<?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>scribblearea.cpp Example File | Qt Widgets 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="qtwidgets-index.html">Qt Widgets</a></td><td ><a href="qtwidgets-widgets-scribble-example.html">Scribble Example</a></td><td >scribblearea.cpp Example File</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtwidgets-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">scribblearea.cpp Example File</h1> <span class="subtitle">widgets/scribble/scribblearea.cpp</span> <!-- $$$widgets/scribble/scribblearea.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 <QtWidgets></span> <span class="preprocessor">#if defined(QT_PRINTSUPPORT_LIB)</span> <span class="preprocessor">#include <QtPrintSupport/qtprintsupportglobal.h></span> <span class="preprocessor">#if QT_CONFIG(printdialog)</span> <span class="preprocessor">#include <QPrinter></span> <span class="preprocessor">#include <QPrintDialog></span> <span class="preprocessor">#endif</span> <span class="preprocessor">#endif</span> <span class="preprocessor">#include "scribblearea.h"</span> ScribbleArea<span class="operator">::</span>ScribbleArea(<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) { setAttribute(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>WA_StaticContents); modified <span class="operator">=</span> <span class="keyword">false</span>; scribbling <span class="operator">=</span> <span class="keyword">false</span>; myPenWidth <span class="operator">=</span> <span class="number">1</span>; myPenColor <span class="operator">=</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>blue; } bool ScribbleArea<span class="operator">::</span>openImage(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&</span>fileName) { <span class="type"><a href="../qtgui/qimage.html">QImage</a></span> loadedImage; <span class="keyword">if</span> (<span class="operator">!</span>loadedImage<span class="operator">.</span>load(fileName)) <span class="keyword">return</span> <span class="keyword">false</span>; <span class="type"><a href="../qtcore/qsize.html">QSize</a></span> newSize <span class="operator">=</span> loadedImage<span class="operator">.</span>size()<span class="operator">.</span>expandedTo(size()); resizeImage(<span class="operator">&</span>loadedImage<span class="operator">,</span> newSize); image <span class="operator">=</span> loadedImage; modified <span class="operator">=</span> <span class="keyword">false</span>; update(); <span class="keyword">return</span> <span class="keyword">true</span>; } bool ScribbleArea<span class="operator">::</span>saveImage(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&</span>fileName<span class="operator">,</span> <span class="keyword">const</span> <span class="type">char</span> <span class="operator">*</span>fileFormat) { <span class="type"><a href="../qtgui/qimage.html">QImage</a></span> visibleImage <span class="operator">=</span> image; resizeImage(<span class="operator">&</span>visibleImage<span class="operator">,</span> size()); <span class="keyword">if</span> (visibleImage<span class="operator">.</span>save(fileName<span class="operator">,</span> fileFormat)) { modified <span class="operator">=</span> <span class="keyword">false</span>; <span class="keyword">return</span> <span class="keyword">true</span>; } <span class="keyword">else</span> { <span class="keyword">return</span> <span class="keyword">false</span>; } } <span class="type">void</span> ScribbleArea<span class="operator">::</span>setPenColor(<span class="keyword">const</span> <span class="type"><a href="../qtgui/qcolor.html">QColor</a></span> <span class="operator">&</span>newColor) { myPenColor <span class="operator">=</span> newColor; } <span class="type">void</span> ScribbleArea<span class="operator">::</span>setPenWidth(<span class="type">int</span> newWidth) { myPenWidth <span class="operator">=</span> newWidth; } <span class="type">void</span> ScribbleArea<span class="operator">::</span>clearImage() { image<span class="operator">.</span>fill(<a href="../qtgui/qcolor.html#qRgb">qRgb</a>(<span class="number">255</span><span class="operator">,</span> <span class="number">255</span><span class="operator">,</span> <span class="number">255</span>)); modified <span class="operator">=</span> <span class="keyword">true</span>; update(); } <span class="type">void</span> ScribbleArea<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="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>LeftButton) { lastPoint <span class="operator">=</span> event<span class="operator">-</span><span class="operator">></span>pos(); scribbling <span class="operator">=</span> <span class="keyword">true</span>; } } <span class="type">void</span> ScribbleArea<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="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>LeftButton) <span class="operator">&</span><span class="operator">&</span> scribbling) drawLineTo(event<span class="operator">-</span><span class="operator">></span>pos()); } <span class="type">void</span> ScribbleArea<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="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>LeftButton <span class="operator">&</span><span class="operator">&</span> scribbling) { drawLineTo(event<span class="operator">-</span><span class="operator">></span>pos()); scribbling <span class="operator">=</span> <span class="keyword">false</span>; } } <span class="type">void</span> ScribbleArea<span class="operator">::</span>paintEvent(<span class="type"><a href="../qtgui/qpaintevent.html">QPaintEvent</a></span> <span class="operator">*</span>event) { <span class="type"><a href="../qtgui/qpainter.html">QPainter</a></span> painter(<span class="keyword">this</span>); <span class="type"><a href="../qtcore/qrect.html">QRect</a></span> dirtyRect <span class="operator">=</span> event<span class="operator">-</span><span class="operator">></span>rect(); painter<span class="operator">.</span>drawImage(dirtyRect<span class="operator">,</span> image<span class="operator">,</span> dirtyRect); } <span class="type">void</span> ScribbleArea<span class="operator">::</span>resizeEvent(<span class="type"><a href="../qtgui/qresizeevent.html">QResizeEvent</a></span> <span class="operator">*</span>event) { <span class="keyword">if</span> (width() <span class="operator">></span> image<span class="operator">.