feat: add option to avoid reset transform when switching between images

It's not enabled for now so it's not available to end-users.

app/actionmanager.cpp

@@ -68,6 +68,7 @@ void ActionManager::setupAction(MainWindow *mainWindow)
     CREATE_NEW_ACTION(mainWindow, actionPaste);
     CREATE_NEW_ACTION(mainWindow, actionToggleStayOnTop);
     CREATE_NEW_ACTION(mainWindow, actionToggleProtectMode);
+    CREATE_NEW_ACTION(mainWindow, actionToggleAvoidResetTransform);
     CREATE_NEW_ACTION(mainWindow, actionSettings);
     CREATE_NEW_ACTION(mainWindow, actionHelp);
     CREATE_NEW_ACTION(mainWindow, actionLocateInFileManager);
@@ -104,6 +105,7 @@ void ActionManager::retranslateUi(MainWindow *mainWindow)
     actionPaste->setText(QCoreApplication::translate("MainWindow", "&Paste", nullptr));
     actionToggleStayOnTop->setText(QCoreApplication::translate("MainWindow", "Stay on top", nullptr));
     actionToggleProtectMode->setText(QCoreApplication::translate("MainWindow", "Protected mode", nullptr));
+    actionToggleAvoidResetTransform->setText("Avoid reset transform"); // TODO: what should it called?
     actionSettings->setText(QCoreApplication::translate("MainWindow", "Configure...", nullptr));
     actionHelp->setText(QCoreApplication::translate("MainWindow", "Help", nullptr));
 #ifdef Q_OS_WIN

app/actionmanager.h

@@ -42,6 +42,7 @@ public:
     QAction *actionPaste;
     QAction *actionToggleStayOnTop;
     QAction *actionToggleProtectMode;
+    QAction *actionToggleAvoidResetTransform;
     QAction *actionSettings;
     QAction *actionHelp;
     QAction *actionLocateInFileManager;

app/graphicsview.cpp

@@ -121,8 +121,10 @@ qreal GraphicsView::scaleFactor() const
 
 void GraphicsView::resetTransform()
 {
+    if (!m_avoidResetTransform) {
         QGraphicsView::resetTransform();
     }
+}
 
 void GraphicsView::zoomView(qreal scaleFactor)
 {
@@ -197,6 +199,11 @@ void GraphicsView::fitByOrientation(Qt::Orientation ori, bool scaleDownOnly)
 
 void GraphicsView::displayScene()
 {
+    if (m_avoidResetTransform) {
+        emit navigatorViewRequired(!isThingSmallerThanWindowWith(transform()), transform());
+        return;
+    }
+
     if (isSceneBiggerThanView()) {
         fitInView(sceneRect(), Qt::KeepAspectRatio);
     }
@@ -219,6 +226,16 @@ void GraphicsView::setEnableAutoFitInView(bool enable)
     m_enableFitInView = enable;
 }
 
+bool GraphicsView::avoidResetTransform() const
+{
+    return m_avoidResetTransform;
+}
+
+void GraphicsView::setAvoidResetTransform(bool avoidReset)
+{
+    m_avoidResetTransform = avoidReset;
+}
+
 inline double zeroOrOne(double number)
 {
     return qFuzzyIsNull(number) ? 0 : (number > 0 ? 1 : -1);

app/graphicsview.h

@@ -40,6 +40,9 @@ public:
     bool isSceneBiggerThanView() const;
     void setEnableAutoFitInView(bool enable = true);
 
+    bool avoidResetTransform() const;
+    void setAvoidResetTransform(bool avoidReset);
+
     static QTransform resetScale(const QTransform & orig);
 
 signals:
@@ -70,6 +73,7 @@ private:
     // ... or even more? e.g. "fit/snap width" things...
     // Currently it's "no fit" when it's false and "fit when view is smaller" when it's true.
     bool m_enableFitInView = false;
+    bool m_avoidResetTransform = false;
     bool m_checkerboardEnabled = false;
     bool m_isLastCheckerboardColorInverted = false;
 };

app/mainwindow.cpp

@@ -453,6 +453,10 @@ void MainWindow::contextMenuEvent(QContextMenuEvent *event)
     protectedMode->setCheckable(true);
     protectedMode->setChecked(m_protectedMode);
 
+    QAction * avoidResetTransform = m_am->actionToggleAvoidResetTransform;
+    avoidResetTransform->setCheckable(true);
+    avoidResetTransform->setChecked(m_graphicsView->avoidResetTransform());
+
     QAction * toggleSettings = m_am->actionSettings;
     QAction * helpAction = m_am->actionHelp;
     QAction * propertiesAction = m_am->actionProperties;
@@ -481,6 +485,9 @@ void MainWindow::contextMenuEvent(QContextMenuEvent *event)
     menu->addSeparator();
     menu->addAction(stayOnTopMode);
     menu->addAction(protectedMode);
+#if 0
+    menu->addAction(avoidResetTransform);
+#endif // 0
     menu->addSeparator();
     menu->addAction(toggleSettings);
     menu->addAction(helpAction);
@@ -545,6 +552,11 @@ void MainWindow::toggleStayOnTop()
     show();
 }
 
+void MainWindow::toggleAvoidResetTransform()
+{
+    m_graphicsView->setAvoidResetTransform(!m_graphicsView->avoidResetTransform());
+}
+
 bool MainWindow::stayOnTop() const
 {
     return windowFlags().testFlag(Qt::WindowStaysOnTopHint);
@@ -727,6 +739,11 @@ void MainWindow::on_actionToggleProtectMode_triggered()
     toggleProtectedMode();
 }
 
+void MainWindow::on_actionToggleAvoidResetTransform_triggered()
+{
+    toggleAvoidResetTransform();
+}
+
 void MainWindow::on_actionSettings_triggered()
 {
     SettingsDialog * sd = new SettingsDialog(this);

app/mainwindow.h

@@ -63,6 +63,7 @@ protected slots:
     void updateWidgetsPosition();
     void toggleProtectedMode();
     void toggleStayOnTop();
+    void toggleAvoidResetTransform();
     bool stayOnTop() const;
     bool canPaste() const;
     void quitAppAction(bool force = false);
@@ -93,6 +94,7 @@ private slots:
     void on_actionPaste_triggered();
     void on_actionToggleStayOnTop_triggered();
     void on_actionToggleProtectMode_triggered();
+    void on_actionToggleAvoidResetTransform_triggered();
     void on_actionSettings_triggered();
     void on_actionHelp_triggered();
     void on_actionProperties_triggered();