csswg-drafts/css3-2d-transforms/Overview.html at 857e535d3c76b6a0cf62ffe0a4fa0ffe4dd44f03 · 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>
  <title>CSS 2D Transforms Module Level 3</title>
  <link href=default.css rel=stylesheet type="text/css">

  <style type="text/css">
    .rhs { white-space: pre-wrap; }
    code { font-size: inherit; }
    #box-shadow-samples td { background: white; color: black; }
  </style>
  <link href="http://www.w3.org/StyleSheets/TR/W3C-ED.css" rel=stylesheet
  type="text/css">

 <body>
  <div class=head> <!--begin-logo-->
   <p><a href="http://www.w3.org/"><img alt=W3C height=48
    src="http://www.w3.org/Icons/w3c_home" width=72></a> <!--end-logo-->

   <h1>CSS 2D Transforms Module Level 3</h1>

   <h2 class="no-num no-toc" id=longstatus-date>Editor's Draft 10 February
    2009</h2>

   <dl>
    <dt>This version:

    <dd> <a
     href="http://dev.w3.org/csswg/css3-2d-transforms/">http://dev.w3.org/csswg/css3-2d-transforms/</a>


    <dt>Latest version:

    <dd><a
     href="http://www.w3.org/TR/css3-2d-transforms/">http://www.w3.org/TR/unknown-shortname</a>


    <dt>Previous versions:

    <dt id=editors-list>Editors:

    <dd><a href="mailto:dino@apple.com">Dean Jackson</a> (<a
     href="http://www.apple.com/">Apple Inc</a>)
   </dl>
   <!--begin-copyright-->
   <p class=copyright><a
    href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright"
    rel=license>Copyright</a> &copy; 2009 <a
    href="http://www.w3.org/"><acronym title="World Wide Web
    Consortium">W3C</acronym></a><sup>&reg;</sup> (<a
    href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute
    of Technology">MIT</acronym></a>, <a
    href="http://www.ercim.org/"><acronym title="European Research Consortium
    for Informatics and Mathematics">ERCIM</acronym></a>, <a
    href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C <a
    href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
    <a
    href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a>
    and <a
    href="http://www.w3.org/Consortium/Legal/copyright-documents">document
    use</a> rules apply.</p>
   <!--end-copyright-->
   <hr title="Separator for header">
  </div>

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

  <p>CSS 2D Transforms allows elements rendered by CSS to be transformed in
   two-dimensional space.

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

  <p>This is a public copy of the editors' draft. It is provided for
   discussion only and may change at any moment. Its publication here does
   not imply endorsement of its contents by W3C. Don't cite this document
   other than as work in progress.

  <p>The (<a
   href="http://lists.w3.org/Archives/Public/www-style/">archived</a>) public
   mailing list <a href="mailto:www-style@w3.org">www-style@w3.org</a> (see
   <a href="http://www.w3.org/Mail/Request">instructions</a>) is preferred
   for discussion of this specification. When sending e-mail, please put the
   text &#8220;unknown-shortname&#8221; in the subject, preferably like this:
   &#8220;[<!---->unknown-shortname<!---->] <em>&hellip;summary of
   comment&hellip;</em>&#8221;

  <p>This document was produced by the <a href="/Style/CSS/members">CSS
   Working Group</a> (part of the <a href="/Style/">Style Activity</a>).

  <p>This document was produced by a group operating under the <a
   href="/Consortium/Patent-Policy-20040205/">5 February 2004 W3C Patent
   Policy</a>. W3C maintains a <a href="/2004/01/pp-impl/32061/status"
   rel=disclosure>public list of any patent disclosures</a> made in
   connection with the deliverables of the group; that page also includes
   instructions for disclosing a patent. An individual who has actual
   knowledge of a patent which the individual believes contains <a
   href="/Consortium/Patent-Policy-20040205/#def-essential">Essential
   Claim(s)</a> must disclose the information in accordance with <a
   href="/Consortium/Patent-Policy-20040205/#sec-Disclosure">section 6 of the
   W3C Patent Policy</a>.</p>
  <!--end-status-->

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

  <ul class=toc>
   <li><a href="#introduction"><span class=secno>1 </span>Introduction</a>

