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<h1 class="title">composition.cpp Example File</h1>
<span class="small-subtitle">demos/composition/composition.cpp</span>
<!-- $$$demos/composition/composition.cpp-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp"> <span class="comment">/****************************************************************************
 **
 ** Copyright (C) 2015 The Qt Company Ltd.
 ** Contact: http://www.qt.io/licensing/
 **
 ** This file is part of the demonstration applications of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:LGPL$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and The Qt Company. For licensing terms
 ** and conditions see http://www.qt.io/terms-conditions. For further
 ** information use the contact form at http://www.qt.io/contact-us.
 **
 ** GNU Lesser General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU Lesser
 ** General Public License version 2.1 or version 3 as published by the Free
 ** Software Foundation and appearing in the file LICENSE.LGPLv21 and
 ** LICENSE.LGPLv3 included in the packaging of this file. Please review the
 ** following information to ensure the GNU Lesser General Public License
 ** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
 ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
 **
 ** As a special exception, The Qt Company gives you certain additional
 ** rights. These rights are described in The Qt Company LGPL Exception
 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
 **
 ** GNU General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU
 ** General Public License version 3.0 as published by the Free Software
 ** Foundation and appearing in the file LICENSE.GPL included in the
 ** packaging of this file.  Please review the following information to
 ** ensure the GNU General Public License version 3.0 requirements will be
 ** met: http://www.gnu.org/copyleft/gpl.html.
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/</span>

 <span class="preprocessor">#include &quot;composition.h&quot;</span>
 <span class="preprocessor">#include &lt;QBoxLayout&gt;</span>
 <span class="preprocessor">#include &lt;QRadioButton&gt;</span>
 <span class="preprocessor">#include &lt;QTimer&gt;</span>
 <span class="preprocessor">#include &lt;QDateTime&gt;</span>
 <span class="preprocessor">#include &lt;QSlider&gt;</span>
 <span class="preprocessor">#include &lt;QMouseEvent&gt;</span>
 <span class="preprocessor">#include &lt;qmath.h&gt;</span>

 <span class="keyword">const</span> <span class="type">int</span> animationInterval <span class="operator">=</span> <span class="number">15</span>; <span class="comment">// update every 16 ms = ~60FPS</span>

 CompositionWidget<span class="operator">::</span>CompositionWidget(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent)
     : <span class="type"><a href="qwidget.html">QWidget</a></span>(parent)
 {
     CompositionRenderer <span class="operator">*</span>view <span class="operator">=</span> <span class="keyword">new</span> CompositionRenderer(<span class="keyword">this</span>);

     <span class="type"><a href="qgroupbox.html">QGroupBox</a></span> <span class="operator">*</span>mainGroup <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qgroupbox.html">QGroupBox</a></span>(parent);
     mainGroup<span class="operator">-</span><span class="operator">&gt;</span>setTitle(tr(<span class="string">&quot;Composition Modes&quot;</span>));

     <span class="type"><a href="qgroupbox.html">QGroupBox</a></span> <span class="operator">*</span>modesGroup <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qgroupbox.html">QGroupBox</a></span>(mainGroup);
     modesGroup<span class="operator">-</span><span class="operator">&gt;</span>setTitle(tr(<span class="string">&quot;Mode&quot;</span>));

     rbClear <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Clear&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbClear<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setClearMode()));
     rbSource <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Source&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbSource<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setSourceMode()));
     rbDest <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Destination&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbDest<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setDestMode()));
     rbSourceOver <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Source Over&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbSourceOver<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setSourceOverMode()));
     rbDestOver <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Destination Over&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbDestOver<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setDestOverMode()));
     rbSourceIn <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Source In&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbSourceIn<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setSourceInMode()));
     rbDestIn <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Dest In&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbDestIn<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setDestInMode()));
     rbSourceOut <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Source Out&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbSourceOut<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setSourceOutMode()));
     rbDestOut <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Dest Out&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbDestOut<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setDestOutMode()));
     rbSourceAtop <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Source Atop&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbSourceAtop<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setSourceAtopMode()));
     rbDestAtop <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Dest Atop&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbDestAtop<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setDestAtopMode()));
     rbXor <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Xor&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbXor<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setXorMode()));

     rbPlus <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Plus&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbPlus<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setPlusMode()));
     rbMultiply <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Multiply&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbMultiply<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setMultiplyMode()));
     rbScreen <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Screen&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbScreen<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setScreenMode()));
     rbOverlay <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Overlay&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbOverlay<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setOverlayMode()));
     rbDarken <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Darken&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbDarken<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setDarkenMode()));
     rbLighten <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Lighten&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbLighten<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setLightenMode()));
     rbColorDodge <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Color Dodge&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbColorDodge<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setColorDodgeMode()));
     rbColorBurn <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Color Burn&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbColorBurn<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setColorBurnMode()));
     rbHardLight <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Hard Light&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbHardLight<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setHardLightMode()));
     rbSoftLight <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Soft Light&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbSoftLight<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setSoftLightMode()));
     rbDifference <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Difference&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbDifference<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setDifferenceMode()));
     rbExclusion <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qradiobutton.html">QRadioButton</a></span>(tr(<span class="string">&quot;Exclusion&quot;</span>)<span class="operator">,</span> modesGroup);
     connect(rbExclusion<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(setExclusionMode()));

