<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <!-- rotations.qdoc --> <title>Rotations Example | Qt Data Visualization 5.12.2</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // 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 5.12</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> </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="#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> </ul> </div> <div class="sidebar-content" id="sidebar-content"></div></div> <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> </div> <!-- @@@rotations --> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2019 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners.<br/> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br/> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners. </p> </div> </body> </html>