   <li><a href="#transform-property"><span class=secno>2 </span> The <span
    class=prop-name>&lsquo;<code
    class=property>transform</code>&rsquo;</span> Property </a>

   <li><a href="#transform-origin-property"><span class=secno>3 </span> The
    <span class=prop-name>&lsquo;<code
    class=property>transform-origin</code>&rsquo;</span> Property </a>

   <li><a href="#transform-functions"><span class=secno>4 </span> The
    Transformation Functions </a>

   <li><a href="#transform-values"><span class=secno>5 </span> Transform
    Values and Lists </a>

   <li><a href="#animation"><span class=secno>6 </span> Transitions and
    animations between transform values </a>

   <li><a href="#dom-interfaces"><span class=secno>7 </span> DOM Interfaces
    </a>
    <ul class=toc>
     <li><a href="#point-interface"><span class=secno>7.1 </span> Point </a>

     <li><a href="#window-interface"><span class=secno>7.2 </span> Window
      </a>

     <li><a href="#cssmatrix-interface"><span class=secno>7.3 </span>
      CSSMatrix </a>

     <li><a href="#csstransformvalue-interface"><span class=secno>7.4 </span>
      CSSTransformValue </a>
    </ul>

   <li><a href="#references"><span class=secno>8 </span>References</a>
    <ul class=toc>
     <li class=no-num><a href="#normative-references">Normative
      references</a>

     <li class=no-num><a href="#other-references">Other references</a>
    </ul>

   <li class=no-num><a href="#property-index">Property index</a>

   <li class=no-num><a href="#index">Index</a>
  </ul>
  <!--end-toc-->

  <h2 id=introduction><span class=secno>1 </span>Introduction</h2>

  <p><em>This section is not normative.</em>

  <p> The CSS <a href="http://www.w3.org/TR/REC-CSS2/visuren.html">visual
   formatting model</a> describes a coordinate system within which each
   element is positioned. Positions and sizes in this coordinate space can be
   thought of as being expressed in pixels, starting in the upper left corner
   of the parent with positive values proceeding to the right and down.

  <p> This coordinate space can be modified with the <span
   class=prop-name>&lsquo;<code class=property><a
   href="#effects">transform</a></code>&rsquo;</span> property. Using
   transform, elements can be translated, rotated and scaled in two
   dimensional space. The coordinate space behaves as described in the <a
   href="http://www.w3.org/TR/SVG/coords.html#EstablishingANewUserSpace">coordinate
   system transformations</a> section of the SVG 1.1 specification. This is a
   coordinate system with two axes: the X axis increases horizontally to the
   right; the Y axis increases vertically downwards.

  <p> Specifying a value other than &lsquo;<code
   class=property>none</code>&rsquo; for the <span
   class=prop-name>&lsquo;<code class=property><a
   href="#effects">transform</a></code>&rsquo;</span> property establishes a
   new <em>local coordinate system</em> at the element that it is applied to.
   Transformations are cumulative. That is, elements establish their local
   coordinate system within the coordinate system of their parent. In this
   way, a <span class=prop-name>&lsquo;<code class=property><a
   href="#effects">transform</a></code>&rsquo;</span> property effectively
   accumulates all the <span class=prop-name>&lsquo;<code class=property><a
   href="#effects">transform</a></code>&rsquo;</span> properties of its
   ancestors. The accumulation of these transforms defines a <em>current
   transformation matrix (CTM)</em> for the element.

  <p> The transform property does not affect the flow of the content
   surrounding the transformed element. However, the value of the overflow
   area takes into account transformed elements. This behavior is similar to
   what happens when elements are translated via relative positioning.
   Therefore, if the value of the <span class=prop-name>&lsquo;<code
   class=property>overflow</code>&rsquo;</span> property is <span
   class=prop-value>&lsquo;<code class=property>scroll</code>&rsquo;</span>
   or <span class=prop-value>&lsquo;<code
   class=property>auto</code>&rsquo;</span>, scrollbars will appear as needed
   to see content that is transformed outside the visible area.

  <p> Any value other than &lsquo;<code class=property>none</code>&rsquo; for
   the transform results in the creation of both a stacking context and a
   containing block. The object acts as though position: relative has been
   specified, but also acts as a containing block for fixed positioned
   descendants.

