Skip to content

Commit c7213b9

Browse files
ianbjacobsianbjacobs
committed
[css2] Added definitions of media groups, cleaned up media type section, added table of media groups/types
--HG-- extra : convert_revision : svn%3A73dc7c4b-06e6-40f3-b4f7-9ed1dbc14bfc/trunk%40567
1 parent 45fd1cb commit c7213b9

1 file changed

Lines changed: 108 additions & 96 deletions

File tree

‎css2/media.src‎

Lines changed: 108 additions & 96 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,6 @@
11
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
22
<html lang="en">
3-
<!-- $Id: media.src,v 1.28 1997-12-12 18:03:09 ijacobs Exp $ -->
3+
<!-- $Id: media.src,v 1.29 1997-12-16 20:50:03 ijacobs Exp $ -->
44
<HEAD>
55
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
66
<TITLE>Media types</TITLE>
@@ -10,7 +10,6 @@
1010
</HEAD>
1111
<BODY>
1212
<H1 align="center">Media types</H1>
13-
<!-- What is the definitive list of media types? -->
1413
<!-- Are values case-sensitive? -->
1514

1615
<H2>Introduction to media types</H2>
@@ -20,6 +19,14 @@ authors to specify how a document is to be presented on different
2019
media: on the screen, on paper, with a speech synthesizer, with a
2120
braille device, etc.
2221

22+
<P>For all media, the term <span class="index-def" title="canvas"> <a
23+
name="canvas"><dfn>canvas</dfn></a></span> means "the space where
24+
rendering objects are rendered." For a screen, the canvas is a
25+
rectangular space generally of fixed width and "infinite" length. For
26+
paged media, the canvas is a sequence of rectangular page boxes of
27+
fixed width and height. For aural media, the canvas is a three
28+
dimensional audio space.
29+
2330
<P>Certain CSS properties only make sense for certain media (e.g., the
2431
<span class="propinst-cue-before">'cue-before'</span> property for
2532
aural style sheets). On occasion, however, style sheets for different
@@ -57,10 +64,10 @@ style sheets:
5764
</PRE>
5865
</div>
5966

60-
<LI>Specify the target medium within the document language. For example,
61-
in <a rel="biblioentry" href="./refs.html#ref-HTML40" class="informref">[HTML40]</a>,
62-
the "media" attribute on the LINK element specifies the target medium
63-
of an external style sheet.
67+
<LI>Specify the target medium within the document language. For
68+
example, in <a rel="biblioentry" href="./refs.html#ref-HTML40"
69+
class="informref">[HTML40]</a>, the "media" attribute on the LINK
70+
element specifies the target medium of an external style sheet:
6471

6572
<div class="example"><P>
6673

@@ -69,15 +76,10 @@ of an external style sheet.
6976
media="print" href="foo.css"&gt;
7077
</PRE>
7178
</div>
72-
73-
<P>Please consult the <a rel="biblioentry"
74-
href="./refs.html#ref-HTML40" class="informref">[HTML40]</a> specification for
75-
information about specifying alternate style sheets according
76-
to different media types.
7779
</UL>
7880

79-
<P>Since these two examples have the same <a href="#media-types">media
80-
type</a>, they are semantically equivalent.
81+
<P>Since these two examples specify the same <a
82+
href="#media-types">media type</a>, they are semantically equivalent.
8183

8284
<H3>The @media rule</H3>
8385

@@ -133,27 +135,18 @@ that elect to support the devices in the following list must recognize
133135
the associated media type:
134136

135137
<dl>
136-
<dt><strong>screen</strong>
137-
<dd>Intended primarily for color computer screens. See the section on
138-
<a href="#continuous-media">continuous media</a> for more information.
139-
140-
<dt><strong>tty</strong>
141-
<dd>Intended for media using a fixed-pitch character
142-
grid, such as teletypes, terminals, or portable devices with limited
143-
display capabilities.
138+
<dt><strong>all</strong>
139+
<dd>Suitable for all devices.
144140

145-
<P>Authors should not use <a href="syndata.html#pixel-units">pixel
146-
units</a> with the "tty" media type.
141+
<dt><strong>aural</strong>
142+
<dd>Intended for speech synthesizers. See the
143+
section on <a href="./aural.html">aural style sheets</a> for details.
147144

