csswg-drafts/css-shapes/Overview.src.html at 730b33577bf6961b2ea1842577efb9aa1260cd40 · w3c/csswg-drafts · GitHub

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<!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 Shapes Module Level 1</title>
  <script src='http://test.csswg.org/harness/annotate.js#css-shapes-1_dev' type='text/javascript' defer></script>
  <link rel="stylesheet" type="text/css" href="../shared/style/default.css" >


  <style type="text/css">
    .singleImgExample {
    	display: block;
    	margin: auto;
    }

    .example-table {
    	table-layout: fixed;
    	width: 100%;
    }

    .example-table tr td img {
    	width: 90%;
    }
  </style>

        <link rel="stylesheet" type="text/css"
         href="issues.css">
       <link rel="stylesheet" type="text/css"
        href="http://www.w3.org/StyleSheets/TR/W3C-ED.css">


       <link id="st" href="../shared/style/alternate-spec-style.css" rel="stylesheet"
              type="text/css" title="alternate spec style">


</head>
<body>
    <div id="div-head" class="head">
        <!--begin-logo-->
        <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>


        <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-shapes-module">CSS Shapes Module Level 1</h1>
        <h2 class="no-num no-toc">[LONGSTATUS] [DATE]</h2>
        <dl>
            <dt>This version:</dt>
            <dd><a href="[VERSION]">[VERSION]</a></dd>

            <dt>Latest version:</dt>
            <dd><a href="http://www.w3.org/TR/[SHORTNAME]/">http://www.w3.org/TR/css-shapes/</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>
            <dd class="vcard"><span class="fn">Alan Stearns</span>, <span class="org">Adobe Systems, Inc.</span>, <span class="email">stearns@adobe.com</span></dd>

            <dt>Issues List:</dt>
            <dd><a href="https://www.w3.org/Bugs/Public/buglist.cgi?query_format=advanced&amp;product=CSS&amp;component=Shapes&amp;resolution=---&amp;cmdtype=doit">in Bugzilla</a></dd>

  <dt>Feedback:</dt>
    <dd><a href="mailto:www-style@w3.org?subject=%5B[css-shapes]%5D%20feedback"
         >www-style@w3.org</a>
         with subject line &ldquo;<kbd>[css-shapes]
         <var>&hellip; message topic &hellip;</var></kbd>&rdquo;
         (<a rel="discussion" href="http://lists.w3.org/Archives/Public/www-style/"
           >archives</a>)

    <dt>Test Suite:</dt>
    <dd><a href="http://test.csswg.org/suites/css3-shapes/nightly-unstable/">http://test.csswg.org/suites/css3-regions/nightly-unstable/</a></dd>

        </dl>
        <!--copyright-->
        <hr title="Separator for header">
    </div>

    <h2 class="no-num no-toc" id="abstract">Abstract</h2>

    <p>CSS Shapes control the geometric shapes used
        for wrapping inline flow content outside an element.
        For Level 1, CSS Shapes can be applied to floats.
        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 class="note">
        Future levels of CSS Shapes will allow use of shapes
        on elements other than floats
    </p>

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

<p>A previous version of this draft has been published as part of the
Working Draft <a
href="http://www.w3.org/TR/2012/WD-css3-exclusions-20120503/"
>“<cite>CSS Exclusions and Shapes</cite>” dated 3 May 2012.</a>

    <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>
        This specification defines properties to control the geometry of
        an element's <span>float area</span>.
    </p>

    <h2 id="definitions">Definitions</h2>

    <p><dfn>Wrap</dfn>

    <p>
      This specification uses the term 'wrap' to refer to flowing content around the sides of a float area. Content wraps around the right side of a left-floated box, and content wraps around the left side of a right-floated box. Line boxes next to a float are shortened as necessary to avoid intersections with the float area.
    </p>

    <p><dfn>Float area</dfn>

    <p>
      The area used
      for wrapping (or flowing) content
      around a float element.
      The rules for float behavior
      use the sides of the float area
      to determine where content flows.
      By default,
      the float area is the float element's
      <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>

