278 lines
8.6 KiB
C++
278 lines
8.6 KiB
C++
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/****************************************************************************
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**
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** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
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** All rights reserved.
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** Contact: Nokia Corporation (qt-info@nokia.com)
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**
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** This file is part of the examples of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:BSD$
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** You may use this file under the terms of the BSD license as follows:
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**
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** "Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions are
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** met:
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** * Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** * Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in
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** the documentation and/or other materials provided with the
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** distribution.
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** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
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** the names of its contributors may be used to endorse or promote
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** products derived from this software without specific prior written
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** permission.
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**
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** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#include <QtGui>
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#include "imageviewer.h"
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//! [0]
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ImageViewer::ImageViewer()
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{
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imageLabel = new QLabel;
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imageLabel->setBackgroundRole(QPalette::Base);
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imageLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
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imageLabel->setScaledContents(true);
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scrollArea = new QScrollArea;
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scrollArea->setBackgroundRole(QPalette::Dark);
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scrollArea->setWidget(imageLabel);
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setCentralWidget(scrollArea);
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createActions();
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createMenus();
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setWindowTitle(tr("Image Viewer"));
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resize(500, 400);
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}
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//! [0]
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//! [1]
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void ImageViewer::open()
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//! [1] //! [2]
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{
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QString fileName = QFileDialog::getOpenFileName(this,
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tr("Open File"), QDir::currentPath());
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if (!fileName.isEmpty()) {
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QImage image(fileName);
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if (image.isNull()) {
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QMessageBox::information(this, tr("Image Viewer"),
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tr("Cannot load %1.").arg(fileName));
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return;
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}
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//! [2] //! [3]
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imageLabel->setPixmap(QPixmap::fromImage(image));
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//! [3] //! [4]
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scaleFactor = 1.0;
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printAct->setEnabled(true);
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fitToWindowAct->setEnabled(true);
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updateActions();
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if (!fitToWindowAct->isChecked())
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imageLabel->adjustSize();
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}
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}
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//! [4]
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//! [5]
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void ImageViewer::print()
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//! [5] //! [6]
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{
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Q_ASSERT(imageLabel->pixmap());
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#ifndef QT_NO_PRINTER
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//! [6] //! [7]
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QPrintDialog dialog(&printer, this);
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//! [7] //! [8]
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if (dialog.exec()) {
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QPainter painter(&printer);
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QRect rect = painter.viewport();
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QSize size = imageLabel->pixmap()->size();
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size.scale(rect.size(), Qt::KeepAspectRatio);
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painter.setViewport(rect.x(), rect.y(), size.width(), size.height());
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painter.setWindow(imageLabel->pixmap()->rect());
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painter.drawPixmap(0, 0, *imageLabel->pixmap());
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}
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#endif
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}
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//! [8]
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//! [9]
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void ImageViewer::zoomIn()
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//! [9] //! [10]
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{
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scaleImage(1.25);
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}
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void ImageViewer::zoomOut()
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{
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scaleImage(0.8);
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}
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//! [10] //! [11]
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void ImageViewer::normalSize()
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//! [11] //! [12]
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{
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imageLabel->adjustSize();
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scaleFactor = 1.0;
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}
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//! [12]
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//! [13]
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void ImageViewer::fitToWindow()
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//! [13] //! [14]
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{
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bool fitToWindow = fitToWindowAct->isChecked();
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scrollArea->setWidgetResizable(fitToWindow);
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if (!fitToWindow) {
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normalSize();
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}
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updateActions();
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}
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//! [14]
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//! [15]
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void ImageViewer::about()
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//! [15] //! [16]
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{
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QMessageBox::about(this, tr("About Image Viewer"),
