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<h1 class="title">mandelbrotwidget.cpp Example File</h1>
<span class="subtitle">threads/mandelbrot/mandelbrotwidget.cpp</span>
<!-- $$$threads/mandelbrot/mandelbrotwidget.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 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 <QPainter></span>
<span class="preprocessor">#include <QKeyEvent></span>
<span class="preprocessor">#include <math.h></span>
<span class="preprocessor">#include "mandelbrotwidget.h"</span>
<span class="keyword">const</span> <span class="type">double</span> DefaultCenterX <span class="operator">=</span> <span class="operator">-</span><span class="number">0.637011f</span>;
<span class="keyword">const</span> <span class="type">double</span> DefaultCenterY <span class="operator">=</span> <span class="operator">-</span><span class="number">0.0395159f</span>;
<span class="keyword">const</span> <span class="type">double</span> DefaultScale <span class="operator">=</span> <span class="number">0.00403897f</span>;
<span class="keyword">const</span> <span class="type">double</span> ZoomInFactor <span class="operator">=</span> <span class="number">0.8f</span>;
<span class="keyword">const</span> <span class="type">double</span> ZoomOutFactor <span class="operator">=</span> <span class="number">1</span> <span class="operator">/</span> ZoomInFactor;
<span class="keyword">const</span> <span class="type">int</span> ScrollStep <span class="operator">=</span> <span class="number">20</span>;
MandelbrotWidget<span class="operator">::</span>MandelbrotWidget(<span class="type"><a href="../qtwidgets/qwidget.html">QWidget</a></span> <span class="operator">*</span>parent)
: <span class="type"><a href="../qtwidgets/qwidget.html">QWidget</a></span>(parent)
{
centerX <span class="operator">=</span> DefaultCenterX;
centerY <span class="operator">=</span> DefaultCenterY;
pixmapScale <span class="operator">=</span> DefaultScale;
curScale <span class="operator">=</span> DefaultScale;
connect(<span class="operator">&</span>thread<span class="operator">,</span> SIGNAL(renderedImage(<span class="type"><a href="../qtgui/qimage.html">QImage</a></span><span class="operator">,</span><span class="type">double</span>))<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(updatePixmap(<span class="type"><a href="../qtgui/qimage.html">QImage</a></span><span class="operator">,</span><span class="type">double</span>)));
setWindowTitle(tr(<span class="string">"Mandelbrot"</span>));
<span class="preprocessor">#ifndef QT_NO_CURSOR</span>
setCursor(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>CrossCursor);
<span class="preprocessor">#endif</span>
resize(<span class="number">550</span><span class="operator">,</span> <span class="number">400</span>);
}
<span class="type">void</span> MandelbrotWidget<span class="operator">::</span>paintEvent(<span class="type"><a href="../qtgui/qpaintevent.html">QPaintEvent</a></span> <span class="operator">*</span> <span class="comment">/* event */</span>)
{
<span class="type"><a href="../qtgui/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">if</span> (pixmap<span class="operator">.</span>isNull()) {
painter<span class="operator">.</span>setPen(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>white);
painter<span class="operator">.</span>drawText(rect()<span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>AlignCenter<span class="operator">,</span> tr(<span class="string">"Rendering initial image, please wait..."</span>));
<span class="keyword">return</span>;
}
<span class="keyword">if</span> (curScale <span class="operator">=</span><span class="operator">=</span> pixmapScale) {
painter<span class="operator">.</span>drawPixmap(pixmapOffset<span class="operator">,</span> pixmap);
} <span class="keyword">else</span> {
<span class="type">double</span> scaleFactor <span class="operator">=</span> pixmapScale <span class="operator">/</span> curScale;
<span class="type">int</span> newWidth <span class="operator">=</span> <span class="type">int</span>(pixmap<span class="operator">.</span>width() <span class="operator">*</span> scaleFactor);
<span class="type">int</span> newHeight <span class="operator">=</span> <span class="type">int</span>(pixmap<span class="operator">.</span>height() <span class="operator">*</span> scaleFactor);
<span class="type">int</span> newX <span class="operator">=</span> pixmapOffset<span class="operator">.</span>x() <span class="operator">+</span> (pixmap<span class="operator">.</span>width() <span class="operator">-</span> newWidth) <span class="operator">/</span> <span class="number">2</span>;
<span class="type">int</span> newY <span class="operator">=</span> pixmapOffset<span class="operator">.</span>y() <span class="operator">+</span> (pixmap<span class="operator">.</span>height() <span class="operator">-</span> newHeight) <span class="operator">/</span> <span class="number">2</span>;
painter<span class="operator">.</span>save();
painter<span class="operator">.</span>translate(newX<span class="operator">,</span> newY);
