The fxcanvas's intro from kejemas

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        <a href="http://code.google.com/p/fxcanvas/"><img src="docs/images/fxcanvas.png" /></a>
<h2>Intro <a class='hh' name='Intro'>⁋</a></h2><p>fxCanvas is an implementation of the HTML5 Canvas element for Internet Explorer (two-dimensional graphics only).  <h2>Requirements <a class='hh' name='Requirements'>⁋</a></h2></p><ul><li>Flash player 9+ on Internet Explorer (some versions from 10.1 branch does not work properly, see <a href="http://code.google.com/p/fxcanvas/issues/detail?id=5">Issue 5</a>)</li><li>Internet Explorer 5.5+ (IE9 not supported at this moment)</li></ul>
<h2>Contents <a class='hh' name='Contents'>⁋</a></h2><ul><li><a href="#Usage">Usage</a></li><li><a href="#Compatibility">Compatibility</a></li><li><a href="#Extended_features">Extended features</a></li><li><a href="#Known_bugs">Known bugs</a></li><li><a href="#Demos_and_examples">Demos and examples</a></li><li><a href="#Applications">Applications</a></li><li><a href="#Download_and_source">Download and source</a></li><li><a href="#References">References</a></li><li><a href="#Related_projects">Related projects</a></li><li><a href="#Volunteers_wanted!_Couple_of_impossible_tasks_are_there_(TODO):">TODO</a></li><li><a href="#Bugs_and_feedbacks">Bugs and feedbacks</a></li><li><a href="#What's_up">News</a></li></ul>
<h2>Usage <a class='hh' name='Usage'>⁋</a></h2><p>Download <a href="http://code.google.com/p/fxcanvas/downloads/detail?name=fxcanvas-0.2(beta4)-supersonic.zip">package</a>, unzip it into a public directory on the server and then paste in head section of the page following tags:</p><pre class="active4d code-block">
<span class="TagContainer"><span class="TagContainer">&lt;</span><span class="TagName">head</span><span class="TagContainer">&gt;</span></span>
  &lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span> <span class="TagAttribute">src</span>=<span class="String"><span class="String">&quot;</span>/public/path/jooscript.js<span class="String">&quot;</span></span>&gt;&lt;/<span class="TagName">script</span>&gt;
  &lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span> <span class="TagAttribute">src</span>=<span class="String"><span class="String">&quot;</span>/public/path/fxcanvas.js<span class="String">&quot;</span></span>&gt;&lt;/<span class="TagName">script</span>&gt;
  <span class="BlockComment"><span class="BlockComment">&lt;!--</span>[if IE]&gt;&lt;script type=&quot;text/javascript&quot; src=&quot;/public/path/flash_backend.js&quot;&gt;&lt;/script&gt;&lt;![endif]<span class="BlockComment">--&gt;</span></span>
  <span class="TagContainer"><span class="TagContainer">&lt;</span><span class="TagName">comment</span><span class="TagContainer">&gt;</span></span><span class="TagContainer"><span class="TagContainer">&lt;</span><span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span> <span class="TagAttribute">src</span>=<span class="String"><span class="String">&quot;</span>/public/path/canvas_backend.js<span class="String">&quot;</span></span><span class="TagContainer">&gt;<span class="TagContainer">&lt;</span>/</span><span class="TagName">script</span><span class="TagContainer">&gt;</span></span><span class="TagContainer"><span class="TagContainer">&lt;/</span><span class="TagName">comment</span><span class="TagContainer">&gt;</span></span>
<span class="TagContainer"><span class="TagContainer">&lt;/</span><span class="TagName">head</span><span class="TagContainer">&gt;</span></span>
</pre><p>If you are not familiar with Canvas API, it may be useful to read this: <ul> <li style="list-style-image:url(docs/images/moz.ico);"><a href="https://developer.mozilla.org/en/HTML/Canvas">Canvas tutorial on Mozzila.org</a></li> <li style="list-style-image:url(docs/images/opera.ico);"><a href="http://dev.opera.com/articles/view/html-5-canvas-the-basics/">... on dev.Opera.com</a></li> </ul></p><p><strong>New!</strong> Images and text are now <a href="http://burzak.com/proj/fxcanvas/tests/test_clip.html">clipable</a>.</p><p>fxCanvas also works properly with <code>data:</code> URIs in Internet Explorer. <a href="http://burzak.com/proj/fxcanvas/tests/image_data_example.html">Example</a>. <h2>Compatibility <a class='hh' name='Compatibility'>⁋</a></h2></p><p>fxCanvas supports almost all the Canvas features.  The differences is in:</p><p><strong> Invoke command and chaining operations </strong></p><p>Context commands are keeping in a buffer before they will be applyed (IE only), so that to get values you have to use method <code>invoke()</code>:</p><pre class="active4d code-block">
&lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span>&gt;
    <span class="Storage">var</span> cv <span class="Operator">=</span> <span class="LibraryClassType">document</span>.<span class="CommandMethod">getElementById</span>(<span class="String"><span class="String">&quot;</span>cv<span class="String">&quot;</span></span>);