  <div class=todo> Need to go into more detail here about why fixed
   positioned objects should do this, i.e., that it's much harder to
   implement otherwise.</div>

  <div class=issue> Transforms should perhaps be allowed to affect layout.
   Using the position property to do this seems to be the logical choice, but
   there are lots of questions about how this would work.</div>

  <div class=issue> What do fixed backgrounds do in transforms? They should
   probably ignore the transform completely, since - even transformed - the
   object should be acting as "porthole" through which the fixed background
   can be viewed in its original form.</div>

  <div class=issue> This property should also be applicable to SVG elements.</div>

  <div class=issue> We also need to specify that SVG transforms *do* combine
   with this transform, e.g., if a &lt;foreignObject&gt; is inside
   transformed SVG and then defines a transform of its own. This means we may
   potentially have to examine the current SVG transform and combine with it
   to set the correct transform.</div>
  <!-- ======================================================================================================= -->

  <h2 id=transform-property><span class=secno>2 </span> The <span
   class=prop-name>&lsquo;<code class=property><a
   href="#effects">transform</a></code>&rsquo;</span> Property</h2>

  <p> A two-dimensional transformation is applied to an element through the
   <span class=prop-name>&lsquo;<code class=property><a
   href="#effects">transform</a></code>&rsquo;</span> property. This property
   contains a list of <a href="#transform-functions">transform functions</a>.
   The final transformation value for an element is obtained by performing a
   matrix concatenation of each entry in the list. The set of transform
   functions is similar to those allowed by SVG.

  <table class=propdef>
   <tbody>
    <tr>
     <td> <em>Name:</em>

     <td> <dfn id=effects>transform</dfn>

    <tr>
     <td> <em>Value:</em>

     <td> none | &lt;transform-function&gt; [ &lt;transform-function&gt; ]*

    <tr>
     <td> <em>Initial:</em>

     <td> none

    <tr>
     <td> <em>Applies&nbsp;to:</em>

     <td> block-level and inline-level elements

    <tr>
     <td> <em>Inherited:</em>

     <td> no

    <tr>
     <td> <em>Percentages:</em>

     <td> refer to the size of the element's box
    <tr>
     <td> <em>Media:</em>

     <td> visual

    <tr>
     <td> <em>Computed value:</em>

     <td> Same as specified value.
  </table>
  <!-- ======================================================================================================= -->

  <h2 id=transform-origin-property><span class=secno>3 </span> The <span
   class=prop-name>&lsquo;<code class=property><a
   href="#transform-origin">transform-origin</a></code>&rsquo;</span>
   Property</h2>

  <p> The <span class=prop-name>&lsquo;<code class=property><a
   href="#transform-origin">transform-origin</a></code>&rsquo;</span>
   property establishes the origin of transformation for an element. This
   property is applied by first translating the element by the negated value
   of the property, then applying the element's transform, then translating
   by the property value. This effectively moves the desired transformation
   origin of the element to (0,0) in the local coordinate system, then
   applies the element's transform, then moves the element back to its
   original position.

  <table class=propdef>
   <tbody>
    <tr>
     <td> <em>Name:</em>

     <td> <dfn id=transform-origin>transform-origin</dfn>

    <tr>
     <td> <em>Value:</em>

     <td> [ [ &lt;percentage&gt; | &lt;length&gt; | left | center | right ] [
      &lt;percentage&gt; | &lt;length&gt; | top | center | bottom ]? ] | [ [
      left | center | right ] || [ top | center | bottom ] ]

    <tr>
     <td> <em>Initial:</em>

     <td> 50% 50%

    <tr>
     <td> <em>Applies&nbsp;to:</em>

     <td> block-level and inline-level elements

    <tr>
     <td> <em>Inherited:</em>

     <td> no

    <tr>
     <td> <em>Percentages:</em>

     <td> refer to the size of the element's box

    <tr>
     <td> <em>Media:</em>

     <td> visual

    <tr>
     <td> <em>Computed value:</em>

     <td> For &lt;length&gt; the absolute value, otherwise a percentage
  </table>
  <!-- ======================================================================================================= -->

  <h2 id=transform-functions><span class=secno>4 </span> The Transformation
   Functions</h2>

  <p> The value of the <a class=prop-name href="#effects">transform</a>
   property is a list of &lt;transform-functions&gt;, applied in the order
   provided. The individual transform functions are separated by whitespace.
   The following is a list of allowed transform functions. In this list the
   type &lt;translation-value&gt; is defined as a &lt;length&gt; or
   &lt;percentage&gt; value, and the &lt;angle&gt; type is defined by <a
   href="http://www.w3.org/TR/css3-values/">CSS Values and Units.</a>

  <dl>
   <dt> <span class=prop-value>none</span>

   <dd> specifies an identity transform.

