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
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
用于显示、打印和传真的媒体功能
Status of this Memo
本备忘录的状况
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.
本文件规定了互联网社区的互联网标准跟踪协议，并要求进行讨论和提出改进建议。有关本协议的标准化状态和状态，请参考当前版本的“互联网官方协议标准”（STD 1）。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (C) The Internet Society (1999). All Rights Reserved.
版权所有（C）互联网协会（1999年）。版权所有。
Abstract
摘要
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].
本规范定义了一些常见的媒体功能，用于描述网络浏览、打印和传真应用中常见的图像分辨率、大小、颜色和图像表示方法。这些功能在[REG]框架内注册使用。
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.
这项工作最初是基于web浏览器的要求，即将浏览器的显示特征发送到web服务器，以允许服务器选择适当的表示形式。
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.
本规范定义了一些常见的媒体功能[REG]，通过这些功能，收件人可以通知发件人其消息处理的特征。然后，发送方可以提供最适合接收方的消息变体。
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.
不同的变体通常是更高或更低分辨率的图像（例如），视情况而定。在发送到打印机的情况下，结果将是更高质量的输出。在小屏幕设备（手机、便携式数字助理）的情况下，传输速度会更快。
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.
媒体功能可用于许多不同的协议情况。本规范中定义的可指示显示器或打印机尺寸、分辨率、颜色能力。显示器的物理尺寸可以从显示器尺寸和显示器分辨率推断出来。在纸张输出的情况下，纸张尺寸可以表示为标准纸张尺寸列表中的标记。这些将在注释部分正式介绍。
This section defines several media features, using the form specified in [REG].
本节使用[REG]中指定的格式定义了几种媒体功能。
- Media Feature tag name(s):
- 媒体功能标签名称：
pix-x pix-y
pix-x-pix-y
- ASN.1 identifier associated with this feature tag:
- 与此功能标签关联的ASN.1标识符：
1.3.6.1.8.1.1 1.3.6.1.8.1.2
1.3.6.1.8.1.1 1.3.6.1.8.1.2
- Summary of the media features indicated by this feature tag:
- 此功能标签指示的媒体功能摘要：
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.
这些特征指示用于显示或打印的收件人的显示大小，以像素为单位；它们表示水平（pix-x）和垂直（pix-y）尺寸。
- Values appropriate for use with this feature tag:
- 适用于此功能标记的值：
Signed Integer
有符号整数
- The feature tag is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms:
- 功能标签主要用于以下应用程序、协议、服务或协商机制：
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.
显示和打印应用程序，其中将根据收件人设备的大小选择不同的媒体。例如，在240x480显示器上使用的web应用程序可能使用与在1024x768显示器上使用的HTML页面不同的HTML页面。
- Media Feature tag name:
- 媒体功能标签名称：
dpi
新闻部
- ASN.1 identifier associated with this feature tag:
- 与此功能标签关联的ASN.1标识符：
1.3.6.1.8.1.3
1.3.6.1.8.1.3
- Summary of the media features indicated by this feature tag:
- 此功能标签指示的媒体功能摘要：
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.
此功能表示收件人可以显示或打印而不会丢失的分辨率，单位为每英寸像素。通常分辨率能力表示为每英寸点数，而不是SI单位[SI]。dpi的值可以表示为合理的，以适应基于SI的器件的分辨率；例如，dpi=19558/100可用于表示每厘米77点的分辨率。
- Values appropriate for use with this feature tag:
- 适用于此功能标记的值：
Rational
合理的
- The feature tag is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms:
- 功能标签主要用于以下应用程序、协议、服务或协商机制：
Printing and fax applications typically choose representations of a transmitted document depending on the resolution of the recipient rather than pixel size.
打印和传真应用程序通常根据收件人的分辨率而不是像素大小来选择传输文档的表示形式。
- Examples of typical use:
- 典型使用示例：
Choosing a version of a printable document to send to a printer.
选择要发送到打印机的可打印文档的版本。
- Considerations particular to use in individual applications, protocols, services, or negotiation mechanisms:
- 在单个应用程序、协议、服务或协商机制中使用的特殊注意事项：
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.