painter<span class="operator">.</span>scale(scaleFactor<span class="operator">,</span> scaleFactor);
<span class="type"><a href="qrectf.html">QRectF</a></span> exposed <span class="operator">=</span> painter<span class="operator">.</span>matrix()<span class="operator">.</span>inverted()<span class="operator">.</span>mapRect(rect())<span class="operator">.</span>adjusted(<span class="operator">-</span><span class="number">1</span><span class="operator">,</span> <span class="operator">-</span><span class="number">1</span><span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">1</span>);
painter<span class="operator">.</span>drawPixmap(exposed<span class="operator">,</span> pixmap<span class="operator">,</span> exposed);
painter<span class="operator">.</span>restore();
}
<span class="type"><a href="qstring.html">QString</a></span> text <span class="operator">=</span> tr(<span class="string">"Use mouse wheel or the '+' and '-' keys to zoom. "</span>
<span class="string">"Press and hold left mouse button to scroll."</span>);
<span class="type"><a href="../qtgui/qfontmetrics.html">QFontMetrics</a></span> metrics <span class="operator">=</span> painter<span class="operator">.</span>fontMetrics();
<span class="type">int</span> textWidth <span class="operator">=</span> metrics<span class="operator">.</span>width(text);
painter<span class="operator">.</span>setPen(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>NoPen);
painter<span class="operator">.</span>setBrush(<span class="type"><a href="../qtgui/qcolor.html">QColor</a></span>(<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="operator">,</span> <span class="number">127</span>));
painter<span class="operator">.</span>drawRect((width() <span class="operator">-</span> textWidth) <span class="operator">/</span> <span class="number">2</span> <span class="operator">-</span> <span class="number">5</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> textWidth <span class="operator">+</span> <span class="number">10</span><span class="operator">,</span> metrics<span class="operator">.</span>lineSpacing() <span class="operator">+</span> <span class="number">5</span>);
painter<span class="operator">.</span>setPen(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>white);
painter<span class="operator">.</span>drawText((width() <span class="operator">-</span> textWidth) <span class="operator">/</span> <span class="number">2</span><span class="operator">,</span> metrics<span class="operator">.</span>leading() <span class="operator">+</span> metrics<span class="operator">.</span>ascent()<span class="operator">,</span> text);
}
<span class="type">void</span> MandelbrotWidget<span class="operator">::</span>resizeEvent(<span class="type"><a href="../qtgui/qresizeevent.html">QResizeEvent</a></span> <span class="operator">*</span> <span class="comment">/* event */</span>)
{
thread<span class="operator">.</span>render(centerX<span class="operator">,</span> centerY<span class="operator">,</span> curScale<span class="operator">,</span> size());
}
<span class="type">void</span> MandelbrotWidget<span class="operator">::</span>keyPressEvent(<span class="type"><a href="../qtgui/qkeyevent.html">QKeyEvent</a></span> <span class="operator">*</span>event)
{
<span class="keyword">switch</span> (event<span class="operator">-</span><span class="operator">></span>key()) {
<span class="keyword">case</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Key_Plus:
zoom(ZoomInFactor);
<span class="keyword">break</span>;
<span class="keyword">case</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Key_Minus:
zoom(ZoomOutFactor);
<span class="keyword">break</span>;
<span class="keyword">case</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Key_Left:
scroll(<span class="operator">-</span>ScrollStep<span class="operator">,</span> <span class="number">0</span>);
<span class="keyword">break</span>;
<span class="keyword">case</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Key_Right:
scroll(<span class="operator">+</span>ScrollStep<span class="operator">,</span> <span class="number">0</span>);
<span class="keyword">break</span>;
<span class="keyword">case</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Key_Down:
scroll(<span class="number">0</span><span class="operator">,</span> <span class="operator">-</span>ScrollStep);
<span class="keyword">break</span>;
<span class="keyword">case</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Key_Up:
scroll(<span class="number">0</span><span class="operator">,</span> <span class="operator">+</span>ScrollStep);
<span class="keyword">break</span>;
<span class="keyword">default</span>:
<span class="type"><a href="../qtwidgets/qwidget.html">QWidget</a></span><span class="operator">::</span>keyPressEvent(event);
}
}
<span class="preprocessor">#if QT_CONFIG(wheelevent)</span>
<span class="type">void</span> MandelbrotWidget<span class="operator">::</span>wheelEvent(<span class="type"><a href="../qtgui/qwheelevent.html">QWheelEvent</a></span> <span class="operator">*</span>event)
