2023-11-01 18:02:52 +01:00

364 lines
11 KiB
C++

// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include "imageviewer.h"
#include <QApplication>
#include <QClipboard>
#include <QColorSpace>
#include <QDir>
#include <QFileDialog>
#include <QImageReader>
#include <QImageWriter>
#include <QLabel>
#include <QMenuBar>
#include <QMessageBox>
#include <QMimeData>
#include <QPainter>
#include <QScreen>
#include <QScrollArea>
#include <QScrollBar>
#include <QStandardPaths>
#include <QStatusBar>
#if defined(QT_PRINTSUPPORT_LIB)
# include <QtPrintSupport/qtprintsupportglobal.h>
# if QT_CONFIG(printdialog)
# include <QPrintDialog>
# endif
#endif
//! [0]
ImageViewer::ImageViewer(QWidget *parent)
: QMainWindow(parent), imageLabel(new QLabel)
, scrollArea(new QScrollArea)
{
imageLabel->setBackgroundRole(QPalette::Base);
imageLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
imageLabel->setScaledContents(true);
scrollArea->setBackgroundRole(QPalette::Dark);
scrollArea->setWidget(imageLabel);
scrollArea->setVisible(false);
setCentralWidget(scrollArea);
createActions();
resize(QGuiApplication::primaryScreen()->availableSize() * 3 / 5);
}
//! [0]
//! [2]
bool ImageViewer::loadFile(const QString &fileName)
{
QImageReader reader(fileName);
reader.setAutoTransform(true);
const QImage newImage = reader.read();
if (newImage.isNull()) {
QMessageBox::information(this, QGuiApplication::applicationDisplayName(),
tr("Cannot load %1: %2")
.arg(QDir::toNativeSeparators(fileName), reader.errorString()));
return false;
}
//! [2]
setImage(newImage);
setWindowFilePath(fileName);
const QString description = image.colorSpace().isValid()
? image.colorSpace().description() : tr("unknown");
const QString message = tr("Opened \"%1\", %2x%3, Depth: %4 (%5)")
.arg(QDir::toNativeSeparators(fileName)).arg(image.width()).arg(image.height())
.arg(image.depth()).arg(description);
statusBar()->showMessage(message);
return true;
}
void ImageViewer::setImage(const QImage &newImage)
{
image = newImage;
if (image.colorSpace().isValid())
image.convertToColorSpace(QColorSpace::SRgb);
imageLabel->setPixmap(QPixmap::fromImage(image));
//! [4]
scaleFactor = 1.0;
scrollArea->setVisible(true);
printAct->setEnabled(true);
fitToWindowAct->setEnabled(true);
updateActions();
if (!fitToWindowAct->isChecked())
imageLabel->adjustSize();
}
//! [4]
bool ImageViewer::saveFile(const QString &fileName)
{
QImageWriter writer(fileName);
if (!writer.write(image)) {
QMessageBox::information(this, QGuiApplication::applicationDisplayName(),
tr("Cannot write %1: %2")
.arg(QDir::toNativeSeparators(fileName), writer.errorString()));
return false;
}
const QString message = tr("Wrote \"%1\"").arg(QDir::toNativeSeparators(fileName));
statusBar()->showMessage(message);
return true;
}
//! [1]
static void initializeImageFileDialog(QFileDialog &dialog, QFileDialog::AcceptMode acceptMode)
{
static bool firstDialog = true;
if (firstDialog) {
firstDialog = false;
const QStringList picturesLocations = QStandardPaths::standardLocations(QStandardPaths::PicturesLocation);
dialog.setDirectory(picturesLocations.isEmpty() ? QDir::currentPath() : picturesLocations.last());
}
QStringList mimeTypeFilters;
const QByteArrayList supportedMimeTypes = acceptMode == QFileDialog::AcceptOpen
? QImageReader::supportedMimeTypes() : QImageWriter::supportedMimeTypes();
for (const QByteArray &mimeTypeName : supportedMimeTypes)
mimeTypeFilters.append(mimeTypeName);
mimeTypeFilters.sort();
dialog.setMimeTypeFilters(mimeTypeFilters);
dialog.selectMimeTypeFilter("image/jpeg");
dialog.setAcceptMode(acceptMode);
if (acceptMode == QFileDialog::AcceptSave)
dialog.setDefaultSuffix("jpg");
}
void ImageViewer::open()
{
QFileDialog dialog(this, tr("Open File"));
initializeImageFileDialog(dialog, QFileDialog::AcceptOpen);
while (dialog.exec() == QDialog::Accepted && !loadFile(dialog.selectedFiles().constFirst())) {}
}
//! [1]
void ImageViewer::saveAs()
{
QFileDialog dialog(this, tr("Save File As"));
