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<h1 class="title">spectrograph.cpp Example File</h1>
<span class="small-subtitle">demos/spectrum/app/spectrograph.cpp</span>
<!-- $$$demos/spectrum/app/spectrograph.cpp-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp"> <span class="comment">/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** &quot;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
** &quot;AS IS&quot; 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.&quot;
**
** $QT_END_LICENSE$
**
****************************************************************************/</span>
<span class="preprocessor">#include &quot;spectrograph.h&quot;</span>
<span class="preprocessor">#include &lt;QPainter&gt;</span>
<span class="preprocessor">#include &lt;QMouseEvent&gt;</span>
<span class="preprocessor">#include &lt;QDebug&gt;</span>
<span class="preprocessor">#include &lt;QTimerEvent&gt;</span>
<span class="keyword">const</span> <span class="type">int</span> NullTimerId <span class="operator">=</span> <span class="operator">-</span><span class="number">1</span>;
<span class="keyword">const</span> <span class="type">int</span> NullIndex <span class="operator">=</span> <span class="operator">-</span><span class="number">1</span>;
<span class="keyword">const</span> <span class="type">int</span> BarSelectionInterval <span class="operator">=</span> <span class="number">2000</span>;
Spectrograph<span class="operator">::</span>Spectrograph(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent)
: <span class="type"><a href="qwidget.html">QWidget</a></span>(parent)
<span class="operator">,</span> m_barSelected(NullIndex)
<span class="operator">,</span> m_timerId(NullTimerId)
<span class="operator">,</span> m_lowFreq(<span class="number">0.0</span>)
<span class="operator">,</span> m_highFreq(<span class="number">0.0</span>)
{
setMinimumHeight(<span class="number">100</span>);
}
Spectrograph<span class="operator">::</span><span class="operator">~</span>Spectrograph()
{
}
<span class="type">void</span> Spectrograph<span class="operator">::</span>setParams(<span class="type">int</span> numBars<span class="operator">,</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> lowFreq<span class="operator">,</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> highFreq)
{
Q_ASSERT(numBars <span class="operator">&gt;</span> <span class="number">0</span>);
Q_ASSERT(highFreq <span class="operator">&gt;</span> lowFreq);
m_bars<span class="operator">.</span>resize(numBars);
m_lowFreq <span class="operator">=</span> lowFreq;
m_highFreq <span class="operator">=</span> highFreq;
updateBars();
}
<span class="type">void</span> Spectrograph<span class="operator">::</span>timerEvent(<span class="type"><a href="qtimerevent.html">QTimerEvent</a></span> <span class="operator">*</span>event)
{
Q_ASSERT(event<span class="operator">-</span><span class="operator">&gt;</span>timerId() <span class="operator">=</span><span class="operator">=</span> m_timerId);
Q_UNUSED(event) <span class="comment">// suppress warnings in release builds</span>
killTimer(m_timerId);
m_timerId <span class="operator">=</span> NullTimerId;
m_barSelected <span class="operator">=</span> NullIndex;
update();
}
<span class="type">void</span> Spectrograph<span class="operator">::</span>paintEvent(<span class="type"><a href="qpaintevent.html">QPaintEvent</a></span> <span class="operator">*</span>event)
{
Q_UNUSED(event)
<span class="type"><a href="qpainter.html">QPainter</a></span> painter(<span class="keyword">this</span>);
painter<span class="operator">.</span>fillRect(rect()<span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>black);
<span class="keyword">const</span> <span class="type">int</span> numBars <span class="operator">=</span> m_bars<span class="operator">.</span>count();
<span class="comment">// Highlight region of selected bar</span>
<span class="keyword">if</span> (m_barSelected <span class="operator">!</span><span class="operator">=</span> NullIndex <span class="operator">&amp;</span><span class="operator">&amp;</span> numBars) {
<span class="type"><a href="qrect.html">QRect</a></span> regionRect <span class="operator">=</span> rect();
regionRect<span class="operator">.</span>setLeft(m_barSelected <span class="operator">*</span> rect()<span class="operator">.</span>width() <span class="operator">/</span> numBars);
regionRect<span class="operator">.</span>setWidth(rect()<span class="operator">.</span>width() <span class="operator">/</span> numBars);
<span class="type"><a href="qcolor.html">QColor</a></span> regionColor(<span class="number">202</span><span class="operator">,</span> <span class="number">202</span><span class="operator">,</span> <span class="number">64</span>);
painter<span class="operator">.</span>setBrush(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>DiagCrossPattern);
painter<span class="operator">.</span>fillRect(regionRect<span class="operator">,</span> regionColor);