   <dt> <span class=prop-value>matrix(&lt;number&gt;, &lt;number&gt;,
    &lt;number&gt;, &lt;number&gt;, &lt;number&gt;, &lt;number&gt;)</span>

   <dd> specifies a 2D transformation in the form of a <a
    href="http://www.w3.org/TR/SVG/coords.html#TransformMatrixDefined">transformation
    matrix</a> of six values. <span
    class=prop-value>matrix(a,b,c,d,e,f)</span> is equivalent to applying the
    transformation matrix <strong>[a b c d e f]</strong>.

   <dt> <span class=prop-value>translate(&lt;translation-value&gt;[,
    &lt;translation-value&gt;])</span>

   <dd> specifies a <a
    href="http://www.w3.org/TR/SVG/coords.html#TranslationDefined">2D
    translation</a> by the vector [tx, ty], where tx is the first
    translation-value parameter and ty is the optional second
    translation-value parameter. If <em>&lt;ty&gt;</em> is not provided, ty
    has zero as a value.

   <dt> <span class=prop-value>translateX(&lt;translation-value&gt;)</span>

   <dd> specifies a <a
    href="http://www.w3.org/TR/SVG/coords.html#TranslationDefined">translation</a>
    by the given amount in the X direction.

   <dt> <span class=prop-value>translateY(&lt;translation-value&gt;)</span>

   <dd> specifies a <a
    href="http://www.w3.org/TR/SVG/coords.html#TranslationDefined">translation</a>
    by the given amount in the Y direction.

   <dt> <span class=prop-value>scale(&lt;number&gt;[, &lt;number&gt;])</span>


   <dd> specifies a <a
    href="http://www.w3.org/TR/SVG/coords.html#ScalingDefined">2D scale</a>
    operation by the [sx,sy] scaling vector described by the 2 parameters. If
    the second parameter is not provided, it is takes a value equal to the
    first.

   <dt> <span class=prop-value>scaleX(&lt;number&gt;)</span>

   <dd> specifies a scale operation using the [sx,1] scaling vector, where sx
    is given as the parameter.

   <dt> <span class=prop-value>scaleY(&lt;number&gt;)</span>

   <dd> specifies a scale operation using the [1,sy] scaling vector, where sy
    is given as the parameter.

   <dt> <span class=prop-value>rotate(&lt;angle&gt;)</span>

   <dd> specifies a <a
    href="http://www.w3.org/TR/SVG/coords.html#RotationDefined">2D
    rotation</a> by the angle specified in the parameter about the origin of
    the element, as defined by the <em><a
    href="#transform-origin">transform-origin</a></em> property.

   <dt> <span class=prop-value>skewX(&lt;angle&gt;)</span>

   <dd> specifies a <a
    href="http://www.w3.org/TR/SVG/coords.html#SkewXDefined">skew
    transformation along the X axis</a> by the given angle.

   <dt> <span class=prop-value>skewY(&lt;angle&gt;)</span>

   <dd> specifies a <a
    href="http://www.w3.org/TR/SVG/coords.html#SkewYDefined">skew
    transformation along the Y axis</a> by the given angle.

   <dt> <span class=prop-value>skew(&lt;angle&gt; [, &lt;angle&gt;])</span>

   <dd> specifies a <a
    href="http://www.w3.org/TR/SVG/coords.html#SkewXDefined">skew
    transformation along the X and Y axes</a>. The first angle parameter
    specifies the skew on the X axis. The second angle parameter specifies
    the skew on the Y axis. If the second parameter is not given then a value
    of 0 is used for the Y angle (ie. no skew on the Y axis).
  </dl>

  <h2 id=transform-values><span class=secno>5 </span> Transform Values and
   Lists</h2>

