<?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>histogramwidget.cpp Example File | Qt Multimedia 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="qtmultimedia-index.html">Qt Multimedia</a></td><td ><a href="qtmultimedia-multimediawidgets-player-example.html">Media Player Example</a></td><td >histogramwidget.cpp Example File</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtmultimedia-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">histogramwidget.cpp Example File</h1> <span class="subtitle">multimediawidgets/player/histogramwidget.cpp</span> <!-- $$$multimediawidgets/player/histogramwidget.cpp-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">#include "histogramwidget.h"</span> <span class="preprocessor">#include <QPainter></span> <span class="preprocessor">#include <QHBoxLayout></span> <span class="keyword">template</span> <span class="operator"><</span><span class="keyword">class</span> T<span class="operator">></span> <span class="keyword">static</span> <span class="type">QVector</span><span class="operator"><</span><span class="type">qreal</span><span class="operator">></span> getBufferLevels(<span class="keyword">const</span> T <span class="operator">*</span>buffer<span class="operator">,</span> <span class="type">int</span> frames<span class="operator">,</span> <span class="type">int</span> channels); <span class="keyword">class</span> <span class="type">QAudioLevel</span> : <span class="keyword">public</span> <span class="type">QWidget</span> { Q_OBJECT <span class="keyword">public</span>: <span class="keyword">explicit</span> <span class="type">QAudioLevel</span>(<span class="type">QWidget</span> <span class="operator">*</span>parent <span class="operator">=</span> nullptr); <span class="comment">// Using [0; 1.0] range</span> <span class="type">void</span> setLevel(<span class="type">qreal</span> level); <span class="keyword">protected</span>: <span class="type">void</span> paintEvent(<span class="type">QPaintEvent</span> <span class="operator">*</span>event); <span class="keyword">private</span>: <span class="type">qreal</span> m_level <span class="operator">=</span> <span class="number">0</span>; }; <span class="type">QAudioLevel</span><span class="operator">::</span><span class="type">QAudioLevel</span>(<span class="type">QWidget</span> <span class="operator">*</span>parent) : <span class="type">QWidget</span>(parent) { setMinimumHeight(<span class="number">15</span>); setMaximumHeight(<span class="number">50</span>); } <span class="type">void</span> <span class="type">QAudioLevel</span><span class="operator">::</span>setLevel(<span class="type">qreal</span> level) { <span class="keyword">if</span> (m_level <span class="operator">!</span><span class="operator">=</span> level) { m_level <span class="operator">=</span> level; update(); } } <span class="type">void</span> <span class="type">QAudioLevel</span><span class="operator">::</span>paintEvent(<span class="type">QPaintEvent</span> <span class="operator">*</span>event) { Q_UNUSED(event); <span class="type">QPainter</span> painter(<span class="keyword">this</span>); <span class="comment">// draw level</span> <span class="type">qreal</span> widthLevel <span class="operator">=</span> m_level <span class="operator">*</span> width(); painter<span class="operator">.</span>fillRect(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> widthLevel<span class="operator">,</span> height()<span class="operator">,</span> <span class="type">Qt</span><span class="operator">::</span>red); <span class="comment">// clear the rest of the control</span> painter<span class="operator">.</span>fillRect(widthLevel<span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> width()<span class="operator">,</span> height()<span class="operator">,</span> <span class="type">Qt</span><span class="operator">::</span>black); } HistogramWidget<span class="operator">::</span>HistogramWidget(<span class="type">QWidget</span> <span class="operator">*</span>parent) : <span class="type">QWidget</span>(parent) { m_processor<span class="operator">.</span>moveToThread(<span class="operator">&</span>m_processorThread); qRegisterMetaType<span class="operator"><</span><span class="type">QVector</span><span class="operator"><</span><span class="type">qreal</span><span class="operator">></span><span class="operator">></span>(<span class="string">"QVector<qreal>"</span>); connect(<span class="operator">&</span>m_processor<span class="operator">,</span> <span class="operator">&</span>FrameProcessor<span class="operator">::</span>histogramReady<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>HistogramWidget<span class="operator">::</span>setHistogram); m_processorThread<span class="operator">.