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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]