<?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>mandelbrotwidget.cpp Example File | Qt Core 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="qtcore-index.html">Qt Core</a></td><td ><a href="qtcore-threads-mandelbrot-example.html">Mandelbrot Example</a></td><td >mandelbrotwidget.cpp Example File</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtcore-index.html">Qt 5.12.2 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">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>horizontalAdvance(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> </div> <!-- @@@threads/mandelbrot/mandelbrotwidget.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>