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<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"><a href="qtdatavisualization-qmlmodule.html">QtDataVisualization</a></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>
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<!-- @@@audiolevels/audiolevelsiodevice.cpp -->
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distrib
>
Mageia
>
7
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armv7hl
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media
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core-updates
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by-pkgid
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845e36bb3ecce380666d628d88446962
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files
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207
