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:
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, RFC2119, March 1997.
[MIME1] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC2045, 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
Copyright (C) The Internet Society (2001). All Rights Reserved.
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