软件应用程序通常不知道显示器的分辨率。注意，存在在不同方向上具有不同分辨率的设备，即单个像素不是正方形。但是，此功能仅包含统一的分辨率。
- Media Feature tag name(s):
- 媒体功能标签名称：
ua-media
ua媒体
- ASN.1 identifier associated with this feature tag:
- 与此功能标签关联的ASN.1标识符：
1.3.6.1.8.1.4
1.3.6.1.8.1.4
- Summary of the media features indicated by this feature tag:
- 此功能标签指示的媒体功能摘要：
This feature indicates the recipients device media, indicated with an simple token.
此功能指示收件人设备媒体，用简单令牌表示。
- Values appropriate for use with this feature tag:
- 适用于此功能标记的值：
Token with an equality relationship. Values include:
具有平等关系的令牌。价值包括：
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
屏幕可刷新显示屏分页可刷新显示屏不能滚动文具不透明材料的单张透明材料的单张透明材料信封可用于常规邮寄目的的信封未预印且无窗口的普通信封不透明材料连续连接的薄片
- The feature tag is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms:
- 功能标签主要用于以下应用程序、协议、服务或协商机制：
Most of the feature values are useful for printing applications, or to distinguish printing from display.
大多数特征值对于打印应用程序或区分打印与显示非常有用。
- Examples of typical use:
- 典型使用示例：
This might typically be used for selecting between a rendition that is intended to be printed and one that is intended to be displayed.
这通常可用于在要打印的格式副本和要显示的格式副本之间进行选择。
- Considerations particular to use in individual applications, protocols, services, or negotiation mechanisms:
- 在单个应用程序、协议、服务或协商机制中使用的特殊注意事项：
Other media values were not included because their utility seemed relative.
其他媒体价值没有包括在内，因为它们的效用似乎是相对的。
- Interoperability considerations:
- 互操作性注意事项：
Interoperability with the Internet Print Protocol means that some additional feature values may need to be registered.
与Internet打印协议的互操作性意味着可能需要注册一些附加功能值。
- Media Feature tag name(s):
- 媒体功能标签名称：
paper-size
纸张尺寸
- ASN.1 identifier associated with this feature tag:
- 与此功能标签关联的ASN.1标识符：
1.3.6.1.8.1.5
1.3.6.1.8.1.5
- Summary of the media features indicated by this feature tag:
- 此功能标签指示的媒体功能摘要：
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.
对于文具而言，了解所用显示器的大小通常很有用。虽然使用绝对分辨率和像素大小更精确、更可预测，但一些应用程序发现，除了这些信息之外，还可以提供纸张大小。请注意，并非所有纸张都有可打印区域。
- Values appropriate for use with this feature tag:
- 适用于此功能标记的值：
Token with an equality relationship. Typical values include:
具有平等关系的令牌。典型值包括：
letter 8.5x11.0 inches a4 210x297 mm b4 250x353 mm a3 297x420 mm legal 8.5x14 inches
字母8.5x11.0英寸a4 210x297毫米b4 250x353毫米a3 297x420毫米法定8.5x14英寸
- The feature tag is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms:
- 功能标签主要用于以下应用程序、协议、服务或协商机制：
This feature tag seems most useful for the printing application.
此功能标签似乎对打印应用程序最有用。
- Examples of typical use:
- 典型使用示例：
Choosing between a4 and letter size renditions of the same printable document.
在同一可打印文档的a4格式副本和字母大小格式副本之间进行选择。
- Media Feature tag name(s):
- 媒体功能标签名称：
color
颜色
- ASN.1 identifier associated with this feature tag:
- 与此功能标签关联的ASN.1标识符：
1.3.6.1.8.1.6
1.3.6.1.8.1.6
- Summary of the media features indicated by this feature tag:
- 此功能标签指示的媒体功能摘要：
This feature indicates a gross level of capability to represent (or need for) for handling of color, out of a limited set of choices.
此功能表示在有限的一组选择中表示（或需要）处理颜色的总体能力水平。
- Values appropriate for use with this feature tag:
- 适用于此功能标记的值：
Token with an equality relationship. Values include:
具有平等关系的令牌。价值包括：
binary black-and-white, or other bi-level capability.
二进制黑白或其他两级功能。
grey more than two levels of intensity; for example, at least two bits of grey-scale data
灰色强度超过两级；例如，至少两位灰度数据
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.
