drafts: css3-exclusions/Exclusions.src.html@757d9e99cd55 (annotated)

css3-exclusions/Exclusions.src.html@757d9e99cd55 (annotated)

css3-exclusions/Exclusions.src.html

Thu, 12 Apr 2012 12:57:08 -0700

author: Vincent Hardy <vhardy@adobe.com>
date: Thu, 12 Apr 2012 12:57:08 -0700
changeset 5468: 757d9e99cd55
parent 5466: fb0270eb9aa2
child 5488: d3306d846020
permissions: -rw-r--r--

Added note about animated images, as per https://www.w3.org/Style/CSS/Tracker/actions/441

 <!DOCTYPE html public '-//W3C//DTD HTML 4.01//EN' 'http://www.w3.org/TR/html4/strict.dtd'>
 <html lang="en">
 <head profile="http://www.w3.org/2006/03/hcard">
   <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
   <title>CSS Exclusions and Shapes Module Level 3</title>
   <link rel="stylesheet" type="text/css" href="../default.css" />
   <style type="text/css">
   /* Alternate stylesheet fonts are here because in some browsers (Opera 11.5) */
   /* The fonts are not applied if only loaded from the alternate stylesheet    */
   /* License font the following two fonts: fonts/Droid-Serif-fontfacekit/Google Android License.txt */
   @import url(fonts/Droid-Serif-fontfacekit/stylesheet.css);
   @import url(fonts/Droid-Sans-Mono-fontfacekit/stylesheet.css);
     .singleImgExample {
     	display: block;
     	margin: auto;
     }
     .example-table {
     	table-layout: fixed;
     	width: 100%;
     }
     .example-table tr td img {
     	width: 90%;
     }
     @media screen and (min-width: 68em){
         .issue-marker {
             position: absolute;
             width: 20ex;
             margin-left: -22ex;
             text-align: right;
             margin-bottom: 1em;
         }
         div.issue-marker .issue-marker {
             position: static;
             width: auto;
             margin-left: 0;
             text-align: right;
         }
         div.issue-marker {
             position: absolute;
             width: 20ex;
             margin-left: -22ex;
         }
     }
     @media screen and (max-width: 68em){
         .issue-marker {
             margin-bottom: 1em;
         }
         .issue-marker a:link {
             padding-left: 0.5em;
         }
     }
       .issue-marker {
           background:#eee;
           border:1px solid #ddd;
           font-size: 1em;
       }
       .issue-marker.wrapper {
           background: none;
           border: none;
       }
       .issue-marker a:link {
           color: #c00;
           background: none;
           font-weight: normal;
           padding-right: 0.5em;
       }
     .issue-details {
         padding:0.5em;
         font-size: 0.8em;
         line-height: 1.5;
     }
     .issue-details p{
         padding:0;
         margin:0;
     }
     .issue-details .status{
         background:#333;
         color:white;
         float:left;
         padding:0.15em 0.8em;
         font-size:0.8em;
         margin-right:0.8em;
         text-transform:uppercase;
     }
   </style>
   <link rel="stylesheet" type="text/css" href="http://www.w3.org/StyleSheets/TR/W3C-ED.css" />
   <link id="st" href="../alternate-spec-style.css" rel="stylesheet"
       type="text/css" title="alternate spec styles">
 </head>
 <body>
     <div id="div-head" class="head">
         <p><a href="http://www.w3.org/"><img id="mobile-logo" alt="W3C" height="53" src=
         "http://www.w3.org/2008/site/images/logo-w3c-mobile-lg" width="90"></a>
         <!--begin-logo-->
         <p><a href="http://www.w3.org/"><img id="logo" alt="W3C" height="48" src=
         "http://www.w3.org/Icons/w3c_home" width="72"></a> <!--end-logo--></p>
         <h1 id="css-exclusions-module">CSS Exclusions and Shapes Module Level 3</h1>
         <h2 class="no-num no-toc">[LONGSTATUS] [DATE]</h2>
         <dl>
             <dt>This version:</dt>
             <dd><a href="http://dev.w3.org/csswg/css3-exclusions/">http://dev.w3.org/csswg/css3-exclusions/</a></dd>
             <!--<dd><a href="[VERSION]">http://www.w3.org/TR/[YEAR]/WD-css3-exclusions-[CDATE]/</a></dd>-->
             <dt>Latest version:</dt>
             <dd><a href="http://www.w3.org/TR/[SHORTNAME]/">http://www.w3.org/TR/[SHORTNAME]/</a></dd>
             <dt>Editor's Draft:</dt>
             <dd><a href="http://dev.w3.org/csswg/[SHORTNAME]/">http://dev.w3.org/csswg/[SHORTNAME]/</a>
             <dt>Previous version:</dt>
             <dd>None</dd>
             <dt>Editors:</dt>
             <dd class="vcard"><span class="fn">Vincent Hardy</span>, <span class="org">Adobe Systems, Inc.</span>, <span class="email">vhardy@adobe.com</span></dd>
             <dd class="vcard"><span class="fn">Rossen Atanassov</span>, <span class="org">Microsoft Corporation</span>, <span class="email">ratan@microsoft.com</span></dd>
             <dt>Issues List:</dt>
             <dd><a href="https://www.w3.org/Bugs/Public/buglist.cgi?query_format=advanced&product=CSS&component=Exclusions&resolution=---&cmdtype=doit">in Bugzilla</a></dd>
             <dt>Discussion:</dt>
             <dd><a href="http://lists.w3.org/Archives/Public/www-style/">www-style@w3.org</a> with subject line "<code>[css3-exclusions] message topic</code>"
         </dl>
         <!--copyright-->
         <hr title="Separator for header">
     </div>
     <h2 class="no-num no-toc" id="abstract">Abstract</h2>
     <p>
         CSS Exclusions define arbitrary areas around which <a href="http://www.w3.org/TR/CSS2/visuren.html#inline-boxes">inline content</a> ([[!CSS21]]) content can flow.
     CSS Exclusions can be defined on any CSS block-level elements. CSS
     Exclusions extend the notion of content wrapping previously limited to
     floats.</p>
     <p>CSS Shapes control the geometric shapes used for wrapping inline flow
     content outside or inside an element. CSS Shapes can be applied to any
     element. A circle shape on a float will cause inline content to wrap around
     the circle shape instead of the float's bounding box.</p>
     <p>Combining CSS Exclusions and CSS Shapes allows sophisticated layouts,
     allowing interactions between shapes in complex positioning schemes.</p>
     <h2 class="no-num no-toc" id="status">Status of this document</h2>
     <!--status-->
     <p>This is the First Public Working Draft of the CSS Exclusions and Shapes Level 3 Module.</p>
     <h2 class="no-num no-toc" id="contents">Table of contents</h2>
     <!--toc-->
     <h2 id="intro">Introduction</h2>
     <p><em>This section is not normative.</em></p>
     <p>
         The exclusions section of this specification defines features that allow inline flow
         content to wrap around outside the <span>exclusion area</span> of elements.
     </p>
     <p>
         The shapes section of the specification defines properties to control the geometry of
         an element's <span>exclusion area</span> as well as the geometry used for wrapping
         an element's inline flow content.
     </p>
     <h2 id="definitions">Definitions</h2>
     <dfn>Exclusion box</dfn>
     <p>
         A <a href="http://www.w3.org/TR/css3-box/">box</a> ([[!CSS3BOX]]) that defines an <span>exclusion area</span> for other boxes. The 'wrap-flow'
         property is used to make an element's generated box an exclusion box. An exclusion box contributes
         its <span>exclusion area</span> to its <a href="http://www.w3.org/TR/CSS2/visudet.html#containing-block-details">
         containing block's</a> <span>wrapping context</span>. An element with a 'float'
         computed value other than 'none' does not become an exclusion.
     </p>
     <dfn>Exclusion area</dfn>
     <div class="issue-marker" data-bug_id="15087" data-bug_status="NEW">
         <a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=15087">Bug-15087</a>
         <div class="issue-details">
             <p class="short-desc">Interaction of floats and exclusions (Howcome's questions)</p>
         </div>
     </div>
     <p>
         The area used for excluding inline flow content around an exclusion element. The
         exclusion area is equivalent to the <a href="http://www.w3.org/TR/CSS2/box.html#box-dimensions">
         border box</a>.
         This specification's
         'shape-outside' property can be used to define arbitrary, non-rectangular exclusion
         areas.
