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<h1 class="title">mainwindow.cpp Example File</h1>
<span class="subtitle">widgets/scribble/mainwindow.cpp</span>
<!-- $$$widgets/scribble/mainwindow.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">#include "mainwindow.h"</span>
<span class="preprocessor">#include "scribblearea.h"</span>
MainWindow<span class="operator">::</span>MainWindow()
{
scribbleArea <span class="operator">=</span> <span class="keyword">new</span> ScribbleArea;
setCentralWidget(scribbleArea);
createActions();
createMenus();
setWindowTitle(tr(<span class="string">"Scribble"</span>));
resize(<span class="number">500</span><span class="operator">,</span> <span class="number">500</span>);
}
<span class="type">void</span> MainWindow<span class="operator">::</span>closeEvent(<span class="type"><a href="../qtgui/qcloseevent.html">QCloseEvent</a></span> <span class="operator">*</span>event)
{
<span class="keyword">if</span> (maybeSave()) {
event<span class="operator">-</span><span class="operator">></span>accept();
} <span class="keyword">else</span> {
event<span class="operator">-</span><span class="operator">></span>ignore();
}
}
<span class="type">void</span> MainWindow<span class="operator">::</span>open()
{
<span class="keyword">if</span> (maybeSave()) {
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> fileName <span class="operator">=</span> <span class="type"><a href="qfiledialog.html">QFileDialog</a></span><span class="operator">::</span>getOpenFileName(<span class="keyword">this</span><span class="operator">,</span>
tr(<span class="string">"Open File"</span>)<span class="operator">,</span> <span class="type"><a href="../qtcore/qdir.html">QDir</a></span><span class="operator">::</span>currentPath());
<span class="keyword">if</span> (<span class="operator">!</span>fileName<span class="operator">.</span>isEmpty())
scribbleArea<span class="operator">-</span><span class="operator">></span>openImage(fileName);
}
}
<span class="type">void</span> MainWindow<span class="operator">::</span>save()
{
<span class="type"><a href="qaction.html">QAction</a></span> <span class="operator">*</span>action <span class="operator">=</span> qobject_cast<span class="operator"><</span><span class="type"><a href="qaction.html">QAction</a></span> <span class="operator">*</span><span class="operator">></span>(sender());
<span class="type"><a href="../qtcore/qbytearray.html">QByteArray</a></span> fileFormat <span class="operator">=</span> action<span class="operator">-</span><span class="operator">></span>data()<span class="operator">.</span>toByteArray();
saveFile(fileFormat);
}
<span class="type">void</span> MainWindow<span class="operator">::</span>penColor()
{
<span class="type"><a href="../qtgui/qcolor.html">QColor</a></span> newColor <span class="operator">=</span> <span class="type"><a href="qcolordialog.html">QColorDialog</a></span><span class="operator">::</span>getColor(scribbleArea<span class="operator">-</span><span class="operator">></span>penColor());
<span class="keyword">if</span> (newColor<span class="operator">.</span>isValid())
scribbleArea<span class="operator">-</span><span class="operator">></span>setPenColor(newColor);
}
<span class="type">void</span> MainWindow<span class="operator">::</span>penWidth()
{
bool ok;
<span class="type">int</span> newWidth <span class="operator">=</span> <span class="type"><a href="qinputdialog.html">QInputDialog</a></span><span class="operator">::</span>getInt(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"Scribble"</span>)<span class="operator">,</span>
tr(<span class="string">"Select pen width:"</span>)<span class="operator">,</span>
scribbleArea<span class="operator">-</span><span class="operator">></span>penWidth()<span class="operator">,</span>
<span class="number">1</span><span class="operator">,</span> <span class="number">50</span><span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="operator">&</span>ok);
<span class="keyword">if</span> (ok)
scribbleArea<span class="operator">-</span><span class="operator">></span>setPenWidth(newWidth);
}
<span class="type">void</span> MainWindow<span class="operator">::</span>about()
{
<span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>about(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"About Scribble"</span>)<span class="operator">,</span>
tr(<span class="string">"<p>The <b>Scribble</b> example shows how to use QMainWindow as the "</span>
<span class="string">"base widget for an application, and how to reimplement some of "</span>
<span class="string">"QWidget's event handlers to receive the events generated for "</span>
<span class="string">"the application's widgets:</p><p> We reimplement the mouse event "</span>
<span class="string">"handlers to facilitate drawing, the paint event handler to "</span>
<span class="string">"update the application and the resize event handler to optimize "</span>
<span class="string">"the application's appearance. In addition we reimplement the "</span>
<span class="string">"close event handler to intercept the close events before "</span>
<span class="string">"terminating the application.</p><p> The example also demonstrates "</span>