     <span class="type"><a href="qgroupbox.html">QGroupBox</a></span> <span class="operator">*</span>circleColorGroup <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qgroupbox.html">QGroupBox</a></span>(mainGroup);
     circleColorGroup<span class="operator">-</span><span class="operator">&gt;</span>setTitle(tr(<span class="string">&quot;Circle color&quot;</span>));
     <span class="type"><a href="qslider.html">QSlider</a></span> <span class="operator">*</span>circleColorSlider <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qslider.html">QSlider</a></span>(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Horizontal<span class="operator">,</span> circleColorGroup);
     circleColorSlider<span class="operator">-</span><span class="operator">&gt;</span>setRange(<span class="number">0</span><span class="operator">,</span> <span class="number">359</span>);
     circleColorSlider<span class="operator">-</span><span class="operator">&gt;</span>setSizePolicy(<span class="type"><a href="qsizepolicy.html">QSizePolicy</a></span><span class="operator">::</span>Preferred<span class="operator">,</span> <span class="type"><a href="qsizepolicy.html">QSizePolicy</a></span><span class="operator">::</span>Fixed);
     connect(circleColorSlider<span class="operator">,</span> SIGNAL(valueChanged(<span class="type">int</span>))<span class="operator">,</span> view<span class="operator">,</span> SLOT(setCircleColor(<span class="type">int</span>)));

     <span class="type"><a href="qgroupbox.html">QGroupBox</a></span> <span class="operator">*</span>circleAlphaGroup <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qgroupbox.html">QGroupBox</a></span>(mainGroup);
     circleAlphaGroup<span class="operator">-</span><span class="operator">&gt;</span>setTitle(tr(<span class="string">&quot;Circle alpha&quot;</span>));
     <span class="type"><a href="qslider.html">QSlider</a></span> <span class="operator">*</span>circleAlphaSlider <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qslider.html">QSlider</a></span>(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Horizontal<span class="operator">,</span> circleAlphaGroup);
     circleAlphaSlider<span class="operator">-</span><span class="operator">&gt;</span>setRange(<span class="number">0</span><span class="operator">,</span> <span class="number">255</span>);
     circleAlphaSlider<span class="operator">-</span><span class="operator">&gt;</span>setSizePolicy(<span class="type"><a href="qsizepolicy.html">QSizePolicy</a></span><span class="operator">::</span>Preferred<span class="operator">,</span> <span class="type"><a href="qsizepolicy.html">QSizePolicy</a></span><span class="operator">::</span>Fixed);
     connect(circleAlphaSlider<span class="operator">,</span> SIGNAL(valueChanged(<span class="type">int</span>))<span class="operator">,</span> view<span class="operator">,</span> SLOT(setCircleAlpha(<span class="type">int</span>)));

     <span class="type"><a href="qpushbutton.html">QPushButton</a></span> <span class="operator">*</span>showSourceButton <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qpushbutton.html">QPushButton</a></span>(mainGroup);
     showSourceButton<span class="operator">-</span><span class="operator">&gt;</span>setText(tr(<span class="string">&quot;Show Source&quot;</span>));
 <span class="preprocessor">#if defined(QT_OPENGL_SUPPORT) &amp;&amp; !defined(QT_OPENGL_ES)</span>
     <span class="type"><a href="qpushbutton.html">QPushButton</a></span> <span class="operator">*</span>enableOpenGLButton <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qpushbutton.html">QPushButton</a></span>(mainGroup);
     enableOpenGLButton<span class="operator">-</span><span class="operator">&gt;</span>setText(tr(<span class="string">&quot;Use OpenGL&quot;</span>));
     enableOpenGLButton<span class="operator">-</span><span class="operator">&gt;</span>setCheckable(<span class="keyword">true</span>);
     enableOpenGLButton<span class="operator">-</span><span class="operator">&gt;</span>setChecked(view<span class="operator">-</span><span class="operator">&gt;</span>usesOpenGL());

     <span class="keyword">if</span> (<span class="operator">!</span><span class="type"><a href="qglformat.html">QGLFormat</a></span><span class="operator">::</span>hasOpenGL() <span class="operator">|</span><span class="operator">|</span> <span class="operator">!</span><span class="type"><a href="qglpixelbuffer.html">QGLPixelBuffer</a></span><span class="operator">::</span>hasOpenGLPbuffers())
         enableOpenGLButton<span class="operator">-</span><span class="operator">&gt;</span>hide();
 <span class="preprocessor">#endif</span>
     <span class="type"><a href="qpushbutton.html">QPushButton</a></span> <span class="operator">*</span>whatsThisButton <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qpushbutton.html">QPushButton</a></span>(mainGroup);
     whatsThisButton<span class="operator">-</span><span class="operator">&gt;</span>setText(tr(<span class="string">&quot;What's This?&quot;</span>));
     whatsThisButton<span class="operator">-</span><span class="operator">&gt;</span>setCheckable(<span class="keyword">true</span>);

     <span class="type"><a href="qpushbutton.html">QPushButton</a></span> <span class="operator">*</span>animateButton <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qpushbutton.html">QPushButton</a></span>(mainGroup);
     animateButton<span class="operator">-</span><span class="operator">&gt;</span>setText(tr(<span class="string">&quot;Animated&quot;</span>));
     animateButton<span class="operator">-</span><span class="operator">&gt;</span>setCheckable(<span class="keyword">true</span>);
     animateButton<span class="operator">-</span><span class="operator">&gt;</span>setChecked(<span class="keyword">true</span>);

     <span class="type"><a href="qhboxlayout.html">QHBoxLayout</a></span> <span class="operator">*</span>viewLayout <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qhboxlayout.html">QHBoxLayout</a></span>(<span class="keyword">this</span>);
     viewLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(view);
     viewLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(mainGroup);

