feat: basic image flip support

app/actionmanager.cpp

@@ -23,6 +23,7 @@ void ActionManager::setupAction(MainWindow *mainWindow)
 {
     CREATE_NEW_ACTION(mainWindow, actionZoomIn);
     CREATE_NEW_ACTION(mainWindow, actionZoomOut);
+    CREATE_NEW_ACTION(mainWindow, actionHorizontalFlip);
     CREATE_NEW_ACTION(mainWindow, actionCopyPixmap);
     CREATE_NEW_ACTION(mainWindow, actionCopyFilePath);
     CREATE_NEW_ACTION(mainWindow, actionPaste);
@@ -45,6 +46,7 @@ void ActionManager::retranslateUi(MainWindow *mainWindow)
 
     actionZoomIn->setText(QCoreApplication::translate("MainWindow", "Zoom in", nullptr));
     actionZoomOut->setText(QCoreApplication::translate("MainWindow", "Zoom out", nullptr));
+    actionHorizontalFlip->setText(QCoreApplication::translate("MainWindow", "Horizontal flip", nullptr));
     actionCopyPixmap->setText(QCoreApplication::translate("MainWindow", "Copy P&ixmap", nullptr));
     actionCopyFilePath->setText(QCoreApplication::translate("MainWindow", "Copy &File Path", nullptr));
     actionPaste->setText(QCoreApplication::translate("MainWindow", "&Paste", nullptr));

app/actionmanager.h

@@ -18,6 +18,7 @@ public:
 public:
     QAction *actionZoomIn;
     QAction *actionZoomOut;
+    QAction *actionHorizontalFlip;
     QAction *actionCopyPixmap;
     QAction *actionCopyFilePath;
     QAction *actionPaste;

app/graphicsview.cpp

@@ -134,6 +134,17 @@ void GraphicsView::zoomView(qreal scaleFactor)
     emit navigatorViewRequired(!isThingSmallerThanWindowWith(transform()), m_rotateAngle);
 }
 
+void GraphicsView::flipView(bool horizontal)
+{
+    if (horizontal) {
+        scale(-1, 1);
+    } else {
+        scale(1, -1);
+    }
+    // I guess we don't need to check if we need to trigger navigator view here
+    // since fliping doesn't affact the image rectangle size.
+}
+
 void GraphicsView::resetScale()
 {
     resetWithScaleAndRotate(1, m_rotateAngle);

app/graphicsview.h

@@ -26,6 +26,7 @@ public:
 
     void resetTransform();
     void zoomView(qreal scaleFactor);
+    void flipView(bool horizontal = true);
     void resetScale();
     void rotateView(qreal rotateAngel);
     void fitInView(const QRectF &rect, Qt::AspectRatioMode aspectRadioMode = Qt::IgnoreAspectRatio);

app/mainwindow.cpp

@@ -420,6 +420,10 @@ void MainWindow::contextMenuEvent(QContextMenuEvent *event)
         menu->addAction(paste);
     }
 
+    menu->addSeparator();
+
+    menu->addAction(m_am->actionHorizontalFlip);
+
     menu->addSeparator();
     menu->addAction(stayOnTopMode);
     menu->addAction(protectedMode);
@@ -554,6 +558,11 @@ void MainWindow::on_actionZoomOut_triggered()
     m_graphicsView->zoomView(0.8);
 }
 
+void MainWindow::on_actionHorizontalFlip_triggered()
+{
+    m_graphicsView->flipView();
+}
+
 void MainWindow::on_actionCopyPixmap_triggered()
 {
     QClipboard *cb = QApplication::clipboard();

app/mainwindow.h

@@ -65,6 +65,7 @@ protected:
 private slots:
     void on_actionZoomIn_triggered();
     void on_actionZoomOut_triggered();
+    void on_actionHorizontalFlip_triggered();
     void on_actionCopyPixmap_triggered();
     void on_actionCopyFilePath_triggered();
     void on_actionPaste_triggered();