<span class="string">"how to use QPainter to draw an image in real time, as well as "</span>
<span class="string">"to repaint widgets.</p>"</span>));
}
<span class="type">void</span> MainWindow<span class="operator">::</span>createActions()
{
openAct <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaction.html">QAction</a></span>(tr(<span class="string">"&Open..."</span>)<span class="operator">,</span> <span class="keyword">this</span>);
openAct<span class="operator">-</span><span class="operator">></span>setShortcuts(<span class="type"><a href="../qtgui/qkeysequence.html">QKeySequence</a></span><span class="operator">::</span>Open);
connect(openAct<span class="operator">,</span> SIGNAL(triggered())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(open()));
foreach (<span class="type"><a href="../qtcore/qbytearray.html">QByteArray</a></span> format<span class="operator">,</span> <span class="type"><a href="../qtgui/qimagewriter.html">QImageWriter</a></span><span class="operator">::</span>supportedImageFormats()) {
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> text <span class="operator">=</span> tr(<span class="string">"%1..."</span>)<span class="operator">.</span>arg(<span class="type"><a href="../qtcore/qstring.html">QString</a></span>(format)<span class="operator">.</span>toUpper());
<span class="type"><a href="qaction.html">QAction</a></span> <span class="operator">*</span>action <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaction.html">QAction</a></span>(text<span class="operator">,</span> <span class="keyword">this</span>);
action<span class="operator">-</span><span class="operator">></span>setData(format);
connect(action<span class="operator">,</span> SIGNAL(triggered())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(save()));
saveAsActs<span class="operator">.</span>append(action);
}
printAct <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaction.html">QAction</a></span>(tr(<span class="string">"&Print..."</span>)<span class="operator">,</span> <span class="keyword">this</span>);
connect(printAct<span class="operator">,</span> SIGNAL(triggered())<span class="operator">,</span> scribbleArea<span class="operator">,</span> SLOT(print()));
exitAct <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaction.html">QAction</a></span>(tr(<span class="string">"E&xit"</span>)<span class="operator">,</span> <span class="keyword">this</span>);
exitAct<span class="operator">-</span><span class="operator">></span>setShortcuts(<span class="type"><a href="../qtgui/qkeysequence.html">QKeySequence</a></span><span class="operator">::</span>Quit);
connect(exitAct<span class="operator">,</span> SIGNAL(triggered())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(close()));
penColorAct <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaction.html">QAction</a></span>(tr(<span class="string">"&Pen Color..."</span>)<span class="operator">,</span> <span class="keyword">this</span>);
connect(penColorAct<span class="operator">,</span> SIGNAL(triggered())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(penColor()));
penWidthAct <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaction.html">QAction</a></span>(tr(<span class="string">"Pen &Width..."</span>)<span class="operator">,</span> <span class="keyword">this</span>);
connect(penWidthAct<span class="operator">,</span> SIGNAL(triggered())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(penWidth()));
clearScreenAct <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaction.html">QAction</a></span>(tr(<span class="string">"&Clear Screen"</span>)<span class="operator">,</span> <span class="keyword">this</span>);
clearScreenAct<span class="operator">-</span><span class="operator">></span>setShortcut(tr(<span class="string">"Ctrl+L"</span>));
connect(clearScreenAct<span class="operator">,</span> SIGNAL(triggered())<span class="operator">,</span>
scribbleArea<span class="operator">,</span> SLOT(clearImage()));
aboutAct <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaction.html">QAction</a></span>(tr(<span class="string">"&About"</span>)<span class="operator">,</span> <span class="keyword">this</span>);
connect(aboutAct<span class="operator">,</span> SIGNAL(triggered())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(about()));
aboutQtAct <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaction.html">QAction</a></span>(tr(<span class="string">"About &Qt"</span>)<span class="operator">,</span> <span class="keyword">this</span>);
connect(aboutQtAct<span class="operator">,</span> SIGNAL(triggered())<span class="operator">,</span> qApp<span class="operator">,</span> SLOT(aboutQt()));
}
<span class="type">void</span> MainWindow<span class="operator">::</span>createMenus()
{
saveAsMenu <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qmenu.html">QMenu</a></span>(tr(<span class="string">"&Save As"</span>)<span class="operator">,</span> <span class="keyword">this</span>);
foreach (<span class="type"><a href="qaction.html">QAction</a></span> <span class="operator">*</span>action<span class="operator">,</span> saveAsActs)