     <span class="type"><a href="qvboxlayout.html">QVBoxLayout</a></span> <span class="operator">*</span>mainGroupLayout <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qvboxlayout.html">QVBoxLayout</a></span>(mainGroup);
     mainGroupLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(circleColorGroup);
     mainGroupLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(circleAlphaGroup);
     mainGroupLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(modesGroup);
     mainGroupLayout<span class="operator">-</span><span class="operator">&gt;</span>addStretch();
     mainGroupLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(animateButton);
     mainGroupLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(whatsThisButton);
     mainGroupLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(showSourceButton);
 <span class="preprocessor">#if defined(QT_OPENGL_SUPPORT) &amp;&amp; !defined(QT_OPENGL_ES)</span>
     mainGroupLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(enableOpenGLButton);
 <span class="preprocessor">#endif</span>

     <span class="type"><a href="qgridlayout.html">QGridLayout</a></span> <span class="operator">*</span>modesLayout <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qgridlayout.html">QGridLayout</a></span>(modesGroup);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbClear<span class="operator">,</span>             <span class="number">0</span><span class="operator">,</span>      <span class="number">0</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbSource<span class="operator">,</span>            <span class="number">1</span><span class="operator">,</span>      <span class="number">0</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbDest<span class="operator">,</span>              <span class="number">2</span><span class="operator">,</span>      <span class="number">0</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbSourceOver<span class="operator">,</span>        <span class="number">3</span><span class="operator">,</span>      <span class="number">0</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbDestOver<span class="operator">,</span>          <span class="number">4</span><span class="operator">,</span>      <span class="number">0</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbSourceIn<span class="operator">,</span>          <span class="number">5</span><span class="operator">,</span>      <span class="number">0</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbDestIn<span class="operator">,</span>            <span class="number">6</span><span class="operator">,</span>      <span class="number">0</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbSourceOut<span class="operator">,</span>         <span class="number">7</span><span class="operator">,</span>      <span class="number">0</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbDestOut<span class="operator">,</span>           <span class="number">8</span><span class="operator">,</span>      <span class="number">0</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbSourceAtop<span class="operator">,</span>        <span class="number">9</span><span class="operator">,</span>      <span class="number">0</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbDestAtop<span class="operator">,</span>         <span class="number">10</span><span class="operator">,</span>      <span class="number">0</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbXor<span class="operator">,</span>              <span class="number">11</span><span class="operator">,</span>      <span class="number">0</span>);

     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbPlus<span class="operator">,</span>              <span class="number">0</span><span class="operator">,</span>      <span class="number">1</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbMultiply<span class="operator">,</span>          <span class="number">1</span><span class="operator">,</span>      <span class="number">1</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbScreen<span class="operator">,</span>            <span class="number">2</span><span class="operator">,</span>      <span class="number">1</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbOverlay<span class="operator">,</span>           <span class="number">3</span><span class="operator">,</span>      <span class="number">1</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbDarken<span class="operator">,</span>            <span class="number">4</span><span class="operator">,</span>      <span class="number">1</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbLighten<span class="operator">,</span>           <span class="number">5</span><span class="operator">,</span>      <span class="number">1</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbColorDodge<span class="operator">,</span>        <span class="number">6</span><span class="operator">,</span>      <span class="number">1</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbColorBurn<span class="operator">,</span>         <span class="number">7</span><span class="operator">,</span>      <span class="number">1</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbHardLight<span class="operator">,</span>         <span class="number">8</span><span class="operator">,</span>      <span class="number">1</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbSoftLight<span class="operator">,</span>         <span class="number">9</span><span class="operator">,</span>      <span class="number">1</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbDifference<span class="operator">,</span>       <span class="number">10</span><span class="operator">,</span>      <span class="number">1</span>);
     modesLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(rbExclusion<span class="operator">,</span>        <span class="number">11</span><span class="operator">,</span>      <span class="number">1</span>);

     <span class="type"><a href="qvboxlayout.html">QVBoxLayout</a></span> <span class="operator">*</span>circleColorLayout <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qvboxlayout.html">QVBoxLayout</a></span>(circleColorGroup);
     circleColorLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(circleColorSlider);

     <span class="type"><a href="qvboxlayout.html">QVBoxLayout</a></span> <span class="operator">*</span>circleAlphaLayout <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qvboxlayout.html">QVBoxLayout</a></span>(circleAlphaGroup);
     circleAlphaLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(circleAlphaSlider);

     view<span class="operator">-</span><span class="operator">&gt;</span>loadDescription(<span class="string">&quot;:res/composition/composition.html&quot;</span>);
     view<span class="operator">-</span><span class="operator">&gt;</span>loadSourceFile(<span class="string">&quot;:res/composition/composition.cpp&quot;</span>);

     connect(whatsThisButton<span class="operator">,</span> SIGNAL(clicked(<span class="type">bool</span>))<span class="operator">,</span> view<span class="operator">,</span> SLOT(setDescriptionEnabled(<span class="type">bool</span>)));
     connect(view<span class="operator">,</span> SIGNAL(descriptionEnabledChanged(<span class="type">bool</span>))<span class="operator">,</span> whatsThisButton<span class="operator">,</span> SLOT(setChecked(<span class="type">bool</span>)));
     connect(showSourceButton<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> view<span class="operator">,</span> SLOT(showSource()));
 <span class="preprocessor">#if defined(QT_OPENGL_SUPPORT) &amp;&amp; !defined(QT_OPENGL_ES)</span>
     connect(enableOpenGLButton<span class="operator">,</span> SIGNAL(clicked(<span class="type">bool</span>))<span class="operator">,</span> view<span class="operator">,</span> SLOT(enableOpenGL(<span class="type">bool</span>)));
 <span class="preprocessor">#endif</span>
     connect(animateButton<span class="operator">,</span> SIGNAL(toggled(<span class="type">bool</span>))<span class="operator">,</span> view<span class="operator">,</span> SLOT(setAnimationEnabled(<span class="type">bool</span>)));

     circleColorSlider<span class="operator">-</span><span class="operator">&gt;</span>setValue(<span class="number">270</span>);
     circleAlphaSlider<span class="operator">-</span><span class="operator">&gt;</span>setValue(<span class="number">200</span>);
     rbSourceOut<span class="operator">-</span><span class="operator">&gt;</span>animateClick();

     setWindowTitle(tr(<span class="string">&quot;Composition Modes&quot;</span>));
 }

