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author | Thomas Voss <mail@thomasvoss.com> | 2024-11-27 20:54:24 +0100 |
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committer | Thomas Voss <mail@thomasvoss.com> | 2024-11-27 20:54:24 +0100 |
commit | 4bfd864f10b68b71482b35c818559068ef8d5797 (patch) | |
tree | e3989f47a7994642eb325063d46e8f08ffa681dc /doc/rfc/rfc2534.txt | |
parent | ea76e11061bda059ae9f9ad130a9895cc85607db (diff) |
doc: Add RFC documents
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diff --git a/doc/rfc/rfc2534.txt b/doc/rfc/rfc2534.txt new file mode 100644 index 0000000..41cdf64 --- /dev/null +++ b/doc/rfc/rfc2534.txt @@ -0,0 +1,507 @@ + + + + + + +Network Working Group L. Masinter +Request for Comments: 2534 Xerox Corporation +Category: Standards Track D. Wing + Cisco Systems, Inc. + A. Mutz + Jutvision Corporation + K. Holtman + TUE + March 1999 + + + Media Features for Display, Print, and Fax + +Status of this Memo + + This document specifies an Internet standards track protocol for the + Internet community, and requests discussion and suggestions for + improvements. Please refer to the current edition of the "Internet + Official Protocol Standards" (STD 1) for the standardization state + and status of this protocol. Distribution of this memo is unlimited. + +Copyright Notice + + Copyright (C) The Internet Society (1999). 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]. + +1. 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. + + + +Masinter, et al. Standards Track [Page 1] + +RFC 2534 Media Features for Display, Print, and Fax March 1999 + + + Media features may be used in many different protocol situations. + Those defined in this specification can indicate the display or + printer dimensions, resolution, color capability. The physical + dimensions of a display may 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 standard paper sizes. These + are presented formally in the Notation section. + +2. Media Feature Registrations + + This section defines several media features, using the form specified + in [REG]. + +2.1 Image Size + + - Media Feature tag name(s): + + pix-x + pix-y + + - ASN.1 identifier associated with this feature tag: + + 1.3.6.1.8.1.1 + 1.3.6.1.8.1.2 + + - Summary of the media features indicated by this feature tag: + + 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. + + - Values appropriate for use with this feature tag: + + Signed Integer + + - The feature tag is intended primarily for use in the following + applications, protocols, services, or negotiation mechanisms: + + Display and print applications where different media choices will + be made depending on the size of the recipient device. For + example, a web application for use on a 240x480 display might use + different HTML pages than one intended for use on a 1024x768 + display. + + + + + + + + +Masinter, et al. Standards Track [Page 2] + +RFC 2534 Media Features for Display, Print, and Fax March 1999 + + +2.2 Resolution + + - Media Feature tag name: + + dpi + + - ASN.1 identifier associated with this feature tag: + + 1.3.6.1.8.1.3 + + - Summary of the media features indicated by this feature tag: + + This feature indicates the resolution that the recipient can + display or print without loss, measured in pixels per inch. + Typically resolution capability is represented as dots-per-inch + rather than in SI units [SI]. Values for dpi may be expressed as a + rational to accomodate resolution of SI-based devices; for example + dpi=19558/100 can be used to represent a resolution of 77 dots per + centimeter. + + - Values appropriate for use with this feature tag: + + Rational + + - The feature tag is intended primarily for use in the following + applications, protocols, services, or negotiation mechanisms: + + Printing and fax applications typically choose representations of + a transmitted document depending on the resolution of the + recipient rather than pixel size. + + - Examples of typical use: + + Choosing a version of a printable document to send to a printer. + + - Considerations particular to use in individual applications, + protocols, services, or negotiation mechanisms: + + Software applications are typically unaware of the resolution of + the display. Note that there exist devices with different + resolution in different directions, i.e., individual pixels are + not square. However, this feature only encompasses the + uniform resolution. + + + + + + + + +Masinter, et al. Standards Track [Page 3] + +RFC 2534 Media Features for Display, Print, and Fax March 1999 + + +2.3 Registration of 'ua-media' + + - Media Feature tag name(s): + + ua-media + + - ASN.1 identifier associated with this feature tag: + + 1.3.6.1.8.1.4 + + - Summary of the media features indicated by this feature tag: + + This feature indicates the recipients device media, indicated with + an simple token. + + - Values appropriate for use with this feature tag: + + Token with an equality relationship. Values include: + + 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 + continuous Continuously connected sheets of an opaque + material + + - The feature tag is intended primarily for use in the following + applications, protocols, services, or negotiation mechanisms: + + Most of the feature values are useful for printing applications, or + to distinguish printing from display. + + - Examples of typical use: + + This might typically be used for selecting between a rendition that + is intended to be printed and one that is intended to be displayed. + + - Considerations particular to use in individual applications, + protocols, services, or negotiation mechanisms: + + Other media values were not included because their utility seemed + relative. + + + + + +Masinter, et al. Standards Track [Page 4] + +RFC 2534 Media Features for Display, Print, and