</span>start(<span class="type">QThread</span><span class="operator">::</span>LowestPriority); setLayout(<span class="keyword">new</span> <span class="type">QHBoxLayout</span>); } HistogramWidget<span class="operator">::</span><span class="operator">~</span>HistogramWidget() { m_processorThread<span class="operator">.</span>quit(); m_processorThread<span class="operator">.</span>wait(<span class="number">10000</span>); } <span class="type">void</span> HistogramWidget<span class="operator">::</span>processFrame(<span class="keyword">const</span> <span class="type"><a href="qvideoframe.html">QVideoFrame</a></span> <span class="operator">&</span>frame) { <span class="keyword">if</span> (m_isBusy <span class="operator">&</span><span class="operator">&</span> frame<span class="operator">.</span>isValid()) <span class="keyword">return</span>; <span class="comment">//drop frame</span> m_isBusy <span class="operator">=</span> <span class="keyword">true</span>; <span class="type">QMetaObject</span><span class="operator">::</span>invokeMethod(<span class="operator">&</span>m_processor<span class="operator">,</span> <span class="string">"processFrame"</span><span class="operator">,</span> <span class="type">Qt</span><span class="operator">::</span>QueuedConnection<span class="operator">,</span> Q_ARG(<span class="type"><a href="qvideoframe.html">QVideoFrame</a></span><span class="operator">,</span> frame)<span class="operator">,</span> Q_ARG(<span class="type">int</span><span class="operator">,</span> m_levels)); } <span class="comment">// This function returns the maximum possible sample value for a given audio format</span> <span class="type">qreal</span> getPeakValue(<span class="keyword">const</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">&</span> format) { <span class="comment">// Note: Only the most common sample formats are supported</span> <span class="keyword">if</span> (<span class="operator">!</span>format<span class="operator">.</span>isValid()) <span class="keyword">return</span> <span class="type">qreal</span>(<span class="number">0</span>); <span class="keyword">if</span> (format<span class="operator">.</span>codec() <span class="operator">!</span><span class="operator">=</span> <span class="string">"audio/pcm"</span>) <span class="keyword">return</span> <span class="type">qreal</span>(<span class="number">0</span>); <span class="keyword">switch</span> (format<span class="operator">.</span>sampleType()) { <span class="keyword">case</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>Unknown: <span class="keyword">break</span>; <span class="keyword">case</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>Float: <span class="keyword">if</span> (format<span class="operator">.</span>sampleSize() <span class="operator">!</span><span class="operator">=</span> <span class="number">32</span>) <span class="comment">// other sample formats are not supported</span> <span class="keyword">return</span> <span class="type">qreal</span>(<span class="number">0</span>); <span class="keyword">return</span> <span class="type">qreal</span>(<span class="number">1.00003</span>); <span class="keyword">case</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>SignedInt: <span class="keyword">if</span> (format<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">32</span>) <span class="keyword">return</span> <span class="type">qreal</span>(INT_MAX); <span class="keyword">if</span> (format<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">16</span>) <span class="keyword">return</span> <span class="type">qreal</span>(SHRT_MAX); <span class="keyword">if</span> (format<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">8</span>) <span class="keyword">return</span> <span class="type">qreal</span>(CHAR_MAX); <span class="keyword">break</span>; <span class="keyword">case</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>UnSignedInt: <span class="keyword">if</span> (format<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">32</span>) <span class="keyword">return</span> <span class="type">qreal</span>(UINT_MAX); <span class="keyword">if</span> (format<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">16</span>) <span class="keyword">return</span> <span class="type">qreal</span>(USHRT_MAX); <span class="keyword">if</span> (format<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">8</span>) <span class="keyword">return</span> <span class="type">qreal</span>(UCHAR_MAX); <span class="keyword">break</span>; } <span class="keyword">return</span> <span class="type">qreal</span>(<span class="number">0</span>); } <span class="comment">// returns the audio level for each channel</span> <span class="type">QVector</span><span class="operator"><</span><span class="type">qreal</span><span class="operator">></span> getBufferLevels(<span class="keyword">const</span> <span class="type"><a href="qaudiobuffer.html">QAudioBuffer</a></span><span class="operator">&</span> buffer) { <span class="type">QVector</span><span class="operator"><</span><span class="type">qreal</span><span class="operator">></span> values; <span class="keyword">if</span> (<span class="operator">!