 <span class="type">void</span> CompositionWidget<span class="operator">::</span>nextMode()
 {
     <span class="comment">/*
       if (!m_animation_enabled)
       return;
       if (rbClear-&gt;isChecked()) rbSource-&gt;animateClick();
       if (rbSource-&gt;isChecked()) rbDest-&gt;animateClick();
       if (rbDest-&gt;isChecked()) rbSourceOver-&gt;animateClick();
       if (rbSourceOver-&gt;isChecked()) rbDestOver-&gt;animateClick();
       if (rbDestOver-&gt;isChecked()) rbSourceIn-&gt;animateClick();
       if (rbSourceIn-&gt;isChecked()) rbDestIn-&gt;animateClick();
       if (rbDestIn-&gt;isChecked()) rbSourceOut-&gt;animateClick();
       if (rbSourceOut-&gt;isChecked()) rbDestOut-&gt;animateClick();
       if (rbDestOut-&gt;isChecked()) rbSourceAtop-&gt;animateClick();
       if (rbSourceAtop-&gt;isChecked()) rbDestAtop-&gt;animateClick();
       if (rbDestAtop-&gt;isChecked()) rbXor-&gt;animateClick();
       if (rbXor-&gt;isChecked()) rbClear-&gt;animateClick();
     */</span>
 }

 CompositionRenderer<span class="operator">::</span>CompositionRenderer(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent)
     : ArthurFrame(parent)
 {
     m_animation_enabled <span class="operator">=</span> <span class="keyword">true</span>;
     m_animationTimer <span class="operator">=</span> startTimer(animationInterval);
 <span class="preprocessor">#ifdef Q_WS_QWS</span>
     m_image <span class="operator">=</span> <span class="type"><a href="qpixmap.html">QPixmap</a></span>(<span class="string">&quot;:res/composition/flower.jpg&quot;</span>);
     m_image<span class="operator">.</span>setAlphaChannel(<span class="type"><a href="qpixmap.html">QPixmap</a></span>(<span class="string">&quot;:res/composition/flower_alpha.jpg&quot;</span>));
 <span class="preprocessor">#else</span>
     m_image <span class="operator">=</span> <span class="type"><a href="qimage.html">QImage</a></span>(<span class="string">&quot;:res/composition/flower.jpg&quot;</span>);
     m_image<span class="operator">.</span>setAlphaChannel(<span class="type"><a href="qimage.html">QImage</a></span>(<span class="string">&quot;:res/composition/flower_alpha.jpg&quot;</span>));
 <span class="preprocessor">#endif</span>
     m_circle_alpha <span class="operator">=</span> <span class="number">127</span>;
     m_circle_hue <span class="operator">=</span> <span class="number">255</span>;
     m_current_object <span class="operator">=</span> NoObject;
     m_composition_mode <span class="operator">=</span> <span class="type"><a href="qpainter.html">QPainter</a></span><span class="operator">::</span>CompositionMode_SourceOut;

     m_circle_pos <span class="operator">=</span> <span class="type"><a href="qpoint.html">QPoint</a></span>(<span class="number">200</span><span class="operator">,</span> <span class="number">100</span>);

     setSizePolicy(<span class="type"><a href="qsizepolicy.html">QSizePolicy</a></span><span class="operator">::</span>Expanding<span class="operator">,</span> <span class="type"><a href="qsizepolicy.html">QSizePolicy</a></span><span class="operator">::</span>Expanding);
 <span class="preprocessor">#ifdef QT_OPENGL_SUPPORT</span>
     m_pbuffer <span class="operator">=</span> <span class="number">0</span>;
     m_pbuffer_size <span class="operator">=</span> <span class="number">1024</span>;
 <span class="preprocessor">#endif</span>
 }

 <span class="type"><a href="qrectf.html">QRectF</a></span> rectangle_around(<span class="keyword">const</span> <span class="type"><a href="qpointf.html">QPointF</a></span> <span class="operator">&amp;</span>p<span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="qsizef.html">QSizeF</a></span> <span class="operator">&amp;</span>size <span class="operator">=</span> <span class="type"><a href="qsize.html">QSize</a></span>(<span class="number">250</span><span class="operator">,</span> <span class="number">200</span>))
 {
     <span class="type"><a href="qrectf.html">QRectF</a></span> rect(p<span class="operator">,</span> size);
     rect<span class="operator">.</span>translate(<span class="operator">-</span>size<span class="operator">.</span>width()<span class="operator">/</span><span class="number">2</span><span class="operator">,</span> <span class="operator">-</span>size<span class="operator">.</span>height()<span class="operator">/</span><span class="number">2</span>);
     <span class="keyword">return</span> rect;
 }

