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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html>
<html lang="en">
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<!-- GammaAdjust.qml -->
  <title>GammaAdjust QML Type | Qt Graphical Effects 5.9</title>
  <link rel="stylesheet" type="text/css" href="style/offline-simple.css" />
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    // loading style sheet breaks anchors that were jumped to before
    // so force jumping to anchor again
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        // need to jump to different anchor first (e.g. none)
        location.hash = "#";
        setTimeout(function() {
            location.hash = anchor;
        }, 0);
    }, 0);
  </script>
</head>
<body>
<div class="header" id="qtdocheader">
  <div class="main">
    <div class="main-rounded">
      <div class="navigationbar">
        <table><tr>
<td >Qt 5.9</td><td ><a href="qtgraphicaleffects-index.html">Qt Graphical Effects</a></td><td ><a href="graphicaleffects.html">QML Types</a></td><td >GammaAdjust QML Type</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right">Qt 5.9.5 Reference Documentation</td>
        </tr></table>
      </div>
    </div>
<div class="content">
<div class="line">
<div class="content mainContent">
<div class="sidebar">
<div class="toc">
<h3><a name="toc">Contents</a></h3>
<ul>
<li class="level1"><a href="#properties">Properties</a></li>
<li class="level1"><a href="#details">Detailed Description</a></li>
<li class="level2"><a href="#example">Example</a></li>
</ul>
</div>
<div class="sidebar-content" id="sidebar-content"></div></div>
<h1 class="title">GammaAdjust QML Type</h1>
<span class="subtitle"></span>
<!-- $$$GammaAdjust-brief -->
<p>Alters the luminance of the source item. <a href="#details">More...</a></p>
<!-- @@@GammaAdjust -->
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> Import Statement:</td><td class="memItemRight bottomAlign"> import QtGraphicalEffects 1.0</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Since:</td><td class="memItemRight bottomAlign">  QtGraphicalEffects 1.0</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Inherits:</td><td class="memItemRight bottomAlign"> <p><a href="../qtquick/qml-qtquick-item.html">Item</a></p>
</td></tr></table></div><ul>
<li><a href="qml-qtgraphicaleffects-gammaadjust-members.html">List of all members, including inherited members</a></li>
</ul>
<a name="properties"></a>
<h2 id="properties">Properties</h2>
<ul>
<li class="fn"><b><b><a href="qml-qtgraphicaleffects-gammaadjust.html#cached-prop">cached</a></b></b> : bool</li>
<li class="fn"><b><b><a href="qml-qtgraphicaleffects-gammaadjust.html#gamma-prop">gamma</a></b></b> : real</li>
<li class="fn"><b><b><a href="qml-qtgraphicaleffects-gammaadjust.html#source-prop">source</a></b></b> : variant</li>
</ul>
<!-- $$$GammaAdjust-description -->
<a name="details"></a>
<h2 id="details">Detailed Description</h2>
<p><a href="qml-qtgraphicaleffects-gammaadjust.html">GammaAdjust</a> is applied to each pixel according to the curve which is pre-defined as a power-law expression, where the property gamma is used as the reciprocal scaling exponent. Refer to the property documentation of <a href="qml-qtgraphicaleffects-gammaadjust.html#gamma-prop">gamma</a> for more details.</p>
<div class="table"><table class="generic">
 <thead><tr class="qt-style"><th >Source</th><th >Effect applied</th></tr></thead>
<tr valign="top" class="odd"><td ><p class="centerAlign"><img src="images/Original_bug.png" alt="" /></p></td><td ><p class="centerAlign"><img src="images/GammaAdjust_bug.png" alt="" /></p></td></tr>
</table></div>
<p><b>Note: </b>This effect is available when running with OpenGL.</p><a name="example"></a>
<h2 id="example">Example</h2>
<p>The following example shows how to apply the effect.</p>
<pre class="qml">

  import QtQuick 2.0
  import QtGraphicalEffects 1.0

  <span class="type"><a href="../qtquick/qml-qtquick-item.html">Item</a></span> {
      <span class="name">width</span>: <span class="number">300</span>
      <span class="name">height</span>: <span class="number">300</span>

      <span class="type"><a href="../qtquick/qml-qtquick-image.html">Image</a></span> {
          <span class="name">id</span>: <span class="name">bug</span>
          <span class="name">source</span>: <span class="string">&quot;images/bug.jpg&quot;</span>
          <span class="name">sourceSize</span>: <span class="name">Qt</span>.<span class="name">size</span>(<span class="name">parent</span>.<span class="name">width</span>, <span class="name">parent</span>.<span class="name">height</span>)
          <span class="name">smooth</span>: <span class="number">true</span>
          <span class="name">visible</span>: <span class="number">false</span>
      }

