/**************************************************************************** ** ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies). ** All rights reserved. ** Contact: Nokia Corporation (qt-info@nokia.com) ** ** This file is part of the examples of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:BSD$ ** 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 Nokia Corporation and its Subsidiary(-ies) 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." ** $QT_END_LICENSE$ ** ****************************************************************************/ #include #include "imageviewer.h" //! [0] ImageViewer::ImageViewer() { imageLabel = new QLabel; imageLabel->setBackgroundRole(QPalette::Base); imageLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored); imageLabel->setScaledContents(true); scrollArea = new QScrollArea; scrollArea->setBackgroundRole(QPalette::Dark); scrollArea->setWidget(imageLabel); setCentralWidget(scrollArea); createActions(); createMenus(); setWindowTitle(tr("Image Viewer")); resize(500, 400); } //! [0] //! [1] void ImageViewer::open() //! [1] //! [2] { QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"), QDir::currentPath()); if (!fileName.isEmpty()) { QImage image(fileName); if (image.isNull()) { QMessageBox::information(this, tr("Image Viewer"), tr("Cannot load %1.").arg(fileName)); return; } //! [2] //! [3] imageLabel->setPixmap(QPixmap::fromImage(image)); //! [3] //! [4] scaleFactor = 1.0; printAct->setEnabled(true); fitToWindowAct->setEnabled(true); updateActions(); if (!fitToWindowAct->isChecked()) imageLabel->adjustSize(); } } //! [4] //! [5] void ImageViewer::print() //! [5] //! [6] { Q_ASSERT(imageLabel->pixmap()); #ifndef QT_NO_PRINTER //! [6] //! [7] QPrintDialog dialog(&printer, this); //! [7] //! [8] if (dialog.exec()) { QPainter painter(&printer); QRect rect = painter.viewport(); QSize size = imageLabel->pixmap()->size(); size.scale(rect.size(), Qt::KeepAspectRatio); painter.setViewport(rect.x(), rect.y(), size.width(), size.height()); painter.setWindow(imageLabel->pixmap()->rect()); painter.drawPixmap(0, 0, *imageLabel->pixmap()); } #endif } //! [8] //! [9] void ImageViewer::zoomIn() //! [9] //! [10] { scaleImage(1.25); } void ImageViewer::zoomOut() { scaleImage(0.8); } //! [10] //! [11] void ImageViewer::normalSize() //! [11] //! [12] { imageLabel->adjustSize(); scaleFactor = 1.0; } //! [12] //! [13] void ImageViewer::fitToWindow() //! [13] //! [14] { bool fitToWindow = fitToWindowAct->isChecked(); scrollArea->setWidgetResizable(fitToWindow); if (!fitToWindow) { normalSize(); } updateActions(); } //! [14] //! [15] void ImageViewer::about() //! [15] //! [16] { QMessageBox::about(this, tr("About Image Viewer"), tr("

The Image Viewer example shows how to combine QLabel " "and QScrollArea to display an image. QLabel is typically used " "for displaying a text, but it can also display an image. " "QScrollArea provides a scrolling view around another widget. " "If the child widget exceeds the size of the frame, QScrollArea " "automatically provides scroll bars.

The example " "demonstrates how QLabel's ability to scale its contents " "(QLabel::scaledContents), and QScrollArea's ability to " "automatically resize its contents " "(QScrollArea::widgetResizable), can be used to implement " "zooming and scaling features.

In addition the example " "shows how to use QPainter to print an image.

")); } //! [16] //! [17] void ImageViewer::createActions() //! [17] //! [18] { openAct = new QAction(tr("&Open..."), this); openAct->setShortcut(tr("Ctrl+O")); connect(openAct, SIGNAL(triggered()), this, SLOT(open())); printAct = new QAction(tr("&Print..."), this); printAct->setShortcut(tr("Ctrl+P")); printAct->setEnabled(false); connect(printAct, SIGNAL(triggered()), this, SLOT(print())); exitAct = new QAction(tr("E&xit"), this); exitAct->setShortcut(tr("Ctrl+Q")); connect(exitAct, SIGNAL(triggered()), this, SLOT(close())); zoomInAct = new QAction(tr("Zoom &In (25%)"), this); zoomInAct->setShortcut(tr("Ctrl++")); zoomInAct->setEnabled(false); connect(zoomInAct, SIGNAL(triggered()), this, SLOT(zoomIn())); zoomOutAct = new QAction(tr("Zoom &Out (25%)"), this); zoomOutAct->setShortcut(tr("Ctrl+-")); zoomOutAct->setEnabled(false); connect(zoomOutAct, SIGNAL(triggered()), this, SLOT(zoomOut())); normalSizeAct = new QAction(tr("&Normal Size"), this); normalSizeAct->setShortcut(tr("Ctrl+S")); normalSizeAct->setEnabled(false); connect(normalSizeAct, SIGNAL(triggered()), this, SLOT(normalSize())); fitToWindowAct = new QAction(tr("&Fit to Window"), this); fitToWindowAct->setEnabled(false); fitToWindowAct->setCheckable(true); fitToWindowAct->setShortcut(tr("Ctrl+F")); connect(fitToWindowAct, SIGNAL(triggered()), this, SLOT(fitToWindow())); aboutAct = new QAction(tr("&About"), this); connect(aboutAct, SIGNAL(triggered()), this, SLOT(about())); aboutQtAct = new QAction(tr("About &Qt"), this); connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt())); } //! [18] //! [19] void ImageViewer::createMenus() //! [19] //! [20] { fileMenu = new QMenu(tr("&File"), this); fileMenu->addAction(openAct); fileMenu->addAction(printAct); fileMenu->addSeparator(); fileMenu->addAction(exitAct); viewMenu = new QMenu(tr("&View"), this); viewMenu->addAction(zoomInAct); viewMenu->addAction(zoomOutAct); viewMenu->addAction(normalSizeAct); viewMenu->addSeparator(); viewMenu->addAction(fitToWindowAct); helpMenu = new QMenu(tr("&Help"), this); helpMenu->addAction(aboutAct); helpMenu->addAction(aboutQtAct); menuBar()->addMenu(fileMenu); menuBar()->addMenu(viewMenu); menuBar()->addMenu(helpMenu); } //! [20] //! [21] void ImageViewer::updateActions() //! [21] //! [22] { zoomInAct->setEnabled(!fitToWindowAct->isChecked()); zoomOutAct->setEnabled(!fitToWindowAct->isChecked()); normalSizeAct->setEnabled(!fitToWindowAct->isChecked()); } //! [22] //! [23] void ImageViewer::scaleImage(double factor) //! [23] //! [24] { Q_ASSERT(imageLabel->pixmap()); scaleFactor *= factor; imageLabel->resize(scaleFactor * imageLabel->pixmap()->size()); adjustScrollBar(scrollArea->horizontalScrollBar(), factor); adjustScrollBar(scrollArea->verticalScrollBar(), factor); zoomInAct->setEnabled(scaleFactor < 3.0); zoomOutAct->setEnabled(scaleFactor > 0.333); } //! [24] //! [25] void ImageViewer::adjustScrollBar(QScrollBar *scrollBar, double factor) //! [25] //! [26] { scrollBar->setValue(int(factor * scrollBar->value() + ((factor - 1) * scrollBar->pageStep()/2))); } //! [26]