painter<span class="operator">.</span>setBrush(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>NoBrush);
}
<span class="type"><a href="qcolor.html">QColor</a></span> barColor(<span class="number">51</span><span class="operator">,</span> <span class="number">204</span><span class="operator">,</span> <span class="number">102</span>);
<span class="type"><a href="qcolor.html">QColor</a></span> clipColor(<span class="number">255</span><span class="operator">,</span> <span class="number">255</span><span class="operator">,</span> <span class="number">0</span>);
<span class="comment">// Draw the outline</span>
<span class="keyword">const</span> <span class="type"><a href="qcolor.html">QColor</a></span> gridColor <span class="operator">=</span> barColor<span class="operator">.</span>darker();
<span class="type"><a href="qpen.html">QPen</a></span> gridPen(gridColor);
painter<span class="operator">.</span>setPen(gridPen);
painter<span class="operator">.</span>drawLine(rect()<span class="operator">.</span>topLeft()<span class="operator">,</span> rect()<span class="operator">.</span>topRight());
painter<span class="operator">.</span>drawLine(rect()<span class="operator">.</span>topRight()<span class="operator">,</span> rect()<span class="operator">.</span>bottomRight());
painter<span class="operator">.</span>drawLine(rect()<span class="operator">.</span>bottomRight()<span class="operator">,</span> rect()<span class="operator">.</span>bottomLeft());
painter<span class="operator">.</span>drawLine(rect()<span class="operator">.</span>bottomLeft()<span class="operator">,</span> rect()<span class="operator">.</span>topLeft());
<span class="type"><a href="qvector.html">QVector</a></span><span class="operator">&lt;</span><span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span><span class="operator">&gt;</span> dashes;
dashes <span class="operator">&lt;</span><span class="operator">&lt;</span> <span class="number">2</span> <span class="operator">&lt;</span><span class="operator">&lt;</span> <span class="number">2</span>;
gridPen<span class="operator">.</span>setDashPattern(dashes);
painter<span class="operator">.</span>setPen(gridPen);
<span class="comment">// Draw vertical lines between bars</span>
<span class="keyword">if</span> (numBars) {
<span class="keyword">const</span> <span class="type">int</span> numHorizontalSections <span class="operator">=</span> numBars;
<span class="type"><a href="qline.html">QLine</a></span> line(rect()<span class="operator">.</span>topLeft()<span class="operator">,</span> rect()<span class="operator">.</span>bottomLeft());
<span class="keyword">for</span> (<span class="type">int</span> i<span class="operator">=</span><span class="number">1</span>; i<span class="operator">&lt;</span>numHorizontalSections; <span class="operator">+</span><span class="operator">+</span>i) {
line<span class="operator">.</span>translate(rect()<span class="operator">.</span>width()<span class="operator">/</span>numHorizontalSections<span class="operator">,</span> <span class="number">0</span>);
painter<span class="operator">.</span>drawLine(line);
}
}
<span class="comment">// Draw horizontal lines</span>
<span class="keyword">const</span> <span class="type">int</span> numVerticalSections <span class="operator">=</span> <span class="number">10</span>;
<span class="type"><a href="qline.html">QLine</a></span> line(rect()<span class="operator">.</span>topLeft()<span class="operator">,</span> rect()<span class="operator">.</span>topRight());
<span class="keyword">for</span> (<span class="type">int</span> i<span class="operator">=</span><span class="number">1</span>; i<span class="operator">&lt;</span>numVerticalSections; <span class="operator">+</span><span class="operator">+</span>i) {
line<span class="operator">.</span>translate(<span class="number">0</span><span class="operator">,</span> rect()<span class="operator">.</span>height()<span class="operator">/</span>numVerticalSections);
painter<span class="operator">.</span>drawLine(line);
}
barColor <span class="operator">=</span> barColor<span class="operator">.</span>lighter();
barColor<span class="operator">.</span>setAlphaF(<span class="number">0.75</span>);
clipColor<span class="operator">.</span>setAlphaF(<span class="number">0.75</span>);
<span class="comment">// Draw the bars</span>
<span class="keyword">if</span> (numBars) {
<span class="comment">// Calculate width of bars and gaps</span>
<span class="keyword">const</span> <span class="type">int</span> widgetWidth <span class="operator">=</span> rect()<span class="operator">.</span>width();
<span class="keyword">const</span> <span class="type">int</span> barPlusGapWidth <span class="operator">=</span> widgetWidth <span class="operator">/</span> numBars;
<span class="keyword">const</span> <span class="type">int</span> barWidth <span class="operator">=</span> <span class="number">0.8</span> <span class="operator">*</span> barPlusGapWidth;
