W3C home > Mailing lists > Public > public-html-commits@w3.org > August 2008

html5/spec Overview.html,1.1179,1.1180

From: Ian Hickson via cvs-syncmail <cvsmail@w3.org>
Date: Mon, 04 Aug 2008 20:37:03 +0000
To: public-html-commits@w3.org
Message-Id: <E1KQ6nf-0001iG-NV@lionel-hutz.w3.org>

Update of /sources/public/html5/spec
In directory hutz:/tmp/cvs-serv6544

Modified Files:
	Overview.html 
Log Message:
Changes to fix the problems Lachy found. (credit: lh) (whatwg r1988)

Index: Overview.html
===================================================================
RCS file: /sources/public/html5/spec/Overview.html,v
retrieving revision 1.1179
retrieving revision 1.1180
diff -u -d -r1.1179 -r1.1180
--- Overview.html	4 Aug 2008 20:11:38 -0000	1.1179
+++ Overview.html	4 Aug 2008 20:37:00 -0000	1.1180
@@ -15765,27 +15765,6 @@
 
    <dt>If the <code title=attr-img-src><a href="#src">src</a></code>
     attribute is set and the <code title=attr-img-alt><a
-    href="#alt0">alt</a></code> attribute is set to a string with at least
-    one character whose first character is not a U+007B LEFT CURLY BRACKET
-    character ({) or whose last character is not a U+007D RIGHT CURLY BRACKET
-    character (})
-
-   <dd>
-    <p>The image is a key part of the content; the <code
-     title=attr-img-alt><a href="#alt0">alt</a></code> attribute gives a
-     textual equivalent or replacement for the image.</p>
-
-    <p>If the image is available and the user agent is configured to display
-     that image, then the element represents the image specified by the <code
-     title=attr-img-src><a href="#src">src</a></code> attribute.</p>
-
-    <p>Otherwise, the element represents the text given by the <code
-     title=attr-img-alt><a href="#alt0">alt</a></code> attribute. User agents
-     may provide the user with a notification that an image is present but
-     has been omitted from the rendering.</p>
-
-   <dt>If the <code title=attr-img-src><a href="#src">src</a></code>
-    attribute is set and the <code title=attr-img-alt><a
     href="#alt0">alt</a></code> attribute is set to a string whose first
     character is a U+007B LEFT CURLY BRACKET character ({) and whose last
     character is a U+007D RIGHT CURLY BRACKET character (})
@@ -15795,16 +15774,40 @@
      equivalent of the image available. The string consisting of all the
      characters between the first and the last character of the value of the
      <code title=attr-img-alt><a href="#alt0">alt</a></code> attribute gives
-     the kind of image (e.g. photo, diagram, user-uploaded image).</p>
+     the kind of image (e.g. photo, diagram, user-uploaded image). If that
+     value is the empty string (i.e. the attribute is just "<code
+     title="">{}</code>"), then even the kind of image being shown is not
+     known.</p>
 
     <p>If the image is available, the element represents the image specified
      by the <code title=attr-img-src><a href="#src">src</a></code> attribute.</p>
 
     <p>If the image is not available or if the user agent is not configured
      to display the image, then the user agent should display some sort of
-     indicator that the image is not being rendered, providing to the user
-     the information regarding the kind of image that is (as derived from the
-     <code title=attr-img-alt><a href="#alt0">alt</a></code> attribute).</p>
+     indicator that the image is not being rendered, if possible providing to
+     the user the information regarding the kind of image that is (as derived
+     from the <code title=attr-img-alt><a href="#alt0">alt</a></code>
+     attribute).</p>
+
+   <dt>If the <code title=attr-img-src><a href="#src">src</a></code>
+    attribute is set and the <code title=attr-img-alt><a
+    href="#alt0">alt</a></code> attribute is set to a value that isn't
+    matched by the previous two entries (not empty, not "<code
+    title="">{...}</code>"
+
+   <dd>
+    <p>The image is a key part of the content; the <code
+     title=attr-img-alt><a href="#alt0">alt</a></code> attribute gives a
+     textual equivalent or replacement for the image.</p>
+
+    <p>If the image is available and the user agent is configured to display
+     that image, then the element represents the image specified by the <code
+     title=attr-img-src><a href="#src">src</a></code> attribute.</p>
+
+    <p>Otherwise, the element represents the text given by the <code
+     title=attr-img-alt><a href="#alt0">alt</a></code> attribute. User agents
+     may provide the user with a notification that an image is present but
+     has been omitted from the rendering.</p>
 