    <h2 id="shapes">Shapes</h2>

    <p>
        Shapes define arbitrary geometric contours around which inline
        content flows. The shape-outside property defines the <span>float area</span> for a float.
    </p>

    <p class="note">
        If a user agent implements both CSS Shapes and CSS Exclusions,
        the shape-outside property defines
        the exclusion area for an exclusion.
    </p>

    <p class="note">
        A future level of CSS Shapes will define a shape-inside property,
        which will define a shape to wrap content within the element.
    </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 a float
        can be defined using shapes,
        the actual box model does not change.
        If the element has specified
        margins, borders or padding
        they will be computed and rendered
        according to the [[!CSS3BOX]] module.
    </p>

    <p>
      When a shape is used to define
      a <span>float area</span>,
      the shape is clipped
      to the float's margin box.
      In other words,
      a shape can only ever reduce
      a <span>float area</span>,
      not increase it.
      A reduced float area may have no effect
      on some line boxes
      that would normally be affected by the float.
    </p>

      <div class="example">
          <p>
              In the following example
              the left and right floating
              <code class="html">div</code> elements
              specify a triangular shape
              using the 'shape-outside' property.
          </p>

<pre><code class="html">
&lt;div style="text-align:center;"&gt;
      &lt;div id="float-left"&gt;&lt;/div&gt;
      &lt;div id="float-right"&gt;&lt;/div&gt;
      &lt;div&gt;
      Sometimes a web page's text content appears to be
      funneling your attention towards a spot on the page
      to drive you to follow a particular link.  Sometimes
      you don't notice.
      &lt;/div&gt;
&lt;/div&gt;

&lt;style type="text/css"&gt;
#float-left {
      shape-outside: polygon(0 0, 100% 100%, 0 100%);
      float: left;
      width: 40%;
      height: 12ex;
  }

#float-right {
      shape-outside: polygon(100% 0, 100% 100%, 0 100%);
      float: right;
      width: 40%;
      height: 12ex;
  }
  &lt;/style&gt;
&lt;/div&gt;</code></pre>

        <img class="singleImgExample" src="images/float-shape-outside.png" alt="Using the shape-outside property with a float"/>
      </div>

      <div class="example">
        <p>
          Since shapes are clipped to the float's margin box,
          adding this shape to the left float above
          would result in the same rendering.
        <p>
<pre><code class="css">
      shape-outside: polygon(0 0, 500% 500%, 0 500%);
</code></pre>
      </div>

      <div class="example">
        <p>
          A shape with no extent will create
          a <span>float area</span> with no extent.
          Because wrapping only considers the float area,
          the shape below applied to a left float
          will allow inline content
          to flow through all of the float's box.
        <p>
<pre><code class="css">
      shape-outside: rectangle(0,0,0%,0%);
</code></pre>
      </div>

      <div class="example">
        <p>
          A shape-outside can create open areas
          on both the left and right
          of a float area.
          Content still wraps only on one side
          of a float in this case.
          In the picture,
          the shape is rendered in blue,
          and the content area outside the shape in mauve.
        <p>
<pre><code class="css">
      shape-outside: polygon(50px 0px, 100px 100px, 0px 100px);
</code></pre>
      <img class="singleImgExample" src="images/float-side-example.png" alt="Wrapping around right side of a left-float float area"/>
      </div>

      <div class="example">
        <p>
          The following styling creates
          a shape much smaller than
          the float's content area,
          and adds a margin-top to the float.
          In the picture,
          the shape is rendered in blue,
          the content area outside the shape in mauve,
          and the margin area of the float box in yellow.
          The inline content only wraps around the shape,
          and otherwise overlays the rest
          of the float margin box.
        </p>
<pre><code class="html">
.float-left {
      shape-outside: polygon(0% 50%, 50% 100%, 0 100%);
      float: left;
      width: 100px;
      height: 100px;
      margin-top: 20px;
}
</code></pre>
        <img class="singleImgExample" src="images/float-margin-example.png" alt="Adding margin-top to a float with a small shape-outside"/>

        <p>
          The next picture shows a possible result
          if two of these floats
          were stacked next to each other.
          Note that the floats are positioned
          using their margin boxes,
          not the float area.
        </p>
        <img class="singleImgExample" src="images/stacked-float-example.png" alt="Stacking two floats with a small shape-outside"/>
      </div>