<span class="keyword">const</span> <span class="type">int</span> gapWidth <span class="operator">=</span> barPlusGapWidth <span class="operator">-</span> barWidth;
<span class="keyword">const</span> <span class="type">int</span> paddingWidth <span class="operator">=</span> widgetWidth <span class="operator">-</span> numBars <span class="operator">*</span> (barWidth <span class="operator">+</span> gapWidth);
<span class="keyword">const</span> <span class="type">int</span> leftPaddingWidth <span class="operator">=</span> (paddingWidth <span class="operator">+</span> gapWidth) <span class="operator">/</span> <span class="number">2</span>;
<span class="keyword">const</span> <span class="type">int</span> barHeight <span class="operator">=</span> rect()<span class="operator">.</span>height() <span class="operator">-</span> <span class="number">2</span> <span class="operator">*</span> gapWidth;
<span class="keyword">for</span> (<span class="type">int</span> i<span class="operator">=</span><span class="number">0</span>; i<span class="operator">&lt;</span>numBars; <span class="operator">+</span><span class="operator">+</span>i) {
<span class="keyword">const</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> value <span class="operator">=</span> m_bars<span class="operator">[</span>i<span class="operator">]</span><span class="operator">.</span>value;
Q_ASSERT(value <span class="operator">&gt;</span><span class="operator">=</span> <span class="number">0.0</span> <span class="operator">&amp;</span><span class="operator">&amp;</span> value <span class="operator">&lt;</span><span class="operator">=</span> <span class="number">1.0</span>);
<span class="type"><a href="qrect.html">QRect</a></span> bar <span class="operator">=</span> rect();
bar<span class="operator">.</span>setLeft(rect()<span class="operator">.</span>left() <span class="operator">+</span> leftPaddingWidth <span class="operator">+</span> (i <span class="operator">*</span> (gapWidth <span class="operator">+</span> barWidth)));
bar<span class="operator">.</span>setWidth(barWidth);
bar<span class="operator">.</span>setTop(rect()<span class="operator">.</span>top() <span class="operator">+</span> gapWidth <span class="operator">+</span> (<span class="number">1.0</span> <span class="operator">-</span> value) <span class="operator">*</span> barHeight);
bar<span class="operator">.</span>setBottom(rect()<span class="operator">.</span>bottom() <span class="operator">-</span> gapWidth);
<span class="type"><a href="qcolor.html">QColor</a></span> color <span class="operator">=</span> barColor;
<span class="keyword">if</span> (m_bars<span class="operator">[</span>i<span class="operator">]</span><span class="operator">.</span>clipped)
color <span class="operator">=</span> clipColor;
painter<span class="operator">.</span>fillRect(bar<span class="operator">,</span> color);
}
}
}
<span class="type">void</span> Spectrograph<span class="operator">::</span>mousePressEvent(<span class="type"><a href="qmouseevent.html">QMouseEvent</a></span> <span class="operator">*</span>event)
{
<span class="keyword">const</span> <span class="type"><a href="qpoint.html">QPoint</a></span> pos <span class="operator">=</span> event<span class="operator">-</span><span class="operator">&gt;</span>pos();
<span class="keyword">const</span> <span class="type">int</span> index <span class="operator">=</span> m_bars<span class="operator">.</span>count() <span class="operator">*</span> (pos<span class="operator">.</span>x() <span class="operator">-</span> rect()<span class="operator">.</span>left()) <span class="operator">/</span> rect()<span class="operator">.</span>width();
selectBar(index);
}
<span class="type">void</span> Spectrograph<span class="operator">::</span><a href="qtextstream.html#reset">reset</a>()
{
m_spectrum<span class="operator">.</span>reset();
spectrumChanged(m_spectrum);
}
<span class="type">void</span> Spectrograph<span class="operator">::</span>spectrumChanged(<span class="keyword">const</span> FrequencySpectrum <span class="operator">&amp;</span>spectrum)
{
m_spectrum <span class="operator">=</span> spectrum;
updateBars();
}
<span class="type">int</span> Spectrograph<span class="operator">::</span>barIndex(<span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> frequency) <span class="keyword">const</span>
{
Q_ASSERT(frequency <span class="operator">&gt;</span><span class="operator">=</span> m_lowFreq <span class="operator">&amp;</span><span class="operator">&amp;</span> frequency <span class="operator">&lt;</span> m_highFreq);
<span class="keyword">const</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> bandWidth <span class="operator">=</span> (m_highFreq <span class="operator">-</span> m_lowFreq) <span class="operator">/</span> m_bars<span class="operator">.</span>count();
<span class="keyword">const</span> <span class="type">int</span> index <span class="operator">=</span> (frequency <span class="operator">-</span> m_lowFreq) <span class="operator">/</span> bandWidth;