    <span class="Storage">var</span> ctx <span class="Operator">=</span> cv.getContext(<span class="String"><span class="String">&quot;</span>2d<span class="String">&quot;</span></span>);
    ctx.setFillStyle(<span class="String"><span class="String">&quot;</span>#ff0<span class="String">&quot;</span></span>)
        .setStrokeStyle(<span class="String"><span class="String">&quot;</span>#0ff<span class="String">&quot;</span></span>)
        .strokeRect(<span class="Number">10</span>, <span class="Number">20</span>, <span class="Number">30</span>, <span class="Number">30</span>)
        .fillRect(<span class="Number">30</span>, <span class="Number">40</span>, <span class="Number">50</span>, <span class="Number">50</span>)
        .invoke(<span class="String"><span class="String">&quot;</span>getImageData<span class="String">&quot;</span></span>, <span class="Number">0</span>, <span class="Number">0</span>, cv.<span class="NamedConstant">width</span>, cv.<span class="NamedConstant">height</span>, <span class="Storage">function</span> (<span class="FunctionArgument">imageData</span>) {
            <span class="LineComment"><span class="LineComment">//</span> ... processing image data</span>
        });
&lt;/<span class="TagName">script</span>&gt;
</pre>
 
<strong> Images </strong><p>Prior to using images you have to preload them:</p><pre class="active4d code-block">
&lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span>&gt;
    <span class="Storage">var</span> cv <span class="Operator">=</span> <span class="LibraryClassType">document</span>.<span class="CommandMethod">getElementById</span>(<span class="String"><span class="String">&quot;</span>cv<span class="String">&quot;</span></span>);
    <span class="Storage">var</span> ctx <span class="Operator">=</span> cv.getContext(<span class="String"><span class="String">&quot;</span>2d<span class="String">&quot;</span></span>);
    <span class="Storage">var</span> image_src <span class="Operator">=</span> <span class="String"><span class="String">&quot;</span>sample.jpg<span class="String">&quot;</span></span>;
    <span class="LibraryClassType">cv</span>.<span class="FunctionName">onload</span> = <span class="Storage">function</span>(<span class="FunctionArgument">img</span>) {
        <span class="Keyword">if</span> (img.<span class="NamedConstant">src</span>.<span class="CommandMethod">indexOf</span>(image_src) <span class="Operator">&gt;</span> <span class="Operator">-</span><span class="Number">1</span>) {
            ctx.drawImage(img, <span class="Number">10</span>, <span class="Number">10</span>);
        }
    }
    cv.loadImages(image_src <span class="BlockComment"><span class="BlockComment">/*</span> ... img1, img2, ... imgX <span class="BlockComment">*/</span></span>);
&lt;/<span class="TagName">script</span>&gt;
</pre>
 
<strong> Image data array </strong><p>We cannot use canvas image data as it declared in specs, because of IE using extremely ineffective memory manager so it may eats all available memory in some circumstances. So that fxCanvas is using slightly different image data format. </p><p>Take a look at example:</p><pre class="active4d code-block">
&lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span>&gt;
    <span class="Storage">var</span> cv <span class="Operator">=</span> <span class="LibraryClassType">document</span>.<span class="CommandMethod">getElementById</span>(<span class="String"><span class="String">&quot;</span>cv<span class="String">&quot;</span></span>);
    <span class="Storage">var</span> ctx <span class="Operator">=</span> cv.getContext(<span class="String"><span class="String">&quot;</span>2d<span class="String">&quot;</span></span>);
    ctx.invoke(<span class="String"><span class="String">&quot;</span>getImageData<span class="String">&quot;</span></span>, <span class="Number">0</span>, <span class="Number">0</span>, cv.<span class="NamedConstant">width</span>, cv.<span class="NamedConstant">height</span>, <span class="Storage">function</span>(buf) {
        <span class="Keyword">for</span> (<span class="Storage">var</span> i <span class="Operator">=</span> <span class="Number">0</span>; i <span class="Operator">&lt;</span> cv.<span class="NamedConstant">width</span><span class="Operator">*</span>cv.<span class="NamedConstant">width</span>; i<span class="Operator">++</span>) {
             <span class="Storage">var</span> pixelValue <span class="Operator">=</span> buf.<span class="NamedConstant">data</span>[i], <span class="LineComment"><span class="LineComment">//</span> pixel value is 32-bit integer</span>
                 red <span class="Operator">=</span> pixelValue <span class="Operator">&gt;</span><span class="Operator">&gt;</span> <span class="Number">24</span> <span class="Operator">&amp;</span> <span class="Number">0xFF</span>,
