Extend the image viewer example.

Add:
- Save As
- Copy
- Paste from clipboard into new image

Change-Id: Ibbc308e9bbd2ce407119cd9358874f5c22a6bb83
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>

examples/widgets/widgets/imageviewer/imageviewer.cpp

@@ -72,25 +72,16 @@ bool ImageViewer::loadFile(const QString &fileName)
 {
     QImageReader reader(fileName);
     reader.setAutoTransform(true);
-    const QImage image = reader.read();
-    if (image.isNull()) {
+    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] //! [3]
-    imageLabel->setPixmap(QPixmap::fromImage(image));
-//! [3] //! [4]
-    scaleFactor = 1.0;
+//! [2]
 
-    scrollArea->setVisible(true);
-    printAct->setEnabled(true);
-    fitToWindowAct->setEnabled(true);
-    updateActions();
-
-    if (!fitToWindowAct->isChecked())
-        imageLabel->adjustSize();
+    setImage(newImage);
 
     setWindowFilePath(fileName);
 
@@ -100,28 +91,80 @@ bool ImageViewer::loadFile(const QString &fileName)
     return true;
 }
 
+void ImageViewer::setImage(const QImage &newImage)
+{
+    image = newImage;
+    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]
 
-//! [2]
+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]
-void ImageViewer::open()
+
+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;
-    foreach (const QByteArray &mimeTypeName, QImageReader::supportedMimeTypes())
+    const QByteArrayList supportedMimeTypes = acceptMode == QFileDialog::AcceptOpen
+        ? QImageReader::supportedMimeTypes() : QImageWriter::supportedMimeTypes();
+    foreach (const QByteArray &mimeTypeName, supportedMimeTypes)
         mimeTypeFilters.append(mimeTypeName);
     mimeTypeFilters.sort();
-    const QStringList picturesLocations = QStandardPaths::standardLocations(QStandardPaths::PicturesLocation);
-    QFileDialog dialog(this, tr("Open File"),
-                       picturesLocations.isEmpty() ? QDir::currentPath() : picturesLocations.last());
-    dialog.setAcceptMode(QFileDialog::AcceptOpen);
     dialog.setMimeTypeFilters(mimeTypeFilters);
     dialog.selectMimeTypeFilter("image/jpeg");
+    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().first())) {}
 }
 //! [1]
 
+void ImageViewer::saveAs()
+{
+    QFileDialog dialog(this, tr("Save File As"));
+    initializeImageFileDialog(dialog, QFileDialog::AcceptSave);
+
+    while (dialog.exec() == QDialog::Accepted && !saveFile(dialog.selectedFiles().first())) {}
+}
+
 //! [5]
 void ImageViewer::print()
 //! [5] //! [6]
@@ -144,6 +187,43 @@ void ImageViewer::print()
 }
 //! [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]
@@ -207,6 +287,9 @@ void ImageViewer::createActions()
     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);
@@ -216,6 +299,15 @@ void ImageViewer::createActions()
     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);
@@ -248,6 +340,8 @@ void ImageViewer::createActions()
 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());

examples/widgets/widgets/imageviewer/imageviewer.h

@@ -42,6 +42,7 @@
 #define IMAGEVIEWER_H
 
 #include <QMainWindow>
+#include <QImage>
 #ifndef QT_NO_PRINTER
 #include <QPrinter>
 #endif
@@ -65,7 +66,10 @@ public:
 
 private slots:
     void open();
+    void saveAs();
     void print();
+    void copy();
+    void paste();
     void zoomIn();
     void zoomOut();
     void normalSize();
@@ -76,9 +80,12 @@ private:
     void createActions();
     void createMenus();
     void updateActions();
+    bool saveFile(const QString &fileName);
+    void setImage(const QImage &newImage);
     void scaleImage(double factor);
     void adjustScrollBar(QScrollBar *scrollBar, double factor);
 
+    QImage image;
     QLabel *imageLabel;
     QScrollArea *scrollArea;
     double scaleFactor;
@@ -87,7 +94,9 @@ private:
     QPrinter printer;
 #endif
 
+    QAction *saveAsAct;
     QAction *printAct;
+    QAction *copyAct;
     QAction *zoomInAct;
     QAction *zoomOutAct;
     QAction *normalSizeAct;