     </p>
     <dfn>Float area</dfn>
     <p>
         The area used for excluding inline flow content around a float element. By default, the
         float area is the <a href="http://www.w3.org/TR/CSS2/box.html#box-dimensions">margin box</a>.
         This specification's
         'shape-outside' property can be used to define arbitrary, non-rectangular float
         areas.
     </p>
     <dfn>Wrapping context</dfn>
     <div class="issue-marker" data-bug_id="15086" data-bug_status="NEW">
         <a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=15086">Bug-15086</a>
         <div class="issue-details">
             <p class="short-desc">should the wrapping context be generic and include floats?</p>
         </div>
     </div>
     <p>
         The wrapping context of a box is a collection of 'exclusion areas'. During layout,
         a box wraps its inline flow content in the area that corresponds to the subtraction of
         its wrapping context from its own <span>content area</span>.
     </p>
     <p>
         A box inherits its
         <a href="http://www.w3.org/TR/CSS2/visudet.html#containing-block-details">containing block's</a>
         wrapping context unless it specifically
         resets it using the 'wrap-through' property.
     </p>
     <dfn>Content area</dfn>
     <p>
         The area used for layout of the inline flow content of a box. By default the
         area is equivalent to the <a href="http://www.w3.org/TR/CSS2/box.html#box-dimensions">content box</a>.
         This specification's 'shape-inside' property can define arbitrary, non-rectangular content areas.
     </p>
     <dfn title="outside-inside">Outside and inside</dfn>
     <p>
         In this specification, 'outside' refers to DOM content that is not a descendant of an element
         while 'inside' refers to the element's descendants.
     </p>
     <h2 id="exclusions">Exclusions</h2>
     <p>
         Exclusion elements define exclusion areas that contribute to their containing block's
         <span>wrapping context</span>. As a consequence, exclusions impact the layout of their
         containing block's descendants.
     <p>
     <p>
         Elements layout their inline content in their <span>content area</span> and wrap around the
         areas in their associated wrapping context. If the element is itself an exclusion, it
         does not wrap around its own exclusion shape and the impact of other exclusions on other
         exclusions is controlled by the 'z-index' property as explained in the
         <a href="#exclusions-order">exclusions order</a> section.
     </p>
         The <a href="#shapes">shape properties</a> can be used to change the shape of
         <span>exclusion areas</span>.
     </p>
     <h3 id="declaring-exclusions">Declaring exclusions</h3>
     <p>
         An element becomes an exclusion when its 'wrap-flow' property has a computed value other than
         'auto'.
     </p>
     <h4 id="wrap-flow-property">The 'wrap-flow' property</h4>
     <table class="propdef">
         <tr>
             <th>Name:</th>
             <td><dfn title="'wrap-flow'">wrap-flow</dfn></td>
         </tr>
         <tr>
             <th>Value:</th>
             <td><var>auto</var> | <var>both</var> | <var>start</var> | <var>end</var> | <var>maximum</var> | <var>clear</var></td>
         </tr>
         <tr>
             <th>Initial:</th>
             <td>auto</td>
         </tr>
         <tr>
             <th>Applies to:</th>
             <td>block-level elements. Does not apply to elements with a 'float' computed value other than
                 <code class="css">none</code></td>
         </tr>
         <tr>
             <th>Inherited:</th>
             <td>no</td>
         </tr>
         <tr>
             <th>Percentages:</th>
             <td>N/A</td>
         </tr>
         <tr>
             <th>Media:</th>
             <td>visual</td>
         </tr>
         <tr>
             <th>Computed&nbsp;value:</th>
             <td>as specified</td>
         </tr>
     </table>
     <p>The values of this property have the following meanings:</p>
     <dl>
         <dt><dfn title="'wrap-flow'!!'auto'">auto</dfn></dt>
         <dd>
             No exclusion is created. Inline flow content interacts with the element as usual.
         </dd>
         <dt><dfn title="'wrap-flow'!!'both'">both</dfn></dt>
         <dd>
             Inline flow content can flow on all sides of the exclusion.
         </dd>
         <dt><dfn title="'wrap-flow'!!'start'">start</dfn></dt>
         <dd>
             Inline flow content can flow before the start edge of the exclusion area but
             must leave the area after the end edge of the exclusion empty.
         </dd>
         <dt><dfn title="'wrap-flow'!!'end'">end</dfn></dt>
         <dd>
             Inline flow content can flow after the end edge of the exclusion area but
             must leave the area before the start edge of the exclusion empty.
         </dd>
         <dt><dfn title="'wrap-flow'!!'maximum'">maximum</dfn></dt>
         <dd>
             Inline flow content can flow on the edge of the exclusion with the largest
             available space for the given line, and must leave the other edge of the exclusion
             empty.
         </dd>
         <dt><dfn title="'wrap-flow'!!'clear'">clear</dfn></dt>
         <dd>
             Inline flow content can only flow on top and bottom edges of the exclusion
             and must leave the areas before the start and after the end edges of the
             exclusion empty.
         </dd>
     </dl>
     <p>
         If the property's computed value is 'auto', the element does not become an
         <span>exclusion</span>.
     </p>
     <p>
         Otherwise, a computed 'wrap-flow' property value of 'both', 'start', 'end', 'maximum' or 'clear' on an
         element makes that element an <span>exclusion element</a>. It's <span>exclusion shape</span>
         is contributed to its containing block's <span>wrapping context</span>, causing the containing block's descendants
         to wrap around its exclusion area.
     </p>
     <div class="figure">
         <img alt="General illustration showing how exclusions combine" src="images/exclusions-illustration.png" width="70%" />
         <p class="caption">Combining exclusions</p>
     </div>
     <p>
         The above figure illustrates how exclusions are combined. The outermost box represents
         an element's content box. The A, B, C and D darker gray boxes represent exclusions
         in the element's wrapping context. A, B, C and D have their respective 'wrap-flow'
         set to 'both', 'start', 'end' and 'clear' respectively. The lighter gray areas show
         the additional areas that are excluded for inline layout as a result of the 'wrap-flow'
         value. For example, the area to the right of 'B' cannot be used for inline layout
         because the 'wrap-flow' for 'B' is 'start'.
     </p>
     <p>
         The background 'blue' area shows what areas are available for the element's inline content layout.
         All areas represented with a light or dark shade of gray are not available for inline
         content layout.
     </p>
     <div class="issue-marker" data-bug_id="15088" data-bug_status="FIXED">
         <a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=15088">Bug-15088</a>
         <div class="issue-details">
             <p class="short-desc">Add an example with auto-height content and z-index for exclusions order.</p>
         </div>
     </div>
     <div class="issue-marker" data-bug_id="15084" data-bug_status="NEW">
         <a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=15084">Bug-15084</a>
         <div class="issue-details">
             <p class="short-desc">Fluidity of the layout with respect to different amounts of content</p>
         </div>
     </div>
     <div class="example">
         <p>
             The 'wrap-flow' property values applied to an absolutely positioned element.