      <span class="type"><a href="qml-qtgraphicaleffects-gammaadjust.html">GammaAdjust</a></span> {
          <span class="name">anchors</span>.fill: <span class="name">bug</span>
          <span class="name">source</span>: <span class="name">bug</span>
          <span class="name">gamma</span>: <span class="number">0.45</span>
      }
  }

</pre>
<!-- @@@GammaAdjust -->
<h2>Property Documentation</h2>
<!-- $$$cached -->
<div class="qmlitem"><div class="qmlproto">
<div class="table"><table class="qmlname">
<tr valign="top" class="odd" id="cached-prop">
<td class="tblQmlPropNode"><p>
<a name="cached-prop"></a><span class="name">cached</span> : <span class="type">bool</span></p></td></tr>
</table></div>
</div><div class="qmldoc"><p>This property allows the effect output pixels to be cached in order to improve the rendering performance.</p>
<p>Every time the source or effect properties are changed, the pixels in the cache must be updated. Memory consumption is increased, because an extra buffer of memory is required for storing the effect output.</p>
<p>It is recommended to disable the cache when the source or the effect properties are animated.</p>
<p>By default, the property is set to <code>false</code>.</p>
</div></div><!-- @@@cached -->
<br/>
<!-- $$$gamma -->
<div class="qmlitem"><div class="qmlproto">
<div class="table"><table class="qmlname">
<tr valign="top" class="odd" id="gamma-prop">
<td class="tblQmlPropNode"><p>
<a name="gamma-prop"></a><span class="name">gamma</span> : <span class="type">real</span></p></td></tr>
</table></div>
</div><div class="qmldoc"><p>This property defines the change factor for how the luminance of each pixel is altered according to the equation:</p>
<pre class="cpp">

  luminance <span class="operator">=</span> pow(original_luminance<span class="operator">,</span> <span class="number">1.0</span> <span class="operator">/</span> gamma); <span class="comment">// The luminance is assumed to be between 0.0 and 1.0</span>

</pre>
<p>Setting the gamma values under 1.0 makes the image darker, the values above 1.0 lighten it.</p>
<p>The value ranges from 0.0 (darkest) to inf (lightest). By default, the property is set to <code>1.0</code> (no change).</p>
<div class="table"><table class="generic">
 <thead><tr class="qt-style"><th >Output examples with different gamma values</th><th ></th><th ></th></tr></thead>
<tr valign="top" class="odd"><td ><p class="centerAlign"><img src="images/GammaAdjust_gamma1.png" alt="" /></p></td><td ><p class="centerAlign"><img src="images/GammaAdjust_gamma2.png" alt="" /></p></td><td ><p class="centerAlign"><img src="images/GammaAdjust_gamma3.png" alt="" /></p></td></tr>
<tr valign="top" class="even"><td ><b> gamma: 0.5 </b></td><td ><b> gamma: 1.0 </b></td><td ><b> gamma: 2.0 </b></td></tr>
</table></div>
<div class="table"><table class="generic">
 <thead><tr class="qt-style"><th >Pixel luminance curves of the above images.</th><th ></th><th ></th></tr></thead>
<tr valign="top" class="odd"><td ><p class="centerAlign"><img src="images/GammaAdjust_gamma1_graph.png" alt="" /></p></td><td ><p class="centerAlign"><img src="images/GammaAdjust_gamma2_graph.png" alt="" /></p></td><td ><p class="centerAlign"><img src="images/GammaAdjust_gamma3_graph.png" alt="" /></p></td></tr>
<tr valign="top" class="even"><td >Red curve: default gamma (1.0)</td><td ></td><td ></td></tr>
<tr valign="top" class="odd"><td >Yellow curve: effect applied</td><td ></td><td ></td></tr>
<tr valign="top" class="even"><td >X-axis: pixel original luminance</td><td ></td><td ></td></tr>
<tr valign="top" class="odd"><td >Y-axis: pixel luminance with effect applied</td><td ></td><td ></td></tr>
</table></div>
</div></div><!-- @@@gamma -->
<br/>
<!-- $$$source -->
<div class="qmlitem"><div class="qmlproto">
<div class="table"><table class="qmlname">
<tr valign="top" class="odd" id="source-prop">
<td class="tblQmlPropNode"><p>
<a name="source-prop"></a><span class="name">source</span> : <span class="type"><a href="../qtqml/qml-variant.html">variant</a></span></p></td></tr>
</table></div>
</div><div class="qmldoc"><p>This property defines the source item for which the luminance is going to be adjusted.</p>
<p><b>Note: </b>It is not supported to let the effect include itself, for instance by setting source to the effect's parent.</p></div></div><!-- @@@source -->
<br/>
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