<?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>audiolevelsiodevice.cpp Example File | 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 ><a href="qtdatavisualization-audiolevels-example.html">Audiolevels Example</a></td><td >audiolevelsiodevice.cpp Example File</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="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">audiolevelsiodevice.cpp Example File</h1> <span class="subtitle">audiolevels/audiolevelsiodevice.cpp</span> <!-- $$$audiolevels/audiolevelsiodevice.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 Qt Data Visualization module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:GPL$ ** 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. ** ** GNU General Public License Usage ** Alternatively, this file may be used under the terms of the GNU ** General Public License version 3 or (at your option) any later version ** approved by the KDE Free Qt Foundation. The licenses are as published by ** the Free Software Foundation and appearing in the file LICENSE.GPL3 ** included in the packaging of this file. Please review the following ** information to ensure the GNU General Public License requirements will ** be met: https://www.gnu.org/licenses/gpl-3.0.html. ** ** $QT_END_LICENSE$ ** ****************************************************************************/</span> <span class="preprocessor">#include "audiolevelsiodevice.h"</span> <span class="preprocessor">#include <QtCore/QDebug></span> <span class="keyword">using</span> <span class="keyword">namespace</span> <span class="type">QtDataVisualization</span>; <span class="keyword">static</span> <span class="keyword">const</span> <span class="type">int</span> resolution <span class="operator">=</span> <span class="number">8</span>; <span class="keyword">static</span> <span class="keyword">const</span> <span class="type">int</span> rowSize <span class="operator">=</span> <span class="number">800</span>; <span class="keyword">static</span> <span class="keyword">const</span> <span class="type">int</span> rowCount <span class="operator">=</span> <span class="number">7</span>; <span class="comment">// Must be odd number</span> <span class="keyword">static</span> <span class="keyword">const</span> <span class="type">int</span> middleRow <span class="operator">=</span> rowCount <span class="operator">/</span> <span class="number">2</span>; AudioLevelsIODevice<span class="operator">::</span>AudioLevelsIODevice(<span class="type"><a href="qbardataproxy.html">QBarDataProxy</a></span> <span class="operator">*</span>proxy<span class="operator">,</span> <span class="type">QObject</span> <span class="operator">*</span>parent) : <span class="type">QIODevice</span>(parent)<span class="operator">,</span> m_proxy(proxy)<span class="operator">,</span> m_array(<span class="keyword">new</span> <span class="type"><a href="qbardataproxy.html#QBarDataArray-typedef">QBarDataArray</a></span>) { <span class="comment">// We reuse the existing array for maximum performance, so construct the array here</span> m_array<span class="operator">-</span><span class="operator">></span>reserve(rowCount); <span class="keyword">for</span> (<span class="type">int</span> i <span class="operator">=</span> <span class="number">0</span>; i <span class="operator"><</span> rowCount; i<span class="operator">+</span><span class="operator">+</span>) m_array<span class="operator">-</span><span class="operator">></span>append(<span class="keyword">new</span> <span class="type"><a href="qbardataproxy.html#QBarDataRow-typedef">QBarDataRow</a></span>(rowSize)); qDebug() <span class="operator"><</span><span class="operator"><</span> <span class="string">"Total of"</span> <span class="operator"><</span><span class="operator"><</span> (rowSize <span class="operator">*</span> rowCount) <span class="operator"><</span><span class="operator"><</span> <span class="string">"items in the array."</span>; } <span class="comment">// Implementation required for this pure virtual function</span> <span class="type">qint64</span> AudioLevelsIODevice<span class="operator">::</span>readData(<span class="type">char</span> <span class="operator">*</span>data<span class="operator">,</span> <span class="type">qint64</span> maxSize) { Q_UNUSED(data) Q_UNUSED(maxSize) <span class="keyword">return</span> <span class="operator">-</span><span class="number">1</span>; } <span class="type">qint64</span> AudioLevelsIODevice<span class="operator">::</span>writeData(<span class="keyword">const</span> <span class="type">char</span> <span class="operator">*</span>data<span class="operator">,</span> <span class="type">qint64</span> maxSize) { <span class="comment">// The amount of new data available.</span> <span class="type">int</span> newDataSize <span class="operator">=</span> maxSize <span class="operator">/</span> resolution; <span class="comment">// If we get more data than array size, we need to adjust the start index for new data.</span> <span class="type">int</span> newDataStartIndex <span class="operator">=</span> qMax(<span class="number">0</span><span class="operator">,</span> (newDataSize <span class="operator">-</span> rowSize)); <span class="comment">// Move the old data ahead in the rows (only do first half of rows + middle one now).</span> <span class="comment">// If the amount of new data was larger than row size, skip copying.