                 green <span class="Operator">=</span> pixelValue <span class="Operator">&gt;</span><span class="Operator">&gt;</span> <span class="Number">16</span> <span class="Operator">&amp;</span> <span class="Number">0xFF</span>,
                 blue <span class="Operator">=</span> pixelValue <span class="Operator">&gt;</span><span class="Operator">&gt;</span> <span class="Number">8</span> <span class="Operator">&amp;</span> <span class="Number">0xFF</span>,
                 alpha <span class="Operator">=</span> pixelValue <span class="Operator">&amp;</span> <span class="Number">0xFF</span>;
             <span class="LineComment"><span class="LineComment">//</span> </span>
             <span class="LineComment"><span class="LineComment">//</span> exchange color channels</span>
             buf.<span class="NamedConstant">data</span>[ofs] <span class="Operator">=</span> (blue <span class="Operator">&lt;</span><span class="Operator">&lt;</span> <span class="Number">24</span>) <span class="Operator">+</span> (red <span class="Operator">&lt;</span><span class="Operator">&lt;</span> <span class="Number">16</span>) <span class="Operator">+</span> (green <span class="Operator">&lt;</span><span class="Operator">&lt;</span> <span class="Number">8</span>) <span class="Operator">+</span> alpha;
        }
        ctx.invoke(<span class="String"><span class="String">&quot;</span>putImageData<span class="String">&quot;</span></span>, buf, <span class="Number">0</span>, <span class="Number">0</span>, <span class="Storage">function</span>(){
            <span class="LineComment"><span class="LineComment">//</span> ... print out the buffer after the operation will be completed</span>
            <span class="TypeName">console</span><span class="CommandMethod">.log</span>(<span class="String"><span class="String">&quot;</span>Image data dump:<span class="String">&quot;</span></span> <span class="Operator">+</span> buf); 
        }
    });
&lt;/<span class="TagName">script</span>&gt;
</pre><p>Further explanation can be founded <a href="http://burzak.com/proj/fxcanvas/tests/data-structure-comparison.html">here</a>.</p><p><strong> isPointInPath() </strong></p><p><code>isPointInPath()</code> in Internet Explorer returns <code>true</code> if point in bounding box of the path. To get accurate results, use <code>ctx.invoke("isPointInPath", x, y, ...)</code>.</p><p><strong> toDataURL() </strong></p><p>To get canvas shot you have to call the function with data handler:</p><pre class="active4d code-block">
&lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span>&gt;
    <span class="Storage">var</span> cv <span class="Operator">=</span> <span class="LibraryClassType">document</span>.<span class="CommandMethod">getElementById</span>(<span class="String"><span class="String">&quot;</span>cv<span class="String">&quot;</span></span>);
    <span class="Storage">var</span> type <span class="Operator">=</span> <span class="String"><span class="String">&quot;</span>image/jpeg<span class="String">&quot;</span></span>, quality <span class="Operator">=</span> .<span class="Number">4</span>; <span class="LineComment"><span class="LineComment">//</span> quality is optional argument</span>
    cv.toDataURL(type, quality, <span class="Storage">function</span> (<span class="FunctionArgument">png_data</span>) {
        <span class="LineComment"><span class="LineComment">//</span> draw slice of the canvas on the same canvas at top right corner</span>
        <span class="Storage">var</span> ctx <span class="Operator">=</span> <span class="Variable">this</span>.getContext(<span class="String"><span class="String">&quot;</span>2d<span class="String">&quot;</span></span>);
        <span class="LibraryClassType">this</span>.<span class="FunctionName">onload</span> = <span class="Storage">function</span> (<span class="FunctionArgument">img</span>) {
            ctx.drawImage(img, <span class="Number">0</span>, <span class="Number">0</span>, cv.<span class="NamedConstant">width</span> <span class="Operator">-</span> <span class="Number">100</span>, <span class="Number">0</span>, <span class="Number">100</span>, <span class="Number">100</span>);
        }
        <span class="Variable">this</span>.loadImages(png_data);
    });
&lt;/<span class="TagName">script</span>&gt;
</pre><p>Possible types: <code>image/png</code>, <code>image/jpeg</code>, <strike><code>image/svg+xml</code></strike>.</p><p><strong> How-to create Canvas element in script </strong></p><p>The simpliest way to dynamically create canvas element is:</p><pre class="active4d code-block">
&lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span>&gt;
    <span class="Storage">var</span> cv <span class="Operator">=</span> <span class="LibraryClassType">document</span>.<span class="CommandMethod">createElement</span>(<span class="String"><span class="String">&quot;</span>canvas<span class="String">&quot;</span></span>);
