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].

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

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.

   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>

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

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
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   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.