<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>knob.cpp Example File | Qt Widgets 5.12.6</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="qtwidgets-index.html">Qt Widgets</a></td><td ><a href="qtwidgets-touch-knobs-example.html">Touch Knobs Example</a></td><td >knob.cpp Example File</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtwidgets-index.html">Qt 5.12.6 Reference Documentation</a></td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <div class="sidebar"><div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">knob.cpp Example File</h1> <span class="subtitle">touch/knobs/knob.cpp</span> <!-- $$$touch/knobs/knob.cpp-description --> <div class="descr"> <a name="details"></a> <pre class="cpp"> <span class="comment">/**************************************************************************** ** ** Copyright (C) 2016 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the examples of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:BSD$ ** 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 https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** BSD License Usage ** Alternatively, you may use this file under the terms of the BSD license ** as follows: ** ** "Redistribution and use in source and binary forms, with or without ** modification, are permitted provided that the following conditions are ** met: ** * Redistributions of source code must retain the above copyright ** notice, this list of conditions and the following disclaimer. ** * Redistributions in binary form must reproduce the above copyright ** notice, this list of conditions and the following disclaimer in ** the documentation and/or other materials provided with the ** distribution. ** * Neither the name of The Qt Company Ltd nor the names of its ** contributors may be used to endorse or promote products derived ** from this software without specific prior written permission. ** ** ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." ** ** $QT_END_LICENSE$ ** ****************************************************************************/</span> <span class="preprocessor">#include "knob.h"</span> <span class="preprocessor">#include <QBrush></span> <span class="preprocessor">#include <QTouchEvent></span> Knob<span class="operator">::</span>Knob() : <span class="type"><a href="qgraphicsellipseitem.html">QGraphicsEllipseItem</a></span>(<span class="operator">-</span><span class="number">50</span><span class="operator">,</span> <span class="operator">-</span><span class="number">50</span><span class="operator">,</span> <span class="number">100</span><span class="operator">,</span> <span class="number">100</span>) { setAcceptTouchEvents(<span class="keyword">true</span>); setBrush(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>lightGray); <span class="type"><a href="qgraphicsellipseitem.html">QGraphicsEllipseItem</a></span> <span class="operator">*</span>leftItem <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qgraphicsellipseitem.html">QGraphicsEllipseItem</a></span>(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">20</span><span class="operator">,</span> <span class="number">20</span><span class="operator">,</span> <span class="keyword">this</span>); leftItem<span class="operator">-</span><span class="operator">></span>setPos(<span class="operator">-</span><span class="number">40</span><span class="operator">,</span> <span class="operator">-</span><span class="number">10</span>); leftItem<span class="operator">-</span><span class="operator">></span>setBrush(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>darkGreen); <span class="type"><a href="qgraphicsellipseitem.html">QGraphicsEllipseItem</a></span> <span class="operator">*</span>rightItem <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qgraphicsellipseitem.html">QGraphicsEllipseItem</a></span>(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">20</span><span class="operator">,</span> <span class="number">20</span><span class="operator">,</span> <span class="keyword">this</span>); rightItem<span class="operator">-</span><span class="operator">></span>setPos(<span class="number">20</span><span class="operator">,</span> <span class="operator">-</span><span class="number">10</span>); rightItem<span class="operator">-</span><span class="operator">></span>setBrush(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>darkRed); } bool Knob<span class="operator">::</span>sceneEvent(<span class="type"><a href="../qtcore/qevent.html">QEvent</a></span> <span class="operator">*</span>event) { <span class="keyword">switch</span> (event<span class="operator">-</span><span class="operator">></span>type()) { <span class="keyword">case</span> <span class="type"><a href="../qtcore/qevent.html">QEvent</a></span><span class="operator">::</span>TouchBegin: <span class="keyword">case</span> <span class="type"><a href="../qtcore/qevent.html">QEvent</a></span><span class="operator">::</span>TouchUpdate: <span class="keyword">case</span> <span class="type"><a href="../qtcore/qevent.html">QEvent</a></span><span class="operator">::</span>TouchEnd: { <span class="type"><a href="../qtgui/qtouchevent.html">QTouchEvent</a></span> <span class="operator">*</span>touchEvent <span class="operator">=</span> <span class="keyword">static_cast</span><span class="operator"><</span><span class="type"><a href="../qtgui/qtouchevent.html">QTouchEvent</a></span> <span class="operator">*</span><span class="operator">></span>(event); <span class="keyword">if</span> (touchEvent<span class="operator">-</span><span class="operator">></span>touchPoints()<span class="operator">.</span>count() <span class="operator">=</span><span class="operator">=</span> <span class="number">2</span>) { <span class="keyword">const</span> <span class="type"><a href="../qtgui/qtouchevent.html">QTouchEvent</a></span><span class="operator">::</span>TouchPoint <span class="operator">&</span>touchPoint1 <span class="operator">=</span> touchEvent<span class="operator">-</span><span class="operator">></span>touchPoints()<span class="operator">.</span>first(); <span class="keyword">const</span> <span class="type"><a href="../qtgui/qtouchevent.html">QTouchEvent</a></span><span class="operator">::</span>TouchPoint <span class="operator">&</span>touchPoint2 <span class="operator">=</span> touchEvent<span class="operator">-</span><span class="operator">></span>touchPoints()<span class="operator">.</span>last(); <span class="type"><a href="../qtcore/qlinef.html">QLineF</a></span> line1(touchPoint1<span class="operator">.</span>lastScenePos()<span class="operator">,</span> touchPoint2<span class="operator">.</span>lastScenePos()); <span class="type"><a href="../qtcore/qlinef.html">QLineF</a></span> line2(touchPoint1<span class="operator">.</span>scenePos()<span class="operator">,</span> touchPoint2<span class="operator">.</span>scenePos()); setTransform(<span class="type"><a href="../qtgui/qtransform.html">QTransform</a></span>()<span class="operator">.</span>rotate(line2<span class="operator">.</span>angleTo(line1))<span class="operator">,</span> <span class="keyword">true</span>); } <span class="keyword">break</span>; } <span class="keyword">default</span>: <span class="keyword">return</span> <span class="type"><a href="qgraphicsitem.html">QGraphicsItem</a></span><span class="operator">::</span>sceneEvent(event); } <span class="keyword">return</span> <span class="keyword">true</span>; } </pre> </div> <!-- @@@touch/knobs/knob.cpp --> </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>