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<td >Qt 5.12</td><td ><a href="qtdatavisualization-index.html">Qt Data Visualization</a></td><td >Rotations Example</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right"><a href="qtdatavisualization-index.html">Qt Data Visualization | Commercial or GPLv3</a></td>
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<h3><a name="toc">Contents</a></h3>
<ul>
<li class="level1"><a href="#running-the-example">Running the Example</a></li>
<li class="level1"><a href="#using-rotations">Using Rotations</a></li>
<li class="level1"><a href="#using-custom-item-meshes">Using Custom Item Meshes</a></li>
<li class="level1"><a href="#using-range-gradient">Using Range Gradient</a></li>
<li class="level1"><a href="#example-contents">Example Contents</a></li>
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<h1 class="title">Rotations Example</h1>
<span class="subtitle"></span>
<!-- $$$rotations-brief -->
<p>Using rotated scatter items.</p>
<!-- @@@rotations -->
<!-- $$$rotations-description -->
<div class="descr"> <a name="details"></a>
<p>This example shows how to do the following:</p>
<ul>
<li>Use item rotations</li>
<li>Use custom item meshes</li>
<li>Use range gradient to color the series</li>
</ul>
<p>For more basic example about using Qt Data Visualization graphs, see <a href="qtdatavisualization-bars-example.html">Bars Example</a>.</p>
<p class="centerAlign"><img src="images/rotations-example.png" alt="" /></p><a name="running-the-example"></a>
<h2 id="running-the-example">Running the Example</h2>
<p>To run the example from Qt Creator, open the <b>Welcome</b> mode and select the example from <b>Examples</b>. For more information, visit Building and Running an Example.</p>
<a name="using-rotations"></a>
<h2 id="using-rotations">Using Rotations</h2>
<p>In this example we want to orient the arrow items tangentially to the origin. This requires rotating them, which can be achieved by specifying rotation quaternion to each item:</p>
<pre class="cpp">
<span class="type">QQuaternion</span> yRotation <span class="operator">=</span> <span class="type">QQuaternion</span><span class="operator">::</span>fromAxisAndAngle(<span class="number">0.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> <span class="number">0.0f</span><span class="operator">,</span> horizontalAngle <span class="operator">*</span> radiansToDegrees);
<span class="type">QQuaternion</span> zRotation <span class="operator">=</span> <span class="type">QQuaternion</span><span class="operator">::</span>fromAxisAndAngle(<span class="number">0.0f</span><span class="operator">,</span> <span class="number">0.0f</span><span class="operator">,</span> <span class="number">1.0f</span><span class="operator">,</span> verticalAngle <span class="operator">*</span> radiansToDegrees);
<span class="type">QQuaternion</span> totalRotation <span class="operator">=</span> yRotation <span class="operator">*</span> zRotation;
ptrToDataArray<span class="operator">-</span><span class="operator">></span>setRotation(totalRotation);
</pre>
<p>Since the items need to be rotated along two axes, we define two rotation quaternions, one for Y-axis and one for Z-axis, and then multiply these together to get the total rotation, which we set to the data item.</p>
<a name="using-custom-item-meshes"></a>
<h2 id="using-custom-item-meshes">Using Custom Item Meshes</h2>
<p>The narrow arrow mesh we use for magnetic field arrow items is not a standard mesh. Instead we supply our own <code>narrowarrow.obj</code> file which contains the object definition for the mesh in <code>Wavefront</code> obj format:</p>
<pre class="cpp">
m_magneticField<span class="operator">-</span><span class="operator">></span>setMesh(QAbstract3DSeries<span class="operator">::</span>MeshUserDefined);
m_magneticField<span class="operator">-</span><span class="operator">></span>setUserDefinedMesh(<span class="type">QStringLiteral</span>(<span class="string">":/mesh/narrowarrow.obj"</span>));
</pre>
<a name="using-range-gradient"></a>
<h2 id="using-range-gradient">Using Range Gradient</h2>
<p>Setting the color style to range gradient in a series means that the item is colored according to its relative Y-value on the visible Y-coordinate range. We want the arrows on the bottom part of the graph to be darker and gradually get lighter higher they are, so we define a range gradient with black color at the position 0.0 and white color at the position 1.0:</p>
<pre class="cpp">
<span class="type">QLinearGradient</span> fieldGradient(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">16</span><span class="operator">,</span> <span class="number">1024</span>);
fieldGradient<span class="operator">.</span>setColorAt(<span class="number">0.0</span><span class="operator">,</span> <span class="type">Qt</span><span class="operator">::</span>black);
fieldGradient<span class="operator">.</span>setColorAt(<span class="number">1.0</span><span class="operator">,</span> <span class="type">Qt</span><span class="operator">::</span>white);
m_magneticField<span class="operator">-</span><span class="operator">></span>setBaseGradient(fieldGradient);
m_magneticField<span class="operator">-</span><span class="operator">></span>setColorStyle(<span class="type"><a href="q3dtheme.html">Q3DTheme</a></span><span class="operator">::</span>ColorStyleRangeGradient);
</pre>
<a name="example-contents"></a>
<h2 id="example-contents">Example Contents</h2>
<p>Files:</p>
<ul>
<li><a href="qtdatavisualization-rotations-main-cpp.html">rotations/main.cpp</a></li>
<li><a href="qtdatavisualization-rotations-rotations-pro.html">rotations/rotations.pro</a></li>
<li><a href="qtdatavisualization-rotations-rotations-qrc.html">rotations/rotations.qrc</a></li>
<li><a href="qtdatavisualization-rotations-scatterdatamodifier-cpp.html">rotations/scatterdatamodifier.cpp</a></li>
<li><a href="qtdatavisualization-rotations-scatterdatamodifier-h.html">rotations/scatterdatamodifier.h</a></li>
</ul>
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<!-- @@@rotations -->
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