{
<span class="type">int</span> numDegrees <span class="operator">=</span> event<span class="operator">-</span><span class="operator">></span>delta() <span class="operator">/</span> <span class="number">8</span>;
<span class="type">double</span> numSteps <span class="operator">=</span> numDegrees <span class="operator">/</span> <span class="number">15.0f</span>;
zoom(pow(ZoomInFactor<span class="operator">,</span> numSteps));
}
<span class="preprocessor">#endif</span>
<span class="type">void</span> MandelbrotWidget<span class="operator">::</span>mousePressEvent(<span class="type"><a href="../qtgui/qmouseevent.html">QMouseEvent</a></span> <span class="operator">*</span>event)
{
<span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">></span>button() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>LeftButton)
lastDragPos <span class="operator">=</span> event<span class="operator">-</span><span class="operator">></span>pos();
}
<span class="type">void</span> MandelbrotWidget<span class="operator">::</span>mouseMoveEvent(<span class="type"><a href="../qtgui/qmouseevent.html">QMouseEvent</a></span> <span class="operator">*</span>event)
{
<span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">></span>buttons() <span class="operator">&</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>LeftButton) {
pixmapOffset <span class="operator">+</span><span class="operator">=</span> event<span class="operator">-</span><span class="operator">></span>pos() <span class="operator">-</span> lastDragPos;
lastDragPos <span class="operator">=</span> event<span class="operator">-</span><span class="operator">></span>pos();
update();
}
}
<span class="type">void</span> MandelbrotWidget<span class="operator">::</span>mouseReleaseEvent(<span class="type"><a href="../qtgui/qmouseevent.html">QMouseEvent</a></span> <span class="operator">*</span>event)
{
<span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">></span>button() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>LeftButton) {
pixmapOffset <span class="operator">+</span><span class="operator">=</span> event<span class="operator">-</span><span class="operator">></span>pos() <span class="operator">-</span> lastDragPos;
lastDragPos <span class="operator">=</span> <span class="type"><a href="qpoint.html">QPoint</a></span>();
<span class="type">int</span> deltaX <span class="operator">=</span> (width() <span class="operator">-</span> pixmap<span class="operator">.</span>width()) <span class="operator">/</span> <span class="number">2</span> <span class="operator">-</span> pixmapOffset<span class="operator">.</span>x();
<span class="type">int</span> deltaY <span class="operator">=</span> (height() <span class="operator">-</span> pixmap<span class="operator">.</span>height()) <span class="operator">/</span> <span class="number">2</span> <span class="operator">-</span> pixmapOffset<span class="operator">.</span>y();
scroll(deltaX<span class="operator">,</span> deltaY);
}
}
<span class="type">void</span> MandelbrotWidget<span class="operator">::</span>updatePixmap(<span class="keyword">const</span> <span class="type"><a href="../qtgui/qimage.html">QImage</a></span> <span class="operator">&</span>image<span class="operator">,</span> <span class="type">double</span> scaleFactor)
{
<span class="keyword">if</span> (<span class="operator">!</span>lastDragPos<span class="operator">.</span>isNull())
<span class="keyword">return</span>;
pixmap <span class="operator">=</span> <span class="type"><a href="../qtgui/qpixmap.html">QPixmap</a></span><span class="operator">::</span>fromImage(image);
pixmapOffset <span class="operator">=</span> <span class="type"><a href="qpoint.html">QPoint</a></span>();
lastDragPos <span class="operator">=</span> <span class="type"><a href="qpoint.html">QPoint</a></span>();
pixmapScale <span class="operator">=</span> scaleFactor;
update();
}
<span class="type">void</span> MandelbrotWidget<span class="operator">::</span>zoom(<span class="type">double</span> zoomFactor)
{
curScale <span class="operator">*</span><span class="operator">=</span> zoomFactor;
update();
thread<span class="operator">.</span>render(centerX<span class="operator">,</span> centerY<span class="operator">,</span> curScale<span class="operator">,</span> size());
}
<span class="type">void</span> MandelbrotWidget<span class="operator">::</span>scroll(<span class="type">int</span> deltaX<span class="operator">,</span> <span class="type">int</span> deltaY)
{
centerX <span class="operator">+</span><span class="operator">=</span> deltaX <span class="operator">*</span> curScale;
centerY <span class="operator">+</span><span class="operator">=</span> deltaY <span class="operator">*</span> curScale;
update();
thread<span class="operator">.</span>render(centerX<span class="operator">,</span> centerY<span class="operator">,</span> curScale<span class="operator">,</span> size());
}
</pre>
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<!-- @@@threads/mandelbrot/mandelbrotwidget.cpp -->
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