  <p> The &lt;translation-value&gt; values are defined as [&lt;percentage&gt;
   | &lt;length&gt;]. All other value types are described <a
   href="http://www.w3.org/TR/REC-CSS2/syndata.html#values">as CSS types</a>.
   If a list of transforms is provided, then the net effect is as if each
   transform had been specified separately in the order provided. For
   example,

  <pre>
  &lt;div style="transform:translate(-10px,-20px) scale(2) rotate(45deg) translate(5px,10px)"/&gt;
  </pre>

  <p> is functionally equivalent to:

  <pre>
  &lt;div style="transform:translate(-10px,-20px)"&gt;
    &lt;div style="transform:scale(2)"&gt;
      &lt;div style="transform:rotate(45deg)"&gt;
        &lt;div style="transform:translate(5px,10px)"&gt;
        &lt;/div&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;
  </pre>

  <div class=example>
   <pre>
  div {
      transform: translate(100px, 100px);
  }
  </pre>
   Move the element by 100 pixels in both the X and Y directions.
   <div class=figure> <img alt="The 100px translation in X and Y"
    src=transform1.png></div>
  </div>

  <div class=example>
   <pre>
  div {
      height: 100px; width: 100px;
      transform: translate(80px, 80px) scale(1.5, 1.5) rotate(45deg);
  }
  </pre>
   Move the element by 80 pixels in both the X and Y directions, then scale
   the element by 150%, then rotate it 45 degrees clockwise about the Z axis.
   Note that the scale and rotate operate about the center of the element,
   since the element has the default transform-origin of 50% 50%.
   <div class=figure> <img alt="The transform specified above"
    src=compound_transform.png></div>
  </div>
  <!-- ======================================================================================================= -->

  <h2 id=animation><span class=secno>6 </span> Transitions and animations
   between transform values</h2>

  <p> When animating or transitioning the value of a transform property the
   rules described below are applied. The &lsquo;<code
   class=property>from</code>&rsquo; transform is the transform at the start
   of the transition or current keyframe. The &lsquo;<code
   class=property>end</code>&rsquo; transform is the transform at the end of
   the transition or current keyframe.

  <ul>
   <li> If the &lsquo;<code class=property>from</code>&rsquo; and
    &lsquo;<code class=property>to</code>&rsquo; transforms are both single
    functions of the same type:
    <ul>
     <li> For translate, translateX, translateY, translateZ, scale, scaleX,
      scaleY, rotate, skewX and skewY functions:
      <ul>
       <li> the individual components of the function are interpolated
        numerically.
      </ul>

     <li> For matrix:
      <ul>
       <li> the matrix is decomposed using <a
        href="http://tog.acm.org/GraphicsGems/gemsii/unmatrix.c">the method
        described by unmatrix</a> into separate translation, scale, rotation
        and skew matrices, then each decomposed matrix is interpolated
        numerically, and finally combined in order to produce a resulting 3x2
        matrix.
      </ul>
    </ul>

   <li> If both the &lsquo;<code class=property>from</code>&rsquo; an
E777
d
    &lsquo;<code class=property>to</code>&rsquo; transforms are "none":
    <ul>
     <li> There is no interpolation necessary
    </ul>

   <li> If one of the &lsquo;<code class=property>from</code>&rsquo; or
    &lsquo;<code class=property>to</code>&rsquo; transforms is "none":
    <ul>
     <li> The &lsquo;<code class=property>none</code>&rsquo; is replaced by
      an equivalent identity function list for the corresponding transform
      function list.
      <p> For example, if the &lsquo;<code class=property>from</code>&rsquo;
       transform is "scale(2)" and the &lsquo;<code
       class=property>to</code>&rsquo; transform is "none" then the value
       "scale(1)" will be used as the &lsquo;<code
       class=property>to</code>&rsquo; value, and animation will proceed
       using the rule above. Similarly, if the &lsquo;<code
       class=property>from</code>&rsquo; transform is "none" and the
       &lsquo;<code class=property>to</code>&rsquo; transform is "scale(2)
       rotate(50deg)" then the animation will execute as if the &lsquo;<code
       class=property>from</code>&rsquo; value is "scale(1) rotate(0)".</p>

      <p> The identity functions are translate(0), translateX(0),
       translateY(0), scale(1), scaleX(1), scaleY(1), rotate(0), rotateX(0),
       rotateY(0), skewX(0), skewY(0), and matrix(1, 0, 0, 1, 0, 0).</p>
    </ul>