      <h3 id="basic-shapes-from-svg-syntax">Basic Shapes</h3>
      <p>
          Shapes can be specified using
          syntax similar to SVG's <a href="http://www.w3.org/TR/SVG/shapes.html">basic shapes</a>.
          The definitions use
          <code><a href="http://www.w3.org/TR/css3-values/#lengths">&lt;length&gt;</a></code> type and the
          <code><a href="http://www.w3.org/TR/css3-values/#percentages">&lt;percentage&gt;</a></code>
          types [[!CSS3VAL]].
          When using this syntax
          to define shapes,
          the relevant box is determined
          by the computed value of the
          <a href="http://www.w3.org/TR/css3-ui/#box-sizing">'box-sizing'</a>
          property.
          The coordinate system for the shape
          has its origin on the top-left corner of the
          relevant box with the x-axis
          running to the right
          and the y-axis running downwards.
          All the lengths expressed in percentages
          are resolved from the used dimensions
          of the relevant box.
          For the radius <code>r</code> of the <code>circle</code> shape,
          a percentage value is resolved as
          <a href="http://www.w3.org/TR/SVG/coords.html#Units">specified</a>
          in the SVG recommendation [[!SVG11]].
      </p>


      <h4 id="supported-basic-shapes">Supported Shapes</h4>
      <p>The following basic shapes are supported.
      <dl>
          <dt><dfn id="rectangle">rectangle</dfn>([&lt;length&gt;|&lt;percentage&gt;][, [&lt;length&gt;|&lt;percentage&gt;]]{3,5})</dt>
          <dd>
              <ul>
                  <li>
                      The first four values represent
                      <strong>x, y, width</strong> and
                      <strong>height</strong>
                      of the rectangle.
                      Negative values for width and height are invalid.
                  </li>
                  <li>
                      The last two optional values represent
                      <strong> rx</strong> and <strong>ry</strong>.
                      For rounded rectangles they define
                      the x-axis radius and y-axis radius
                      of the ellipse used to round off
                      the corners of the rectangle.
                      Negative values for rx and ry are invalid.
                      See notes below on edge cases for these values.
                  </li>
              </ul>
          </dd>
          <dt><dfn id="inset-rectangle">inset-rectangle</dfn>([&lt;length&gt;|&lt;percentage&gt;][, [&lt;length&gt;|&lt;percentage&gt;]]{3,5})</dt>
          <dd>
              <ul>
                  <li>
                      The first four values represent the
                      <strong>top, right, bottom</strong> and
                      <strong>left</strong> offsets
                      from the content rectangle inward
                      that define the positions
                      of the edges
                      of the inset rectangle.
                      Negative values for any
                      of these insets are invalid.
                  </li>
                  <li>
                      The last two optional values represent
                      <strong> rx</strong> and <strong>ry</strong>.
                      For rounded inset rectangles they define
                      the x-axis radius and y-axis radius
                      of the ellipse used to round off
                      the corners of the inset rectangle.
                      Negative values for rx and ry are invalid.
                      See notes below on edge cases for these values.
                  </li>
              </ul>
          </dd>
          <dt><dfn id="circle">circle</dfn>([&lt;length&gt;|&lt;percentage&gt;][, [&lt;length&gt;|&lt;percentage&gt;]]{2})</dt>
          <dd>
              <ul>
                  <li>
                      The three values values represent
                      <strong>cx</strong>,
                      <strong>cy</strong>,
                      and <strong>r</strong>.
                      They define the x-axis and y-axis coordinates
                      of the center of the circle
                      and the radius of the circle.
                      A negative value for r is invalid.
                  </li>
              </ul>
          </dd>
          <dt><dfn id="ellipse">ellipse</dfn>([&lt;length&gt;|&lt;percentage&gt;][, [&lt;length&gt;|&lt;percentage&gt;]]{3})</dt>
          <dd>
              <ul>
                  <li>
                      The four values represent
                      <strong>cx</strong>,
                      <strong>cy</strong>,
                      <strong>rx</strong>, and
                      <strong>ry</strong>.
                      They define the x-axis and y-axis coordinates
                      of the center of the ellipse
                      and the x-axis and y-axis radius
                      of the ellipse.
                      Negative values for rx and ry are invalid.
                  </li>
              </ul>
          </dd>
          <dt><dfn id="polygon">polygon</dfn>([&lt;fill-rule&gt;,]?[&lt;length&gt;|&lt;percentage&gt;]{2}#)</dt>
          <dd>
              <ul>
                  <li><strong>fill-rule</strong> - The filling rule used to determine the interior of the
                      polygon. See <a href="http://www.w3.org/TR/SVG/painting.html#FillRuleProperty">fill-rule</a> 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>The UA must close a polygon
                by connecting the last vertex
                with the first vertex of the list.</p>
              <br/>
          </dd>
      </dl>