    cv.<span class="NamedConstant">width</span> <span class="Operator">=</span> <span class="Number">200</span>;
    cv.<span class="NamedConstant">height</span> <span class="Operator">=</span> <span class="Number">100</span>;
    <span class="LibraryClassType">document</span>.<span class="NamedConstant">body</span>.<span class="CommandMethod">appendChild</span>(cv);
    <span class="LineComment"><span class="LineComment">//</span> ...</span>
&lt;/<span class="TagName">script</span>&gt;
</pre><p>Note that if fxCanvas lib is loaded then in newly created elements will be using extended context by default.  To disable this behavior and manually initialize extended context, use following code:</p><pre class="active4d code-block">
&lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span>&gt;
    <span class="Operator">$</span>Import(<span class="String"><span class="String">&quot;</span>buz.fxcanvas<span class="String">&quot;</span></span>);
    <span class="LineComment"><span class="LineComment">//</span> don't forget to disable fxCanvas before page content will loaded</span>
    fxcanvas.config.enable <span class="Operator">=</span> <span class="BuiltInConstant">false</span>;
    <span class="LibraryClassType">window</span>.<span class="FunctionName">onload</span> = <span class="Storage">function</span>(){
        <span class="Storage">var</span> cv <span class="Operator">=</span> <span class="LibraryClassType">document</span>.<span class="CommandMethod">createElement</span>(<span class="String"><span class="String">&quot;</span>canvas<span class="String">&quot;</span></span>);
        fxcanvas.initElement(cv)
        <span class="LineComment"><span class="LineComment">//</span> ...</span>
    }
&lt;/<span class="TagName">script</span>&gt;
</pre><p><strong> Context and Backend </strong></p><p>There are a few two-dimensional Canvas contexts: first is extended context <code>canvas.getContext("2d")</code>, second is original context <code>canvas.getBackend("2d")</code>. Use last one if you want native drawing speed.</p><p><strong> Composite operations </strong></p><p>Only <code>source-over</code> and <code>lighter</code> are supported.</p><p><strong> Handling canvas resize event </strong></p><p>There is a specific problem with canvas resizing due to asynchronous nature. You cannot draw graphics right after the canvas was resizing or it will be clear. As a solution I've added <code>oncanvasresize</code> event which is fired when canvas will be ready after resize. Note that <code>oncanvasresize</code> will not be triggered if the dimensions is the same or  is changed style property.</p><pre class="active4d code-block">
&lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span>&gt;
  ctx.canvas.<span class="NamedConstant">width</span> <span class="Operator">=</span> <span class="Number">400</span>
  ctx.canvas.<span class="NamedConstant">height</span> <span class="Operator">=</span> <span class="Number">300</span>
  <span class="LibraryClassType">ctx</span>.<span class="FunctionName">oncanvasresize</span> = <span class="Storage">function</span>(){
    ctx.beginPath();
    ctx.arc(<span class="Number">75</span>,<span class="Number">75</span>,<span class="Number">50</span>,<span class="Number">0</span>,<span class="LibraryClassType">Math</span>.<span class="NamedConstant">PI</span><span class="Operator">*</span><span class="Number">2</span>,<span class="BuiltInConstant">true</span>);
    ctx.stroke()
  }
&lt;/<span class="TagName">script</span>&gt;
</pre><p><strong> Text API </strong></p><p><!-- Текст АПИ - это самая кастрированная часть. Во-первых, трансформированный текст выглядит "покорябанным", во-вторых не поддерживается метод strokeText(). Зато measureText() возвращает значения width, height, ascent и descent (только там, где используется флеш).  --></p><p>Text API is the most weak part. First is that transformed text looks awkward. Second is not supported method <code>strokeText()</code>. But <code>measureText()</code> returns even four values: width, height, ascent and descent (only for flash backend).</p><pre class="active4d code-block">
&lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span>&gt;
  ctx.font <span class="Operator">=</span> <span class="String"><span class="String">&quot;</span>35px Arial<span class="String">&quot;</span></span>
  ctx.invoke(<span class="String"><span class="String">&quot;</span>measureText<span class="String">&quot;</span></span>, <span class="String"><span class="String">&quot;</span>abc<span class="String">&quot;</span></span>, <span class="Storage">function</span>(dim){
    trace(dim.<span class="NamedConstant">width</span>, dim.<span class="NamedConstant">height</span>, dim.ascent, dim.descent)
  })
&lt;/<span class="TagName">script</span>&gt;