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tr("<p>The <b>Image Viewer</b> example shows how to combine QLabel "
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"and QScrollArea to display an image. QLabel is typically used "
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"for displaying a text, but it can also display an image. "
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"QScrollArea provides a scrolling view around another widget. "
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"If the child widget exceeds the size of the frame, QScrollArea "
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"automatically provides scroll bars. </p><p>The example "
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"demonstrates how QLabel's ability to scale its contents "
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"(QLabel::scaledContents), and QScrollArea's ability to "
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"automatically resize its contents "
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"(QScrollArea::widgetResizable), can be used to implement "
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"zooming and scaling features. </p><p>In addition the example "
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"shows how to use QPainter to print an image.</p>"));
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}
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//! [16]
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//! [17]
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void ImageViewer::createActions()
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//! [17] //! [18]
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{
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openAct = new QAction(tr("&Open..."), this);
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openAct->setShortcut(tr("Ctrl+O"));
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connect(openAct, SIGNAL(triggered()), this, SLOT(open()));
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printAct = new QAction(tr("&Print..."), this);
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printAct->setShortcut(tr("Ctrl+P"));
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printAct->setEnabled(false);
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connect(printAct, SIGNAL(triggered()), this, SLOT(print()));
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exitAct = new QAction(tr("E&xit"), this);
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exitAct->setShortcut(tr("Ctrl+Q"));
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connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));
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zoomInAct = new QAction(tr("Zoom &In (25%)"), this);
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zoomInAct->setShortcut(tr("Ctrl++"));
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zoomInAct->setEnabled(false);
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connect(zoomInAct, SIGNAL(triggered()), this, SLOT(zoomIn()));
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zoomOutAct = new QAction(tr("Zoom &Out (25%)"), this);
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zoomOutAct->setShortcut(tr("Ctrl+-"));
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zoomOutAct->setEnabled(false);
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connect(zoomOutAct, SIGNAL(triggered()), this, SLOT(zoomOut()));
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normalSizeAct = new QAction(tr("&Normal Size"), this);
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normalSizeAct->setShortcut(tr("Ctrl+S"));
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normalSizeAct->setEnabled(false);
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connect(normalSizeAct, SIGNAL(triggered()), this, SLOT(normalSize()));
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fitToWindowAct = new QAction(tr("&Fit to Window"), this);
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fitToWindowAct->setEnabled(false);
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fitToWindowAct->setCheckable(true);
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fitToWindowAct->setShortcut(tr("Ctrl+F"));
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connect(fitToWindowAct, SIGNAL(triggered()), this, SLOT(fitToWindow()));
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aboutAct = new QAction(tr("&About"), this);
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connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));
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aboutQtAct = new QAction(tr("About &Qt"), this);
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connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
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}
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//! [18]
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//! [19]
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void ImageViewer::createMenus()
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//! [19] //! [20]
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{
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fileMenu = new QMenu(tr("&File"), this);
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fileMenu->addAction(openAct);
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fileMenu->addAction(printAct);
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fileMenu->addSeparator();
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fileMenu->addAction(exitAct);
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viewMenu = new QMenu(tr("&View"), this);
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viewMenu->addAction(zoomInAct);
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viewMenu->addAction(zoomOutAct);
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viewMenu->addAction(normalSizeAct);
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viewMenu->addSeparator();
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viewMenu->addAction(fitToWindowAct);
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helpMenu = new QMenu(tr("&Help"), this);
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helpMenu->addAction(aboutAct);
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helpMenu->addAction(aboutQtAct);
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menuBar()->addMenu(fileMenu);
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menuBar()->addMenu(viewMenu);
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menuBar()->addMenu(helpMenu);
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}
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//! [20]
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//! [21]
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void ImageViewer::updateActions()
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//! [21] //! [22]
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{
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zoomInAct->setEnabled(!fitToWindowAct->isChecked());
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zoomOutAct->setEnabled(!fitToWindowAct->isChecked());
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normalSizeAct->setEnabled(!fitToWindowAct->isChecked());
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}
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//! [22]
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//! [23]
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void ImageViewer::scaleImage(double factor)
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//! [23] //! [24]
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{
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Q_ASSERT(imageLabel->pixmap());
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scaleFactor *= factor;
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imageLabel->resize(scaleFactor * imageLabel->pixmap()->size());
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adjustScrollBar(scrollArea->horizontalScrollBar(), factor);
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adjustScrollBar(scrollArea->verticalScrollBar(), factor);
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zoomInAct->setEnabled(scaleFactor < 3.0);
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zoomOutAct->setEnabled(scaleFactor > 0.333);
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}
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//! [24]
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//! [25]
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void ImageViewer::adjustScrollBar(QScrollBar *scrollBar, double factor)
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//! [25] //! [26]
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{
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scrollBar->setValue(int(factor * scrollBar->value()
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+ ((factor - 1) * scrollBar->pageStep()/2)));
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}
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//! [26]
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