</span>buffer<span class="operator">.</span>isValid()) <span class="keyword">return</span> values; <span class="keyword">if</span> (<span class="operator">!</span>buffer<span class="operator">.</span>format()<span class="operator">.</span>isValid() <span class="operator">|</span><span class="operator">|</span> buffer<span class="operator">.</span>format()<span class="operator">.</span>byteOrder() <span class="operator">!</span><span class="operator">=</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>LittleEndian) <span class="keyword">return</span> values; <span class="keyword">if</span> (buffer<span class="operator">.</span>format()<span class="operator">.</span>codec() <span class="operator">!</span><span class="operator">=</span> <span class="string">"audio/pcm"</span>) <span class="keyword">return</span> values; <span class="type">int</span> channelCount <span class="operator">=</span> buffer<span class="operator">.</span>format()<span class="operator">.</span>channelCount(); values<span class="operator">.</span>fill(<span class="number">0</span><span class="operator">,</span> channelCount); <span class="type">qreal</span> peak_value <span class="operator">=</span> getPeakValue(buffer<span class="operator">.</span>format()); <span class="keyword">if</span> (qFuzzyCompare(peak_value<span class="operator">,</span> <span class="type">qreal</span>(<span class="number">0</span>))) <span class="keyword">return</span> values; <span class="keyword">switch</span> (buffer<span class="operator">.</span>format()<span class="operator">.</span>sampleType()) { <span class="keyword">case</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>Unknown: <span class="keyword">case</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>UnSignedInt: <span class="keyword">if</span> (buffer<span class="operator">.</span>format()<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">32</span>) values <span class="operator">=</span> getBufferLevels(buffer<span class="operator">.</span>constData<span class="operator"><</span><span class="type">quint32</span><span class="operator">></span>()<span class="operator">,</span> buffer<span class="operator">.</span>frameCount()<span class="operator">,</span> channelCount); <span class="keyword">if</span> (buffer<span class="operator">.</span>format()<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">16</span>) values <span class="operator">=</span> getBufferLevels(buffer<span class="operator">.</span>constData<span class="operator"><</span><span class="type">quint16</span><span class="operator">></span>()<span class="operator">,</span> buffer<span class="operator">.</span>frameCount()<span class="operator">,</span> channelCount); <span class="keyword">if</span> (buffer<span class="operator">.</span>format()<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">8</span>) values <span class="operator">=</span> getBufferLevels(buffer<span class="operator">.</span>constData<span class="operator"><</span><span class="type">quint8</span><span class="operator">></span>()<span class="operator">,</span> buffer<span class="operator">.</span>frameCount()<span class="operator">,</span> channelCount); <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> values<span class="operator">.</span>size(); <span class="operator">+</span><span class="operator">+</span>i) values<span class="operator">[</span>i<span class="operator">]</span> <span class="operator">=</span> qAbs(values<span class="operator">.</span>at(i) <span class="operator">-</span> peak_value <span class="operator">/</span> <span class="number">2</span>) <span class="operator">/</span> (peak_value <span class="operator">/</span> <span class="number">2</span>); <span class="keyword">break</span>; <span class="keyword">case</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>Float: <span class="keyword">if</span> (buffer<span class="operator">.</span>format()<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">32</span>) { values <span class="operator">=</span> getBufferLevels(buffer<span class="operator">.</span>constData<span class="operator"><</span><span class="type">float</span><span class="operator">></span>()<span class="operator">,</span> buffer<span class="operator">.</span>frameCount()<span class="operator">,</span> channelCount); <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> values<span class="operator">.</span>size(); <span class="operator">+</span><span class="operator">+</span>i) values<span class="operator">[</span>i<span class="operator">]</span> <span class="operator">/</span><span class="operator">=</span> peak_value; } <span class="keyword">break</span>; <span class="keyword">case</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>SignedInt: <span class="keyword">if</span> (buffer<span class="operator">.