</pre><p>The things may change when I add a brand new text renderer.  <h2>Extended features <a class='hh' name='Extended_features'>⁋</a></h2></p><p>Extended context (global <code>extCanvasRenderingContext2D</code>) provides some new useful features for developers . </p><p><strong> Animation </strong></p><p>There are two ways to making animation on Canvas. First case is using <code>setInterval()</code>, second case is using <code>oncanvasframe</code> event:</p><pre class="active4d code-block">
&lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span>&gt;
    <span class="Storage">var</span> ctx <span class="Operator">=</span> <span class="LibraryClassType">document</span>.<span class="CommandMethod">getElementById</span>(<span class="String"><span class="String">&quot;</span>cv<span class="String">&quot;</span></span>).getContext(<span class="String"><span class="String">&quot;</span>2d<span class="String">&quot;</span></span>);
    <span class="BlockComment"><span class="BlockComment">/*</span></span>
<span class="BlockComment">     * variant one</span>
<span class="BlockComment">     <span class="BlockComment">*/</span></span>
    <span class="CommandMethod">setInterval</span>(<span class="Storage">function</span>() {
        <span class="LineComment"><span class="LineComment">//</span> ... draw frame here</span>
    }, <span class="Number">1000</span>);
    <span class="BlockComment"><span class="BlockComment">/*</span></span>
<span class="BlockComment">     * variant two</span>
<span class="BlockComment">     <span class="BlockComment">*/</span></span>
    ctx.canvas.frameDuration <span class="Operator">=</span> <span class="Number">10</span>; <span class="LineComment"><span class="LineComment">//</span> in microseconds</span>
    <span class="LibraryClassType">ctx.canvas</span>.<span class="FunctionName">oncanvasframe</span> = <span class="Storage">function</span>(){ <span class="LineComment"><span class="LineComment">//</span> frame event handler will fired with interval in 10ms</span>
        <span class="LineComment"><span class="LineComment">//</span> ... draw frame here</span>
    };
    <span class="LineComment"><span class="LineComment">//</span> Warning: animations with complex graphics and tiny frameDuration value may hang on the browser!</span>
&lt;/<span class="TagName">script</span>&gt;
</pre><p>Using <code>oncanvasframe</code> event is strongly encouraged, as in Internet Explorer animation running on <code>setInterval()</code> will show incorrect frame rate. Besides in modern browsers (e.g. Firefox 4) animation will be play smoother on frame event (technically: synced with display refresh frame rate).</p><p>Note: <code>oncanvasframe</code> event is non-standard extension.</p><p>Default <code>frameDuration</code> is 100ms.</p><p><strong> Canvas Path </strong></p><p><!-- Начиная с версии 0.2 в fxCanvas предложен новый экспериментальный метод рисования сложных кривых. Для этого добавлен специальный интерфейс CanvasPath, который позволяет разработчику создавать список из сегментов, а затем применять его в контексте холста. Это позволяет быстро рисовать даже очень сложные кривые за счет кеширования. Кеширование используется только в IE, так что в остальных браузерах использование CanvasPath не даст выиграша в производительности. --></p><p>Starting from version 0.2 is introduced a new experimental method for drawing complex curves. For that was added special interface <code>CanvasPath</code>, which allow developers to create array of path segments. It make fast drawings in IE even with complicated curves thanks to caching algorithm.  In other browsers using <code>CanvasPath</code> will not give performance gain. To use this feature set <code>ctx._useCanvasPath</code> or <code>fxcanvas.config.useCanvasPath</code> as <code>true</code>. By default <code>useCanvasPath</code> is <code>false</code>.</p><p>A very generic example:</p><pre class="active4d code-block">
&lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span>&gt;
    <span class="Storage">var</span> cv <span class="Operator">=</span> <span class="LibraryClassType">document</span>.<span class="CommandMethod">createElement</span>(<span class="String"><span class="String">&quot;</span>canvas<span class="String">&quot;</span></span>);
    <span class="Storage">var</span> ctx <span class="Operator">=</span> cv.getContext(<span class="String"><span class="String">&quot;</span>2d<span class="String">&quot;</span></span>)
    <span class="Storage">var</span> longPath <span class="Operator">=</span> ctx.createPath()
    longPath.<span class="CommandMethod">moveTo</span>(<span class="Number">0</span>, <span class="Number">0</span>)
    <span class="Keyword">for</span>(<span class="Storage">var</span> i<span class="Operator">=</span><span class="Number">0</span>; i<span class="Operator">&lt;</span><span class="Number">1000</span>; i<span class="Operator">++</span>) {
      longPath.lineTo(i, i)