 <span class="type">void</span> CompositionRenderer<span class="operator">::</span>setAnimationEnabled(<span class="type">bool</span> enabled)
 {
     <span class="keyword">if</span> (m_animation_enabled <span class="operator">=</span><span class="operator">=</span> enabled)
         <span class="keyword">return</span>;
     m_animation_enabled <span class="operator">=</span> enabled;
     <span class="keyword">if</span> (enabled) {
         Q_ASSERT(<span class="operator">!</span>m_animationTimer);
         m_animationTimer <span class="operator">=</span> startTimer(animationInterval);
     } <span class="keyword">else</span> {
         killTimer(m_animationTimer);
         m_animationTimer <span class="operator">=</span> <span class="number">0</span>;
     }
 }

 <span class="type">void</span> CompositionRenderer<span class="operator">::</span>updateCirclePos()
 {
     <span class="keyword">if</span> (m_current_object <span class="operator">!</span><span class="operator">=</span> NoObject)
         <span class="keyword">return</span>;
     <span class="type"><a href="qdatetime.html">QDateTime</a></span> dt <span class="operator">=</span> <span class="type"><a href="qdatetime.html">QDateTime</a></span><span class="operator">::</span>currentDateTime();
     <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> t <span class="operator">=</span> (dt<span class="operator">.</span>toTime_t() <span class="operator">*</span> <span class="number">1000</span> <span class="operator">+</span> dt<span class="operator">.</span>time()<span class="operator">.</span>msec()) <span class="operator">/</span> <span class="number">1000.0</span>;

     <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> x <span class="operator">=</span> width() <span class="operator">/</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span>(<span class="number">2</span>) <span class="operator">+</span> (<a href="qtcore-qmath-h.html#qCos">qCos</a>(t<span class="operator">*</span><span class="number">8</span><span class="operator">/</span><span class="number">11</span>) <span class="operator">+</span> <a href="qtcore-qmath-h.html#qSin">qSin</a>(<span class="operator">-</span>t)) <span class="operator">*</span> width() <span class="operator">/</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span>(<span class="number">4</span>);
     <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> y <span class="operator">=</span> height() <span class="operator">/</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span>(<span class="number">2</span>) <span class="operator">+</span> (<a href="qtcore-qmath-h.html#qSin">qSin</a>(t<span class="operator">*</span><span class="number">6</span><span class="operator">/</span><span class="number">7</span>) <span class="operator">+</span> <a href="qtcore-qmath-h.html#qCos">qCos</a>(t <span class="operator">*</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span>(<span class="number">1.5</span>))) <span class="operator">*</span> height() <span class="operator">/</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span>(<span class="number">4</span>);

     setCirclePos(<span class="type"><a href="qlinef.html">QLineF</a></span>(m_circle_pos<span class="operator">,</span> <span class="type"><a href="qpointf.html">QPointF</a></span>(x<span class="operator">,</span> y))<span class="operator">.</span>pointAt(<span class="number">0.02</span>));
 }

 <span class="type">void</span> CompositionRenderer<span class="operator">::</span>drawBase(<span class="type"><a href="qpainter.html">QPainter</a></span> <span class="operator">&amp;</span>p)
 {
     p<span class="operator">.</span>setPen(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>NoPen);

     <span class="type"><a href="qlineargradient.html">QLinearGradient</a></span> rect_gradient(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> height());
     rect_gradient<span class="operator">.</span>setColorAt(<span class="number">0</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>red);
     rect_gradient<span class="operator">.</span>setColorAt(<span class="operator">.</span><span class="number">17</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>yellow);
     rect_gradient<span class="operator">.</span>setColorAt(<span class="operator">.</span><span class="number">33</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>green);
     rect_gradient<span class="operator">.</span>setColorAt(<span class="operator">.</span><span class="number">50</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>cyan);
     rect_gradient<span class="operator">.</span>setColorAt(<span class="operator">.</span><span class="number">66</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>blue);
     rect_gradient<span class="operator">.</span>setColorAt(<span class="operator">.</span><span class="number">81</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>magenta);
     rect_gradient<span class="operator">.</span>setColorAt(<span class="number">1</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>red);
     p<span class="operator">.</span>setBrush(rect_gradient);
     p<span class="operator">.</span>drawRect(width() <span class="operator">/</span> <span class="number">2</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> width() <span class="operator">/</span> <span class="number">2</span><span class="operator">,</span> height());

     <span class="type"><a href="qlineargradient.html">QLinearGradient</a></span> alpha_gradient(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> width()<span class="operator">,</span> <span class="number">0</span>);
     alpha_gradient<span class="operator">.</span>setColorAt(<span class="number">0</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>white);
     alpha_gradient<span class="operator">.</span>setColorAt(<span class="number">0.2</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>white);
     alpha_gradient<span class="operator">.</span>setColorAt(<span class="number">0.5</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>transparent);
     alpha_gradient<span class="operator">.</span>setColorAt(<span class="number">0.8</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>white);
     alpha_gradient<span class="operator">.</span>setColorAt(<span class="number">1</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>white);

     p<span class="operator">.</span>setCompositionMode(<span class="type"><a href="qpainter.html">QPainter</a></span><span class="operator">::</span>CompositionMode_DestinationIn);
     p<span class="operator">.</span>setBrush(alpha_gradient);
     p<span class="operator">.</span>drawRect(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> width()<span class="operator">,</span> height());

     p<span class="operator">.</span>setCompositionMode(<span class="type"><a href="qpainter.html">QPainter</a></span><span class="operator">::</span>CompositionMode_DestinationOver);

     p<span class="operator">.</span>setPen(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>NoPen);
     p<span class="operator">.</span>setRenderHint(<span class="type"><a href="qpainter.html">QPainter</a></span><span class="operator">::</span>SmoothPixmapTransform);
 <span class="preprocessor">#ifdef Q_WS_QWS</span>
     p<span class="operator">.</span>drawPixmap(rect()<span class="operator">,</span> m_image);
 <span class="preprocessor">#else</span>
     p<span class="operator">.</span>drawImage(rect()<span class="operator">,</span> m_image);
 <span class="preprocessor">#endif</span>
 }