</span>format()<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">32</span>) values <span class="operator">=</span> getBufferLevels(buffer<span class="operator">.</span>constData<span class="operator"><</span><span class="type">qint32</span><span class="operator">></span>()<span class="operator">,</span> buffer<span class="operator">.</span>frameCount()<span class="operator">,</span> channelCount); <span class="keyword">if</span> (buffer<span class="operator">.</span>format()<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">16</span>) values <span class="operator">=</span> getBufferLevels(buffer<span class="operator">.</span>constData<span class="operator"><</span><span class="type">qint16</span><span class="operator">></span>()<span class="operator">,</span> buffer<span class="operator">.</span>frameCount()<span class="operator">,</span> channelCount); <span class="keyword">if</span> (buffer<span class="operator">.</span>format()<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">8</span>) values <span class="operator">=</span> getBufferLevels(buffer<span class="operator">.</span>constData<span class="operator"><</span><span class="type">qint8</span><span class="operator">></span>()<span class="operator">,</span> buffer<span class="operator">.</span>frameCount()<span class="operator">,</span> channelCount); <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> values<span class="operator">.</span>size(); <span class="operator">+</span><span class="operator">+</span>i) values<span class="operator">[</span>i<span class="operator">]</span> <span class="operator">/</span><span class="operator">=</span> peak_value; <span class="keyword">break</span>; } <span class="keyword">return</span> values; } <span class="keyword">template</span> <span class="operator"><</span><span class="keyword">class</span> T<span class="operator">></span> <span class="type">QVector</span><span class="operator"><</span><span class="type">qreal</span><span class="operator">></span> getBufferLevels(<span class="keyword">const</span> T <span class="operator">*</span>buffer<span class="operator">,</span> <span class="type">int</span> frames<span class="operator">,</span> <span class="type">int</span> channels) { <span class="type">QVector</span><span class="operator"><</span><span class="type">qreal</span><span class="operator">></span> max_values; max_values<span class="operator">.</span>fill(<span class="number">0</span><span class="operator">,</span> channels); <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> frames; <span class="operator">+</span><span class="operator">+</span>i) { <span class="keyword">for</span> (<span class="type">int</span> j <span class="operator">=</span> <span class="number">0</span>; j <span class="operator"><</span> channels; <span class="operator">+</span><span class="operator">+</span>j) { <span class="type">qreal</span> value <span class="operator">=</span> qAbs(<span class="type">qreal</span>(buffer<span class="operator">[</span>i <span class="operator">*</span> channels <span class="operator">+</span> j<span class="operator">]</span>)); <span class="keyword">if</span> (value <span class="operator">></span> max_values<span class="operator">.</span>at(j)) max_values<span class="operator">.</span>replace(j<span class="operator">,</span> value); } } <span class="keyword">return</span> max_values; } <span class="type">void</span> HistogramWidget<span class="operator">::</span>processBuffer(<span class="keyword">const</span> <span class="type"><a href="qaudiobuffer.html">QAudioBuffer</a></span> <span class="operator">&</span>buffer) { <span class="keyword">if</span> (m_audioLevels<span class="operator">.</span>count() <span class="operator">!</span><span class="operator">=</span> buffer<span class="operator">.</span>format()<span class="operator">.</span>channelCount()) { qDeleteAll(m_audioLevels); m_audioLevels<span class="operator">.</span>clear(); <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> buffer<span class="operator">.</span>format()<span class="operator">.</span>channelCount(); <span class="operator">+</span><span class="operator">+</span>i) { <span class="type">QAudioLevel</span> <span class="operator">*</span>level <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QAudioLevel</span>(<span class="keyword">this</span>); m_audioLevels<span class="operator">.</span>append(level); layout()<span class="operator">-</span><span class="operator">></span>addWidget(level); } } <span class="type">QVector</span><span class="operator"><</span><span class="type">qreal</span><span class="operator">></span> levels <span class="operator">=</span> getBufferLevels(buffer); <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> levels<span class="operator">.</span>count(); <span class="operator">+</span><span class="operator">+</span>i) m_audioLevels<span class="operator">.