initializeImageFileDialog(dialog, QFileDialog::AcceptSave);
while (dialog.exec() == QDialog::Accepted && !saveFile(dialog.selectedFiles().constFirst())) {}
}
//! [5]
void ImageViewer::print()
//! [5] //! [6]
{
Q_ASSERT(!imageLabel->pixmap().isNull());
#if defined(QT_PRINTSUPPORT_LIB) && QT_CONFIG(printdialog)
//! [6] //! [7]
QPrintDialog dialog(&printer, this);
//! [7] //! [8]
if (dialog.exec()) {
QPainter painter(&printer);
QPixmap pixmap = imageLabel->pixmap();
QRect rect = painter.viewport();
QSize size = pixmap.size();
size.scale(rect.size(), Qt::KeepAspectRatio);
painter.setViewport(rect.x(), rect.y(), size.width(), size.height());
painter.setWindow(pixmap.rect());
painter.drawPixmap(0, 0, pixmap);
}
#endif
}
//! [8]
void ImageViewer::copy()
{
#ifndef QT_NO_CLIPBOARD
QGuiApplication::clipboard()->setImage(image);
#endif // !QT_NO_CLIPBOARD
}
#ifndef QT_NO_CLIPBOARD
static QImage clipboardImage()
{
if (const QMimeData *mimeData = QGuiApplication::clipboard()->mimeData()) {
if (mimeData->hasImage()) {
const QImage image = qvariant_cast<QImage>(mimeData->imageData());
if (!image.isNull())
return image;
}
}
return QImage();
}
#endif // !QT_NO_CLIPBOARD
void ImageViewer::paste()
{
#ifndef QT_NO_CLIPBOARD
const QImage newImage = clipboardImage();
if (newImage.isNull()) {
statusBar()->showMessage(tr("No image in clipboard"));
} else {
setImage(newImage);
setWindowFilePath(QString());
const QString message = tr("Obtained image from clipboard, %1x%2, Depth: %3")
.arg(newImage.width()).arg(newImage.height()).arg(newImage.depth());
statusBar()->showMessage(message);
}
#endif // !QT_NO_CLIPBOARD
}
//! [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]
{
QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
QAction *openAct = fileMenu->addAction(tr("&Open..."), this, &ImageViewer::open);
openAct->setShortcut(QKeySequence::Open);
saveAsAct = fileMenu->addAction(tr("&Save As..."), this, &ImageViewer::saveAs);
saveAsAct->setEnabled(false);
printAct = fileMenu->addAction(tr("&Print..."), this, &ImageViewer::print);
printAct->setShortcut(QKeySequence::Print);
printAct->setEnabled(false);
fileMenu->addSeparator();
QAction *exitAct = fileMenu->addAction(tr("E&xit"), this, &QWidget::close);
exitAct->setShortcut(tr("Ctrl+Q"));
QMenu *editMenu = menuBar()->addMenu(tr("&Edit"));
copyAct = editMenu->addAction(tr("&Copy"), this, &ImageViewer::copy);
copyAct->setShortcut(QKeySequence::Copy);
copyAct->setEnabled(false);
QAction *pasteAct = editMenu->addAction(tr("&Paste"), this, &ImageViewer::paste);
pasteAct->setShortcut(QKeySequence::Paste);
QMenu *viewMenu = menuBar()->addMenu(tr("&View"));
zoomInAct = viewMenu->addAction(tr("Zoom &In (25%)"), this, &ImageViewer::zoomIn);
zoomInAct->setShortcut(QKeySequence::ZoomIn);
zoomInAct->setEnabled(false);
zoomOutAct = viewMenu->addAction(tr("Zoom &Out (25%)"), this, &ImageViewer::zoomOut);
zoomOutAct->setShortcut(QKeySequence::ZoomOut);
zoomOutAct->setEnabled(false);
normalSizeAct = viewMenu->addAction(tr("&Normal Size"), this, &ImageViewer::normalSize);
normalSizeAct->setShortcut(tr("Ctrl+S"));
normalSizeAct->setEnabled(false);
viewMenu->addSeparator();
fitToWindowAct = viewMenu->addAction(tr("&Fit to Window"), this, &ImageViewer::fitToWindow);
fitToWindowAct->setEnabled(false);
fitToWindowAct->setCheckable(true);
fitToWindowAct->setShortcut(tr("Ctrl+F"));
QMenu *helpMenu = menuBar()->addMenu(tr("&Help"));
helpMenu->addAction(tr("&About"), this, &ImageViewer::about);
helpMenu->addAction(tr("About &Qt"), this, &QApplication::aboutQt);
}
//! [18]
//! [21]
void ImageViewer::updateActions()
//! [21] //! [22]
{
saveAsAct->setEnabled(!image.isNull());
copyAct->setEnabled(!image.isNull());
zoomInAct->setEnabled(!fitToWindowAct->isChecked());
zoomOutAct->setEnabled(!fitToWindowAct->isChecked());
normalSizeAct->setEnabled(!fitToWindowAct->isChecked());
}
//! [22]
//! [23]
void ImageViewer::scaleImage(double factor)
//! [23] //! [24]
{
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]