         </p>
 <code class="html"><pre>
 &lt;div id="grid"&gt;
     &lt;div id="exclusion"&gt;Donec metus …&lt;/div&gt;
     &lt;div id="content"&gt;Lorem ipsum…&lt;/div&gt;
 &lt;/div&gt;
 &lt;style type="text/css"&gt;
 #grid {
     width: 100em;
     height: 100em;
     display: grid;
     grid-columns: 50% 20% 20%;
     grid-rows: 40% 20% 40%;
 }
 #exclusion {
     grid-row: 2;
     grid-column: 2;
     wrap-flow: &lt;see below&gt;
 }
 #content {
     grid-row: 1;
     grid-row-span: 3;
     grid-column: 1;
     grid-column-span: 3;
 }
 &lt;/style&gt;
 </pre></code>
         <table class="example-table">
             <tr>
                 <td><code class="html">#exclusion{ wrap-flow: auto; }</code></td>
                 <td><code class="html">#exclusion{ wrap-flow: both; }</code></td>
             </tr>
             <tr>
                 <td><img src="images/exclusion_wrap_side_auto.png" alt="Example rendering for wrap-side: auto" /></td>
                 <td><img src="images/exclusion_wrap_side_both.png" alt="Example rendering for wrap-side: both" /></td>
             </tr>
             <tr>
                 <td><code class="html">#exclusion{ wrap-flow: start; }</code></td>
                 <td><code class="html">#exclusion{ wrap-flow: end; }</code></td>
             </tr>
             <tr>
                 <td><img src="images/exclusion_wrap_side_left.png" alt="Example rendering for wrap-side: start" /></td>
                 <td><img src="images/exclusion_wrap_side_right.png" alt="Example rendering for wrap-side: end" /></td>
             </tr>
             <tr>
                 <td><code class="html">#exclusion{ wrap-flow: maximum; }</code></td>
                 <td><code class="html">#exclusion{ wrap-flow: maximum; }</code></td>
             </tr>
             <tr>
                 <td><img src="images/exclusion_wrap_side_maximum_L.png" alt="Example rendering for wrap-side: maximum" /></td>
                 <td><img src="images/exclusion_wrap_side_maximum_R.png" alt="Example rendering for wrap-side: maximum" /></td>
             </tr>
             <tr>
                 <td><code class="html">#exclusion{ wrap-flow: clear; }</code></td>
                 <td><code class="html">&nbsp;</code></td>
             </tr>
             <tr>
                 <td><img src="images/exclusion_wrap_side_clear.png" alt="Example rendering for wrap-side: clear" /></td>
                 <td>&nbsp;</td>
             </tr>
         </table>
     </div>
     <!-- End section "wrap-flow Property" -->
     <!-- End section "Declaring Exclusions" -->
     <h3 id="scope-and-effect-of-exclusions">Scope and effect of exclusions</h3>
     <p>
         An <span>exclusion</span> affects the inline flow content descended from the exclusion's containing
         blocks (defined in <a href="http://www.w3.org/TR/CSS2/visudet.html#containing-block-details">
         CSS 2.1 10.1</a>) and that of all descendant elements of the same containing
         block. All inline flow content inside the containing block of the exclusions is
         affected. To stop the effect of exclusions defined outside an element, the 'wrap-through'
         property can be used (see the <a href="#propagation-of-exclusions">propagation of exclusions</a>
         section below).
     </p>
     <p>
         For exclusions with 'position:fixed', the containing block is that of the root
         element.
     </p>
     <h4 id="wrap-margin-property">The 'wrap-margin' property</h4>
     <p>
         The 'wrap-margin' property can be used to offset the inline flow content wrapping
         on the outside of exclusions. Offsets created by the 'wrap-margin' property are
         offset from the outside of the exclusion. This property takes on positive values
         only.
     </p>
     <table class="propdef">
         <tr>
             <th>Name:</th>
             <td><dfn title="'wrap-margin'">wrap-margin</dfn></td>
         </tr>
         <tr>
             <th>Value:</th>
             <td><var>&lt;length&gt;</var></td>
         </tr>
         <tr>
             <th>Initial:</th>
             <td>0</td>
         </tr>
         <tr>
             <th>Applies to:</th>
             <td><span>exclusion</span> elements</td>
         </tr>
         <tr>
             <th>Inherited:</th>
             <td>no</td>
         </tr>
         <tr>
             <th>Percentages:</th>
             <td>N/A</td>
         </tr>
         <tr>
             <th>Media:</th>
             <td>visual</td>
         </tr>
         <tr>
             <th>Computed&nbsp;value:</th>
             <td>the absolute length</td>
         </tr>
     </table>
     <!-- End secion "wrap-margin property" -->
     <h4 id="wrap-padding-property">The 'wrap-padding' Property</h4>
     <p>
         The 'wrap-padding' property can be used to offset the inline flow content wrapping
         on the inside of elements. Offsets created by the 'wrap-padding' property are offset
         from the <span>content area</span> of the element. This property takes on positive values only.
     </p>
     <table class="propdef">
         <tr>
             <th>Name:</th>
             <td><dfn title="'wrap-padding'">wrap-padding</dfn></td>
         </tr>
         <tr>
             <th>Value:</th>
             <td><var>&lt;length&gt;</var></td>
         </tr>
         <tr>
             <th>Initial:</th>
             <td>0</td>
         </tr>
         <tr>
             <th>Applies to:</th>
             <td><span>exclusion</span> elements</td>
         </tr>
         <tr>
             <th>Inherited:</th>
             <td>no</td>
         </tr>
         <tr>
             <th>Percentages:</th>
             <td>N/A</td>
         </tr>
         <tr>
             <th>Media:</th>
             <td>visual</td>
         </tr>
         <tr>
             <th>Computed&nbsp;value:</th>
             <td>the absolute length</td>
         </tr>
     </table>
     <!-- End section "wrap-padding property" -->
     <div class="note">Note that the 'wrap-padding' property affects layout of content inside
         the element it applies to while the 'wrap-margin' property affects layout of content
         outside the element.</div>
     <!-- End section "Scope and Effect of Exclusions" -->
     <h3 id="propagation-of-exclusions">Propagation of Exclusions</h3>
     <p>
         By default, an element inherits its parent <span>wrapping context</span>. In other words
         it is subject to the exclusions defined <span title="outside-inside">outside</sapn> the element.
     </p>
     <p>Setting the 'wrap-through' property to 'none' prevents an element from inheriting its parent
         wrapping context. In other words, exclusions defined 'outside' the element, have not effect
         on the element's children layout.
     </p>
     <div class="note">
         Exclusions defined by an element's descendants still contribute to their containing block's
         <span>wrapping context</span>. If that containing block is a child of an element with 'wrap-through'
         set to none, or the element itself, then exclusion still have an effect on the children of that
         containing block element.
     </div>
     <h4 id="wrap-through-property">The 'wrap-through' Property</h4>
     <div class="issue-marker" data-bug_id="15085" data-bug_status="NEW">
         <a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=15085">Bug-15085</a>
         <div class="issue-details">
             <p class="short-desc">do we need wrap-through?</p>
         </div>
     </div>
     <table class="propdef">
         <tr>
             <th>Name:</th>
             <td><dfn title="'wrap-through'">wrap-through</dfn></td>
         </tr>
         <tr>
             <th>Value:</th>
             <td><var>wrap</var> | <var>none</var></td>
         </tr>
         <tr>
             <th>Initial:</th>
             <td>wrap</td>
         </tr>
         <tr>
             <th>Applies to:</th>
             <td>block-level elements</td>
         </tr>
         <tr>
             <th>Inherited:</th>
             <td>no</td>
         </tr>
         <tr>
             <th>Percentages:</th>
             <td>N/A</td>
         </tr>
         <tr>
             <th>Media:</th>
             <td>visual</td>
         </tr>
         <tr>
             <th>Computed&nbsp;value:</th>
             <td>as specified</td>
         </tr>
     </table>
     <p>The values of this property have the following meanings:</p>
     <dl>
         <dt><dfn title="'wrap-through'!!'wrap'">wrap</dfn></dt>
         <dd>
             The element inherits its parent node's <span>wrapping context</span>. Its descendant
             inline content wraps around exclusions defined <span title="outside-inside">outside</span>
             the element.
         </dd>
     </dl>
     <dl>
         <dt><dfn title="'wrap-through'!!'none'">none</dfn></dt>
         <dd>
             The element does not inherit its parent node's <span>wrapping context</span>. Its
             descendants are only subject to exclusion shapes defined <span title="outside-inside">inside</span>
             the element.
         </dd>
     </dl>
     <div class="example">
         <p>
             Using the 'wrap-through' property to control the effect of exclusions.