</span>at(i)<span class="operator">-</span><span class="operator">></span>setLevel(levels<span class="operator">.</span>at(i)); } <span class="type">void</span> HistogramWidget<span class="operator">::</span>setHistogram(<span class="keyword">const</span> <span class="type">QVector</span><span class="operator"><</span><span class="type">qreal</span><span class="operator">></span> <span class="operator">&</span>histogram) { m_isBusy <span class="operator">=</span> <span class="keyword">false</span>; m_histogram <span class="operator">=</span> histogram; update(); } <span class="type">void</span> HistogramWidget<span class="operator">::</span>paintEvent(<span class="type">QPaintEvent</span> <span class="operator">*</span>event) { Q_UNUSED(event); <span class="keyword">if</span> (<span class="operator">!</span>m_audioLevels<span class="operator">.</span>isEmpty()) <span class="keyword">return</span>; <span class="type">QPainter</span> painter(<span class="keyword">this</span>); <span class="keyword">if</span> (m_histogram<span class="operator">.</span>isEmpty()) { painter<span class="operator">.</span>fillRect(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> width()<span class="operator">,</span> height()<span class="operator">,</span> <span class="type">QColor</span><span class="operator">::</span>fromRgb(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">0</span>)); <span class="keyword">return</span>; } <span class="type">qreal</span> barWidth <span class="operator">=</span> width() <span class="operator">/</span> (<span class="type">qreal</span>)m_histogram<span class="operator">.</span>size(); <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> m_histogram<span class="operator">.</span>size(); <span class="operator">+</span><span class="operator">+</span>i) { <span class="type">qreal</span> h <span class="operator">=</span> m_histogram<span class="operator">[</span>i<span class="operator">]</span> <span class="operator">*</span> height(); <span class="comment">// draw level</span> painter<span class="operator">.</span>fillRect(barWidth <span class="operator">*</span> i<span class="operator">,</span> height() <span class="operator">-</span> h<span class="operator">,</span> barWidth <span class="operator">*</span> (i <span class="operator">+</span> <span class="number">1</span>)<span class="operator">,</span> height()<span class="operator">,</span> <span class="type">Qt</span><span class="operator">::</span>red); <span class="comment">// clear the rest of the control</span> painter<span class="operator">.</span>fillRect(barWidth <span class="operator">*</span> i<span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> barWidth <span class="operator">*</span> (i <span class="operator">+</span> <span class="number">1</span>)<span class="operator">,</span> height() <span class="operator">-</span> h<span class="operator">,</span> <span class="type">Qt</span><span class="operator">::</span>black); } } <span class="type">void</span> FrameProcessor<span class="operator">::</span>processFrame(<span class="type"><a href="qvideoframe.html">QVideoFrame</a></span> frame<span class="operator">,</span> <span class="type">int</span> levels) { <span class="type">QVector</span><span class="operator"><</span><span class="type">qreal</span><span class="operator">></span> histogram(levels); <span class="keyword">do</span> { <span class="keyword">if</span> (<span class="operator">!</span>levels) <span class="keyword">break</span>; <span class="keyword">if</span> (<span class="operator">!</span>frame<span class="operator">.</span>map(<span class="type"><a href="qabstractvideobuffer.html">QAbstractVideoBuffer</a></span><span class="operator">::</span>ReadOnly)) <span class="keyword">break</span>; <span class="keyword">if</span> (frame<span class="operator">.</span>pixelFormat() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qvideoframe.html">QVideoFrame</a></span><span class="operator">::</span>Format_YUV420P <span class="operator">|</span><span class="operator">|</span> frame<span class="operator">.</span>pixelFormat() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qvideoframe.html">QVideoFrame</a></span><span class="operator">::</span>Format_NV12) { <span class="comment">// Process YUV data</span> <span class="type">uchar</span> <span class="operator">*</span>b <span class="operator">=</span> frame<span class="operator">.</span>bits(); <span class="keyword">for</span> (<span class="type">int</span> y <span class="operator">=</span> <span class="number">0</span>; y <span class="operator"><</span> frame<span class="operator">.</span>height(); <span class="operator">+</span><span class="operator">+</span>y) { <span class="type">uchar</span> <span class="operator">*</span>lastPixel <span class="operator">=</span> b <span class="operator">+</span> frame<span class="operator">.