HTTP/1.1 200 OK Date: Tue, 09 Apr 2002 01:41:08 GMT Server: Apache/1.3.20 (Unix) Last-Modified: Tue, 07 Apr 1998 05:45:34 GMT ETag: "2e7a4a-2484-3529bd7e" Accept-Ranges: bytes Content-Length: 9348 Connection: close Content-Type: text/plain INTERNET-DRAFT Larry Masinter draft-ietf-conneg-media-features-00.txt Koen Holtman Andy Mutz Dan Wing expires in 6 months March 11, 1998 Media Features for Display, Print, and Fax Status of this memo This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." To learn the current status of any Internet-Draft, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). Copyright (C) The Internet Society (1997). All Rights Reserved. Abstract This specification defines some common media features for describing image resolution, size, color, and image representation methods that are common to web browsing, printing, and facsimile applications. These features are registered for use within the framework of [REG]. Introduction This work was originally motivated by the requirements from web browsers to send the browser's display characteristics to the web server to allow the server to choose an appropriate representation. This specification defines some common media features [REG] by which a recipient may inform a sender as to the characteristics of its message handling. The sender may then provide the variant of the message that is most suitable for the recipient. Different variants would typically be higher or lower resolution images (for example) as appropriate. In the case of a sending to a printer, the result would be higher quality output. In the case of a small screen device (cellphone, portable digital assistant), the result would be faster transmission. Media features may be used in many different protocol situations. Those defined in this specification can indicate the display or printer dimensions (in pixels), display resolution (in pixels/inch), color capability and bit-depth, display media type, or . The physical dimensions of the display can be inferred from the display size and display resolution. In the case of paper output, the paper size may be expressed as a token from a list of certain standard paper sizes. These are presented formally in the Notation section. pix-x (integer) pix-y (integer) These features indicate the display size of the recipient for display or print, measured in pixels; they indicate horizontal (pix-x) and vertical (pix-y) dimensions. res (integer) This feature indicates a resolution that the recipient can display or print without loss, measured in pixels per inch. Certain resources such as images may have similar total pixel size but differing data size and quality depending on degree of compression. Note: While English units are not universal, it is preferable to avoid multiple unit definitions. Equivalent metric definitions are available. res-x (integer) res-y (integer) In cases where non-square aspect ratio is supported, these features can be used for specifying horizontal (res-x) and vertical (res-y) resolution capabilities. UA-media (token) This feature indicates the recipients device media, indicated with an simple token. All (except for "screen" and "screen-paged") are taken from the Printer MIB MediaType set defined in RFC 1759 [PRINTMIB]. Other tokens may be registered and used as needed. They are defined as: screen A refreshable display screen-paged a refreshable display which cannot scroll stationery Separately cut sheets of an opaque material transparency Separately cut sheets of a transparent material envelope Envelopes that can be used for conventional mailing purposes envelope-plain Envelopes that are not preprinted and have no windows envelope-window Envelopes that have windows for addressing purposes continuous-long Continuously connected sheets of an opaque material connected along the long edge continuous-short Continuously connected sheets of an opaque material connected along the short edge tab-stock Media with tabs multi-part-form Form medium composed of multiple layers not pre-attached to one another; each sheet may be drawn separately from an input source labels Label stock multi-layer Form medium composed of multiple layers which are pre-attached to one another; e.g., for use with impact printers" papersize (token) For stationery, it is often useful to have information about the size of display used. While it is more precise and predictable to use absolute resolution and pixel sizes, some applications find it useful to provide paper size in lieu of or in addition to this information. Paper sizes names and definitions are taken from RFC 1759 [PRINTMIB], which in turn imported the definitions from ISO/IEC 10175: Examples of paper size tokens, with names from [MIB], are: na-letter: 8.5x11.0 inches iso-A4: 210x297 mm iso-B4: 250x353 mm iso-A3: 297x420 mm na-legal: 8.5x14 inches color (integer) grey (integer) The color capabilities of the recipient are indicated with feature tag and a parameter describing the number of color channel bits available. Values of n are typically (but not limited to) 2, 8, or 24. For example: grey=8 indicates a display capable of representing an image in 256 levels of a single color, while color=8 indicates a display capable of representing an image with a palette of 256 colors. tiff (token) The ability to process Internet Media type image/tiff application profiles, defined by [TIFF]. If additional feature tags are given for describing resolution, media sizes and so forth, they are added to those application profiles. This feature is important for Internet Fax [FPIM], [MDN]. Examples of use of features The following examples of feature comparison show how these features can be used to describe various capabilities: pix-x<=1024, pix-y<=768 indicates a 1024x768 display res<=72 indicates a 72 dpi display UA-media=stationery indicates the display is a cut sheet of opaque material, such as paper. papersize=iso-a4 indicates the display size is 210x297mm. color<=24 indicates the display supports 24-bit (8-bit/channel) color. papersize=na-letter,res-x={204,200,300},res-y={98,196,100},tiff=F might be used for a fax machine with 'simple mode'. papersize=na-letter,res-x<=400,res-y<=400,tiff={M,J} might be used for a fax machine with enhanced capabilities. Acknowledgments This document is based on a previous draft co-authored with Lou Montoulli. It had benefited from the comments of Graham Klyne, Ho John Lee, Brian Behlendorf, and Jeff Mogul. References [MIB] R. Smith, F. Wright, T. Hastings, S. Zilles, J. Gyllenskog. "Printer MIB." RFC 1759, March 1995. [REG] K. Holtman, A. Mutz. "Feature Tag Registration Procedures", draft-ietf-conneg-feature-reg-00.txt, March 1998. [MDN] D. Wing, L. Masinter, "Using Message Disposition Notifications to Indicate Capabilities", draft-ietf-fax-mdn-features-01.txt, March 1998. [TIFF] Parsons, G., Rafferty, J., and S. Zilles, "Tag Image File Format (TIFF) - image/tiff MIME Sub-type Registration", Work in Progress, Internet Draft, draft-ietf-fax-tiff-reg-XX.txt. [FPIM] L. Masinter, D. Wing, "Extended Mode of Facsimile Using Internet Mail", draft-ietf-fax-fpim-02.txt, March, 1998. Author's Addresses Larry Masinter Xerox Palo Alto Research Center 3333 Coyote Hill Road Palo Alto CA 94304 Fax +1 415 812 4333 Email: masinter@parc.xerox.com Dan Wing Cisco Systems, Inc. 101 Cooper Street Santa Cruz, CA 95060 USA Phone: +1 408 457 5200 Fax: +1 408 457 5208 EMail: dwing@cisco.com Andrew H. Mutz Hewlett-Packard Company 1501 Page Mill Road 3U-3 Palo Alto CA 94304, USA Fax +1 415 857 4691 Email: mutz@hpl.hp.com Koen Holtman Technische Universiteit Eindhoven Postbus 513 Kamer HG 6.57 5600 MB Eindhoven (The Netherlands) Email: koen@win.tue.nl