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<title>The CSS 'Reader' Media Type</title>

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<h1 id="the-css">The CSS 'Reader' Media Type</h1>

<h2 class="no-num no-toc" id="w3c-working">W3C Working Draft 24 February 2004</h2>

<dl>
<dt>This version:

<dd><a
href="http://www.w3.org/TR/2004/WD-css3-reader-20040224">http://www.w3.org/TR/2004/WD-css3-reader-20040224</a>

<dt>Latest version:

<dd><a
href="http://www.w3.org/TR/css3-reader">http://www.w3.org/TR/css3-reader</a>

<dt>Previous version:

<dd>none

<dt>Editors:

<dd>Bert Bos (W3C), &lt;bert@w3.org&gt;
</dl>
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<h2 class="no-num no-toc" id="abstract">Abstract</h2>

<p><em>This is the first draft of the 'reader' media type. It is published to
get some early feedback, especially on whether 'reader' is necessary and
implementable.</em>

<p>'Reader' is a keyword for use in Media Queries <a href="#MEDIAQ"
rel="biblioentry">[MEDIAQ]</a>. When a Media Query that includes the 'reader'
keyword is attached to (a link to) a style sheet, it indicates that that
style sheet is designed to be used by a "reader" device (typically a screen
reader), that both displays and speaks a document at the same time. It may
also display the document and render it in braille at the same time, or do
all three.

<p>Media Queries (and thus 'reader') can be used in documents in HTML <a
href="#HTML401" rel="biblioentry">[HTML401]</a>, XML <a href="#XML10"
rel="biblioentry">[XML10]</a>, SVG <a href="#SVG10"
rel="biblioentry">[SVG10]</a>, CSS <a href="#CSS21"
rel="biblioentry">[CSS21]</a> and other formats, wherever they link to a
style sheet, and potentially also in links to other resources. (But the
latter is not treated in this specification.)

<h2 class="no-num no-toc" id="status">Status of this document</h2>

<p><em>This section describes the status of this document at the time of its
publication. Other documents may supersede it. A list of current W3C
publications and the latest revision of this technical report can be found in
the <a href="http://www.w3.org/TR/">W3C technical reports index at
http://www.w3.org/TR/.</a></em>

<p>It is inappropriate to use W3C Working Drafts as reference material or to
cite them as other than "work in progress." Its publication does not imply
endorsement by the W3C membership. Implementations for the purpose of
experimenting with the specification are welcomed, as long as they are
clearly marked as experimental.

<p>This document is a working draft of the <a
href="http://www.w3.org/Style/CSS/members"> CSS Working Group</a> which is
part of the <a href="http://www.w3.org/Style/"> style activity</a> (see <a
href="http://www.w3.org/Style/Activity"> summary</a>).

<p><em>Comments</em> on and discussions of this draft can be sent to the (<a
href="http://lists.w3.org/Archives/Public/www-style/">archived</a>) public
mailing list <a href="mailto:www-style@w3.org"> www-style@w3.org</a> (see <a
href="http://www.w3.org/Mail/Request"> instructions</a>). W3C Members can
also send comments directly to the CSS working group.

<p>Patent disclosures relevant to CSS may be found on the Working Group's
public <a href="http://www.w3.org/Style/CSS/Disclosures"> patent disclosure
page.</a>

<p>This is the first draft in this series ("css3-reader").

<h2 class="no-num no-toc" id="contents">Table of contents</h2>
<!--begin-toc-->

<ul class="toc">
<li><a href="#dependencies"><span class="secno">1. </span>Dependencies on
other modules</a>

<li><a href="#intro"><span class="secno">2. </span>Introduction</a>

<li><a href="#reader"><span class="secno">3. </span>The 'reader' media
type</a>

<li><a href="#features"><span class="secno">4. </span>CSS features that apply
to 'reader'</a>

<li><a href="#test-suite"><span class="secno">5. </span>Test suite</a>

<li><a href="#profiles"><span class="secno">6. </span>Profiles</a>

<li><a href="#conformance"><span class="secno">7. </span>Conformance</a>

<li><a href="#acknowledgments">Acknowledgments</a>

<li><a href="#normative-references">Normative references</a>

<li><a href="#other-references">Other references</a>
</ul>
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<h2 id="dependencies"><span class="secno">1. </span>Dependencies on other
modules</h2>

<p>This CSS3 module depends on the following other CSS specifications:

<ul>
<li><cite>CSS&nbsp;2.1</cite> <a href="#CSS21" rel="biblioentry">[CSS21]</a>

<li><cite>Media Queries</cite> <a href="#MEDIAQ"
rel="biblioentry">[MEDIAQ]</a>
</ul>