         </p>
 <pre><code class="html">
 &lt;style type="text/css"&gt;
     #grid {
         display: grid;
         grid-columns: 25% 50% 25%;
         grid-rows: 25% 25% 25% 25%;
     }
     #exclusion {
         grid-row: 2;
         grid-row-span: 2;
         grid-column: 2;
         wrap-flow: &lt;see below&gt;
     }
     #rowA, #rowB {
         grid-row-span: 2;
         grid-column: 1;
         grid-column-span: 3;
     }
     #rowA {
         grid-row: 1;
     }
     #rowB {
         grid-row: 3;
     }
     &lt;/style&gt;
 &lt;style type="text/css"&gt;
     .exclusion  {
     	wrap-flow: both;
     	position: absolute;
     	left: 20%;
     	top: 20%;
     	width: 50%;
     	height: 50%;
     	background-color: rgba(220, 230, 242, 0.5);
     }
 &lt;/style&gt;
 &lt;div id="grid"&gt;
     &lt;div class=”exclusion”&gt;&lt;/div&gt;
     &lt;div id="rowA" style=”wrap-through: wrap;”&gt; Lorem ipsum dolor sit amet...&lt;/div&gt;
     &lt;div id="rowB" style=”wrap-through: none;”&gt; Lorem ipsum dolor sit amet...&lt;/div&gt;
 &lt;/div&gt;
 </code></pre>
         <img class="singleImgExample" src="images/exclusion_wrap_through.png" alt="Example rendering of wrap-through: wrap | none" style="max-width:40%"/>
     </div>
     <!-- End section "wrap-through property" -->
     <h4 id="wrap-shorthand-property">The 'wrap' Shorthand Property</h4>
     <table class="propdef">
         <tr>
             <th>Name:</th>
             <td><dfn title="'wrap'">wrap</dfn></td>
         </tr>
         <tr>
             <th>Value:</th>
             <td><var>&lt;wrap-flow&gt;</var> || <var>&lt;wrap-margin&gt;</var> [ / <var>&lt;wrap-padding&gt;</var>]</td>
         </tr>
         <tr>
             <th>Initial:</th>
             <td>see individual properties</td>
         </tr>
         <tr>
             <th>Applies to:</th>
             <td>block-level elements</td>
         </tr>
         <tr>
             <th>Inherited:</th>
             <td>no</td>
         </tr>
         <tr>
             <th>Percentages:</th>
             <td>N/A</td>
         </tr>
         <tr>
             <th>Media:</th>
             <td>visual</td>
         </tr>
         <tr>
             <th>Computed&nbsp;value:</th>
             <td>see individual properties</td>
         </tr>
     </table>
     <p>
         The 'wrap' property is a shorthand property for setting the exclusions properties
         at the same place in the style sheet.
     </p>
     <!-- End section "wrap shorthand property" -->
     <!-- End section "Propagation of Exclusions" -->
     <h3 id="exclusions-order">Exclusions order</h3>
     <p>
         Exclusions follow the painting order (See [[!CSS21]] Appendix E). Exclusions are
         applied in reverse to the document order in which they are defined. The last exclusion
         appears on top of all other exclusion, thus it affects the inline flow content of
         all other preceding exclusions or elements descendant of the same containing block.
         To change the ordering of exclusions with 'position' property computed to a value
         other than 'static', 'z-index' can be used. Exclusions with 'position' property
         computed to 'static' are not affected by the 'z-index' property, thus follow the painting
         order.
     </p>
     <div class="example">
         <p>Ordering of exclusions.</p>
 <pre><code class="html">
 &lt;style type="text/css"&gt;
     .exclusion  {
     	wrap-flow: both;
     	position: absolute;
     	width: 50%;
     	height: auto;
     }
 &lt;/style&gt;
 &lt;div class=”exclusion” style=”top: 0px; left: 0px;”&gt;
     Lorem ipsum dolor sit amet...
 &lt;/div&gt;
 &lt;div id="orderedExclusion" class=”exclusion” style=”top: 25%; left: 25%;”&gt;
     Lorem ipsum dolor sit amet...
 &lt;/div&gt;
 &lt;div class=”exclusion” style=”top: 50%; left: 50%;”&gt;
     Lorem ipsum dolor sit amet...
 &lt;/div&gt;
 </code></pre>
     <table class="example-table">
         <tr>
             <td style="width:50%"><code class="html">#orderedExclusion{ z-index: auto; }</code></td>
             <td style="width:50%"><code class="html">#orderedExclusion{ z-index: 1; }</code></td>
         </tr>
         <tr>
             <td><img class="singleImgExample" src="images/exclusion_ordering.png" alt="Example rendering of default exclusion ordering." /></td>
             <td><img class="singleImgExample" src="images/exclusion_ordering_z_order.png" alt="Example rendering of default exclusion ordering." /></td>
         </tr>
     </table>
     </div>
     <!-- End section "Order of Exclusions" -->
     <div class="issue-marker" data-bug_id="15183" data-bug_status="NEW">
         <a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=15183">Bug-15183</a>
         <div class="issue-details">
             <p class="short-desc">Is the CSS exclusions processing model incorrect?</p>
         </div>
      </div>
     <div class="issue-marker" data-bug_id="15083" data-bug_status="NEW">
         <a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=15083">Bug-15083</a>
         <div class="issue-details">
             <p class="short-desc">Concerns over Error accumulation vs. performance</p>
         </div>
     </div>
     <p class="issue">
         The rules for exclusions order and exclusions on absolutely positioned elements
         (particularly those with static position) build this exclusions model on top of
         the absolute positioning model in CSS Level 2, rather than on top of floats, the
         existing exclusion model in CSS Level 1 and 2. The CSS Working Group has not reached
         consensus on whether it intends to base the new exclusions features in this specification
         on top of absolute positioning (as these sections of this specification do) or on
         top of floats.
     </p>
     <p class="note">
         This module does not depend on any particular positioning scheme.
     </p>
         <h3 id="exclusions-processing-model">Processing model</h3>
         <h4 id="exclusions-processing-model-description">Description</h4>
         <p>Applying exclusions is a two-step process:</p>
         <ul>
             <li><strong>Step 1</strong>: resolve exclusion boxes belonging to each wrapping context</li>
             <li><strong>Step 2</strong>: resolve wrapping contexts and layout each containing block in turn:
                 <ul>
                     <li><strong>Step 2-A</strong>: resolve the position and size of exclusions</li>
                     <li><strong>Step 2-B</strong>: layout containing block, wrapping around exclusion areas</li>
                 </ul>
                 </li>
         </ul>
         <h4 id="step-1-resolve-exclusion-boxes-belonging-to-each-wrapping-context">Step 1: resolve exclusion boxes belonging to each wrapping context</h4>
         <p>In this step, the user agent determines which <a href="http://www.w3.org/TR/CSS2/visudet.html#containing-block-details">containing block</a> each
             <span>exclusion area</span> belongs to. This is a simple step, based on the
             definition of containing blocks and elements with a computed value for 'wrap-flow'
             that is not <code class="css">none</code>.</p>
         <h4 id="step-2-resolve wrapping-contexts-layout-containing-blocks">Step 2: resolve wrapping contexts and layout containing blocks</h4>
         <p>In this step, starting from the
             top of the rendering tree, the the agent processes each containing block in two sub-steps.</p>
         <h4 id="step-2-A-resolve-exclusions-position-and-size">Step 2-A: resolve exclusions position and size</h4>
         <p>Resolving the position and size of exclusions in the wrapping context may or may not require
             a layout. For example, if an exclusion is absolutely positioned and sized, there is no need to
             perform a layout to resolve its position and size. In other situations, laying out the
             containing block's content is required.</p>
         <p>When a layout is required,
             it is carried out without applying any exclusion area. In other words, the containing
             block is laid out without a wrapping context. </p>
         <p>Step 2-A yields a position and size
             for all exclusion areas in the wrapping context.</p>
         <p>Scrolling is ignored in this step when resolving the position and size of
             'position:fixed' <span>exclusions</span>.</p>
         <h4 id="step-2-B-layout-containing-block-applying-wrapping">Step 2-B: layout containing block applying wrapping</h4>
         <p>Finally, the content of the containing block is laid out, with the
             inline content wrapping around the wrapping content's exclusion areas.</p>
         <h4 id="exclusions-processing-model-example">Example</h4>
         <p>This section illustrates the exclusions processing model with an example. It is meant
             to be simple. Yet, it contains enough complexity to address the issues of
             layout dependencies and re-layout.</p>
         <p>The code snippet in the following example has two exclusions affecting
             the document's inline content.</p>
         <div class="example">
         <pre class="code idl">
     &lt;html&gt;
         &lt;body&gt;
             &lt;div id="d1" style="width:100%;height:auto;position:relative"&gt;
                 Lorem ipsusm ...
                 &lt;p id="e1" style="wrap-flow: both;position:absolute; left:50%; top:50%;
                                   width:40%;height:40%; margin-left:-20%;" &gt;&lt/p&gt;
             &lt;/div&gt;
             &lt;div id="d2" style="width:100%;height:auto;position:static"&gt;
                 Lorem ipsusm ...
                 &lt;p id="e2" style="wrap-flow: both;position:absolute; right:5ex; top:1em;
                                   width:12ex;height:10em; margin-left:-20%;" &gt;&lt/p&gt;
             &lt;/div&gt;
         &lt;/body&gt;
     &lt;/html&gt;
         </pre>
         </div>
         <p>The following figures illustrate:</p>
         <ul>
             <li>the document's DOM tree</li>
             <li>the layout tree of generated block boxes</p>
         </ul>
         <div class="figure">
             <img src="images/processing-model-example-dom.svg" width="200" />
             <p class="caption">DOM tree</p>
         </div>
         <div class="figure">
             <img src="images/processing-model-example-layout-tree.svg" width="250" />
             <p class="caption">Layout tree of generated block boxes</p>
         </div>
         <h5>Step 1: resolve exclusion boxes belonging to each wrapping context</h5>
         <p>The figures illustrate how the boxes corresponding to the element sometimes
             have a different containment hierarchy in the layout tree than in the DOM tree.