    }
    ctx.beginPath()
    ctx.appendPath(longPath)
    ctx.stroke()
    ctx.rotate(<span class="Number">90</span><span class="Operator">*</span><span class="LibraryClassType">Math</span>.<span class="NamedConstant">PI</span>/<span class="Number">180</span>)
    ctx.beginPath()
    ctx.appendPath(longPath)
    ctx.stroke()
&lt;/<span class="TagName">script</span>&gt;
</pre><p><strong> Path bounds </strong></p><p>There are some new methods and properties:   <ul><li>method <code>isPointInPathBounds(x, y) : boolean</code></li><li>method <code>getPathBounds() : Rectangle</code></li><li><code>transformMatrix</code> property</li></ul></p><p>Internally they are used as replacement for <code>isPointInPath</code> in IE. To use these methods in another browsers other than IE, set <code>ctx._tracePathBounds</code> or <code>fxcanvas.config.tracePathBounds</code> property as <code>true</code>. By default <code>tracePathBounds</code> is <code>true</code> for IE and <code>false</code> for others. </p><p>These methods are available even if the flash is disabled.</p><pre class="active4d code-block">
&lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span>&gt;
  ctx.beginPath()
  ctx.rect(<span class="Number">100</span>, <span class="Number">100</span>, <span class="Number">50</span>, <span class="Number">50</span>)
  <span class="Storage">var</span> bounds <span class="Operator">=</span> ctx.getPathBounds()
  trace(bounds.<span class="NamedConstant">x</span>, bounds.<span class="NamedConstant">y</span>, bounds.<span class="NamedConstant">width</span>, bounds.<span class="NamedConstant">height</span>)
  <span class="LineComment"><span class="LineComment">//</span> will output 100 100 50 50</span>
&lt;/<span class="TagName">script</span>&gt;
</pre><p><strong> Basic geometry </strong></p><p><!-- ДжуСкрипт предоставляет некоторые базовые геометрические примитивы, такие как Точка, Треугольних, Матрица2р которые можно использовать с методами расширенного контекста. </p><p>Например --></p><p> JooScript provides some basic geometry primitives such as Point, Rectangle and Matrix2d. They can be used within extended context:</p><pre class="active4d code-block">
&lt;<span class="TagName">script</span> <span class="TagAttribute">type</span>=<span class="String"><span class="String">&quot;</span>text/javascript<span class="String">&quot;</span></span>&gt;
  <span class="Operator">$</span>Import(<span class="String"><span class="String">&quot;</span>geom.*<span class="String">&quot;</span></span>)
  <span class="Storage">var</span> p0 <span class="Operator">=</span> <span class="Operator">new</span> <span class="TypeName">Point</span>(<span class="Number">10</span>,<span class="Number">10</span>)
  <span class="Storage">var</span> p1 <span class="Operator">=</span> <span class="Operator">new</span> <span class="TypeName">Point</span>(<span class="Number">100</span>,<span class="Number">100</span>)
  <span class="Storage">var</span> rect <span class="Operator">=</span> <span class="Operator">new</span> <span class="TypeName">Rectangle</span>(<span class="Number">20</span>,<span class="Number">10</span>,<span class="Number">300</span>,<span class="Number">300</span>)
  <span class="Storage">var</span> pointer <span class="Operator">=</span> {x: <span class="Number">123</span>, y: <span class="Number">45</span>}
  ctx.beginPath()
  ctx.<span class="CommandMethod">moveTo</span>(p0)
  ctx.vectorTo(p1)
  ctx.rect(rect)
  ctx.stroke()
  <span class="Keyword">if</span>( ctx.isPointInPath(pointer) ) {
      <span class="LineComment"><span class="LineComment">//</span> ...</span>
  }
&lt;/<span class="TagName">script</span>&gt;
</pre><p>Extended context also has <code>transformMatrix</code> property which is a 3x2 transformation matrix. It is available only if <code>tracePathBounds</code> is on.</p><p>For futher info refer to <a href="http://burzak.com/proj/jooscript-basics/">JooScript docs</a>. <h2>Known bugs <a class='hh' name='Known_bugs'>⁋</a></h2></p><ul><li>Sometime if user switching from Internet Explorer window to another desktop window, canvas element have lost focus, after that mouse events will not be triggered. He must click somewhere on a page (not on the canvas element!) to restore events. Workaround for this bug seems to be either impossible or very hard to code.</li><li>Dynamic canvas resize may not working properly with <code>setInterval</code>. Use <code>oncanvasresize</code> event as workaround. <a href="http://burzak.com/proj/fxcanvas/tests/explorercanvas.googlecode.com/examples/example3.html">Here is</a> an example.</li><li>In IE canvas element will be disabled if HTML page is loaded from local filesystem.</li></ul>