 <span class="type">void</span> CompositionRenderer<span class="operator">::</span>drawSource(<span class="type"><a href="qpainter.html">QPainter</a></span> <span class="operator">&amp;</span>p)
 {
     p<span class="operator">.</span>setPen(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>NoPen);
     p<span class="operator">.</span>setRenderHint(<span class="type"><a href="qpainter.html">QPainter</a></span><span class="operator">::</span>Antialiasing);
     p<span class="operator">.</span>setCompositionMode(m_composition_mode);

     <span class="type"><a href="qrectf.html">QRectF</a></span> circle_rect <span class="operator">=</span> rectangle_around(m_circle_pos);
     <span class="type"><a href="qcolor.html">QColor</a></span> color <span class="operator">=</span> <span class="type"><a href="qcolor.html">QColor</a></span><span class="operator">::</span>fromHsvF(m_circle_hue <span class="operator">/</span> <span class="number">360.0</span><span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> m_circle_alpha <span class="operator">/</span> <span class="number">255.0</span>);
     <span class="type"><a href="qlineargradient.html">QLinearGradient</a></span> circle_gradient(circle_rect<span class="operator">.</span>topLeft()<span class="operator">,</span> circle_rect<span class="operator">.</span>bottomRight());
     circle_gradient<span class="operator">.</span>setColorAt(<span class="number">0</span><span class="operator">,</span> color<span class="operator">.</span>light());
     circle_gradient<span class="operator">.</span>setColorAt(<span class="number">0.5</span><span class="operator">,</span> color);
     circle_gradient<span class="operator">.</span>setColorAt(<span class="number">1</span><span class="operator">,</span> color<span class="operator">.</span>dark());
     p<span class="operator">.</span>setBrush(circle_gradient);

     p<span class="operator">.</span>drawEllipse(circle_rect);
 }

 <span class="type">void</span> CompositionRenderer<span class="operator">::</span>paint(<span class="type"><a href="qpainter.html">QPainter</a></span> <span class="operator">*</span>painter)
 {
 <span class="preprocessor">#if defined(QT_OPENGL_SUPPORT) &amp;&amp; !defined(QT_OPENGL_ES)</span>
     <span class="keyword">if</span> (usesOpenGL()) {

         <span class="type">int</span> new_pbuf_size <span class="operator">=</span> m_pbuffer_size;
         <span class="keyword">if</span> (size()<span class="operator">.</span>width() <span class="operator">&gt;</span> m_pbuffer_size <span class="operator">|</span><span class="operator">|</span>
             size()<span class="operator">.</span>height() <span class="operator">&gt;</span> m_pbuffer_size)
             new_pbuf_size <span class="operator">*</span><span class="operator">=</span> <span class="number">2</span>;

         <span class="keyword">if</span> (size()<span class="operator">.</span>width() <span class="operator">&lt;</span> m_pbuffer_size<span class="operator">/</span><span class="number">2</span> <span class="operator">&amp;</span><span class="operator">&amp;</span>
             size()<span class="operator">.</span>height() <span class="operator">&lt;</span> m_pbuffer_size<span class="operator">/</span><span class="number">2</span>)
             new_pbuf_size <span class="operator">/</span><span class="operator">=</span> <span class="number">2</span>;

         <span class="keyword">if</span> (<span class="operator">!</span>m_pbuffer <span class="operator">|</span><span class="operator">|</span> new_pbuf_size <span class="operator">!</span><span class="operator">=</span> m_pbuffer_size) {
             <span class="keyword">if</span> (m_pbuffer) {
                 m_pbuffer<span class="operator">-</span><span class="operator">&gt;</span>deleteTexture(m_base_tex);
                 m_pbuffer<span class="operator">-</span><span class="operator">&gt;</span>deleteTexture(m_compositing_tex);
                 <span class="keyword">delete</span> m_pbuffer;
             }

             m_pbuffer <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qglpixelbuffer.html">QGLPixelBuffer</a></span>(<span class="type"><a href="qsize.html">QSize</a></span>(new_pbuf_size<span class="operator">,</span> new_pbuf_size)<span class="operator">,</span> <span class="type"><a href="qglformat.html">QGLFormat</a></span><span class="operator">::</span>defaultFormat()<span class="operator">,</span> glWidget());
             m_pbuffer<span class="operator">-</span><span class="operator">&gt;</span>makeCurrent();
             m_base_tex <span class="operator">=</span> m_pbuffer<span class="operator">-</span><span class="operator">&gt;</span>generateDynamicTexture();
             m_compositing_tex <span class="operator">=</span> m_pbuffer<span class="operator">-</span><span class="operator">&gt;</span>generateDynamicTexture();
             m_pbuffer_size <span class="operator">=</span> new_pbuf_size;
         }

         <span class="keyword">if</span> (size() <span class="operator">!</span><span class="operator">=</span> m_previous_size) {
             m_previous_size <span class="operator">=</span> size();
             <span class="type"><a href="qpainter.html">QPainter</a></span> p(m_pbuffer);
             p<span class="operator">.</span>setCompositionMode(<span class="type"><a href="qpainter.html">QPainter</a></span><span class="operator">::</span>CompositionMode_Source);
             p<span class="operator">.</span>fillRect(<span class="type"><a href="qrect.html">QRect</a></span>(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> m_pbuffer<span class="operator">-</span><span class="operator">&gt;</span>width()<span class="operator">,</span> m_pbuffer<span class="operator">-</span><span class="operator">&gt;</span>height())<span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>transparent);
             drawBase(p);
             p<span class="operator">.</span>end();
             m_pbuffer<span class="operator">-</span><span class="operator">&gt;</span>updateDynamicTexture(m_base_tex);
         }