</span>width(); <span class="keyword">for</span> (<span class="type">uchar</span> <span class="operator">*</span>curPixel <span class="operator">=</span> b; curPixel <span class="operator"><</span> lastPixel; curPixel<span class="operator">+</span><span class="operator">+</span>) histogram<span class="operator">[</span>(<span class="operator">*</span>curPixel <span class="operator">*</span> levels) <span class="operator">></span><span class="operator">></span> <span class="number">8</span><span class="operator">]</span> <span class="operator">+</span><span class="operator">=</span> <span class="number">1.0</span>; b <span class="operator">+</span><span class="operator">=</span> frame<span class="operator">.</span>bytesPerLine(); } } <span class="keyword">else</span> { <span class="type">QImage</span><span class="operator">::</span>Format imageFormat <span class="operator">=</span> <span class="type"><a href="qvideoframe.html">QVideoFrame</a></span><span class="operator">::</span>imageFormatFromPixelFormat(frame<span class="operator">.</span>pixelFormat()); <span class="keyword">if</span> (imageFormat <span class="operator">!</span><span class="operator">=</span> <span class="type">QImage</span><span class="operator">::</span>Format_Invalid) { <span class="comment">// Process RGB data</span> <span class="type">QImage</span> image(frame<span class="operator">.</span>bits()<span class="operator">,</span> frame<span class="operator">.</span>width()<span class="operator">,</span> frame<span class="operator">.</span>height()<span class="operator">,</span> imageFormat); image <span class="operator">=</span> image<span class="operator">.</span>convertToFormat(<span class="type">QImage</span><span class="operator">::</span>Format_RGB32); <span class="keyword">const</span> <span class="type">QRgb</span><span class="operator">*</span> b <span class="operator">=</span> (<span class="keyword">const</span> <span class="type">QRgb</span><span class="operator">*</span>)image<span class="operator">.</span>bits(); <span class="keyword">for</span> (<span class="type">int</span> y <span class="operator">=</span> <span class="number">0</span>; y <span class="operator"><</span> image<span class="operator">.</span>height(); <span class="operator">+</span><span class="operator">+</span>y) { <span class="keyword">const</span> <span class="type">QRgb</span> <span class="operator">*</span>lastPixel <span class="operator">=</span> b <span class="operator">+</span> frame<span class="operator">.</span>width(); <span class="keyword">for</span> (<span class="keyword">const</span> <span class="type">QRgb</span> <span class="operator">*</span>curPixel <span class="operator">=</span> b; curPixel <span class="operator"><</span> lastPixel; curPixel<span class="operator">+</span><span class="operator">+</span>) histogram<span class="operator">[</span>(qGray(<span class="operator">*</span>curPixel) <span class="operator">*</span> levels) <span class="operator">></span><span class="operator">></span> <span class="number">8</span><span class="operator">]</span> <span class="operator">+</span><span class="operator">=</span> <span class="number">1.0</span>; b <span class="operator">=</span> (<span class="keyword">const</span> <span class="type">QRgb</span><span class="operator">*</span>)((<span class="type">uchar</span><span class="operator">*</span>)b <span class="operator">+</span> image<span class="operator">.</span>bytesPerLine()); } } } <span class="comment">// find maximum value</span> <span class="type">qreal</span> maxValue <span class="operator">=</span> <span class="number">0.0</span>; <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> histogram<span class="operator">.</span>size(); i<span class="operator">+</span><span class="operator">+</span>) { <span class="keyword">if</span> (histogram<span class="operator">[</span>i<span class="operator">]</span> <span class="operator">></span> maxValue) maxValue <span class="operator">=</span> histogram<span class="operator">[</span>i<span class="operator">]</span>; } <span class="keyword">if</span> (maxValue <span class="operator">></span> <span class="number">0.0</span>) { <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> histogram<span class="operator">.</span>size(); i<span class="operator">+</span><span class="operator">+</span>) histogram<span class="operator">[</span>i<span class="operator">]</span> <span class="operator">/</span><span class="operator">=</span> maxValue; } frame<span class="operator">.</span>unmap(); } <span class="keyword">while</span> (<span class="keyword">false</span>); <span class="keyword">emit</span> histogramReady(histogram); } <span class="preprocessor">#include "histogramwidget.moc"</span> </pre> </div> <!-- @@@multimediawidgets/player/histogramwidget.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>