<h2 id="intro"><span class="secno">2. </span>Introduction</h2>

<p>HTML <a href="#HTML401" rel="biblioentry">[HTML401]</a>, XML <a
href="#XML10" rel="biblioentry">[XML10]</a>, SVG <a href="#SVG10"
rel="biblioentry">[SVG10]</a>, CSS <a href="#CSS21"
rel="biblioentry">[CSS21]</a> and other formats can link to one or more style
sheets that help in specifying the way a document is rendered for a human
reader. Media Queries <a href="#MEDIAQ" rel="biblioentry">[MEDIAQ]</a> can be
attached to those links to indicate for what type of device or media the
style sheet is designed, e.g., big screen with color, small monochrome
screen, printer, slide projector or speech synthesizer.

<div class="example">
<p>E.g., an HTML4 document can link to a style sheet for use on (computer)
screens and another for use on printers like this:

<pre>
&lt;html>
 &lt;head>
  &lt;title>My HTML document&lt;/title>
  &lt;link rel="stylesheet" <strong>media="screen"</strong> href="my-screen-style.css">
  &lt;link rel="stylesheet" <strong>media="print"</strong> href="my-print-style.css">
 &lt;/head>
 &lt;body>
  ...
 &lt;/body>
&lt;/html>
</pre>

<p>The following example CSS style sheet links to another style sheet for
printing and includes style rules that apply to a slide projection:

<pre>
@import "my-print-style.css" <strong>print</strong>;

@media <strong>projection</strong> {
  h1 { page-break-before: always }
  h2 { color: red }
  ...
}
</pre>
</div>

<p>Media Queries contain a media type ('screen', 'print', 'projection',
'speech', etc.) optionally followed by further constraints ('min-width',
'max-width', 'color', etc.). 'Reader' is one such media type, applying to
devices like screen readers, that display a document visually and read it
with the help of a speech synthesizer at the same time.

<div class="example">
<p>The following is an XML document in some hypothetical format, that
includes the standard style sheet Processing Instruction (the "style PI") <a
href="#XMLSTYLE" rel="biblioentry">[XMLSTYLE]</a> to link to two style
sheets, one for rendering on color screens in a window that is less then 400
pixels wide and another for readers that have a monitor in portrait mode:

<pre>
&lt;?xml-stylesheet href="style1.css" type="text/css"
  <strong>media="screen and (color) and (max-width: 400px"</strong>?>
&lt;?xml-stylesheet href="style2.css" type="text/css"
  <strong>media="reader and (max-device-ratio: 1/1)</strong>"?>
&lt;doc>
  ...
&lt;/doc>
</pre>
</div>

<h2 id="reader"><span class="secno">3. </span>The 'reader' media type</h2>

<p>The keyword 'reader' is a "media type" as defined by Media Queries <a
href="#MEDIAQ" rel="biblioentry">[MEDIAQ]</a>. It can be used in all places
where Media Queries can be used (including LINK elements in HTML, the style
PI in XML and @import/@media in CSS).

<p>'Reader' is exclusive with all other media types defined in Media Queries,
except with the keyword 'all'. That is, a user agent that applies style rules
marked as being for a 'reader' must not at the same time apply style rules
marked for some other media.

<p>However, a single user agent might operate in different "modes" at
different times or even at the same time in different windows (different
"canvasses"). A user agent can, e.g., provide a print preview (using style
rules for the 'print' media) and a simulation of a handheld device (using
style rules for 'handheld').

<p>This specification does not define which UAs must use which media type.
UAs (or the users using them) can select which media type best fits them and
the environment in which they run. The following are therefore only
informative guidelines:

<p>The 'reader' media type typically is used by a UA that:

<ul>
<li> is a "screen reader" (often designed as an accessibility aid);

<li> displays a document on screen and speaks what is on screen;

<li> either scrolls the screen automatically in sync with the speech; or

<li> waits for the user to scroll;

<li> allows the user to indicate the part to be spoken, by pointing or by
using fast-forward/fast-reverse or similar functions;

<li> instead of or in addition to speaking, it may also render the displayed
text on a dynamic braille device.
</ul>

<p class="issue">Do we need a pseudo-class for the element currently being
spoken? (Karaoke!)

<h2 id="features"><span class="secno">4. </span>CSS features that apply to
'reader'</h2>

<p>The CSS features that apply to the 'reader' media type are all properties
and other features that apply to the following media groups. See <a
href="http://www.w3.org/TR/CSS21/media.html#media-groups">section 7.3.1
"Media Groups"</a> of CSS&nbsp;2.1 <a href="#CSS21"
rel="biblioentry">[CSS21]</a> for definitions of these groups. <span
class="issue">[No section to point to in CSS3 yet?]</span>

<table class="equiv-table">
<tbody>
<tr>
<th>

<th>continuous / paged?