<h2>Demos and examples <a class='hh' name='Demos_and_examples'>⁋</a></h2><ul><li><a href="http://burzak.com/proj/fxcanvas/tests/drawarea.html">Drawarea</a></li><li><a href="http://burzak.com/proj/fxcanvas/demo/colorize.html">Colorize image</a></li><li><a href="http://burzak.com/proj/fxcanvas/tests/image_data_example.html">Example of using image data</a></li><li><a href="http://burzak.com/proj/fxcanvas/demo/plasma.html">Interferoplasma</a></li><li><a href="http://burzak.com/proj/fxcanvas/demo/watercolor.html">Watercolor</a></li><li><a href="http://burzak.com/proj/fxcanvas/demo/index.html">all demos</a>...</li><li><a href="http://burzak.com/proj/fxcanvas/tests/index.html">all tests and examples</a>...</li></ul><p><!-- <ul><li><a href="http://burzak.com/proj/fxcanvas/demo/cakejs/examples/canvas.html">CAKE</a></li></ul> --> <h2>Applications <a class='hh' name='Applications'>⁋</a></h2></p><ul><li><a href="http://burzak.com/proj/drawform/">DrawForm</a> is a graphical input form for web-pages</li></ul>
<h2>Download and source <a class='hh' name='Download_and_source'>⁋</a></h2><p><a href="http://code.google.com/p/fxcanvas/downloads/detail?name=fxcanvas-0.2(beta4)-supersonic.zip">Download zip</a> or <a href="http://code.google.com/p/fxcanvas/source/checkout">grab fresh trunk from SVN repo</a>. <h2>References <a class='hh' name='References'>⁋</a></h2></p><ul><li><a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html">WHATWG Canvas spec</a>.</li><li>fxCanvas is a fork of <a href="http://code.google.com/p/flashcanvas/">flashcanvas</a>.</li><li><a href="http://flashcanvas.net">FlashCanvas Pro</a> offers commercial support.</li></ul>
<h2>Related projects <a class='hh' name='Related_projects'>⁋</a></h2><ul><li><a href="http://code.google.com/p/web-forkers/">Web Forkers</a>, is a <a href="http://www.whatwg.org/specs/web-workers/current-work/">Web Workers</a> fake for IE and other browsers.</li><li><a href="http://burzak.com/proj/jooscript-basics/">JooScript basics</a> is a JavaScript library used for building complex web-apps.</li><li><a href="http://code.google.com/p/svgweb/">SVG Web</a>, is a JS lib which provides SVG support on many browsers, including Internet Explorer, Firefox, and Safari.</li></ul>
<h2>Volunteers wanted! Couple of impossible tasks are there (TODO): <a class='hh' name='Volunteers_wanted!_Couple_of_impossible_tasks_are_there_(TODO):'>⁋</a></h2><ul><li><strike>rewrite Cubic Bezier Curves approximation algorithm;</strike></li><li><strike>rewrite arc drawing algorithm (see <a href="http://burzak.com/proj/fxcanvas/tests/canvas-rounded-corners.html">this bug</a>);</strike></li><li><strike>stroke to path conversion (=> patterns on strokes, strokeText() etc..) - seems to be impossible, required a  new low level rendering system</strike> ;</li><li><strike>fix <code>isPointInPath()</code></strike>;</li><li>improve text API;</li><li>improve drawImage: <strike><code>drawImage(canvasElement, ...)</code></strike>, <code>drawImage(videoElement, ...)</code>;</li><li>translation from Canvas to SVG and vice versa, <code>toDataURL("image/xml+svg")</code>;</li><li>composite operations;</li><li>shadows;</li></ul>
 <h2>Bugs and feedbacks <a class='hh' name='Bugs_and_feedbacks'>⁋</a></h2>
 
<ul><li><a href="http://code.google.com/p/fxcanvas/issues/list">Issue tracker</a></li><li><a href="http://groups.google.com/group/fxcanvas">Discussion group</a></li></ul><h2>What&#39;s up <a class='hh' name='What&#39;s_up'>⁋</a></h2><h3>fxCanvas 0.2 - Super Sonic <a class='hh' name='fxCanvas_0.2_-_Super_Sonic'>⁋</a></h3><p>
<img src="docs/images/super_sonic.gif" />
</p><p>  <strong>Beta 4 (2011-02-05)</strong></p><p>  It seems basic Canvas API is implemented. I wonder is it ready for production?</p><ul><li><code>jooscript.js</code> is updated to the latest beta with bright shiny new features.</li><li><code>oncanvasframe</code> now based on new approach from Mozzila: <code>mozRequestAnimationFrame</code> which gives pretty smooth playback for animations and games. Great introduction to <code>mozRequestAnimationFrame</code> <a href="http://nokarma.org/2010/02/02/javascript-game-development-the-game-loop/">is here</a>.</li><li>Added demo <a href="http://burzak.com/proj/fxcanvas/demo/watercolor.html">Watercolor</a>.</li><li>(IE) Method <code>canvas.loadImage</code> renamed to <code>loadImages</code> as it handle multiple arguments.</li><li>(IE) Fixed my mistake in load queue.</li><li>(IE) <a href="http://www.timotheegroleau.com/Flash/articles/cubic_bezier_in_flash.htm">Tangent approximation</a>  was replaced with Fixed MidPoint approach. In most cases end-users will not see any differences between two approaches (bezier curve will be wrong on extremal arguments only), but Fixed MidPoint algorithm will works a lot faster especially with complex graphic with tons of cubic bezier curves.</li><li>(IE) In the same time was refactored arcs drawing method. And it became faster too.</li><li>(IE) Now unexpected arguments will <a href="http://burzak.com/proj/fxcanvas/tests/test_exceptions.html">raise an exception</a>.</li><li>(IE) Now URLs with ports are supported (<a href="http://code.google.com/p/fxcanvas/issues/detail?id=6">issue 6</a>).</li><li>(IE) Implemented accurate method <code>isPointInPath</code> (via <code>ctx.invoke("isPointInPath", x, y, ...)</code>).</li></ul>
  