   <li> If both the &lsquo;<code class=property>from</code>&rsquo; and
    &lsquo;<code class=property>to</code>&rsquo; transforms have the same
    number of transform functions and corresponding functions in each
    transform list are of the same type:
    <ul>
     <li> Each transform function is animated with its corresponding
      destination function in isolation using the rules described above. The
      individual values are then applied as a list to produce resulting
      transform value.
    </ul>

   <li> Otherwise:
    <ul>
     <li> The transform function lists are each converted into the equivalent
      matrix value and animation proceeds using the rule for a single
      function above.
    </ul>
  </ul>

  <h2 id=dom-interfaces><span class=secno>7 </span> DOM Interfaces</h2>

  <p> This section describes the interfaces and functionality added to the
   DOM to support runtime access to the functionality described above.

  <h3 id=point-interface><span class=secno>7.1 </span> Point</h3>

  <dl>
   <dt> <b>Interface <i><a id=DOM-Point name=DOM-Point>Point</a></i></b>

   <dd>
    <p> The <code>Point</code> interface represents a point in
     two-dimensional space.</p>

    <dl>
     <dt> <b>IDL Definition</b>

     <dd>
      <div class=idl-code>
       <pre>
  interface Point {
      attribute float x;
      attribute float y;
  };</pre>
      </div>
     </dd>
     <!-- IDL -->

     <dt> <b>Attributes</b>

     <dd>
      <dl>
       <dt> <code class=attribute-name><a id=DOM-Point-x
        name=DOM-Point-x>x</a></code> of type <code>float</code>

       <dd> The value of the point along the X dimension.

       <dt> <code class=attribute-name><a id=DOM-Point-y
        name=DOM-Point-y>y</a></code> of type <code>float</code>

       <dd> The value of the point along the Y dimension.
      </dl>
     </dd>
     <!-- Attributes -->
    </dl>
   </dd>
   <!-- interface Point -->
  </dl>
  <!-- ====================================================================== -->

  <h3 id=window-interface><span class=secno>7.2 </span> Window</h3>

  <dl>
   <dt> <b>Interface <i><a id=DOM-Window name=DOM-Window>Window</a></i></b>

   <dd>
    <p> The following 2 functions are added to the <code>Window</code>
     interface. They provide conversions between the page and node coordinate
     spaces.</p>

    <dl>
     <dt> <b>IDL Definition</b>

     <dd>
      <div class=idl-code>
       <pre>
  interface Window {
    ...
    Point convertPointFromPageToNode(in Node node, in Point point);
    Point convertPointFromNodeToPage(in Node node, in Point point);
    ...
  };</pre>
      </div>
     </dd>
     <!-- IDL -->

     <dt> <b>Methods</b>

     <dd>
      <dl><!-- ============================================================ -->

       <dt> <code class=method-name><a
        id=DOM-Window-convertPointFromPageToNode
        name=DOM-Window-convertPointFromPageToNode>convertPointFromPageToNode</a></code>


       <dd>
        <div class=method> The <code>convertPointFromPageToNode</code> method
         returns a point in the coordinate space of the passed Node that is
         at the same location in the page as the passed point, which is in
         the coordinate space of the page.
         <div class=parameters> <b>Parameters</b>
          <div class=paramtable>
           <dl>
            <dt> <code class=parameter-name>node</code> of type
             <code>Node</code>

            <dd> The Node which defines the desired coordinate space of the
             returned point.<br>

            <dt> <code class=parameter-name>point</code> of type
             <code>Point</code>

            <dd> The point, in the page's coordinate space, for which the
             desired point, in the Node's coordinate space, should be
             returned.<br>
           </dl>
          </div>
         </div>
         <!-- parameters -->
         <div class=return-value> <b>Return Value</b></div>

         <div class=returnvalue>
          <dl>
           <dt> <code>Point</code>

           <dd> The resultant point in the coordinate space of the passed
            Node.<br>
          </dl>
         </div>
        </div>

        <div> <b>No Exceptions</b></div>
       </dd>
       <!-- convertPointFromPageToNode -->
       <!-- ============================================================ -->

       <dt> <code class=method-name><a
        id=DOM-Window-convertPointFromNodeToPage
        name=DOM-Window-convertPointFromNodeToPage>convertPointFromNodeToPage</a></code>


