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.
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].
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
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.
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.
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
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.
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>
Collins Informational [Page 4]
RFC 3073 PFR March 2001
[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
Copyright (C) The Internet Society (2001). All Rights Reserved.
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Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
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