148-
<dt><strong>tv</strong>
149-
<dd>Intended for television-type devices (low
150-
resolution, color, limited scrollability).
145+
<dt><strong>braille</strong>
146+
<dd>Intended for braille tactile feedback devices.
151147

152-
<dt><strong>projection</strong>
153-
<dd>Intended for projected presentations, for
154-
example projectors or print to transparencies.
155-
Please consult the section on <a href="page.html">paged media</a> for
156-
information about formatting issues that are specific to paged media.
148+
<dt><strong>embossed</strong>
149+
<dd>Intended for paged braille printers.
157150

158151
<dt><strong>handheld</strong>
159152
<dd>Intended for handheld devices (small
@@ -165,77 +158,96 @@ screen in print preview mode. Please consult the section on <a
165158
href="page.html">paged media</a> for information about formatting
166159
issues that are specific to paged media.
167160

168-
<dt><strong>braille</strong>
169-
<dd>Intended for braille tactile feedback devices.
170-
171-
<dt><strong>embossed</strong>
172-
<dd>Intended for paged braille printers.
173-
161+
<dt><strong>projection</strong>
162+
<dd>Intended for projected presentations, for
163+
example projectors or print to transparencies.
164+
Please consult the section on <a href="page.html">paged media</a> for
165+
information about formatting issues that are specific to paged media.
174166

167+
<dt><strong>screen</strong>
168+
<dd>Intended primarily for color computer screens. See the section on
169+
<a href="flowobj.html#continuous-media">rendering to continuous
170+
media</a> for more information.
175171

176-
<dt><strong>aural</strong>
177-
<dd>Intended for speech synthesizers. See the
178-
section on <a href="./aural.html">aural style sheets</a> for details.
172+
<dt><strong>tty</strong>
173+
<dd>Intended for media using a fixed-pitch character grid, such as
174+
teletypes, terminals, or portable devices with limited display
175+
capabilities. Authors should not use <a
176+
href="syndata.html#pixel-units">pixel units</a> with the "tty" media
177+
type.
179178

180-
<dt><strong>all</strong>
181-
<dd>Suitable for all devices.
179+
<dt><strong>tv</strong>
180+
<dd>Intended for television-type devices (low
181+
resolution, color, limited scrollability).
182182
</dl>
183183