       <dd>
        <div class=method> The <code>convertPointFromNodeToPage</code> method
         returns a point in the coordinate space of the page that is at the
         same location in the page as the passed point, which is in the
         coordinate space of the passed Node.
         <div class=parameters> <b>Parameters</b>
          <div class=paramtable>
           <dl>
            <dt> <code class=parameter-name>node</code> of type
             <code>Node</code>

            <dd> The Node which defines the coordinate space of the passed
             point.<br>

            <dt> <code class=parameter-name>point</code> of type
             <code>Point</code>

            <dd> The point, in the Node's coordinate space, for which the
             desired point, in the page's coordinate space, should be
             returned.<br>
           </dl>
          </div>
         </div>
         <!-- parameters -->
         <div class=return-value> <b>Return Value</b></div>

         <div class=returnvalue>
          <dl>
           <dt> <code>Point</code>

           <dd> The resultant point in the coordinate space of the page.<br>
          </dl>
         </div>
        </div>

        <div> <b>No Exceptions</b></div>
       </dd>
       <!-- convertPointFromNodeToPage -->
      </dl>
     </dd>
     <!-- Methods -->
    </dl>
   </dd>
   <!-- Interface Window -->
  </dl>
  <!-- ============================================================ -->

  <h3 id=cssmatrix-interface><span class=secno>7.3 </span> CSSMatrix</h3>

  <dl>
   <dt> <b>Interface <i><a id=DOM-CSSMatrix
    name=DOM-CSSMatrix>CSSMatrix</a></i></b>

   <dd>
    <p> The <code>CSSMatrix</code> interface represents a 4x4 homogeneous
     matrix.</p>

    <dl>
     <dt> <b>IDL Definition</b>

     <dd>
      <div class=idl-code>
       <pre>
  interface CSSMatrix {
      attribute float a;
      attribute float b;
      attribute float c;
      attribute float d;
      attribute float e;
      attribute float f;

      void        setMatrixValue(in DOMString string) raises(DOMException);
      CSSMatrix   multiply(in CSSMatrix secondMatrix);
      CSSMatrix   inverse() raises(DOMException);
      CSSMatrix   translate(in float x, in float y);
      CSSMatrix   scale(in float scaleX, in float scaleY);
      CSSMatrix   rotate(in float angle);
  };</pre>
      </div>
      <br>
     </dd>
     <!-- IDL -->

     <dt> <b>Attributes</b>

     <dd>
      <dl>
       <dt> <code class=attribute-name><a id=DOM-CSSMatrix-matrix
        name=DOM-CSSMatrix-matrix>a-f</a></code> of type <code>float</code>

       <dd> Each of these attributes represents one of the values in the 3x2
        matrix.<br>
      </dl>
     </dd>
     <!-- Attributes -->

     <dt> <b>Methods</b>

     <dd>
      <dl><!-- ===================================================== -->

       <dt> <code class=method-name><a id=DOM-CSSMatrix-setMatrixValue
        name=DOM-CSSMatrix-setMatrixValue>setMatrixValue</a></code>

       <dd>
        <div class=method> The <code>setMatrixValue</code> method replaces
         the existing matrix with one computed from parsing the passed string
         as though it had been assigned to the transform property in a CSS
         style rule.
         <div class=parameters> <b>Parameters</b>
          <div class=paramtable>
           <dl>
            <dt> <code class=parameter-name>string</code> of type
             <code>DOMString</code>

            <dd> The string to parse.<br>
           </dl>
          </div>
         </div>
         <!-- parameters -->
         <div class=return-value> <b>No Return Value</b></div>

         <div> <b>Exceptions</b>
          <div class=returnvalue>
           <dl>
            <dt> <code>SYNTAX_ERR</code>

            <dd> Thrown when the provided string can not be parsed into a
             CSSMatrix.
           </dl>
          </div>
         </div>
        </div>
       </dd>
       <!-- setMatrixValue -->
       <!-- ===================================================== -->

       <dt> <code class=method-name><a id=DOM-CSSMatrix-multiply
        name=DOM-CSSMatrix-multiply>multiply</a></code>

