As per Relevance of the word features, we have this rfc below:
Network Working Group L.
Request for Comments: 2534 Xerox
Category: Standards Track D.
Cisco Systems, Inc
A.
Jutvision
K.
March 1999
Media Features for Display, Print, and
Status of this
This document specifies an Internet standards track protocol for
Internet community, and requests discussion and suggestions
improvements. Please refer to the current edition of the "
Official Protocol Standards" (STD 1) for the standardization
and status of this protocol. Distribution of this memo is unlimited
Copyright
Copyright (C) The Internet Society (1999). All Rights Reserved
This specification defines some common media features for
image resolution, size, color, and image representation methods
are common to web browsing, printing, and facsimile applications
These features are registered for use within the framework of [REG].
1.
This work was originally motivated by the requirements from
browsers to send the browser's display characteristics to the
server to allow the server to choose an appropriate representation
This specification defines some common media features [REG] by
a recipient may inform a sender as to the characteristics of
message handling. The sender may then provide the variant of
message that is most suitable for the recipient
Different variants would typically be higher or lower
images (for example) as appropriate. In the case of a sending to
printer, the result would be higher quality output. In the case of
small screen device (cellphone, portable digital assistant),
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
printer dimensions, resolution, color capability. The
dimensions of a display may be inferred from the display size
display resolution. In the case of paper output, the paper size
be expressed as a token from a list of standard paper sizes.
are presented formally in the Notation section
2. Media Feature
This section defines several media features, using the form
in [REG].
2.1 Image
- Media Feature tag name(s):
pix-
pix-
- 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
display or print, measured in pixels; they indicate
(pix-x) and vertical (pix-y) dimensions
- Values appropriate for use with this feature tag
Signed
- The feature tag is intended primarily for use in the
applications, protocols, services, or negotiation mechanisms
Display and print applications where different media choices
be made depending on the size of the recipient device.
example, a web application for use on a 240x480 display might
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
- Media Feature tag name
- 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
display or print without loss, measured in pixels per inch
Typically resolution capability is represented as dots-per-
rather than in SI units [SI]. Values for dpi may be expressed as
rational to accomodate resolution of SI-based devices; for
dpi=19558/100 can be used to represent a resolution of 77 dots
centimeter
- Values appropriate for use with this feature tag
- The feature tag is intended primarily for use in the
applications, protocols, services, or negotiation mechanisms
Printing and fax applications typically choose representations
a transmitted document depending on the resolution of
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
the display. Note that there exist devices with
resolution in different directions, i.e., individual pixels
not square. However, this feature only encompasses
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-
- 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
an simple token
- Values appropriate for use with this feature tag
Token with an equality relationship. Values include
screen A refreshable
screen-paged a refreshable display which cannot
stationery Separately cut sheets of an opaque
transparency Separately cut sheets of a transparent
envelope Envelopes that can be used for
mailing
envelope-plain Envelopes that are not preprinted and have
continuous Continuously connected sheets of an
- The feature tag is intended primarily for use in the
applications, protocols, services, or negotiation mechanisms
Most of the feature values are useful for printing applications,
to distinguish printing from display
- Examples of typical use
This might typically be used for selecting between a rendition
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
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
additional feature values may need to be registered
2.4 Paper
- Media Feature tag name(s):
paper-
- 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
size of display used. While it is more precise and predictable
use absolute resolution and pixel sizes, some applications find
useful to provide paper size in addition to this information.
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
a4 210x297
b4 250x353
a3 297x420
legal 8.5x14
- The feature tag is intended primarily for use in the
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
printable document
Masinter, et al. Standards Track [Page 5]
RFC 2534 Media Features for Display, Print, and Fax March 1999
2.5 Color and
- Media Feature tag name(s):
- 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 (
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
limited availability of a small number of colors, such
might be provided by a highlight printer, pen plotter
or limited color display. Such capability is
for business graphics. At the lowest level
capability, this implies at least one color other
black ("highlight color"). At the high end, a
number (less than 32) colors. No implication is
that any particular color is available
mapped pixel color values are mapped in some specifable
to a multi-component color space. Sufficient levels
display are available to represent a continuous
photographic image, but the result will be mapped
a more limited space
full ability (or at least willingness) to represent a
color image and present it. Full continuous tone
capability
- The feature tag is intended primarily for use in the
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
representations. Fax or printing applications might choose
color and non-color renditions, for example
- Examples of typical use
Someone preparing a map of directions to a restaurant might
different maps for each kind of value
- Intended usage
3. Examples of use of
The following examples of feature comparison show how these
can be used to describe various capabilities. The syntax used
express combinations of features is purely illustrative and
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=a
indicates the display size is 210x297mm
4. IANA
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
body of the registration
5. Security
Inaccurate media feature information ascribed to a recipient
cause a sender to subsequently send content that the recipient is
actually able to process, thus causing a denial of service
6.
This document is based on a previous memo co-authored with
Montoulli. It had benefited from the comments of Graham Klyne,
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.
[REG] Holtman, K., Mutz, A. and T. Hardie. "Feature Tag
Procedures", BCP 31, RFC 2506, March 1999.
[SI] ISO 1000:1992 "SI units and recommendations for the use
their multiples and of certain other units",
Organization for Standardization, 1992.
Authors'
Larry
Xerox
Palo Alto Research
3333 Coyote Hill
Palo Alto CA 94304
Fax +1 650 812 4333
EMail: masinter@parc.xerox.
Dan
Cisco Systems, Inc
101 Cooper
Santa Cruz, CA 95060
Phone: +1 831 457 5200
Fax: +1 831 457 5208
EMail: dwing@cisco.
Andrew H.
Jutvision
124 University Avenue Suite 202
Palo Alto CA 94301
Phone: +1 650 325 6787
Fax: +1 650 325 9337
Email: mutz@alum.mit.
Koen
Technische Universiteit
Postbus 513
Kamer HG 6.57
5600 MB Eindhoven (The Netherlands
EMail: koen@win.tue.
Masinter, et al. Standards Track [Page 8]
RFC 2534 Media Features for Display, Print, and Fax March 1999
Full Copyright
Copyright (C) The Internet Society (1999). All Rights Reserved
This document and translations of it may be copied and furnished
others, and derivative works that comment on or otherwise explain
or assist in its implementation may be prepared, copied,
and distributed, in whole or in part, without restriction of
kind, provided that the above copyright notice and this paragraph
included on all such copies and derivative works. However,
document itself may not be modified in any way, such as by
the copyright notice or references to the Internet Society or
Internet organizations, except as needed for the purpose
developing Internet standards in which case the procedures
copyrights defined in the Internet Standards process must
followed, or as required to translate it into languages other
English
The limited permissions granted above are perpetual and will not
revoked by the Internet Society or its successors or assigns
This document and the information contained herein is provided on
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED,
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
Masinter, et al. Standards Track [Page 9]
if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.
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