<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>Qt 4.3: imageviewer.cpp Example File (widgets/imageviewer/imageviewer.cpp)</title>
<link href="classic.css" rel="stylesheet" type="text/css" />
</head>
<body>
<table border="0" cellpadding="0" cellspacing="0" width="100%">
<tr>
<td align="left" valign="top" width="32"><a href="http://www.trolltech.com/products/qt"><img src="images/qt-logo.png" align="left" width="32" height="32" border="0" /></a></td>
<td width="1"> </td><td class="postheader" valign="center"><a href="index.html"><font color="#004faf">Home</font></a> · <a href="classes.html"><font color="#004faf">All Classes</font></a> · <a href="mainclasses.html"><font color="#004faf">Main Classes</font></a> · <a href="groups.html"><font color="#004faf">Grouped Classes</font></a> · <a href="modules.html"><font color="#004faf">Modules</font></a> · <a href="functions.html"><font color="#004faf">Functions</font></a></td>
<td align="right" valign="top" width="230"><a href="http://www.trolltech.com"><img src="images/trolltech-logo.png" align="right" width="203" height="32" border="0" /></a></td></tr></table><h1 align="center">imageviewer.cpp Example File<br /><sup><sup>widgets/imageviewer/imageviewer.cpp</sup></sup></h1>
<pre><span class="comment"> /****************************************************************************
**
** Copyright (C) 2005-2008 Trolltech ASA. All rights reserved.
**
** This file is part of the example classes of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License versions 2.0 or 3.0 as published by the Free Software
** Foundation and appearing in the files LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Alternatively you may (at
** your option) use any later version of the GNU General Public
** License if such license has been publicly approved by Trolltech ASA
** (or its successors, if any) and the KDE Free Qt Foundation. In
** addition, as a special exception, Trolltech gives you certain
** additional rights. These rights are described in the Trolltech GPL
** Exception version 1.1, which can be found at
** http://www.trolltech.com/products/qt/gplexception/ and in the file
** GPL_EXCEPTION.txt in this package.
**
** Please review the following information to ensure GNU General
** Public Licensing requirements will be met:
** http://trolltech.com/products/qt/licenses/licensing/opensource/. If
** you are unsure which license is appropriate for your use, please
** review the following information:
** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
** or contact the sales department at sales@trolltech.com.
**
** In addition, as a special exception, Trolltech, as the sole
** copyright holder for Qt Designer, grants users of the Qt/Eclipse
** Integration plug-in the right for the Qt/Eclipse Integration to
** link to functionality provided by Qt Designer and its related
** libraries.
**
** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE. Trolltech reserves all rights not expressly
** granted herein.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/</span>
#include <QtGui>
#include "imageviewer.h"
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);
}
void ImageViewer::open()
{
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;
}
imageLabel->setPixmap(QPixmap::fromImage(image));
scaleFactor = 1.0;
printAct->setEnabled(true);
fitToWindowAct->setEnabled(true);
updateActions();
if (!fitToWindowAct->isChecked())
imageLabel->adjustSize();
}
}
void ImageViewer::print()
{
Q_ASSERT(imageLabel->pixmap());
QPrintDialog dialog(&printer, this);
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());
}
}
void ImageViewer::zoomIn()
{
scaleImage(1.25);
}
void ImageViewer::zoomOut()
{
scaleImage(0.8);
}
void ImageViewer::normalSize()
{
imageLabel->adjustSize();
scaleFactor = 1.0;
}
void ImageViewer::fitToWindow()
{
bool fitToWindow = fitToWindowAct->isChecked();
scrollArea->setWidgetResizable(fitToWindow);
if (!fitToWindow) {
normalSize();
}
updateActions();
}
void ImageViewer::about()
{
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>"));
}
void ImageViewer::createActions()
{
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()));
}
void ImageViewer::createMenus()
{
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);
}
void ImageViewer::updateActions()
{
zoomInAct->setEnabled(!fitToWindowAct->isChecked());
zoomOutAct->setEnabled(!fitToWindowAct->isChecked());
normalSizeAct->setEnabled(!fitToWindowAct->isChecked());
}
void ImageViewer::scaleImage(double factor)
{
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);
}
void ImageViewer::adjustScrollBar(QScrollBar *scrollBar, double factor)
{
scrollBar->setValue(int(factor * scrollBar->value()
+ ((factor - 1) * scrollBar->pageStep()/2)));
}</pre>
<p /><address><hr /><div align="center">
<table width="100%" cellspacing="0" border="0"><tr class="address">
<td width="30%">Copyright © 2008 <a href="trolltech.html">Trolltech</a></td>
<td width="40%" align="center"><a href="trademarks.html">Trademarks</a></td>
<td width="30%" align="right"><div align="right">Qt 4.3.4</div></td>
</tr></table></div></address></body>
</html>
distrib
>
Mandriva
>
2008.1
>
x86_64
>
media
>
main-release
>
by-pkgid
>
c5a68a1bfbb41dd7ab32131d8bbca747
>
files
>
4046