<th>visual / audio / speech / tactile?

<th>grid / bitmap?

<th>interactive / static?

<tr>
<th>reader

<td>continuous

<td>all

<td>both

<td>interactive
</table>

<p>All property definitions in CSS3 modules include a line that specifies to
which of these media groups the property applies.

<p class="note">Note that 'reader' can be used both with bitmapped and with
grid-based screens. To distinguish between the two types, a designer can use
the 'grid' media feature as defined by Media Queries <a href="#MEDIAQ"
rel="biblioentry">[MEDIAQ]</a>.

<div class="example">
<p>E.g., a style sheet might be written as follows:

<pre>
@media reader and (grid: 0) {
    /* styles for bitmapped displays */
    ...
}
@media reader and (grid: 1) {
    /* Styles for grid-based displays */
    ...
}
</pre>
</div>

<p class="issue">Can it be "static" as well? A reader that just starts
reading at the top and continues until the end of the document, scrolling the
display as needed, without user interaction? Maybe not important.

<h2 id="test-suite"><span class="secno">5. </span>Test suite</h2>

<p class="issue">[TBD]

<h2 id="profiles"><span class="secno">6. </span>Profiles</h2>

<p class="issue">[TBD]

<h2 id="conformance"><span class="secno">7. </span>Conformance</h2>

<p class="issue">[TBD]

<h2 class="no-num" id="acknowledgments">Acknowledgments</h2>

<p>Joe Clark (<a
href="http://lists.w3.org/Archives/Public/www-style/2003Oct/0328.html">see
message on www-style</a> and <a href="#FIR" rel="biblioentry">[FIR]</a>)

<h2 class="no-num" id="normative-references">Normative references</h2>
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<dt id="CSS21">[CSS21]

<dd>Bert Bos; Tantek Çelik; Ian Hickson; Håkon Wium Lie. <cite>Cascading
Style Sheets, level 2 revision 1.</cite> 15 September 2003. W3C Working
Draft. (Work in progress) URL: <a
href="http://www.w3.org/TR/2003/WD-CSS21-20030915">http://www.w3.org/TR/2003/WD-CSS21-20030915</a>
<!---->

<dt id="MEDIAQ">[MEDIAQ]

<dd>Håkon Wium Lie; Tantek Çelik; Daniel Glazman. <cite>Media queries.</cite>
8 July 2002. W3C Candidate Recommendation. (Work in progress.) URL: <a
href="http://www.w3.org/TR/2002/CR-css3-mediaqueries-20020708">http://www.w3.org/TR/2002/CR-css3-mediaqueries-20020708</a>
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<h2 class="no-num" id="other-references">Other references</h2>
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<dt id="FIR">[FIR]

<dd>Joe Clark. "Facts and Opinion About Fahrner Image Replacement" in:
<cite>A List Apart.</cite> Issue No. 160. 20 October 2003. URL: <a
href="http://www.alistapart.com/articles/fir/">http://www.alistapart.com/articles/fir/</a>
<!---->

<dt id="HTML401">[HTML401]

<dd>Raggett, D.; Le Hors, A.; Jacobs, I.. <cite>HTML 4.01
Specification.</cite> Dec 1999. W3C Recommendation. URL: <a
href="http://www.w3.org/TR/1999/REC-html401-19991224">http://www.w3.org/TR/1999/REC-html401-19991224</a>
<!---->

<dt id="SVG10">[SVG10]

<dd>Various. <cite>Scalable Vector Graphics (SVG) 1.0 Specification.</cite>
Sep 2001. W3C Recommendation. URL: <a
href="http://www.w3.org/TR/2001/REC-SVG-20010904">http://www.w3.org/TR/2001/REC-SVG-20010904</a>
<!---->

<dt id="XML10">[XML10]

<dd>Tim Bray; Jean Paoli; C. M. Sperberg-McQueen; Eve Maler. <cite>Extensible
Markup Language (XML) 1.0 (Second Edition).</cite> Oct 2000. W3C
Recommendation. URL: <a
href="http://www.w3.org/TR/2000/REC-xml-20001006">http://www.w3.org/TR/2000/REC-xml-20001006</a>
<!---->

<dt id="XMLSTYLE">[XMLSTYLE]

<dd>J. Clark. <cite>Associating Style Sheets with XML documents.</cite> 29
June 1999. W3C Recommendation. URL: <a
href="http://www.w3.org/TR/xml-stylesheet">http://www.w3.org/TR/xml-stylesheet</a>
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