feat: animation pause and manually step to next frame

Resolve: https://github.com/BLumia/pineapple-pictures/issues/85

app/actionmanager.cpp

@@ -61,6 +61,9 @@ void ActionManager::setupAction(MainWindow *mainWindow)
     CREATE_NEW_ACTION(mainWindow, actionPrevPicture);
     CREATE_NEW_ACTION(mainWindow, actionNextPicture);
 
+    CREATE_NEW_ACTION(mainWindow, actionTogglePauseAnimation);
+    CREATE_NEW_ACTION(mainWindow, actionAnimationNextFrame);
+
     CREATE_NEW_THEMEICON_ACTION(mainWindow, actionOpen, document-open);
     CREATE_NEW_ACTION(mainWindow, actionHorizontalFlip);
     CREATE_NEW_ACTION(mainWindow, actionFitInView);
@@ -102,6 +105,9 @@ void ActionManager::retranslateUi(MainWindow *mainWindow)
     actionPrevPicture->setText(QCoreApplication::translate("MainWindow", "Previous image", nullptr));
     actionNextPicture->setText(QCoreApplication::translate("MainWindow", "Next image", nullptr));
 
+    actionTogglePauseAnimation->setText(QCoreApplication::translate("MainWindow", "Pause/Resume Animation", nullptr));
+    actionAnimationNextFrame->setText(QCoreApplication::translate("MainWindow", "Animation Go to Next Frame", nullptr));
+
     actionHorizontalFlip->setText(QCoreApplication::translate("MainWindow", "Flip &Horizontally", nullptr));
     actionFitInView->setText(QCoreApplication::translate("MainWindow", "Fit to view", nullptr));
     actionFitByWidth->setText(QCoreApplication::translate("MainWindow", "Fit to width", nullptr));

app/actionmanager.h

@@ -35,6 +35,9 @@ public:
     QAction *actionPrevPicture;
     QAction *actionNextPicture;
 
+    QAction *actionTogglePauseAnimation;
+    QAction *actionAnimationNextFrame;
+
     QAction *actionHorizontalFlip;
     QAction *actionFitInView;
     QAction *actionFitByWidth;

app/graphicsscene.cpp

@@ -21,6 +21,9 @@ public:
         : QGraphicsPixmapItem(pixmap, parent)
     {}
 
+    enum { Type = UserType + 1 };
+    int type() const override { return Type; }
+
     void setScaleHint(float scaleHint) {
         m_scaleHint = scaleHint;
     }
@@ -61,6 +64,9 @@ class PGraphicsMovieItem : public QGraphicsItem
 public:
     PGraphicsMovieItem(QGraphicsItem *parent = nullptr) : QGraphicsItem(parent) {}
 
+    enum { Type = UserType + 2 };
+    int type() const override { return Type; }
+
     void setMovie(QMovie* movie) {
         if (m_movie) m_movie->disconnect();
         m_movie.reset(movie);
@@ -80,6 +86,10 @@ public:
         }
     }
 
+    inline QMovie * movie() const {
+        return m_movie.data();
+    }
+
 private:
     QScopedPointer<QMovie> m_movie;
 };
@@ -158,6 +168,29 @@ bool GraphicsScene::trySetTransformationMode(Qt::TransformationMode mode, float
     return false;
 }
 
+bool GraphicsScene::togglePauseAnimation()
+{
+    PGraphicsMovieItem * animatedItem = qgraphicsitem_cast<PGraphicsMovieItem *>(m_theThing);
+    if (animatedItem) {
+        animatedItem->movie()->setPaused(animatedItem->movie()->state() != QMovie::Paused);
+        return true;
+    }
+    return false;
+}
+
+bool GraphicsScene::skipAnimationFrame(int delta)
+{
+    PGraphicsMovieItem * animatedItem = qgraphicsitem_cast<PGraphicsMovieItem *>(m_theThing);
+    if (animatedItem) {
+        const int frameCount = animatedItem->movie()->frameCount();
+        const int currentFrame = animatedItem->movie()->currentFrameNumber();
+        const int targetFrame = (currentFrame + delta) % frameCount;
+        animatedItem->movie()->setPaused(true);
+        return animatedItem->movie()->jumpToFrame(targetFrame);
+    }
+    return false;
+}
+
 QPixmap GraphicsScene::renderToPixmap()
 {
     PGraphicsPixmapItem * pixmapItem = qgraphicsitem_cast<PGraphicsPixmapItem *>(m_theThing);

app/graphicsscene.h

@@ -21,10 +21,13 @@ public:
 
     bool trySetTransformationMode(Qt::TransformationMode mode, float scaleHint);
 
+    bool togglePauseAnimation();
+    bool skipAnimationFrame(int delta = 1);
+
     QPixmap renderToPixmap();
 
 private:
-    QGraphicsItem * m_theThing;
+    QGraphicsItem * m_theThing = nullptr;
 };
 
 #endif // GRAPHICSSCENE_H

app/mainwindow.cpp

@@ -801,6 +801,16 @@ void MainWindow::on_actionNextPicture_triggered()
     galleryNext();
 }
 
+void MainWindow::on_actionTogglePauseAnimation_triggered()
+{
+    m_graphicsView->scene()->togglePauseAnimation();
+}
+
+void MainWindow::on_actionAnimationNextFrame_triggered()
+{
+    m_graphicsView->scene()->skipAnimationFrame(1);
+}
+
 void MainWindow::on_actionToggleStayOnTop_triggered()
 {
     toggleStayOnTop();

app/mainwindow.h

@@ -92,6 +92,9 @@ private slots:
     void on_actionPrevPicture_triggered();
     void on_actionNextPicture_triggered();
 
+    void on_actionTogglePauseAnimation_triggered();
+    void on_actionAnimationNextFrame_triggered();
+
     void on_actionHorizontalFlip_triggered();
     void on_actionFitInView_triggered();
     void on_actionFitByWidth_triggered();