      <p>The values for corner radii
        on rectangle or inset-rectangle
        are determined implicitly
        if either the rx or ry values
        are not specified,
        or are specified but with invalid values.
        If neither rx nor ry are properly specified,
        the values are 0 for both.
        If only one value is properly specified,
        that value is used for both.
        And if the values cause any
        of the curves to overlap,
        the solution for
        <a href="http://www.w3.org/TR/css3-background/#corner-overlap">overlapping curves</a>
        from CSS Backgrounds and Borders [[!CSS3BG]]
        is used to avoid the overlap.
      <p>

      <h4 id='basic-shape-interpolation'>Interpolation of Basic Shapes</h4>

        <p>For interpolating between
            one basic shape and a second,
            the rules described below are applied.
        </p>
        <ul>
            <li>If both basic shapes are of the same type and not of type polygon:
                <ul><li>Interpolate between each value.</li></ul>
            </li>
                <ul><li>Replace the circle/ellipse with a temporary rectangle of equal dimension.</li>
                <li>Set the values for rx and ry on the temporary rectangle to ‘50%’.</li>
                <li>Interpolate between the two rectangles as above.</li></ul>
            </li>
            <li>If one basic shape is an inset-rectangle and the second is of type rectangle, circle or ellipse:
                <ul><li>Replace the inset-rectangle with a temporary rectangle of equal dimension.</li>
                <li>Interpolate between the basic shapes as above.</li></ul>
            <li>If both basic shapes are of type polygon and if both polygons have the same number of vertices:
                <ul><li>Interpolate between each value.</li></ul>
            </li>
            <li>In all other cases:
                <ul><li>No interpolation is specified.</li></ul></li>
            </ul>

      <h3 id="shapes-from-image">Shapes from Image</h3>

      <p>
          Another way of defining shapes
          is by specifying a source image
          whose alpha channel is used
          to compute the 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 0.0.
      </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>

      <div class="example">
        <p>An image is floating to the left of a paragraph. The image shows the 3D version of the
           CSS logo over a transparent background. The logo has a shadow using an alpha-channel.</p>
        <p>The image defines its <span>float area</span> through the 'shape-outside' property.</p>
           <pre><code class="html">
&lt;p&gt;
  &lt;img id="CSSlogo" src="CSS-logo1s.png"/&gt;
  blah blah blah blah...
&lt;/p&gt;

&lt;style&gt;
  #CSSlogo {
    float: left;
    shape-outside: attr(src url);
    shape-image-threshold: 0.1;
  }
&lt;/style&gt;</code></pre>

       <p>The shape-outside property re-uses the url from the src attribute of the img element.</p>
       <p>It is perfectly possible to display an image and use a different image for its
          <span>float area</span>.</p>

       <p>In the figure below, the alpha-channel threshold is represented by the dotted line around
          the CSS logo.</p>
       <p>It's then possible to affect where the lines of the paragraph start in three ways:</p>
       <ol>
         <li>Modifying the alpha channel in the image</li>
         <li>Changing the value of the 'shape-image-threshold' property</li>
         <li>Changing the value of the 'shape-margin' property (see example 8)</li>
       </ol>
        <div class='figure'>
            <img alt="A float shape around an image using its alpha-channel" src="images/shape-outside-image.png" width="70%"/>
            <p class="caption">A float shape around an image using its alpha-channel.</p>
        </div>
      </div>
      <!-- End section "Shapes from image" -->