<!--
<ul><li>Added <a href="http://burzak.com/proj/fxcanvas/demo/cakejs/examples/canvas.html">CAKE demo</a>.</li></ul>
--><p>  <strong>Beta 3 (2010-12-25)</strong></p><p>  <p>There are a lot of constructive changes and only a few new features.</p></p><ul><li>Added demo <a href="http://burzak.com/proj/fxcanvas/demo/colorize.html">Colorize image</a>.</li><li>Added demo <a href="http://burzak.com/proj/fxcanvas/demo/plasma.html">Interferoplasma</a>.</li><li>In Firefox 4 will be used new <a href="https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/doc/spec/TypedArray-spec.html">typed arrays</a> for ImageData.</li><li>(IE) Added <a href="http://burzak.com/proj/fxcanvas/tests/test_distorted_canvas_resize.html">distorted canvas resizing</a>.</li><li>(IE) Added <code>oncanvasresize</code> event. <a href="http://burzak.com/proj/fxcanvas/tests/explorercanvas.googlecode.com/examples/example3.html">Example</a>.</li><li>(IE) Fixed other bugs.</li></ul>
  
  <strong>Beta 2 (2010-12-06)</strong><ul><li><code>onframe</code> attribute renamed to <code>oncanvasframe</code>.</li><li>Fixed <code>frameDuration</code> property for canvas backend.</li><li>(IE) Fixed <a href="http://burzak.com/proj/fxcanvas/tests/test_cursor_style.html">canvas cursor style</a>.</li><li>(IE) Fixed canvas.loadImage() for <a href="http://burzak.com/proj/fxcanvas/tests/developer.mozilla.org/samples/canvas-tutorial/3_4_canvas_gallery.html">series of images</a>.</li><li>(IE) Fixed <a href="http://burzak.com/proj/fxcanvas/tests/explorercanvas.googlecode.com/testcases/resizing.html">canvas resizing</a>.</li></ul><p>  <strong>Beta 1 (2010-11-12)</strong></p><ul><li>Changed image data format, now it is array with length = image width <code>x</code> height where element is pixel value encoded in 32-bit integer. <a href="http://burzak.com/proj/fxcanvas/tests/data-structure-comparison.html">Data structure comparison</a>.</li><li>Experimental implementation of reusable Canvas path.</li><li>(IE) Images and text are now <a href="http://burzak.com/proj/fxcanvas/tests/test_clip.html">clipable</a>.</li><li>(IE) Improved Canvas Text API.</li><li>(IE) Rewritten initialization routine.</li><li>(IE) Some optimizations in Flash backend.</li><li>(IE) Basic implementation of method <code>drawImage([Canvas element], ...)</code>.</li><li>(IE) Now it is possible to draw image from another domain via proxy script (required PHP and cURL).</li></ul>
<h3>fxCanvas 0.15d - Super Mario - (2010-05-26) <a class='hh' name='fxCanvas_0.15d_-_Super_Mario_-_(2010-05-26)'>⁋</a></h3><ul><li>Fixed extended context in modest browser (Chrome, Firefox and company).</li></ul>
<h3>fxCanvas 0.15c - Super Mario - (2010-05-01) <a class='hh' name='fxCanvas_0.15c_-_Super_Mario_-_(2010-05-01)'>⁋</a></h3><p><img src="docs/images/hum14o.jpg" /></p><ul><li>Opera: added stub in <code>createImageData()</code>;</li><li>Internet Explorer: added configurable brand new context menu;</li><li>..... and freeing (right-) click event;</li><li>..... and now mouse behavior similar to standard-compliant browsers;</li><li>released extended canvas context (window.extCanvasRenderingContext2D), reasons: in some browsers native rendering context is not extendable;</li><li>solved animation interval problem, as a solution introduced canvas parameters <code>onframe</code> and <code>frameDuration</code>;</li><li>new, clear project structure;</li><li>the code splitting into IE and non-IE part;</li><li>fixed <code>HTMLCanvasElement</code> and <code>CanvasRenderingContext2D</code> in Internet Explorer;</li><li>as usual cleaned the code up and small optimizations;</li><li>... some other minor updates;</li></ul>
  <h3>fxCanvas 0.1a - Mario - (2010-04-14) <a class='hh' name='fxCanvas_0.1a_-_Mario_-_(2010-04-14)'>⁋</a></h3><p><img src="docs/images/mario2.png" />    <ul><li>Fixed probably all stupid bugs.</li><li>Support of basic text API. (Thanks Fabien!)</li><li>Image data support. (Thanks jamie!)</li><li>Fixed isPointInPath() (on JS side).</li><li>Fixed extended context in Safari 3.</li><li>Clean up and code optimizations.</li><li>Flash exceptions handling.</li><li>drawImage chews Base64-encoded images and Canvas element.</li><li>Sync with flashcanvas trunk.</li><li>and other positive changes ...</li></ul></p><p><a href="http://code.google.com/p/fxcanvas/downloads/detail?name=fxcanvas-0.2(beta4)-supersonic.zip">Download source</a> (don't forget to file an <a href="http://code.google.com/p/fxcanvas/issues/list">issue</a> when you find something bad).</p>
        <hr/>
        Updated: Sat Feb 05 21:15:18 +0300 2011
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