<span class="keyword">if</span>(index <span class="operator">&lt;</span><span class="number">0</span> <span class="operator">|</span><span class="operator">|</span> index <span class="operator">&gt;</span><span class="operator">=</span> m_bars<span class="operator">.</span>count())
Q_ASSERT(<span class="keyword">false</span>);
<span class="keyword">return</span> index;
}
<span class="type"><a href="qpair.html">QPair</a></span><span class="operator">&lt;</span><span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span><span class="operator">,</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span><span class="operator">&gt;</span> Spectrograph<span class="operator">::</span>barRange(<span class="type">int</span> index) <span class="keyword">const</span>
{
Q_ASSERT(index <span class="operator">&gt;</span><span class="operator">=</span> <span class="number">0</span> <span class="operator">&amp;</span><span class="operator">&amp;</span> index <span class="operator">&lt;</span> m_bars<span class="operator">.</span>count());
<span class="keyword">const</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> bandWidth <span class="operator">=</span> (m_highFreq <span class="operator">-</span> m_lowFreq) <span class="operator">/</span> m_bars<span class="operator">.</span>count();
<span class="keyword">return</span> <span class="type"><a href="qpair.html">QPair</a></span><span class="operator">&lt;</span><span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span><span class="operator">,</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span><span class="operator">&gt;</span>(index <span class="operator">*</span> bandWidth<span class="operator">,</span> (index<span class="operator">+</span><span class="number">1</span>) <span class="operator">*</span> bandWidth);
}
<span class="type">void</span> Spectrograph<span class="operator">::</span>updateBars()
{
m_bars<span class="operator">.</span>fill(Bar());
FrequencySpectrum<span class="operator">::</span>const_iterator i <span class="operator">=</span> m_spectrum<span class="operator">.</span>begin();
<span class="keyword">const</span> FrequencySpectrum<span class="operator">::</span>const_iterator end <span class="operator">=</span> m_spectrum<span class="operator">.</span>end();
<span class="keyword">for</span> ( ; i <span class="operator">!</span><span class="operator">=</span> end; <span class="operator">+</span><span class="operator">+</span>i) {
<span class="keyword">const</span> FrequencySpectrum<span class="operator">::</span>Element e <span class="operator">=</span> <span class="operator">*</span>i;
<span class="keyword">if</span> (e<span class="operator">.</span>frequency <span class="operator">&gt;</span><span class="operator">=</span> m_lowFreq <span class="operator">&amp;</span><span class="operator">&amp;</span> e<span class="operator">.</span>frequency <span class="operator">&lt;</span> m_highFreq) {
Bar <span class="operator">&amp;</span>bar <span class="operator">=</span> m_bars<span class="operator">[</span>barIndex(e<span class="operator">.</span>frequency)<span class="operator">]</span>;
bar<span class="operator">.</span>value <span class="operator">=</span> <a href="qtglobal.html#qMax">qMax</a>(bar<span class="operator">.</span>value<span class="operator">,</span> e<span class="operator">.</span>amplitude);
bar<span class="operator">.</span>clipped <span class="operator">|</span><span class="operator">=</span> e<span class="operator">.</span>clipped;
}
}
update();
}
<span class="type">void</span> Spectrograph<span class="operator">::</span>selectBar(<span class="type">int</span> index) {
<span class="keyword">const</span> <span class="type"><a href="qpair.html">QPair</a></span><span class="operator">&lt;</span><span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span><span class="operator">,</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span><span class="operator">&gt;</span> frequencyRange <span class="operator">=</span> barRange(index);
<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> message <span class="operator">=</span> <span class="type"><a href="qstring.html">QString</a></span>(<span class="string">&quot;%1 - %2 Hz&quot;</span>)
<span class="operator">.</span>arg(frequencyRange<span class="operator">.</span>first)
<span class="operator">.</span>arg(frequencyRange<span class="operator">.</span>second);
<span class="keyword">emit</span> infoMessage(message<span class="operator">,</span> BarSelectionInterval);
<span class="keyword">if</span> (NullTimerId <span class="operator">!</span><span class="operator">=</span> m_timerId)
killTimer(m_timerId);
m_timerId <span class="operator">=</span> startTimer(BarSelectionInterval);
m_barSelected <span class="operator">=</span> index;
update();
}</pre>
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<!-- @@@demos/spectrum/app/spectrograph.cpp -->
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