Fax March 1999 + + + - Interoperability considerations: + + Interoperability with the Internet Print Protocol means that some + additional feature values may need to be registered. + +2.4 Paper Size + + - Media Feature tag name(s): + + paper-size + + - ASN.1 identifier associated with this feature tag: + + 1.3.6.1.8.1.5 + + - Summary of the media features indicated by this feature tag: + + 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 addition to this information. Note + that not all of the paper may have a printable area. + + - Values appropriate for use with this feature tag: + + Token with an equality relationship. Typical values include: + + letter 8.5x11.0 inches + a4 210x297 mm + b4 250x353 mm + a3 297x420 mm + legal 8.5x14 inches + + - The feature tag is intended primarily for use in the following + applications, protocols, services, or negotiation mechanisms: + + This feature tag seems most useful for the printing application. + + - Examples of typical use: + + Choosing between a4 and letter size renditions of the same + printable document. + + + + + + + + + +Masinter, et al. Standards Track [Page 5] + +RFC 2534 Media Features for Display, Print, and Fax March 1999 + + +2.5 Color and greyscale + + - Media Feature tag name(s): + + color + + - ASN.1 identifier associated with this feature tag: + + 1.3.6.1.8.1.6 + + - Summary of the media features indicated by this feature tag: + + This feature indicates a gross level of capability to represent (or + need for) for handling of color, out of a limited set of choices. + + - Values appropriate for use with this feature tag: + + Token with an equality relationship. Values include: + + binary black-and-white, or other bi-level capability. + + grey more than two levels of intensity; for example, + at least two bits of grey-scale data + + limited availability of a small number of colors, such as + might be provided by a highlight printer, pen plotter, + or limited color display. Such capability is useful + for business graphics. At the lowest level of + capability, this implies at least one color other than + black ("highlight color"). At the high end, a small + number (less than 32) colors. No implication is made + that any particular color is available. + + mapped pixel color values are mapped in some specifable way + to a multi-component color space. Sufficient levels of + display are available to represent a continuous tone + photographic image, but the result will be mapped into + a more limited space. + + full ability (or at least willingness) to represent a full + color image and present it. Full continuous tone color + capability. + + - The feature tag is intended primarily for use in the following + applications, protocols, services, or negotiation mechanisms: + + + + + + +Masinter, et al. Standards Track [Page 6] + +RFC 2534 Media Features for Display, Print, and Fax March 1999 + + + Web applications may choose between color, grey, or binary + representations. Fax or printing applications might choose between + color and non-color renditions, for example. + + - Examples of typical use: + + Someone preparing a map of directions to a restaurant might prepare + different maps for each kind of value. + + - Intended usage: + + COMMON + +3. Examples of use of features + + The following examples of feature comparison show how these features + can be used to describe various capabilities. The syntax used to + express combinations of features is purely illustrative and not + normative: + + pix-x<=1024, pix-y<=768 + might be used for a 1024x768 display. + + dpi=300 + might be used for a 300 dpi printer. + + paper-size=a4 + indicates the display size is 210x297mm. + +4. IANA considerations + + This document calls for registration of the following feature tags, + as per [REG]: pix-x, pix-y, dpi, ua-media, paper-size, color. ASN.1 + identifiers should be assigned to each of these and replaced in the + body of the registration. + +5. Security Considerations + + Inaccurate media feature information ascribed to a recipient might + cause a sender to subsequently send content that the recipient is not + actually able to process, thus causing a denial of service. + +6. Acknowledgments + + This document is based on a previous memo co-authored with Lou + Montoulli. It had benefited from the comments of Graham Klyne, Ho + John Lee, Brian Behlendorf, Jeff Mogul, Ted Hardie, and Dan Wing. + + + + +Masinter, et al. Standards Track [Page 7] + +RFC 2534 Media Features for Display, Print, and Fax March 1999 + + +7. References + + [REG] Holtman, K., Mutz, A. and T. Hardie. "Feature Tag Registration + Procedures", BCP 31, RFC 2506, March 1999. + + [SI] ISO 1000:1992 "SI units and recommendations for the use of + their multiples and of certain other units", International + Organization for Standardization, 1992. + +Authors' Addresses + + Larry Masinter + Xerox Corporation + Palo Alto Research Center + 3333 Coyote Hill Road + Palo Alto CA 94304 + + Fax +1 650 812 4333 + EMail: masinter@parc.xerox.com + + + Dan Wing + Cisco Systems, Inc. + 101 Cooper Street + Santa Cruz, CA 95060 USA + + Phone: +1 831 457 5200 + Fax: +1 831 457 5208 + EMail: dwing@cisco.com + + + Andrew H. Mutz + Jutvision Corporation + 124 University Avenue Suite 202 + Palo Alto CA 94301 + + Phone: +1 650 325 6787 + Fax: +1 650 325 9337 + Email: mutz@alum.mit.edu + + + Koen Holtman + Technische Universiteit Eindhoven + Postbus 513 + Kamer HG 6.57 + 5600 MB Eindhoven (The Netherlands) + + EMail: koen@win.tue.nl + + + +Masinter, et al. Standards Track [Page 8] + +RFC 2534 Media Features for Display, Print, and Fax March 1999 + + +Full Copyright Statement + + Copyright (C) The Internet Society (1999). 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. + + + + + + + + + + + + + + + + + + + + + + + + +Masinter, et al. Standards Track [Page 9] + |