         <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> x_fraction <span class="operator">=</span> width()<span class="operator">/</span><span class="type">float</span>(m_pbuffer<span class="operator">-</span><span class="operator">&gt;</span>width());
         <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> y_fraction <span class="operator">=</span> height()<span class="operator">/</span><span class="type">float</span>(m_pbuffer<span class="operator">-</span><span class="operator">&gt;</span>height());

         {
             <span class="type"><a href="qpainter.html">QPainter</a></span> p(m_pbuffer);
             p<span class="operator">.</span>setCompositionMode(<span class="type"><a href="qpainter.html">QPainter</a></span><span class="operator">::</span>CompositionMode_Source);
             p<span class="operator">.</span>fillRect(<span class="type"><a href="qrect.html">QRect</a></span>(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> m_pbuffer<span class="operator">-</span><span class="operator">&gt;</span>width()<span class="operator">,</span> m_pbuffer<span class="operator">-</span><span class="operator">&gt;</span>height())<span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>transparent);

             p<span class="operator">.</span>save(); <span class="comment">// Needed when using the GL1 engine</span>
             p<span class="operator">.</span>beginNativePainting(); <span class="comment">// Needed when using the GL2 engine</span>

             glBindTexture(GL_TEXTURE_2D<span class="operator">,</span> m_base_tex);
             glEnable(GL_TEXTURE_2D);
             glColor4f(<span class="number">1.</span><span class="operator">,</span><span class="number">1.</span><span class="operator">,</span><span class="number">1.</span><span class="operator">,</span><span class="number">1.</span>);

             glBegin(GL_QUADS);
             {
                 glTexCoord2f(<span class="number">0</span><span class="operator">,</span> <span class="number">1.0</span>);
                 glVertex2f(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span>);

                 glTexCoord2f(x_fraction<span class="operator">,</span> <span class="number">1.0</span>);
                 glVertex2f(width()<span class="operator">,</span> <span class="number">0</span>);

                 glTexCoord2f(x_fraction<span class="operator">,</span> <span class="number">1.0</span><span class="operator">-</span>y_fraction);
                 glVertex2f(width()<span class="operator">,</span> height());

                 glTexCoord2f(<span class="number">0</span><span class="operator">,</span> <span class="number">1.0</span><span class="operator">-</span>y_fraction);
                 glVertex2f(<span class="number">0</span><span class="operator">,</span> height());
             }
             glEnd();

             glDisable(GL_TEXTURE_2D);

             p<span class="operator">.</span>endNativePainting(); <span class="comment">// Needed when using the GL2 engine</span>
             p<span class="operator">.</span>restore(); <span class="comment">// Needed when using the GL1 engine</span>

             drawSource(p);
             p<span class="operator">.</span>end();
             m_pbuffer<span class="operator">-</span><span class="operator">&gt;</span>updateDynamicTexture(m_compositing_tex);
         }

         painter<span class="operator">-</span><span class="operator">&gt;</span>beginNativePainting(); <span class="comment">// Needed when using the GL2 engine</span>
         glWidget()<span class="operator">-</span><span class="operator">&gt;</span>makeCurrent(); <span class="comment">// Needed when using the GL1 engine</span>
         glBindTexture(GL_TEXTURE_2D<span class="operator">,</span> m_compositing_tex);
         glEnable(GL_TEXTURE_2D);
         glEnable(GL_BLEND);
         glBlendFunc(GL_ONE<span class="operator">,</span> GL_ONE_MINUS_SRC_ALPHA);
         glColor4f(<span class="number">1.</span><span class="operator">,</span><span class="number">1.</span><span class="operator">,</span><span class="number">1.</span><span class="operator">,</span><span class="number">1.</span>);
         glBegin(GL_QUADS);
         {
             glTexCoord2f(<span class="number">0</span><span class="operator">,</span> <span class="number">1.0</span>);
             glVertex2f(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span>);

             glTexCoord2f(x_fraction<span class="operator">,</span> <span class="number">1.0</span>);
             glVertex2f(width()<span class="operator">,</span> <span class="number">0</span>);

             glTexCoord2f(x_fraction<span class="operator">,</span> <span class="number">1.0</span><span class="operator">-</span>y_fraction);
             glVertex2f(width()<span class="operator">,</span> height());

             glTexCoord2f(<span class="number">0</span><span class="operator">,</span> <span class="number">1.0</span><span class="operator">-</span>y_fraction);
             glVertex2f(<span class="number">0</span><span class="operator">,</span> height());
         }
         glEnd();
         glDisable(GL_TEXTURE_2D);
         painter<span class="operator">-</span><span class="operator">&gt;</span>endNativePainting(); <span class="comment">// Needed when using the GL2 engine</span>
     } <span class="keyword">else</span>
 <span class="preprocessor">#endif</span>
     {
         <span class="comment">// using a QImage</span>
         <span class="keyword">if</span> (m_buffer<span class="operator">.</span>size() <span class="operator">!</span><span class="operator">=</span> size()) {
 <span class="preprocessor">#ifdef Q_WS_QWS</span>
             m_base_buffer <span class="operator">=</span> <span class="type"><a href="qpixmap.html">QPixmap</a></span>(size());
             m_base_buffer<span class="operator">.</span>fill(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>transparent);
 <span class="preprocessor">#else</span>
             m_buffer <span class="operator">=</span> <span class="type"><a href="qimage.html">QImage</a></span>(size()<span class="operator">,</span> <span class="type"><a href="qimage.html">QImage</a></span><span class="operator">::</span>Format_ARGB32_Premultiplied);
             m_base_buffer <span class="operator">=</span> <span class="type"><a href="qimage.html">QImage</a></span>(size()<span class="operator">,</span> <span class="type"><a href="qimage.html">QImage</a></span><span class="operator">::</span>Format_ARGB32_Premultiplied);

             m_base_buffer<span class="operator">.</span>fill(<span class="number">0</span>);
 <span class="preprocessor">#endif</span>

