Support timeline zooming & panning with mouse

Timeline can be zoomed and panned using ALT + mouse as specified
by design.

Task-number: QT3DS-1585
Change-Id: I97c49e3e3f61564a840521d51bb8cf95f4fbccd3
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>

4 files changed, 51 insertions, 8 deletions

diff --git a/src/Authoring/Studio/Palettes/TimelineGraphicsView/TimelineGraphicsScene.cpp b/src/Authoring/Studio/Palettes/TimelineGraphicsView/TimelineGraphicsScene.cpp
index 16b7a20e..37d3700f 100644
--- a/src/Authoring/Studio/Palettes/TimelineGraphicsView/TimelineGraphicsScene.cpp
+++ b/src/Authoring/Studio/Palettes/TimelineGraphicsView/TimelineGraphicsScene.cpp
@@ -84,6 +84,7 @@ TimelineGraphicsScene::TimelineGraphicsScene(TimelineWidget *timelineWidget)
     , m_rowManager(new RowManager(this, m_layoutTree, m_layoutTimeline))
     , m_keyframeManager(new KeyframeManager(this))
     , m_pressPos(invalidPoint)
+    , m_pressScreenPos(invalidPoint)
     , m_timelineControl(new TimelineControl(this))
     , m_currentCursor(-1)
 {
@@ -451,6 +452,22 @@ void TimelineGraphicsScene::mousePressEvent(QGraphicsSceneMouseEvent *event)
 {
     g_StudioApp.setLastActiveView(m_widgetTimeline);
 
+    if ((event->modifiers() & Qt::AltModifier) && !m_dragging) {
+        if (event->button() == Qt::RightButton && !m_timelinePanning) {
+            // Start zooming
+            m_timelineZooming = true;
+            m_pressScreenPos = event->screenPos();
+            event->accept();
+            return;
+        } else if (event->button() == Qt::MiddleButton && !m_timelineZooming) {
+            // Start panning
+            m_timelinePanning = true;
+            m_pressPos = event->scenePos();
+            event->accept();
+            return;
+        }
+    }
+
     // Ignore non-left presses if dragging
     if (event->button() != Qt::LeftButton && (m_dragging || m_startRowMoverOnNextDrag)) {
         event->accept();
@@ -561,10 +578,30 @@ void TimelineGraphicsScene::mousePressEvent(QGraphicsSceneMouseEvent *event)
 
 void TimelineGraphicsScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
 {
+    if (m_timelineZooming) {
+        int deltaY = event->screenPos().y() - m_pressScreenPos.y();
+        int deltaX = event->screenPos().x() - m_pressScreenPos.x();
+        // Zooming in when moving down/right.
+        int delta = -deltaX - deltaY;
+        const int threshold = 20;
+        if (delta < -threshold) {
+            m_widgetTimeline->toolbar()->onZoomInButtonClicked();
+            m_pressScreenPos = event->screenPos();
+        } else if (delta > threshold) {
+            m_widgetTimeline->toolbar()->onZoomOutButtonClicked();
+            m_pressScreenPos = event->screenPos();
+        }
+    } else if (m_timelinePanning) {
+        int deltaX = event->scenePos().x() - m_pressPos.x();
+        QScrollBar *scrollbar = m_widgetTimeline->viewTimelineContent()->horizontalScrollBar();
+        scrollbar->setValue(scrollbar->value() - deltaX);
+    }
+
     if (m_editedTimelineRow.isNull())
         updateHoverStatus(event->scenePos());
 
-    if (!m_dragging && m_pressPos != invalidPoint
+    if (!m_dragging && !m_timelineZooming && !m_timelinePanning
+            && m_pressPos != invalidPoint
             && (event->scenePos() - m_pressPos).manhattanLength() > 10) {
         m_dragging = true;
     }
@@ -670,6 +707,8 @@ void TimelineGraphicsScene::resetMousePressParams()
     m_selectionRect->end();
     m_rowMover->end();
     m_dragging = false;
+    m_timelineZooming = false;
+    m_timelinePanning = false;
     m_startRowMoverOnNextDrag = false;
     m_rulerPressed = false;
     m_keyframePressed = false;
@@ -680,6 +719,7 @@ void TimelineGraphicsScene::resetMousePressParams()
     m_autoScrollTriggerTimer.stop();
     m_timebarToolTip->hide();
     m_pressPos = invalidPoint;
+    m_pressScreenPos = invalidPoint;
     m_lastAutoScrollX = -1.0;
     m_lastAutoScrollY = -1.0;
 }
@@ -768,10 +808,10 @@ void TimelineGraphicsScene::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
             if (!m_releaseSelectRow.isNull())
                 m_rowManager->selectRow(m_releaseSelectRow);
         }
-
-        resetMousePressParams();
     }
 