</span> <span class="keyword">if</span> (<span class="operator">!</span>newDataStartIndex) { <span class="keyword">for</span> (<span class="type">int</span> i <span class="operator">=</span> <span class="number">0</span>; i <span class="operator"><</span><span class="operator">=</span> middleRow; i<span class="operator">+</span><span class="operator">+</span>) { <span class="type"><a href="qbardataitem.html">QBarDataItem</a></span> <span class="operator">*</span>srcPos <span class="operator">=</span> m_array<span class="operator">-</span><span class="operator">></span>at(i)<span class="operator">-</span><span class="operator">></span>data(); <span class="type"><a href="qbardataitem.html">QBarDataItem</a></span> <span class="operator">*</span>dstPos <span class="operator">=</span> srcPos <span class="operator">+</span> newDataSize; memmove((<span class="type">void</span> <span class="operator">*</span>)dstPos<span class="operator">,</span> (<span class="type">void</span> <span class="operator">*</span>)srcPos<span class="operator">,</span> (rowSize <span class="operator">-</span> newDataSize) <span class="operator">*</span> <span class="keyword">sizeof</span>(<span class="type"><a href="qbardataitem.html">QBarDataItem</a></span>)); } } <span class="comment">// Insert data in reverse order, so that newest data is always at the front of the row.</span> <span class="type">int</span> index <span class="operator">=</span> <span class="number">0</span>; <span class="keyword">for</span> (<span class="type">int</span> i <span class="operator">=</span> newDataSize <span class="operator">-</span> <span class="number">1</span>; i <span class="operator">></span><span class="operator">=</span> newDataStartIndex; i<span class="operator">-</span><span class="operator">-</span>) { <span class="comment">// Add 0.01 to the value to avoid gaps in the graph (i.e. zero height bars).</span> <span class="comment">// Also, scale to 0...100</span> <span class="type">float</span> value <span class="operator">=</span> <span class="type">float</span>(<span class="type">quint8</span>(data<span class="operator">[</span>resolution <span class="operator">*</span> i<span class="operator">]</span>) <span class="operator">-</span> <span class="number">128</span>) <span class="operator">/</span> <span class="number">1.28f</span> <span class="operator">+</span> <span class="number">0.01f</span>; (<span class="operator">*</span>m_array<span class="operator">-</span><span class="operator">></span>at(middleRow))<span class="operator">[</span>index<span class="operator">]</span><span class="operator">.</span>setValue(value); <span class="comment">// Insert a fractional value into front half of the rows.</span> <span class="keyword">for</span> (<span class="type">int</span> j <span class="operator">=</span> <span class="number">1</span>; j <span class="operator"><</span><span class="operator">=</span> middleRow; j<span class="operator">+</span><span class="operator">+</span>) { <span class="type">float</span> fractionalValue <span class="operator">=</span> value <span class="operator">/</span> <span class="type">float</span>(j <span class="operator">+</span> <span class="number">1</span>); (<span class="operator">*</span>m_array<span class="operator">-</span><span class="operator">></span>at(middleRow <span class="operator">-</span> j))<span class="operator">[</span>index<span class="operator">]</span><span class="operator">.</span>setValue(fractionalValue); } index<span class="operator">+</span><span class="operator">+</span>; } <span class="comment">// Copy the front half of rows to the back half for symmetry.</span> index <span class="operator">=</span> <span class="number">0</span>; <span class="keyword">for</span> (<span class="type">int</span> i <span class="operator">=</span> rowCount <span class="operator">-</span> <span class="number">1</span>; i <span class="operator">></span> middleRow; i<span class="operator">-</span><span class="operator">-</span>) { <span class="type"><a href="qbardataitem.html">QBarDataItem</a></span> <span class="operator">*</span>srcPos <span class="operator">=</span> m_array<span class="operator">-</span><span class="operator">></span>at(index<span class="operator">+</span><span class="operator">+</span>)<span class="operator">-</span><span class="operator">></span>data(); <span class="type"><a href="qbardataitem.html">QBarDataItem</a></span> <span class="operator">*</span>dstPos <span class="operator">=</span> m_array<span class="operator">-</span><span class="operator">></span>at(i)<span class="operator">-</span><span class="operator">></span>data(); memcpy((<span class="type">void</span> <span class="operator">*</span>)dstPos<span class="operator">,</span> (<span class="type">void</span> <span class="operator">*</span>)srcPos<span class="operator">,</span> rowSize <span class="operator">*</span> <span class="keyword">sizeof</span>(<span class="type"><a href="qbardataitem.html">QBarDataItem</a></span>)); } <span class="comment">// Reset the proxy array now that data has been updated to trigger a redraw.</span> m_proxy<span class="operator">-</span><span class="operator">></span>resetArray(m_array); <span class="keyword">return</span> maxSize; } </pre> </div> <!-- @@@audiolevels/audiolevelsiodevice.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>