             For example, the box generated by <code class="idl">e1</code> is positioned in
             its containing block's box, which is the <code class="idl">d1-block</code> box, because
             <code class="idl">e1</code> is absolutely positioned and <code class="idl">d1</code>
             is relatively positioned. However, while <code class="idl">e2</code> is also absolutely
             positioned, its containing block is the initial containing block (ICB). See the
             section 10.1 of the CSS 2.1 specification ([[!CSS21]]) for details.</p>
         <p>As a result of the computation of containing blocks for the tree, the boxes belonging
             to the wrapping contexts of all the elements can be determined:</p>
         <ul>
             <li>The wrapping context for the html element contains the <code class="idl">e2</code> box: WC-1 (Wrapping Context 1)</li>
             <li>The wrapping context for the body element inherits the html element's wrapping context: WC-1</li>
             <li>The wrapping context for <code class="idl">d1</code> inherits the body element's
                 wrapping context and adds the <code class="idl">e1</code> box to it. So the wrapping
                 context is made of both the <code class="idl">e1</code> box and the
                 <code class="idl">e2</code> box: WC-2</li>
             <li>The wrapping context for <code class="idl">d2</code> inherits the body element's
                 wrapping context: WC-1</li>
         </ul>
         <h5>Step 2: resolve wrapping contexts and layout containing blocks</h5>
         <p>In this step, each containing block is processed in turn. For each containing block,
             we (conceptually) go through two phases:</p>
         <ol>
             <li>resolve the wrapping context: resolve the position and size of its exclusions</li>
             <li>layout the containing block</li>
         </ol>
         <p>In our example, this breaks down to:</p>
         <ol>
             <li>resolve the position and size of the exclusions belonging to WC-1: RWC-1 (Resolved Wrapping Context 1).</li>
             <li>layout the initial containing block (i.e., layout its content):
                 <ol>
                     <li>resolve the html element's wrapping context: RWC-1</li>
                     <li>layout the html element:
                         <ol>
                             <li>resolve the body element's wrapping context: RWC-1</li>
                             <li>layout the body element:
                                 <ol>
                                     <li>resolve the d1 element's wrapping context: RWC-2</li>
                                     <li>layout the d1 element</li>
                                     <li>resolve the d2 element's wrapping context: RWC-1</li>
                                     <li>layout the d2 element</li>
                                 </ol>
                             </li>
                         </ol>
                     </li>
                 </ol>
                 </li>
         </ol>
         <h6>Resolving RWC-1</h6>
         <p>The top-most wrapping context in the layout tree contains the <code class="idl">e2</code>
             exclusion. Its position and size needs to be resolved. In general, computing an
             exclusion's position and size may or may not require laying out other content.
             In our example, no content needs to be laid out to resolve the <code class="idl">e2</code>
             exclusion's position because it is absolutely positioned and its size can be resolved
             without layout either. At this point, RWC-1 is resolved and can be used when
             laying inline content out.</p>
         <h6>Resolving RWC-2</h6>
         <p>The process is similar: the position of the
             <code class="idl">e1</code> exclusion needs to be resolved. Again, resolving the exclusion's
             position and size may require processing the containing block (d1 here).
             It is the case here because the size and position of
             <code class="idl">e1</code> depend on resolving the percentage lengths. The percentages are relative
             to the size of
             <code class="idl">d1</code>'s box. As a result, in order to resolve
             a size for <code class="idl">d1</code>'s box, a first layout of <code class="idl">d1</code>
             is done without any wrapping context (i.e., no exclusions applied). The layout yields a
             position and size for <code class="idl">e1</code>'s box.
         </p>
         <p>At this point, RWC-2 is resolved because the position and size of both
             e1 and e2 are resolved.</p>
         <p class="note">The important aspect of the above processing example is that once an element's wrapping context
             is resolved (by resolving its exclusions' position and size), the position and size of the
             exclusions are not re-processed if the element's size changes between the layout that may be done
             without considering any wrapping context (as for RWC-2) and the layout done with the resolved wrapping context.
             This is what breaks the possible circular dependency between the resolution of wrapping contexts
             and the layout of containing blocks.</p>
     <h3 id="floats-and-exclusions">Floats and exclusions</h3>
     <h4 id="floats-and-exclusions-similarities">Similarities</h4>
     <p>This section is non-normative.</p>
     <p>There are similarities between floats an exclusions in that inline content wraps around floats
         and also wraps around exclusion areas. However, there are very significant differences.</p>
     <h4 id="floats-and-exclusions-differences">Differences</h4>
     <p>This section is non-normative.</p>
     <ul>
         <li><strong>scope</strong>. While floats apply to content that follows in the
             document, exclusions apply to content in their containing block.</li>
         <li><strong>positioning</strong>. Floats are part of the inline flow and 'float' on the
             line box. Authors can control how the floats move on the line box, to the right or to the
             left. By contrast, exclusions can be positioned using any positioning scheme such
             as grid layout ([[CSS3-GRID-LAYOUT]]), flexible box ([[CSS3-FLEXBOX]]) or any other
             CSS positioning scheme.</li>
         <li><strong>separation of concerns</strong>. Making an element a float determines both
             its positioning scheme and its effect on inline content. Making an element an
             exclusion only determines its impact on inline content and does not impose constraints
             on its positioning method.</li>
     </ul>
     <h4 id="floats-and-exclusions-interoperability">Interoperability</h4>
     <h5 id="effect-of-floats-on-exclusions">Effect of floats on exclusions</h5>
     <p>Floats have an effect on the positioning of exclusions and the layout of their inline content. For
         example, if an exclusion is an inline-box which happens to be on the same line as a float,
         its' position, as computed in <a href="step-2-A-resolve-exclusions-position-and-size">Step 2-A</a> will be impacted by the float, as
         is any other inline content.</p>
     <h5 id="effect-of-exclusions-on-floats">Effect of exclusions on floats</h5>
     <p>Exclusions have an effect on the positioning of floats as they have an effect on inline content.
         Therefore, in <a href="step-2-B-layout-containing-block-applying-wrapping">Step 2-B</a>, floats will avoid <span>exclusion areas</span>.</p>
     <!-- End section "Exclusions" -->
     <h2 id="shapes">Shapes</h2>
     <div class="issue-marker" data-bug_id="15091" data-bug_status="NEW">
         <a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=15091">Bug-15091</a><br />
         <div class="issue-details">
             <p class="short-desc">Simplify the syntax for shapes</p>
         </div>
     </div>
     <p>
         Shapes define arbitrary geometric contours around which or into which inline flow
         content flows. There are two different types of shapes – 'outside' and 'inside'.
         The outside shape defines the <span>exclusion area</span> for an <span>exclusion element</span>
         or the <span>float area</span> for a float.
         The inside shape defines an element's <span>content shape</span> and the element's inline
         content will flow within that shape.
     </p>
     <p class="note">It is important to note that while outside shapes only apply to
         <span>exclusions</span> and floats, inside shapes apply to all block-level elements.</p>
     <h3 id="relation-to-box-model-and-float-behavior">Relation to the box model and float behavior</h3>
     <p>
         While the boundaries used for wrapping inline flow content outside and inside
         an element can be defined using shapes, the actual box model does not change. If
         the element has specified margins, borders or paddings they will be computed and
         rendered according to the [[!CSS3BOX]] module.
     </p>
     <p>
         However, floats are an exception. If a float has an outside shape, its positioning
         is resolved as
         <a href="http://www.w3.org/TR/CSS2/visuren.html#float-position">defined</a> in
         [[!CSS21]] but using the
         outside shape's bounding box is used in lieu of the float's margin box.
     </p>
     <div class="example">
         <p>CSS 'shape' and CSS box model relation.</p>
 <pre><code class="html">
 &lt;style type="text/css"&gt;
     .exclusion  {
     	wrap-flow: both;
     	position: absolute;
     	shape-outside: circle(50%, 50%, 50%);
     	border: 1px solid red;
     }
 &lt;/style&gt;
 &lt;div style=”position: relative;”&gt;
     &lt;div class=”exclusion”&gt;&lt;/div&gt;
     Lorem ipsum dolor sit amet...
