qt5base-lts/examples/widgets/imageviewer/imageviewer.cpp
Janne Anttila 9fe5139e73 Fix building of qtbase examples when printsupport module is disabled.
Printsupport module is not that interesting in embedded environments,
and it also does not compile at the moment for WEC7. Fixed qtbase
examples to obey the availability of printsupport module.

Change-Id: I960d1b628b9ca82450aa3b0df8dd101b2544ee12
Reviewed-by: Björn Breitmeyer <bjoern.breitmeyer@kdab.com>
Reviewed-by: Andreas Holzammer <andreas.holzammer@kdab.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>
2012-06-18 09:48:55 +02:00

281 lines
8.6 KiB
C++

/****************************************************************************
**
** 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.
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** 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
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** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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****************************************************************************/
#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]