<?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>levelmeter.h Example File | Qt Multimedia 5.11</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 ><a href="../qtdoc/index.html">Qt 5.11</a></td><td ><a href="qtmultimedia-index.html">Qt Multimedia</a></td><td ><a href="qtmultimedia-multimedia-spectrum-example.html">Spectrum Example</a></td><td >levelmeter.h Example File</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right">Qt 5.11.2 Reference Documentation</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">levelmeter.h Example File</h1> <span class="subtitle">multimedia/spectrum/app/levelmeter.h</span> <!-- $$$multimedia/spectrum/app/levelmeter.h-description --> <div class="descr"> <a name="details"></a> <pre class="cpp"> <span class="comment">/**************************************************************************** ** ** Copyright (C) 2017 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">#ifndef LEVELMETER_H</span> <span class="preprocessor">#define LEVELMETER_H</span> <span class="preprocessor">#include <QTime></span> <span class="preprocessor">#include <QWidget></span> <span class="comment">/** * Widget which displays a vertical audio level meter, indicating the * RMS and peak levels of the window of audio samples most recently analyzed * by the Engine. */</span> <span class="keyword">class</span> LevelMeter : <span class="keyword">public</span> <span class="type"><a href="../qtwidgets/qwidget.html">QWidget</a></span> { Q_OBJECT <span class="keyword">public</span>: <span class="keyword">explicit</span> LevelMeter(<span class="type"><a href="../qtwidgets/qwidget.html">QWidget</a></span> <span class="operator">*</span>parent <span class="operator">=</span> <span class="number">0</span>); <span class="operator">~</span>LevelMeter(); <span class="type">void</span> paintEvent(<span class="type"><a href="../qtgui/qpaintevent.html">QPaintEvent</a></span> <span class="operator">*</span>event) override; <span class="keyword">public</span> <span class="keyword">slots</span>: <span class="type">void</span> reset(); <span class="type">void</span> levelChanged(<span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> rmsLevel<span class="operator">,</span> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> peakLevel<span class="operator">,</span> <span class="type">int</span> numSamples); <span class="keyword">private</span> <span class="keyword">slots</span>: <span class="type">void</span> redrawTimerExpired(); <span class="keyword">private</span>: <span class="comment">/** * Height of RMS level bar. * Range 0.0 - 1.0. */</span> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> m_rmsLevel; <span class="comment">/** * Most recent peak level. * Range 0.0 - 1.0. */</span> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> m_peakLevel; <span class="comment">/** * Height of peak level bar. * This is calculated by decaying m_peakLevel depending on the * elapsed time since m_peakLevelChanged, and the value of m_decayRate. */</span> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> m_decayedPeakLevel; <span class="comment">/** * Time at which m_peakLevel was last changed. */</span> <span class="type"><a href="../qtcore/qtime.html">QTime</a></span> m_peakLevelChanged; <span class="comment">/** * Rate at which peak level bar decays. * Expressed in level units / millisecond. */</span> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> m_peakDecayRate; <span class="comment">/** * High watermark of peak level. * Range 0.0 - 1.0. */</span> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> m_peakHoldLevel; <span class="comment">/** * Time at which m_peakHoldLevel was last changed. */</span> <span class="type"><a href="../qtcore/qtime.html">QTime</a></span> m_peakHoldLevelChanged; <span class="type"><a href="../qtcore/qtimer.html">QTimer</a></span> <span class="operator">*</span>m_redrawTimer; <span class="type"><a href="../qtgui/qcolor.html">QColor</a></span> m_rmsColor; <span class="type"><a href="../qtgui/qcolor.html">QColor</a></span> m_peakColor; }; <span class="preprocessor">#endif // LEVELMETER_H</span> </pre> </div> <!-- @@@multimedia/spectrum/app/levelmeter.h --> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2018 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>