saveAsMenu<span class="operator">-</span><span class="operator">></span>addAction(action);
fileMenu <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qmenu.html">QMenu</a></span>(tr(<span class="string">"&File"</span>)<span class="operator">,</span> <span class="keyword">this</span>);
fileMenu<span class="operator">-</span><span class="operator">></span>addAction(openAct);
fileMenu<span class="operator">-</span><span class="operator">></span>addMenu(saveAsMenu);
fileMenu<span class="operator">-</span><span class="operator">></span>addAction(printAct);
fileMenu<span class="operator">-</span><span class="operator">></span>addSeparator();
fileMenu<span class="operator">-</span><span class="operator">></span>addAction(exitAct);
optionMenu <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qmenu.html">QMenu</a></span>(tr(<span class="string">"&Options"</span>)<span class="operator">,</span> <span class="keyword">this</span>);
optionMenu<span class="operator">-</span><span class="operator">></span>addAction(penColorAct);
optionMenu<span class="operator">-</span><span class="operator">></span>addAction(penWidthAct);
optionMenu<span class="operator">-</span><span class="operator">></span>addSeparator();
optionMenu<span class="operator">-</span><span class="operator">></span>addAction(clearScreenAct);
helpMenu <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qmenu.html">QMenu</a></span>(tr(<span class="string">"&Help"</span>)<span class="operator">,</span> <span class="keyword">this</span>);
helpMenu<span class="operator">-</span><span class="operator">></span>addAction(aboutAct);
helpMenu<span class="operator">-</span><span class="operator">></span>addAction(aboutQtAct);
menuBar()<span class="operator">-</span><span class="operator">></span>addMenu(fileMenu);
menuBar()<span class="operator">-</span><span class="operator">></span>addMenu(optionMenu);
menuBar()<span class="operator">-</span><span class="operator">></span>addMenu(helpMenu);
}
bool MainWindow<span class="operator">::</span>maybeSave()
{
<span class="keyword">if</span> (scribbleArea<span class="operator">-</span><span class="operator">></span>isModified()) {
<span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>StandardButton ret;
ret <span class="operator">=</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>warning(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"Scribble"</span>)<span class="operator">,</span>
tr(<span class="string">"The image has been modified.\n"</span>
<span class="string">"Do you want to save your changes?"</span>)<span class="operator">,</span>
<span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Save <span class="operator">|</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Discard
<span class="operator">|</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Cancel);
<span class="keyword">if</span> (ret <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Save) {
<span class="keyword">return</span> saveFile(<span class="string">"png"</span>);
} <span class="keyword">else</span> <span class="keyword">if</span> (ret <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Cancel) {
<span class="keyword">return</span> <span class="keyword">false</span>;
}
}
<span class="keyword">return</span> <span class="keyword">true</span>;
}
bool MainWindow<span class="operator">::</span>saveFile(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qbytearray.html">QByteArray</a></span> <span class="operator">&</span>fileFormat)
{
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> initialPath <span class="operator">=</span> <span class="type"><a href="../qtcore/qdir.html">QDir</a></span><span class="operator">::</span>currentPath() <span class="operator">+</span> <span class="string">"/untitled."</span> <span class="operator">+</span> fileFormat;
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> fileName <span class="operator">=</span> <span class="type"><a href="qfiledialog.html">QFileDialog</a></span><span class="operator">::</span>getSaveFileName(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"Save As"</span>)<span class="operator">,</span>
initialPath<span class="operator">,</span>
tr(<span class="string">"%1 Files (*.%2);;All Files (*)"</span>)
<span class="operator">.</span>arg(<span class="type"><a href="../qtcore/qstring.html">QString</a></span><span class="operator">::</span>fromLatin1(fileFormat<span class="operator">.</span>toUpper()))
<span class="operator">.</span>arg(<span class="type"><a href="../qtcore/qstring.html">QString</a></span><span class="operator">::</span>fromLatin1(fileFormat)));
<span class="keyword">if</span> (fileName<span class="operator">.</span>isEmpty()) {
<span class="keyword">return</span> <span class="keyword">false</span>;
} <span class="keyword">else</span> {
<span class="keyword">return</span> scribbleArea<span class="operator">-</span><span class="operator">></span>saveImage(fileName<span class="operator">,</span> fileFormat<span class="operator">.</span>constData());
}
}
</pre>
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<!-- @@@widgets/scribble/mainwindow.cpp -->
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