184184
<P>Media type names are case-insensitive.
185-
186-
<!-- IJ: Include definitions of "visual", "paged", etc. here.
187-
Link to them from the property/descriptor definitions -->
188-
189-
<H3><a name="canvas">The canvas</a></H3>
190-
191-
<P>For all media, the term <span class="index-def" title="canvas"><em>
192-
canvas</em></span> means "the space where rendering objects are rendered."
193-
For a screen, the canvas is a rectangular space generally of fixed
194-
width and "infinite" length. For paged media, the canvas is a sequence
195-
of rectangular page boxes of fixed width and height. For aural media,
196-
the canvas is a three dimensional audio space.
197-
198-
<H4><a name="continuous-media">Continuous media</a></H4>
199-
200-
<P>User agents for continuous media may implement the canvas as an
201-
"infinitely" long (or however long the rendered document is) rectangle
202-
that has a fixed width. Users see this canvas through a user agent's
203-
<span class="index-def" title="viewport"><em>viewport</em></span>, a
204-
window or other viewing area on the screen. The canvas may be larger
205-
or smaller than the viewport. Typically, when the canvas is larger
206-
than the viewport, the user agent will offer the user a scrolling
207-
mechanism to bring hidden parts into view.
208-
209-
<P>The user agent generally determines the width of the canvas and may
210-
change the dimensions of the canvas when the viewport is resized.
211-
212-
<P>In general, when a document doesn't cover the entire canvas, the
213-
User agent should "borrow" the background of the root element. Since
214-
the BODY element is often perceived as the root element in HTML, this
215-
special rules apply to HTML documents: if
216-
the <span class="propinst-background">'background'</span> value of the
217-
HTML element is different from 'transparent' then use it, else use the
218-
<span class="propinst-background">'background'</span> value of the
219-
BODY element. If the resulting value is 'transparent', the rendering
220-
is undefined.
221-
222-
<P>This rule allows the following:
223-
224-
<div class="example"><P>
225-
<PRE>
226-
&lt;HTML style="background: url(http://style.com/marble.png)"&gt;
227-
&lt;BODY style="background: red"&gt;
228-
</PRE>
229-
230-
<P> In the example above, the canvas will be covered with
231-
"marble". The background of the BODY element (which may or may not
232-
fully cover the canvas) will be red.
233-
</div>
234-
235-
<P>Note that no structural element of a document corresponds to the
236-
canvas. In HTML, until other means of addressing the canvas become
237-
available, we recommend that authors set canvas properties on the BODY
238-
element.
185+
<H3><a name="media-groups">Media groups</a></H3>
186+
187+
<P>Each CSS property definition specifies the media types for which
188+
the property must be implemented by a <a
189+
href="convent.html#conformance">conforming user agent</a>. Since
190+
properties generally apply to several media, the "Applies to media"
191+
section of each property definition indicates a <span
192+
class="index-def" title="media group">media group</span> rather than a
193+
list of media types. A property applies to all media types that belong
194+
to a given media group.
195+
196+
<P>CSS2 defines the following media groups:
197+
<ul>
198+
<li>
199+
<span class="index-def" title="'continuous' media group"><a
200+
name="continuous-media-group"><strong>continuous</strong>,</a></span>
201+
<span class="index-def" title="'paged' media group"><a
202+
name="paged-media-group"><strong>paged</strong>,</a></span>
203+
or <span class="index-def" title="'p_c' media group">
204+
<a name="p_c-media-group"><strong>p_c</strong></a></span> (for
205+
paged or continuous).
206+
<li><span
207+
class="index-def" title="'visual' media group"><a
208+
name="visual-media-group"> <strong>visual</strong></a>,</span> <span
209+
class="index-def" title="'aural' media group"><a
210+
name="aural-media-group"><strong>aural</strong></a>,</span> or <span
211+
class="index-def" title="'tactile' media group"><a
212+
name="tactile-media-group"><strong>tactile</strong>,</a></span> or
213+
<span class="index-def" title="'v_a_t' media group">
214+
<a name="v_a_t-media-group"><strong>v_a_t</strong></a></span> (for
215+
visual, aural, and tactile).
216+
<li><span
217+
class="index-def" title="'grid' media group"><a
218+
name="grid-media-group"><strong>grid</strong></a></span> (for
219+
character grid devices), or
220+
<span class="index-def" title="'g_b' media group">
221+
<a name="g_b-media-group"><strong>g_b</strong></a></span> (for
222+
grid and bitmap devices).
223+
<li><span class="index-def" title="'all'
224+
media group"> <a name="all-media-group"><strong>all</strong></a></span>
225+
(includes all media types)
226+
</ul>
227+
228+
<P>The following table shows the relationships
229+
between media groups and media types:</P>
230+
231+
<TABLE border
232+
align="center"
233+
summary="Relationships between media groups and media types">
234+
<CAPTION>Media Groups</CAPTION>
235+
<TR><TH>Media Groups <HR> Media Types
236+
<TH>continuous/paged
237+
<TH>visual/aural/tactile
238+
<TH>character grid
239+
<TR><TH>all<TD align="center">paged/continuous<TD align="center">visual/aural/tactile<TD align="center">&nbsp;</TR>
240+
<TR><TH>aural<TD align="center">continuous<TD align="center">aural<TD align="center">&nbsp;</TR>
241+
<TR><TH>braille<TD align="center">continuous<TD align="center">tactile<TD align="center">grid</TR>
242+
<TR><TH>emboss<TD align="center">paged<TD align="center">tactile<TD align="center">grid</TR>
243+
<TR><TH>handheld<TD align="center">paged/continuous<TD align="center">visual<TD
244+
align="center">&nbsp;</TR>
245+
<TR><TH>print<TD align="center">paged<TD align="center">visual<TD align="center">&nbsp;</TR>
246+
<TR><TH>projection<TD align="center">paged<TD align="center">visual<TD align="center">&nbsp;</TR>
247+
<TR><TH>screen<TD align="center">continuous<TD align="center">visual<TD align="center">&nbsp;</TR>
248+
<TR><TH>tty<TD align="center">continuous<TD align="center">visual<TD align="center">grid</TR>
249+
<TR><TH>tv<TD align="center">paged/continuous<TD align="center">visual/aural<TD align="center">&nbsp;</TR>
250+
</TABLE>
239251

240252
</BODY>
241253
</html>

0 commit comments

Comments
 (0)