures", RFC
         2048, November 1996.

 [PFR]   Bitstream Inc. "PFR Specification",
         http://www.bitstream.com/pfrspec/index.html

8. Author's Address

 John Collins
 Bitstream Inc.
 215 First Street
 Cambridge, MA 02142

 Phone: +1 617 520 8401
 Fax:   +1 617 868 0784
 EMail: jcollins@bitstream.com

Collins Informational [Page 5] RFC 3073 PFR March 2001

9. Full Copyright Statement

 Copyright (C) The Internet Society (2001).  All Rights Reserved.

 This document and translations of it may be copied and furnished to
 others, and derivative works that comment on or otherwise explain it
 or assist in its implementation may be prepared, copied, published
 and distributed, in whole or in part, without restriction of any
 kind, provided that the above copyright notice and this paragraph are
 included on all such copies and derivative works.  However, this
 document itself may not be modified in any way, such as by removing
 the copyright notice or references to the Internet Society or other
 Internet organizations, except as needed for the purpose of
 developing Internet standards in which case the procedures for
 copyrights defined in the Internet Standards process must be
 followed, or as required to translate it into languages other than
 English.

 The limited permissions granted above are perpetual and will not be
 revoked by the Internet Society or its successors or assigns.

 This document and the information contained herein is provided on an
 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

 Funding for the RFC Editor function is currently provided by the
 Internet Society.

Collins Informational [Page 6]