 &lt;/div&gt;
 </code></pre>
         <img class="singleImgExample" src="images/shapes_CSS2.1_MBP.png" alt="Example rendering of circle shape and box model."  style="max-width:40%"/>
     </div>
       <h3 id="shapes-from-svg-syntax">Shapes from SVG Syntax</h3>
       <p>
           Shapes can be specified using <a href="http://www.w3.org/TR/SVG/shapes.html">SVG basic shapes</a>.
       </p>
       <h4 id="supported-svg-shapes">Supported SVG Shapes</h4>
       The following SVG shapes are supported by the CSS shapes module.
       <dl>
           <dt>rectangle(&lt;length&gt;{4} [ curve &lt;length&gt;{1,2} ]? )</dt>
           <dd>
               <ul>
                   <li>The four values represent <strong>x, y, width and height</strong> - define the bounding box of the rectangle</li>
                   <li>
                       The two 'curve' values represent <strong>
                       rx</strong> and <strong>ry</strong> - define the rounded rectangles, the <strong>x</strong>
                       and <strong>y</strong> axis and radius of the ellipse used to round off the corners
                       of the rectangle
                   </li>
               </ul>
           </dd>
           <dt>circle(&lt;length&gt;{3})</dt>
           <dd>
               <ul>
                   <li>
                       The three values values represent <strong>cx</strong>, <strong>cy</strong>,
                       <strong>r</strong> - The <strong>x</strong> and <strong>y</strong> axis coordinate
                       of the center of the circle and the radius of the circle
                   </li>
               </ul>
           </dd>
           <dt>ellipse(&lt;length&gt;{4})</dt>
           <dd>
               <ul>
                   <li>The four values represent <strong>cx</strong>, <strong>cy</strong>, <strong>rx</strong> and <strong>ry</strong> -
                       The <strong>x</strong> and <strong>y</strong> coordinate of the center of the ellipse and
                       the <strong>x</strong> and <strong>y</strong> axis radius of the ellipse
                   </li>
               </ul>
           </dd>
           <dt>polygon([&lt;fill-rule&gt;,]? &lt;length&gt;{2}#)</dt>
           <dd>
               <ul>
                   <li><strong>fillRule</strong> - The filling rule used to determine the interior of the
                       polygon. See fill-rule property in SVG for details. Possible values are nonzero
                       or evenodd. Default value when omitted is nonzero.</li>
                   <li>
                       The two length values represent <strong>xi</strong> and <strong>yi</strong> -
                       the <strong>x</strong> and <strong>y</strong> axis coordinates of the i-th vertex of the polygon.
                   </li>
               </ul>
               <p>
                   If the polygon is not closed the user-agent will automatically add a new vertex
                   at the end.</p>
               <br/>
           </dd>
       </dl>
       <h4 id='referencing-svg-shapes'>Referencing SVG shapes</h4>
       <p>An SVG shape can be referenced using the <code>url()</code> syntax. The shape can be
           any of the <a href="http://www.w3.org/TR/SVG/shapes.html">SVG basic shapes</a> or a
           <a href="http://www.w3.org/TR/SVG/paths.html">path element</a>.</p>
       <p>In all cases, percentages are resolved from the border box of the element.</p>
       <div class="example">
           <code class="html"><pre>
 &lt;style&gt;
 .in-a-circle {
     shape-inside: url(#circle_shape);
 }
 .in-a-path {
     shape-inside: url(#path-shape);
 }
 &lt;/style&gt;
 &lt;svg ...&gt;
 &lt;circle id="circle_shape" cx="50%" cy="50%" r="50%" /&gt;
 &lt;path id="path-shape" d="..." /&gt;
 &lt;/svg&gt;
 &lt;div class="in-a-circle"&gt;...&lt;/div&gt;
 &lt;div class="in-a-path"&gt;...&lt;/div&gt;
           </pre></code>
       </div>
         <p>
             When using the SVG syntax or referencing SVG elements to define shapes, all the
             lengths expressed in percentages are resolved from the border box of the element.
             The coordinate system for the shape has its origin on the top-left corner of the
             border box with the x-axis running to the right and the y-axis running downwards.
             If the SVG element uses unitless coordinate values, they are equivalent to using
             'px' units. If the border box of the element is dependent on auto sizing (i.e.,
             the element's 'width' or 'height' property is 'auto'), then the percentage values
             resolve to 0.
         </p>
         <!-- End section "Shapes from SVG Syntax -->
       <h3 id="shapes-from-image">Shapes from Image</h3>
       <div class="issue-marker" data-bug_id="15093" data-bug_status="NEW">
           <a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=15093">Bug-15093</a><br />
           <div class="issue-details">
               <p class="short-desc">
                   Do we need to provide properties to repeat exclusion images as for the
                   background-image property?
               </p>
           </div>
       </div>
       <div class="issue-marker" data-bug_id="15090" data-bug_status="NEW">
           <a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=15090">Bug-15090</a><br />
           <div class="issue-details">
               <p class="short-desc">
                 Use the contour() keyword. &lt;img id=shape-me url=foo&gt;&lt;style&gt;#shape-me
                 { shape-outside: contour; }&lt;/style&gt; //equal to 'shape-outside: url(foo)'
                 shape-outside: attr(src as url);
               </p>
           </div>
       </div>
       <div class="issue-marker" data-bug_id="15092" data-bug_status="NEW">
           <a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=15092">Bug-15092</a>
           <div class="issue-details">
               <p class="short-desc">Specify what happens with animated images</p>
           </div>
       </div>
       <p>
           Another way of defining shapes is by specifying a source image whose alpha channel
           is used to compute the inside or outside shape. The shape is computed to be the
           path that encloses the area where the opacity of the specified image is greater
           than the 'shape-image-threshold' value. If the 'shape-image-threshold' is not specified,
           the initial value to be considered is 0.5.
       </p>
       <p class="note">
           Note, images can define cavities and inline flow content should wrap inside
           them. In order to avoid that, another exclusion element can be overlaid.
       </p>
       <p>For animated raster image formats (such as <a href="http://www.w3.org/Graphics/GIF/spec-gif89a.txt">GIF</a>), the first frame of the animation
           sequence is used. For <a href="http://www.w3.org/TR/2002/WD-SVG2Reqs-20020422/">SVG</a> images
           ([[SVG11]]), the image is rendered without animations applied.</p>
       <!-- End section "Shapes from image" -->
       <h3 id="declaring-shapes">Declaring Shapes</h3>
       <p>
           Shapes are declared with the 'shape-outside' or 'shape-inside' properties.
           The 'shape-outside' property changes the geometry of an <span>exclusion element</span>'s
           <span>exclusion area</span> or or a float element's <span>float area</span>.
           If the element is not an <span>exclusion element</span>
           (see the 'wrap-flow' property) or a float, then the 'shape-outside' property has no effect.
       </p>
       <p>
           The 'shape-inside' property defines an element's <span>content area</span> and
           the element's inline flow content wraps into that shape. The 'shape-inside' property
           applies to all block-level elements.
       </p>
       <h4 id="shape-outside-property">The 'shape-outside' Property</h4>
         <table class="propdef">
             <tr>
                 <th>Name:</th>
                 <td><dfn title="'shape-outside'">shape-outside</dfn></td>
             </tr>
             <tr>
                 <th>Value:</th>
                 <td><var>auto</var> | <var>&lt;shape&gt;</var> | <var>&lt;uri&gt;</var></td>
             </tr>
             <tr>
                 <th>Initial:</th>
                 <td>auto</td>
             </tr>
             <tr>
                 <th>Applies to:</th>
                 <td>exclusion elements and floats</td>
             </tr>
             <tr>
                 <th>Inherited:</th>
                 <td>no</td>
             </tr>
             <tr>
                 <th>Percentages:</th>
                 <td>N/A</td>
             </tr>
             <tr>
                 <th>Media:</th>
                 <td>visual</td>
             </tr>
             <tr>
                 <th>Computed&nbsp;value:</th>
                 <td>computed lengths for &lt;shape&gt;, the absolute URI for &lt;uri&gt;, otherwise as specified</td>
             </tr>
         </table>
       <p>The values of this property have the following meanings:</p>
       <dl>
           <dt><dfn title="'shape-outside'!!'auto'">auto</dfn></dt>
           <dd>The shape is computed based on the border box of the element.</dd>
       </dl>
       <dl>
           <dt><dfn title="'shape-outside'!!'&lt;shape&gt;'">&lt;shape&gt;</dfn></dt>
           <dd>
               The shape is computed based on the values of one of 'rectangle', 'circle', 'ellipse'
               or 'polygon'.
