    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].

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    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

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    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.

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    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>

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    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

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    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.

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