             <span class="type"><a href="qpainter.html">QPainter</a></span> p(<span class="operator">&amp;</span>m_base_buffer);

             drawBase(p);
         }

 <span class="preprocessor">#ifdef Q_WS_QWS</span>
         m_buffer <span class="operator">=</span> m_base_buffer;
 <span class="preprocessor">#else</span>
         memcpy(m_buffer<span class="operator">.</span>bits()<span class="operator">,</span> m_base_buffer<span class="operator">.</span>bits()<span class="operator">,</span> m_buffer<span class="operator">.</span>byteCount());
 <span class="preprocessor">#endif</span>

         {
             <span class="type"><a href="qpainter.html">QPainter</a></span> p(<span class="operator">&amp;</span>m_buffer);
             drawSource(p);
         }

 <span class="preprocessor">#ifdef Q_WS_QWS</span>
         painter<span class="operator">-</span><span class="operator">&gt;</span>drawPixmap(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> m_buffer);
 <span class="preprocessor">#else</span>
         painter<span class="operator">-</span><span class="operator">&gt;</span>drawImage(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> m_buffer);
 <span class="preprocessor">#endif</span>
     }
 }

 <span class="type">void</span> CompositionRenderer<span class="operator">::</span>mousePressEvent(<span class="type"><a href="qmouseevent.html">QMouseEvent</a></span> <span class="operator">*</span>e)
 {
     setDescriptionEnabled(<span class="keyword">false</span>);

     <span class="type"><a href="qrectf.html">QRectF</a></span> circle <span class="operator">=</span> rectangle_around(m_circle_pos);

     <span class="keyword">if</span> (circle<span class="operator">.</span>contains(e<span class="operator">-</span><span class="operator">&gt;</span>pos())) {
         m_current_object <span class="operator">=</span> Circle;
         m_offset <span class="operator">=</span> circle<span class="operator">.</span>center() <span class="operator">-</span> e<span class="operator">-</span><span class="operator">&gt;</span>pos();
     } <span class="keyword">else</span> {
         m_current_object <span class="operator">=</span> NoObject;
     }
     <span class="keyword">if</span> (m_animation_enabled) {
         killTimer(m_animationTimer);
         m_animationTimer <span class="operator">=</span> <span class="number">0</span>;
     }
 }

 <span class="type">void</span> CompositionRenderer<span class="operator">::</span>mouseMoveEvent(<span class="type"><a href="qmouseevent.html">QMouseEvent</a></span> <span class="operator">*</span>e)
 {
     <span class="keyword">if</span> (m_current_object <span class="operator">=</span><span class="operator">=</span> Circle) setCirclePos(e<span class="operator">-</span><span class="operator">&gt;</span>pos() <span class="operator">+</span> m_offset);
 }

 <span class="type">void</span> CompositionRenderer<span class="operator">::</span>mouseReleaseEvent(<span class="type"><a href="qmouseevent.html">QMouseEvent</a></span> <span class="operator">*</span>)
 {
     m_current_object <span class="operator">=</span> NoObject;

     <span class="keyword">if</span> (m_animation_enabled) {
         Q_ASSERT(<span class="operator">!</span>m_animationTimer);
         m_animationTimer <span class="operator">=</span> startTimer(animationInterval);
     }
 }

 <span class="type">void</span> CompositionRenderer<span class="operator">::</span>timerEvent(<span class="type"><a href="qtimerevent.html">QTimerEvent</a></span> <span class="operator">*</span>event)
 {
     <span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">&gt;</span>timerId() <span class="operator">=</span><span class="operator">=</span> m_animationTimer)
         updateCirclePos();
 }

 <span class="type">void</span> CompositionRenderer<span class="operator">::</span>setCirclePos(<span class="keyword">const</span> <span class="type"><a href="qpointf.html">QPointF</a></span> <span class="operator">&amp;</span>pos)
 {
     <span class="keyword">const</span> <span class="type"><a href="qrect.html">QRect</a></span> oldRect <span class="operator">=</span> rectangle_around(m_circle_pos)<span class="operator">.</span>toAlignedRect();
     m_circle_pos <span class="operator">=</span> pos;
     <span class="keyword">const</span> <span class="type"><a href="qrect.html">QRect</a></span> newRect <span class="operator">=</span> rectangle_around(m_circle_pos)<span class="operator">.</span>toAlignedRect();
 <span class="preprocessor">#if defined(QT_OPENGL_SUPPORT) &amp;&amp; !defined(QT_OPENGL_ES)</span>
     <span class="keyword">if</span> (usesOpenGL())
         update();
     <span class="keyword">else</span>
 <span class="preprocessor">#endif</span>
         update(oldRect <span class="operator">|</span> newRect);
 }</pre>
</div>
<!-- @@@demos/composition/composition.cpp -->
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      License version 1.3</a> as published by the Free Software Foundation.</p>
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      Documentation sources may be obtained from <a href="http://www.qt-project.org">
      www.qt-project.org</a>.</p>
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