           </dd>
       </dl>
       <dl>
           <dt><dfn title="'shape-outside'!!'&lt;uri&gt;'">&lt;uri&gt;</dfn></dt>
           <dd>
               If the &lt;uri&gt; references an SVG shape element, that element defines the shape.
               Otherwise, if the &lt;uri&gt; references an image, the shape is extracted and computed
               based on the alpha channel of the specified image.
               If the &lt;uri&gt; does not reference an SVG shape element or an image, the
               effect is as if the value 'auto' had been specified.
           </dd>
       </dl>
       <div class='figure'>
           <img alt="arbitrary shapes for excluions. Illustrates how content flows around shapes" src="images/shapes-exclusions.png" width="70%"/>
           <p class="caption">Arbitrary shapes for exclusions</p>
       </div>
       <div>
           <p>The above figure shows how 'shape-outside' shapes impact the exclusion areas.
               The red box represents an element's content box and 'A', 'B', 'C' and 'C'
               represent exclusions with a complex shape and their 'wrap-flow' property set
               to 'both', 'start', 'end' and 'clear', respectively.</p>
           <p>As illustrated in the picture, when an exclusion allows wrapping on all sides,
               text can flow inside 'holes' in the exclusion (as for exclusion 'A'). Otherwise,
               the exclusion clears the area on the side(s) defined by wrap flow, as illustrated
               for 'B', 'C' and 'D' above.</p>
       </div>
       <!-- End section "The shape-outside Property" -->
       <h4 id="shape-inside-property">The 'shape-inside' Property</h4>
       <p>
           The 'shape-inside' modifies the shape of the inner inline flow content from rectangular
           content box to an arbitrary geometry.
       </p>
       <table class="propdef">
           <tr>
               <th>Name:</th>
               <td><dfn title="'shape-inside'">shape-inside</dfn></td>
           </tr>
           <tr>
               <th>Value:</th>
               <td><var>outside-shape</var> | <var>auto</var> | <var>&lt;shape&gt;</var> | <var>&lt;uri&gt;</var></td>
           </tr>
           <tr>
               <th>Initial:</th>
               <td>outside-shape</td>
           </tr>
           <tr>
               <th>Applies to:</th>
               <td>block-level elements</td>
           </tr>
           <tr>
               <th>Inherited:</th>
               <td>no</td>
           </tr>
           <tr>
               <th>Percentages:</th>
               <td>N/A</td>
           </tr>
           <tr>
               <th>Media:</th>
               <td>visual</td>
           </tr>
           <tr>
               <th>Computed&nbsp;value:</th>
               <td>computed lengths for &lt;shape&gt;, the absolute URI for &lt;uri&gt;, otherwise as specified</td>
           </tr>
       </table>
     <p>The values of this property have the following meanings:</p>
     <dl>
         <dt><dfn title="'shape-inside'!!'outside-shape'">outside-shape</dfn></dt>
         <dd>
             The shape is computed based on the computed value of the 'shape-outside' property.
         </dd>
     </dl>
     <dl>
         <dt><dfn title="'shape-inside'!!'auto'">auto</dfn></dt>
         <dd>
             The shape is computed based on the content box of the element.
         </dd>
     </dl>
     <dl>
         <dt><dfn title="'shape-inside'!!'&lt;shape&gt;'">&lt;shape&gt;</dfn></dt>
         <dd>
             The shape is computed based on the values of one of 'rectangle',' circle', 'ellipse'
             or 'polygon'.
         </dd>
     </dl>
     <dl>
         <dt><dfn title="'shape-inside'!!'&lt;uri&gt;'">&lt;uri&gt;</dfn></dt>
         <dd>
             If the &lt;uri&gt; references an SVG shape element, that element defines the shape.
               Otherwise, if the &lt;uri&gt; references an image, the shape is extracted and computed
               based on the alpha channel of the specified image.
               If the &lt;uri&gt; does not reference an SVG shape element or an image, the
               effect is as if the value 'auto' had been specified.
         </dd>
     </dl>
     <p>The 'shape-inside' property applies to floats.</p>
     <p>The 'shape-inside' property may not apply on some elements such as elements with a
         computed 'display' value of 'table'.</p>
     <!-- End section "The shape-inside property" -->
     <h4 id="shape-image-threshold-property">The 'shape-image-threshold' Property</h4>
     <p>
         The 'shape-image-threshold' defines the alpha channel threshold used to extract
         the shape using an image. A value of 0.5 means that all the pixels that are more
         than 50% transparent define the path of the exclusion shape. The 'shape-image-threshold'
         applies to both 'shape-outside' and 'shape-inside'.
     </p>
     <p class="note">
         The specified value of 'shape-image-threshold' is applied to both images used for
         'shape-outside' and 'shape-inside'.
     </p>
     <table class="propdef">
         <tr>
             <th>Name:</th>
             <td><dfn title="'shape-image-threshold'">shape-image-threshold</dfn></td>
         </tr>
         <tr>
             <th>Value:</th>
             <td><var>&lt;alphavalue&gt;</var></td>
         </tr>
         <tr>
             <th>Initial:</th>
             <td>0.5</td>
         </tr>
         <tr>
             <th>Applies to:</th>
             <td>block-level elements</td>
         </tr>
         <tr>
             <th>Inherited:</th>
             <td>no</td>
         </tr>
         <tr>
             <th>Percentages:</th>
             <td>alpha channel of the image specified by &lt;uri&gt;</td>
         </tr>
         <tr>
             <th>Media:</th>
             <td>visual</td>
         </tr>
         <tr>
             <th>Computed&nbsp;value:</th>
             <td>The same as the specified value after clipping the &lt;alphavalue&gt; to the range [0.0,1.0].</td>
         </tr>
     </table>
     <p>The values of this property have the following meanings:</p>
     <dl>
         <dt><dfn title="'shape-image-threshold'!!'&lt;alphavalue&gt;'">&lt;alphavalue&gt;</dfn></dt>
         <dd>
             A &lt;number&gt; value used to set the threshold used for extracting a shape from
             an image. Any values outside the range 0.0 (fully transparent) to 1.0 (fully opaque)
             will be clamped to this range.
         </dd>
     </dl>
     <!-- End section "The shape-image-threshold property" -->
     <!--
     <h4 id="shape-shorthand-property">The 'shape' Shorthand Property</h4>
     <table class="propdef">
         <tr>
             <th>Name:</th>
             <td><dfn title="'shape'">shape</dfn></td>
         </tr>
         <tr>
             <th>Value:</th>
             <td><var>&lt;shape-outside&gt;</var> [ / <var>&lt;shape-inside&gt;</var> ] || <var>&lt;shape-image-threshold&gt;</var></td>
         </tr>
         <tr>
             <th>Initial:</th>
             <td>see individual properties</td>
         </tr>
         <tr>
             <th>Applies to:</th>
             <td>block-level elements</td>
         </tr>
         <tr>
             <th>Inherited:</th>
             <td>no</td>
         </tr>
         <tr>
             <th>Percentages:</th>
             <td>N/A</td>
         </tr>
         <tr>
             <th>Media:</th>
             <td>visual</td>
         </tr>
         <tr>
             <th>Computed&nbsp;value:</th>
             <td>see individual properties</td>
         </tr>
     </table>
     <p>
         The 'shape' property is a shorthand property for setting the individual shape properties
         at the same place in a style sheet.
     </p>
     <div class="example">
         <p>Style declaration using the 'shape' shorthand property.</p>
 <pre><code class="html">
 &lt;style type="text/css"&gt;
     .shape {
         shape: rectangle(50px, 50px, 200px, 100px) / url("shape_image.png")  0.7;
     }
 &lt;/style&gt
 </code></pre>
     </div>
     <p class="issue">The example above must be finished.</p>
     -->
     <!-- End section "Shape Shorthand property -->
     <!-- End section "Declaring Shapes" -->
     <p>The shape properties apply to
     <!-- End section "Shapes" -->
     <h2 id="conformance">Conformance</h2>
     <h3 id="conventions">Document Conventions</h3>
     <p>
         Conformance requirements are expressed with a combination of descriptive assertions
         and RFC 2119 terminology. The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”,
         “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in the
         normative parts of this document are to be interpreted as described in RFC 2119.
