Center view when seeking to timeline clip.

Fixes #844

src/timeline2/view/qml/timeline.qml

@@ -201,6 +201,10 @@ Rectangle {
         }
         return col
     }
+    
+    function centerViewOnCursor() {
+        scrollView.contentX = Math.max(0, root.consumerPosition * timeline.scaleFactor - (scrollView.width / 2))
+    }
 
     function clearDropData() {
         clipBeingDroppedId = -1

src/timeline2/view/timelinecontroller.cpp

@@ -1653,6 +1653,7 @@ void TimelineController::focusItem(int itemId)
 {
     int start = m_model->getItemPosition(itemId);
     setPosition(start);
+    emit centerView();
 }
 
 int TimelineController::headerWidth() const

src/timeline2/view/timelinecontroller.h

@@ -697,6 +697,9 @@ signals:
     /* @brief User enabled / disabled snapping, update timeline behavior
      */
     void snapChanged();
+    /* @brief Center timeline view on current position
+     */
+    void centerView();
     Q_INVOKABLE void ungrabHack();
 };
 

src/timeline2/view/timelinetabs.cpp

@@ -87,6 +87,7 @@ void TimelineTabs::connectTimeline(TimelineWidget *timeline)
     connect(timeline->controller(), &TimelineController::updateZoom, this, [&](double value) { emit updateZoom(getCurrentTimeline()->zoomForScale(value)); });
     connect(timeline->controller(), &TimelineController::showItemEffectStack, this, &TimelineTabs::showItemEffectStack);
     connect(timeline->controller(), &TimelineController::showSubtitle, this, &TimelineTabs::showSubtitle);
+    connect(timeline->controller(), &TimelineController::centerView, timeline, &TimelineWidget::slotCenterView);
 }
 
 void TimelineTabs::disconnectTimeline(TimelineWidget *timeline)

src/timeline2/view/timelinewidget.cpp

@@ -365,6 +365,11 @@ void TimelineWidget::slotChangeZoom(int value, bool zoomOnMouse)
     m_proxy->setScaleFactorOnMouse(pixelScale / comboScale[value], zoomOnMouse);
 }
 
+void TimelineWidget::slotCenterView()
+{
+    QMetaObject::invokeMethod(rootObject(), "centerViewOnCursor");
+}
+
 void TimelineWidget::slotFitZoom()
 {
     QVariant returnedValue;

src/timeline2/view/timelinewidget.h

@@ -66,6 +66,8 @@ protected:
 public slots:
     void slotChangeZoom(int value, bool zoomOnMouse);
     void slotFitZoom();
+    /* @brief Center timeline view on current timeline cursor position */
+    void slotCenterView();
     void zoneUpdated(const QPoint &zone);
     void zoneUpdatedWithUndo(const QPoint &oldZone, const QPoint &newZone);
     /* @brief Favorite effects have changed, reload model for context menu */