      <h3 id="declaring-shapes">Declaring Shapes</h3>
      <p>
          Shapes are declared with
          the 'shape-outside' property,
          with possible modifications
          from the 'shape-margin' property.
          The shape defined by
          the 'shape-outside'
          and 'shape-margin' properties
          changes the geometry
          of a float element's
          <span>float area</span>.
      </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;basic-shape&gt;</var> | <var>&lt;image&gt;</var></td>
            </tr>
            <tr>
                <th>Initial:</th>
                <td>auto</td>
            </tr>
            <tr>
                <th>Applies to:</th>
                <td>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;basic-shape&gt;, the image with its URI made absolute, 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 <span>float area</span> uses the margin box as normal.</dd>
      </dl>
      <dl>
          <dt><dfn title="shape-outside!!&lt;basic-shape&gt;">&lt;basic-shape&gt;</dfn></dt>
          <dd>
              The shape is computed based on the values of one of 'rectangle', 'inset-rectangle', 'circle', 'ellipse'
              or 'polygon'.
          </dd>
      </dl>
      <dl>
          <dt><dfn title="shape-outside!!&lt;image&gt;">&lt;image&gt;</dfn></dt>
          <dd>
              The shape is extracted
              and computed based
              on the alpha channel
              of the specified <a href="http://dev.w3.org/csswg/css-values/#images">&lt;image&gt;</a> [[!CSS3VAL]]

              User agents must use the
              <a href="http://www.w3.org/TR/html5/infrastructure.html#cors-enabled-fetch">potentially CORS-enabled fetch</a>
              method defined by the [[!HTML5]] specification
              for all URLs in a shape-outside value.
              When fetching,
              user agents must use "Anonymous" mode,
              set the referrer source
              to the stylesheet's URL
              and set the origin to the URL
              of the containing document.
              If this results in network errors
              such that there is no valid fallback image,
              the effect is as if
              the value 'auto'
              had been specified.
          </dd>
      </dl>
      <!-- End section "The shape-outside 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
        the shape will enclose
        all the pixels
        that are more than 50% opaque.
    </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;threshold&gt;</var></td>
        </tr>
        <tr>
            <th>Initial:</th>
            <td>0.0</td>
        </tr>
        <tr>
            <th>Applies to:</th>
            <td>floats</td>
        </tr>
        <tr>
            <th>Inherited:</th>
            <td>no</td>
        </tr>
        <tr>
            <th>Percentages:</th>
            <td>alpha channel of the image specified by <span>shape-outside</span></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;threshold&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;threshold&gt;">&lt;threshold&gt;</dfn></dt>
        <dd>
            A &lt;number&gt; value that sets
            the threshold used
            for extracting a shape
            from an image.
            The shape is defined
            by the pixels whose alpha value
            is greater than the threshold.
            Any values outside the range
            0.0 (fully transparent)
            to 1.0 (fully opaque)
            will be clamped to this range.
        </dd>
    </dl>
    <div class="note">
      <p>A future level of CSS Shapes may define
        a switch to use the luminance data
        from an image instead of the alpha data.
        When this happens,
        shape-image-threshold will be extended
        to apply its threshold
        to either alpha or luminance,
        depending on the switch state.</p>
    </div>
    <!-- End section "The shape-image-threshold property" -->
    <!-- End section "Declaring Shapes" -->

    <h4 id="shape-margin-property">The 'shape-margin' property</h4>
    <p>
        The 'shape-margin' property adds a margin to a shape-outside.
        This defines a new shape
        that is the smallest contour
        (in the shrink-wrap sense)
        that includes all the points
        that are the shape-margin distance outward
        in the perpendicular direction
        from a point on the underlying shape.
        Note that at points where
        a perpendicular is not defined
        (e.g. sharp points)
        tak
AE7D
e all points
        on the circle centered at the point
        and with a radius of shape-margin.
        This property takes only non-negative values.
    </p>
    <table class="propdef">
        <tr>
            <th>Name:</th>
            <td><dfn title="shape-margin">shape-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>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>the absolute length</td>
        </tr>
    </table>

    <div class="example">
        <p>A 'shape-margin' creating an offset
            from a circlular shape-outside.
            The blue rectangles represent
            inline content affected
            by the shape created
            by the margin.</p>
        <img src="images/shape-margin.png"
            alt="Example of a shape-margin offset"/>
    </div>

    <div class="example">
        <p>If shape-margin is added to the CSS logo from example 6, the line boxes wrapping around the shape are shortened further.</p>
<pre><code class="html">
  #CSSlogo {
    shape-margin: 35px;
  }
</code></pre>
    <div class='figure'>
          <img alt="A float shape around an image using its alpha-channel with a 35 pixels shape-margin" src="images/shape-outside-image-with-margin.png" width="70%"/>
          <p class="caption">A float shape around an image using its alpha-channel with a 35 pixels shape-margin</p>
        </div>
    </div>
    <!-- End secion "shape-margin property" -->
    <!-- End section "Shapes" -->

    <h2 id="conformance">Conformance</h2>
    <!--conformance-->

    <h2 class="no-num" id="acknowledgments">Acknowledgments</h2>
      <p>This specification is made possible by input from
          Andrei Bucur,
          Alexandru Chiculita,
          Arron Eicholz,
          Daniel Glazman,
          Arno Gourdol,
          Zoltan Horvath,
          Chris Jones,
          Bem Jones-Bey,
          Marcus Mielke,
          Alex Mogilevsky,
          Hans Muller,
          Mihnea Ovidenie,
          Virgil Palanciuc,
          Dirk Schulze,
          Peter Sorotokin,
          Bear Travis,
          Eugene Veselov,
          Stephen Zilles
          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 -->

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      <h2 class="no-num" id="change-log">Change Log</h2>

      <h3 class="no-num" >Since <a href="http://www.w3.org/TR/2013/WD-css-shapes-1-20130620/">June 20th 2013</a></h3>
      <ul>
          <li>Future-proof shape-image-threshold to possibly apply to luminance</li>
          <li>Added CORS fetching to shape-outside URLs</li>
          <li>Changed shape-outside value from &lt;uri&gt; to &lt;image&gt;</li>
          <li>Fixed basic shape grammar to use comma separators</li>
          <li>Remove 'percentages based on auto-sizing resolve to 0'</li>
          <li>Change initial value of shape-image-threshold to 0.0</li>
          <li>Change float positioning to be unaffected by shape-outside</li>
          <li>Shapes on floats clipped to float's margin box</li>
          <li>Inline content constrained to at least the float's farthest margin edge</li>
      </ul>

      <h3 class="no-num" >Since <a href="http://www.w3.org/TR/2012/WD-css3-exclusions-20120503/">May 3rd 2012</a></h3>
      <ul>
          <li>Postpone shapes from SVG elements to a future Shapes level</li>
          <li>Postpone shape-inside to a future Shapes level</li>
          <li>split exclusions from shapes into separate modules</li>
          <li>added inset-rectangle() to basic shapes</li>
          <li>Changed shape-inside overflow diagrams to show exclusion behavior</li>
          <li>Changed shape-inside to contribute to the wrapping context</li>
          <li>Defined exclusion edges relative to wrapping content's writing mode</li>
          <li>Made use of start, end, before and after consistent</li>
          <li>Added interpolation for basic shapes</li>
          <li>Changed basic shapes to depend on box specified with box-sizing</li>
          <li>Added overflow behavior for shape-inside.</li>
          <li>Added wrap-flow:minimum.</li>
          <li>Clarified processing model.</li>
          <li>Changed wrap-margin and wrap-padding to shape-margin and shape-padding.</li>
          <li>Removed wrap shorthand.</li>
      </ul>

      <h3 class="no-num" >Since <a href="http://www.w3.org/TR/2011/WD-css3-exclusions-20111213/">December 13th 2011</a></h3>
      <ul>
          <li>Clarified processing model.</li>
          <li>Clarified interaction with floats.</li>
          <li>Clarified that an exclusion element establishes a new block formatting context.</li>
      </ul>

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