       <dd>
        <div class=method> The <code>multiply</code> method returns a new
         CSSMatrix which is the result of this matrix multiplied by the
         passed matrix, with the passed matrix to the right. This matrix is
         not modified.
         <div class=parameters> <b>Parameters</b>
          <div class=paramtable>
           <dl>
            <dt> <code class=parameter-name>secondMatrix</code> of type
             <code>CSSMatrix</code>

            <dd> The matrix to multipy.<br>
           </dl>
          </div>
         </div>
         <!-- parameters -->
         <div class=return-value> <b>Return Value</b>
          <div class=returnvalue>
           <dl>
            <dt> <code>CSSMatrix</code>

            <dd> The result matrix.<br>
           </dl>
          </div>
         </div>

         <div> <b>No Exceptions</b></div>
        </div>
       </dd>
       <!-- multiply() -->
       <!-- ===================================================== -->

       <dt> <code class=method-name><a id=DOM-CSSMatrix-inverse
        name=DOM-CSSMatrix-inverse>inverse</a></code>

       <dd>
        <div class=method> The <code>inverse</code> method returns a new
         matrix which is the inverse of this matrix. This matrix is not
         modified.
         <div class=parameters> <b>No Parameters</b></div>
         <!-- parameters -->
         <div class=return-value> <b>Return Value</b>
          <div class=returnvalue>
           <dl>
            <dt> <code>CSSMatrix</code>

            <dd> The inverted matrix.<br>
           </dl>
          </div>
         </div>

         <div> <b>Exceptions</b>
          <div class=returnvalue>
           <dl>
            <dt> <code>NOT_SUPPORTED_ERROR</code>

            <dd> Thrown when the CSSMatrix can not be inverted.
           </dl>
          </div>
         </div>
        </div>
        <!-- ======================================================================================================= -->
        </dd>
       <!-- inverse() -->
       <!-- ===================================================== -->

       <dt> <code class=method-name><a id=DOM-CSSMatrix-translate
        name=DOM-CSSMatrix-translate>translate</a></code>

       <dd>
        <div class=method> The <code>translate</code> method returns a new
         matrix which is this matrix post multiplied by a translation matrix
         containing the passed values. This matrix is not modified.
         <div class=parameters> <b>Parameters</b>
          <div class=paramtable>
           <dl>
            <dt> <code class=parameter-name>x</code> of type
             <code>float</code>

            <dd> The X component of the translation value.<br>

            <dt> <code class=parameter-name>y</code> of type
             <code>float</code>

            <dd> The Y component of the translation value.<br>
           </dl>
          </div>
         </div>
         <!-- parameters -->
         <div class=return-value> <b>Return Value</b>
          <div class=returnvalue>
           <dl>
            <dt> <code>CSSMatrix</code>

            <dd> The result matrix.<br>
           </dl>
          </div>
         </div>

         <div> <b>No Exceptions</b></div>
        </div>
        <!-- ======================================================================================================= -->
        </dd>
       <!-- translate() -->
       <!-- ===================================================== -->

       <dt> <code class=method-name><a id=DOM-CSSMatrix-scale
        name=DOM-CSSMatrix-scale>scale</a></code>

       <dd>
        <div class=method> The <code>scale</code> method returns a new matrix
         which is this matrix post multiplied by a scale matrix containing
         the passed values. If the z component is undefined, a 1 value is
         used in its place. If the y component is undefined, the x component
         value is used in its place. This matrix is not modified.
         <div class=parameters> <b>Parameters</b>
          <div class=paramtable>
           <dl>
            <dt> <code class=parameter-name>scaleX</code> of type
             <code>float</code>

            <dd> The X component of the scale value.<br>

            <dt> <code class=parameter-name>scaleY</code> of type
             <code>float</code>

            <dd> The (optional) Y component of the scale value.<br>
           </dl>
          </div>
         </div>
         <!-- parameters -->
         <div class=return-value> <b>Return Value</b>
          <div class=returnvalue>
           <dl>
            <dt> <code>CSSMatrix</code>

            <dd> The result matrix.<br>
           </dl>
          </div>
         </div>

         <div> <b>No Exceptions</b></div>
        </div>
        <!-- ======================================================================================================= -->
        </dd>
       <!-- scale() -->
       <!-- ===================================================== -->

       <dt> <code class=method-name><a id=DOM-CSSMatrix-rotate
        name=DOM-CSSMatrix-rotate>rotate</a></code>