</span>width() <span class="operator">|</span><span class="operator">|</span> height() <span class="operator">></span> image<span class="operator">.</span>height()) { <span class="type">int</span> newWidth <span class="operator">=</span> <a href="../qtcore/qtglobal.html#qMax">qMax</a>(width() <span class="operator">+</span> <span class="number">128</span><span class="operator">,</span> image<span class="operator">.</span>width()); <span class="type">int</span> newHeight <span class="operator">=</span> <a href="../qtcore/qtglobal.html#qMax">qMax</a>(height() <span class="operator">+</span> <span class="number">128</span><span class="operator">,</span> image<span class="operator">.</span>height()); resizeImage(<span class="operator">&</span>image<span class="operator">,</span> <span class="type"><a href="../qtcore/qsize.html">QSize</a></span>(newWidth<span class="operator">,</span> newHeight)); update(); } <span class="type"><a href="qwidget.html">QWidget</a></span><span class="operator">::</span>resizeEvent(event); } <span class="type">void</span> ScribbleArea<span class="operator">::</span>drawLineTo(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qpoint.html">QPoint</a></span> <span class="operator">&</span>endPoint) { <span class="type"><a href="../qtgui/qpainter.html">QPainter</a></span> painter(<span class="operator">&</span>image); painter<span class="operator">.</span>setPen(<span class="type"><a href="../qtgui/qpen.html">QPen</a></span>(myPenColor<span class="operator">,</span> myPenWidth<span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>SolidLine<span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>RoundCap<span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>RoundJoin)); painter<span class="operator">.</span>drawLine(lastPoint<span class="operator">,</span> endPoint); modified <span class="operator">=</span> <span class="keyword">true</span>; <span class="type">int</span> rad <span class="operator">=</span> (myPenWidth <span class="operator">/</span> <span class="number">2</span>) <span class="operator">+</span> <span class="number">2</span>; update(<span class="type"><a href="../qtcore/qrect.html">QRect</a></span>(lastPoint<span class="operator">,</span> endPoint)<span class="operator">.</span>normalized() <span class="operator">.</span>adjusted(<span class="operator">-</span>rad<span class="operator">,</span> <span class="operator">-</span>rad<span class="operator">,</span> <span class="operator">+</span>rad<span class="operator">,</span> <span class="operator">+</span>rad)); lastPoint <span class="operator">=</span> endPoint; } <span class="type">void</span> ScribbleArea<span class="operator">::</span>resizeImage(<span class="type"><a href="../qtgui/qimage.html">QImage</a></span> <span class="operator">*</span>image<span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="../qtcore/qsize.html">QSize</a></span> <span class="operator">&</span>newSize) { <span class="keyword">if</span> (image<span class="operator">-</span><span class="operator">></span>size() <span class="operator">=</span><span class="operator">=</span> newSize) <span class="keyword">return</span>; <span class="type"><a href="../qtgui/qimage.html">QImage</a></span> newImage(newSize<span class="operator">,</span> <span class="type"><a href="../qtgui/qimage.html">QImage</a></span><span class="operator">::</span>Format_RGB32); newImage<span class="operator">.</span>fill(<a href="../qtgui/qcolor.html#qRgb">qRgb</a>(<span class="number">255</span><span class="operator">,</span> <span class="number">255</span><span class="operator">,</span> <span class="number">255</span>)); <span class="type"><a href="../qtgui/qpainter.html">QPainter</a></span> painter(<span class="operator">&</span>newImage); painter<span class="operator">.</span>drawImage(<span class="type"><a href="../qtcore/qpoint.html">QPoint</a></span>(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span>)<span class="operator">,</span> <span class="operator">*</span>image); <span class="operator">*</span>image <span class="operator">=</span> newImage; } <span class="type">void</span> ScribbleArea<span class="operator">::</span>print() { <span class="preprocessor">#if QT_CONFIG(printdialog)</span> <span class="type">QPrinter</span> printer(<span class="type">QPrinter</span><span class="operator">::</span>HighResolution); <span class="type">QPrintDialog</span> printDialog(<span class="operator">&</span>printer<span class="operator">,</span> <span class="keyword">this</span>); <span class="keyword">if</span> (printDialog<span class="operator">.</span>exec() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qdialog.html">QDialog</a></span><span class="operator">::</span>Accepted) { <span class="type"><a href="../qtgui/qpainter.html">QPainter</a></span> painter(<span class="operator">&</span>printer); <span class="type"><a href="../qtcore/qrect.html">QRect</a></span> rect <span class="operator">=</span> painter<span class="operator">.</span>viewport(); <span class="type"><a href="../qtcore/qsize.html">QSize</a></span> size <span class="operator">=</span> image<span class="operator">.</span>size(); size<span class="operator">.</span>scale(rect<span class="operator">.</span>size()<span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>KeepAspectRatio); painter<span class="operator">.</span>setViewport(rect<span class="operator">.</span>x()<span class="operator">,</span> rect<span class="operator">.</span>y()<span class="operator">,</span> size<span class="operator">.</span>width()<span class="operator">,</span> size<span class="operator">.</span>height()); painter<span class="operator">.</span>setWindow(image<span class="operator">.</span>rect()); painter<span class="operator">.</span>drawImage(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> image); } <span class="preprocessor">#endif // QT_CONFIG(printdialog)</span> } </pre> </div> <!-- @@@widgets/scribble/scribblearea.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>