+    resetMousePressParams();
+
     QGraphicsScene::mouseReleaseEvent(event);
 }
 
@@ -861,10 +901,11 @@ void TimelineGraphicsScene::keyReleaseEvent(QKeyEvent *keyEvent)
 
 void TimelineGraphicsScene::contextMenuEvent(QGraphicsSceneContextMenuEvent *event)
 {
+    // No context menu if user is pressing ALT (so panning/zooming timeline)
+    bool alt = event->modifiers() & Qt::AltModifier;
     RowTree *row = m_rowManager->getRowAtPos(QPointF(0, event->scenePos().y()));
-
     if (!row || m_widgetTimeline->isFullReconstructPending() || m_dragging
-            || m_startRowMoverOnNextDrag || row->locked()) {
+            || m_startRowMoverOnNextDrag || row->locked() || alt) {
         return;
     }
 
diff --git a/src/Authoring/Studio/Palettes/TimelineGraphicsView/TimelineGraphicsScene.h b/src/Authoring/Studio/Palettes/TimelineGraphicsView/TimelineGraphicsScene.h
index 4166ca18..e452c12b 100644
--- a/src/Authoring/Studio/Palettes/TimelineGraphicsView/TimelineGraphicsScene.h
+++ b/src/Authoring/Studio/Palettes/TimelineGraphicsView/TimelineGraphicsScene.h
@@ -135,6 +135,7 @@ private:
     RowManager *m_rowManager = nullptr;
     KeyframeManager *m_keyframeManager = nullptr;
     QPointF m_pressPos;
+    QPointF m_pressScreenPos;
     QList<double> m_snapSteps;
     CMouseCursor::Qt3DSMouseCursor m_currentCursor;
     TimelineControl *m_timelineControl = nullptr;
@@ -143,6 +144,8 @@ private:
     bool m_keyframePressed = false;
     bool m_dragging = false;
     bool m_startRowMoverOnNextDrag = false;
+    bool m_timelineZooming = false;
+    bool m_timelinePanning = false;
     TimelineControlType m_clickedTimelineControlType = TimelineControlType::None;
     TreeControlType m_clickedTreeControlType = TreeControlType::None;
     double m_pressPosInKeyframe;
diff --git a/src/Authoring/Studio/Palettes/TimelineGraphicsView/ui/TimelineToolbar.cpp b/src/Authoring/Studio/Palettes/TimelineGraphicsView/ui/TimelineToolbar.cpp
index 385dda52..2bdeb2c5 100644
--- a/src/Authoring/Studio/Palettes/TimelineGraphicsView/ui/TimelineToolbar.cpp
+++ b/src/Authoring/Studio/Palettes/TimelineGraphicsView/ui/TimelineToolbar.cpp
@@ -86,7 +86,6 @@ TimelineToolbar::TimelineToolbar() : QToolBar()
     m_scaleSlider->setFixedWidth(100);
     m_scaleSlider->setMinimum(1);
     m_scaleSlider->setMaximum(22);
-    m_scaleSlider->setPageStep(.1);
     m_scaleSlider->setValue(2);
 
     m_timeLabel->setText(tr("0:00.000"));
diff --git a/src/Authoring/Studio/Palettes/TimelineGraphicsView/ui/TimelineToolbar.h b/src/Authoring/Studio/Palettes/TimelineGraphicsView/ui/TimelineToolbar.h
index 0bd37377..3e65e45d 100644
--- a/src/Authoring/Studio/Palettes/TimelineGraphicsView/ui/TimelineToolbar.h
+++ b/src/Authoring/Studio/Palettes/TimelineGraphicsView/ui/TimelineToolbar.h
@@ -74,12 +74,12 @@ public:
 
 public Q_SLOTS:
     void updatePlayButtonState(bool started);
+    void onZoomInButtonClicked();
+    void onZoomOutButtonClicked();
 
 private Q_SLOTS:
     void onPlayButtonClicked();
     void onZoomLevelChanged(int scale);
-    void onZoomInButtonClicked();
-    void onZoomOutButtonClicked();
     void onDiButtonClicked();
 
 private: