diff options
Diffstat (limited to 'examples/widgets/widgets/imageviewer/imageviewer.cpp')
| -rw-r--r-- | examples/widgets/widgets/imageviewer/imageviewer.cpp | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/examples/widgets/widgets/imageviewer/imageviewer.cpp b/examples/widgets/widgets/imageviewer/imageviewer.cpp new file mode 100644 index 0000000000..97ab1d77f8 --- /dev/null +++ b/examples/widgets/widgets/imageviewer/imageviewer.cpp @@ -0,0 +1,280 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/ +** +** 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 <QtWidgets> +#ifndef QT_NO_PRINTER +#include <QPrintDialog> +#endif + +#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("<p>The <b>Image Viewer</b> 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. </p><p>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. </p><p>In addition the example " + "shows how to use QPainter to print an image.</p>")); +} +//! [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] |