         However, for readability, these words do not appear in all uppercase letters in
         this specification.
     </p>
     <p>
         All of the text of this specification is normative except sections explicitly marked
         as non-normative, examples, and notes. [[!RFC2119]]
     </p>
     <p>
         Examples in this specification are introduced with the words “for example” or are
         set apart from the normative text with <code>class="example"</code>, like this:
     </p>
     <div class="example">
         <p>This is an example of an informative example.</p>
     </div>
     <p>
         Informative notes begin with the word “Note” and are set apart from the normative
         text with <code>class="note"</code>, like this:
     </p>
     <p class="note">Note, this is an informative note.</p>
       <h3 id="conformance-classes">Conformance Classes</h3>
       <p>Conformance to CSS Exclusions and Shapes is defined for three conformance classes:</p>
       <dl>
           <dt><dfn title="style sheet!!as conformance class">style sheet</dfn></dt>
           <dd>
               A <a href="http://www.w3.org/TR/CSS21/conform.html#style-sheet">CSS style sheet</a>.</dd>
           <dt><dfn>renderer</dfn></dt>
           <dd>
               A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a> that interprets
               the semantics of a style sheet and renders documents that use them.</dd>
           <dt><dfn id="authoring-tool">authoring tool</dfn></dt>
           <dd>
               A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a> that writes
               a style sheet.</dd>
       </dl>
       <p>
           A style sheet is conformant to CSS Exclusions and Shapes if all of its declarations
           that use properties defined in this module have values that are valid according
           to the generic CSS grammar and the individual grammars of each property as given
           in this module.
       </p>
       <p>
           A renderer is conformant to CSS Exclusions and Shapes if, in addition to interpreting
           the style sheet as defined by the appropriate specifications, it supports all the
           features defined by CSS Exclusions and Shapes by parsing them correctly and rendering
           the document accordingly. However, the inability of a UA to correctly render a document
           due to limitations of the device does not make the UA non-conformant. (For example,
           a UA is not required to render color on a monochrome monitor.)
       </p>
       <p>
           An authoring tool is conformant to CSS Exclusions and Shapes if it writes style
           sheets that are syntactically correct according to the generic CSS grammar and the
           individual grammars of each feature in this module, and meet all other conformance
           requirements of style sheets as described in this module.
       </p>
       <h3 id="partial">
           Partial Implementations</h3>
       <p>
           So that authors can exploit the forward-compatible parsing rules to assign fallback
           values, CSS renderers <strong>must</strong> treat as invalid (and <a href="http://www.w3.org/TR/CSS21/conform.html#ignore">
               ignore as appropriate</a>) any at-rules, properties, property values, keywords,
           and other syntactic constructs for which they have no usable level of support. In
           particular, user agents <strong>must not</strong> selectively ignore unsupported
           component values and honor supported values in a single multi-value property declaration:
           if any value is considered invalid (as unsupported values must be), CSS requires
           that the entire declaration be ignored.
       </p>
       <h3 id="experimental">
           Experimental Implementations</h3>
       <p>
           To avoid clashes with future CSS features, the CSS2.1 specification reserves a <a
               href="http://www.w3.org/TR/CSS21/syndata.html#vendor-keywords">prefixed syntax</a>
           for proprietary and experimental extensions to CSS.</p>
       <p>
           Prior to a specification reaching the Candidate Recommendation stage in the W3C
           process, all implementations of a CSS feature are considered experimental. The CSS
           Working Group recommends that implementations use a vendor-prefixed syntax for such
           features, including those in W3C Working Drafts. This avoids incompatibilities with
           future changes in the draft.
       </p>
       <h3 id="testing">
           Non-Experimental Implementations</h3>
       <p>
           Once a specification reaches the Candidate Recommendation stage, non-experimental
           implementations are possible, and implementors should release an unprefixed implementation
           of any CR-level feature they can demonstrate to be correctly implemented according
           to spec.
       </p>
       <p>
           To establish and maintain the interoperability of CSS across implementations, the
           CSS Working Group requests that non-experimental CSS renderers submit an implementation
           report (and, if necessary, the testcases used for that implementation report) to
           the W3C before releasing an unprefixed implementation of any CSS features. Testcases
           submitted to W3C are subject to review and correction by the CSS Working Group.
       </p>
       <p>
           Further information on submitting testcases and implementation reports can be found
           from on the CSS Working Group's website at <a href="http://www.w3.org/Style/CSS/Test/">
               http://www.w3.org/Style/CSS/Test/</a>. Questions should be directed to the <a href="http://lists.w3.org/Archives/Public/public-css-testsuite">
                   public-css-testsuite@w3.org</a> mailing list.
       </p>
       <h3 id="cr-exit-criteria">
           CR Exit Criteria</h3>
       <p>
           For this specification to be advanced to Proposed Recommendation, there must be
           at least two independent, interoperable implementations of each feature. Each feature
           may be implemented by a different set of products, there is no requirement that
           all features be implemented by a single product. For the purposes of this criterion,
           we define the following terms:
       </p>
       <dl>
           <dt>independent </dt>
           <dd>
               each implementation must be developed by a different party and cannot share, reuse,
               or derive from code used by another qualifying implementation. Sections of code
               that have no bearing on the implementation of this specification are exempt from
               this requirement.</dd>
           <dt>interoperable</dt>
           <dd>
               passing the respective test case(s) in the official CSS test suite, or, if the implementation
               is not a Web browser, an equivalent test. Every relevant test in the test suite
               should have an equivalent test created if such a user agent (UA) is to be used to
               claim interoperability. In addition if such a UA is to be used to claim interoperability,
               then there must one or more additional UAs which can also pass those equivalent
               tests in the same way for the purpose of interoperability. The equivalent tests
               must be made publicly available for the purposes of peer review.
           </dd>
           <dt>implementation</dt>
           <dd>
               a user agent which:
               <ol class="inline">
                   <li>implements the specification.</li>
                   <li>is available to the general public. The implementation may be a shipping product
                       or other publicly available version (i.e., beta version, preview release, or “nightly
                       build”). Non-shipping product releases must have implemented the feature(s) for
                       a period of at least one month in order to demonstrate stability.</li>
                   <li>is not experimental (i.e., a version specifically designed to pass the test suite
                       and is not intended for normal usage going forward).</li>
               </ol>
           </dd>
       </dl>
       <p>
           The specification will remain Candidate Recommendation for at least six months.
       </p>
       <h2 class="no-num" id="acknowledgments">Acknowledgments</h2>
       <p>
           This specification is made possible by input from Stephen Zilles, Alexandru Chiculita,
           Andrei Bucur, Mihnea Ovidenie, Peter Sorotokin, Virgil Palanciuc, Alan Stearns,
           Arno Gourdol, Eugene Veselov, Arron Eicholz, Alex Mogilevsky, Chris Jones, Marcus
           Mielke, and the CSS Working Group members.
       </p>
       <h2 class="no-num" id="references">References</h2>
       <h3 class="no-num" id="normative-references">Normative references</h3>
       <!--normative-->
       <h3 class="no-num" id="other-references">Other references</h3>
       <!--informative-->
       <h2 class="no-num" id="index">Index</h2>
       <!--index-->
       <h2 class="no-num" id="property-index">Property index</h2>
       <!-- properties -->
       <h2 class="no-num" id="change-log">Change Log</h2>
       <h3>Since <a href="http://www.w3.org/TR/2011/WD-css3-exclusions-20111213/">December 13th 2011</h3>
       <ul>
           <li>Clarified processing model</li>
           <li>Clarified interaction with floats</li>
       </ul>
   </body>
 </html>
 <!-- Keep this comment at the end of the file
 Local variables:
 mode: sgml
 sgml-declaration:"~/SGML/HTML4.decl"
 sgml-default-doctype-name:"html"
 sgml-minimize-attributes:t
 sgml-nofill-elements:("pre" "style" "br")
 sgml-live-element-indicator:t
 sgml-omittag:nil
 sgml-shorttag:nil
 sgml-namecase-general:t
 sgml-general-insert-case:lower
 sgml-always-quote-attributes:t
 sgml-indent-step:nil
 sgml-indent-data:t
 sgml-parent-document:nil
 sgml-exposed-tags:nil
 sgml-local-catalogs:nil
 sgml-local-ecat-files:nil
 End:
 -->

Mercurial > drafts / annotate

css3-exclusions/Exclusions.src.html@757d9e99cd55 (annotated)

css3-exclusions/Exclusions.src.html