少量颜色的可用性有限，例如高亮显示打印机、笔式绘图仪或有限的彩色显示。这种功能对于业务图形非常有用。在最低级别的功能中，这意味着至少有一种颜色不是黑色（“高亮颜色”）。在高端，少量（少于32）颜色。没有暗示任何特定的颜色是可用的。
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.
映射的像素颜色值以某种可指定的方式映射到多分量颜色空间。可以使用足够的显示级别来表示连续色调的摄影图像，但结果将映射到更有限的空间中。
full ability (or at least willingness) to represent a full color image and present it. Full continuous tone color capability.
完全有能力（或至少愿意）代表全彩图像并呈现它。全连续色调色彩能力。
- The feature tag is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms:
- 功能标签主要用于以下应用程序、协议、服务或协商机制：
Web applications may choose between color, grey, or binary representations. Fax or printing applications might choose between color and non-color renditions, for example.
Web应用程序可以选择颜色、灰色或二进制表示。例如，传真或打印应用程序可以在彩色和非彩色格式副本之间进行选择。
- Examples of typical use:
- 典型使用示例：
Someone preparing a map of directions to a restaurant might prepare different maps for each kind of value.
准备餐厅方向图的人可能会为每种价值准备不同的地图。
- Intended usage:
- 预期用途：
COMMON
常见的
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:
下面的功能比较示例显示了如何使用这些功能来描述各种功能。用于表示功能组合的语法纯粹是说明性的，而不是规范性的：
pix-x<=1024, pix-y<=768 might be used for a 1024x768 display.
pix-x<=1024，pix-y<=768可用于1024x768显示器。
dpi=300 might be used for a 300 dpi printer.
dpi=300可用于300 dpi打印机。
paper-size=a4 indicates the display size is 210x297mm.
纸张尺寸=a4表示显示尺寸为210x297mm。
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.
本文件要求按照[REG]注册以下功能标签：pix-x、pix-y、dpi、ua介质、纸张尺寸、颜色。ASN.1标识符应分配给每一个，并在注册正文中替换。
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.
归属于收件人的不准确的媒体功能信息可能会导致发件人随后发送收件人实际上无法处理的内容，从而导致拒绝服务。
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.
本文件基于与Lou Montoulli合著的先前备忘录。这得益于Graham Klyne、Ho John Lee、Brian Behlendorf、Jeff Mogul、Ted Hardie和Dan Wing的评论。
[REG] Holtman, K., Mutz, A. and T. Hardie. "Feature Tag Registration Procedures", BCP 31, RFC 2506, March 1999.
[REG]Holtman，K.，Mutz，A.和T.Hardie。“特征标签注册程序”，BCP 31，RFC 2506，1999年3月。
[SI] ISO 1000:1992 "SI units and recommendations for the use of their multiples and of certain other units", International Organization for Standardization, 1992.
[SI]ISO 1000:1992“国际单位制及其倍数和某些其他单位的使用建议”，国际标准化组织，1992年。
Authors' Addresses
作者地址
Larry Masinter Xerox Corporation Palo Alto Research Center 3333 Coyote Hill Road Palo Alto CA 94304
拉里·马斯特施乐公司帕洛阿尔托研究中心加利福尼亚州帕洛阿尔托市郊狼山路3333号94304
Fax +1 650 812 4333 EMail: masinter@parc.xerox.com
传真+1 650 812 4333电子邮件：masinter@parc.xerox.com
Dan Wing Cisco Systems, Inc. 101 Cooper Street Santa Cruz, CA 95060 USA
Dan Wing Cisco Systems，Inc.美国加利福尼亚州圣克鲁斯库珀街101号，邮编95060
Phone: +1 831 457 5200
Fax: +1 831 457 5208
EMail: dwing@cisco.com
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
安德鲁·穆茨·朱特维辛公司加利福尼亚州帕洛阿尔托大学大道124号202室94301
Phone: +1 650 325 6787
Fax: +1 650 325 9337
Email: mutz@alum.mit.edu
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)
科恩·霍特曼埃因霍温技术大学邮政513卡默HG 6.57 5600 MB埃因霍温（荷兰）
EMail: koen@win.tue.nl
EMail: koen@win.tue.nl
Full Copyright Statement
完整版权声明
Copyright (C) The Internet Society (1999). All Rights Reserved.
版权所有（C）互联网协会（1999年）。版权所有。
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.
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The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns.
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