    <dt>If the <code title=attr-img-src><a href="#src">src</a></code>
     attribute is set and the <code title=attr-img-alt><a
@@ -16421,14 +16424,21 @@
    be given as the contents of the <code title=attr-img-alt><a
    href="#alt0">alt</a></code> attribute.
 
-  <p>In a rare subset of these cases, there might be no alternative text
-   available. This could be the case, for instance, on a photo upload site,
-   if the site has received 8000 photos from a user without the user
-   annotating any of them. In such cases, the <code title=attr-img-alt><a
-   href="#alt0">alt</a></code> attribute's value must be a description of the
-   <em>kind</em> of image, surrounded by braces ("{" and "}"). The kind of
-   image is something along the lines of "photo", "diagram", "painting",
-   "user-uploaded image", etc.
+  <p>In some unfortunate cases, there might be no alternative text available,
+   either because the image is obtained in some automated fashion without any
+   associated alternative text, or because the nature of the images is such
+   that no alternative text can be obtained. In such cases, the <code
+   title=attr-img-alt><a href="#alt0">alt</a></code> attribute's value must
+   be a description of the <em>kind</em> of image, surrounded by braces ("{"
+   and "}"), if that is known. The kind of image is something along the lines
+   of "photo", "diagram", "painting", "user-uploaded image", etc. If even the
+   kind of image cannot be determined, then the string <code
+   title="">{}</code> must be used.
+
+  <p class=note>Such cases are to be kept to an absolute minimum. If there is
+   even the slightest possibility of the author having the ability to provide
+   real alternative text, then it would not be acceptable to provide the
+   "<code title="">{...}</code>"-style value.
 
   <p>In any case, if an image is a key part of the content, the <code
    title=attr-img-alt><a href="#alt0">alt</a></code> attribute must not be
@@ -16468,6 +16478,37 @@
   </div>
 
   <div class=example>
+   <p>A blind user's blog in which a photo taken by the user is shown.
+    Initially, the user might not have any idea what the photo he took shows:</p>
+
+   <pre>&lt;article>
+ &lt;h1>I took a photo&lt;/h1>
+ &lt;p>I went out today and took a photo!&lt;/p>
+ &lt;figure>
+  &lt;img src="photo2.jpeg" alt="{photograph}">
+  &lt;legend>A photograph taken blindly from my front porch.&lt;/legend>
+ &lt;/figure>
+&lt;/article></pre>
+
+   <p>Eventually though, the user might obtain a description of the image
+    from his friends and could then include alternative text:</p>
+
+   <pre>&lt;article>
+ &lt;h1>I took a photo&lt;/h1>
+ &lt;p>I went out today and took a photo!&lt;/p>
+ &lt;figure>
+  &lt;img src="photo2.jpeg" alt="The photograph shows my hummingbird
+  feeder hanging from the edge of my roof. It is half full, but there
+  are no birds around. In the background, out-of-focus trees fill the
+  shot. The feeder is made of wood with a metal grate, and it contains
+  peanuts. The edge of the roof is wooden too, and is painted white
+  with light blue streaks.">
+  &lt;legend>A photograph taken blindly from my front porch.&lt;/legend>
+ &lt;/figure>
+&lt;/article></pre>
+  </div>
+
+  <div class=example>
    <p>Sometimes there simply is no text that can do justice to an image. For
     example, there is little that can be said to usefully describe a
     Rorschach inkblot test.</p>
Received on Monday, 4 August 2008 20:37:37 GMT

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