scroll only in increments when dragging the playhead

app/widget/timebased/timebasedview.h

@@ -52,6 +52,11 @@ public:
 
   static bool WheelEventIsAZoomEvent(QWheelEvent* event);
 
+  bool IsDraggingPlayhead() const
+  {
+    return dragging_playhead_;
+  }
+
 public slots:
   void SetTime(const int64_t time);
 

app/widget/timebased/timebasedwidget.cpp

@@ -183,18 +183,12 @@ void TimeBasedWidget::ScrollBarResizeMoved(int movement)
 
 void TimeBasedWidget::PageScrollToPlayhead()
 {
-  int playhead_pos = qRound(TimeToScene(GetTime()));
+  PageScrollInternal(true);
+}
 
-  int viewport_width = ruler()->width();
-  int viewport_padding = viewport_width / 16;
-
-  if (playhead_pos < scrollbar()->value()) {
-    // Anchor the playhead to the RIGHT of where we scroll to
-    scrollbar()->setValue(playhead_pos - viewport_width + viewport_padding);
-  } else if (playhead_pos > scrollbar()->value() + viewport_width) {
-    // Anchor the playhead to the LEFT of where we scroll to
-    scrollbar()->setValue(playhead_pos - viewport_padding);
-  }
+void TimeBasedWidget::CatchUpScrollToPlayhead()
+{
+  PageScrollInternal(false);
 }
 
 TimeRuler *TimeBasedWidget::ruler() const
@@ -259,8 +253,13 @@ TimelinePoints *TimeBasedWidget::GetConnectedTimelinePoints() const
   return points_;
 }
 
-void TimeBasedWidget::ConnectTimelineView(TimeBasedView *base)
+void TimeBasedWidget::ConnectTimelineView(TimeBasedView *base, bool connect_time_change_event)
 {
+  if (connect_time_change_event) {
+    connect(base, &TimeBasedView::TimeChanged, this, &TimeBasedWidget::SetTimestamp);
+    connect(base, &TimeBasedView::TimeChanged, this, &TimeBasedWidget::TimeChanged);
+  }
+
   timeline_views_.append(base);
 }
 
@@ -272,21 +271,29 @@ void TimeBasedWidget::PassWheelEventsToScrollBar(QObject *object)
 
 void TimeBasedWidget::SetTimestamp(int64_t timestamp)
 {
-  ruler_->SetTime(timestamp);
+  if (GetTime() != timestamp) {
+    if (UserIsDraggingPlayhead()) {
+      // If the user is dragging the playhead, we will simply nudge over and not use autoscroll rules.
+      QMetaObject::invokeMethod(this, "CatchUpScrollToPlayhead", Qt::QueuedConnection);
+    } else {
+      // Otherwise, assume we jumped to this out of nowhere and must now autoscroll
+      switch (static_cast<AutoScroll::Method>(Config::Current()["Autoscroll"].toInt())) {
+      case AutoScroll::kNone:
+        // Do nothing
+        break;
+      case AutoScroll::kPage:
+        QMetaObject::invokeMethod(this, "PageScrollToPlayhead", Qt::QueuedConnection);
+        break;
+      case AutoScroll::kSmooth:
+        QMetaObject::invokeMethod(this, "CenterScrollOnPlayhead", Qt::QueuedConnection);
+        break;
+      }
+    }
 
-  switch (static_cast<AutoScroll::Method>(Config::Current()["Autoscroll"].toInt())) {
-  case AutoScroll::kNone:
-    // Do nothing
-    break;
-  case AutoScroll::kPage:
-    QMetaObject::invokeMethod(this, "PageScrollToPlayhead", Qt::QueuedConnection);
-    break;
-  case AutoScroll::kSmooth:
-    QMetaObject::invokeMethod(this, "CenterScrollOnPlayhead", Qt::QueuedConnection);
-    break;
+    ruler_->SetTime(timestamp);
+
+    TimeChangedEvent(timestamp);
   }
-
-  TimeChangedEvent(timestamp);
 }
 
 void TimeBasedWidget::SetTimebase(const rational &timebase)
@@ -474,6 +481,46 @@ void TimeBasedWidget::ResetPoint(Timeline::MovementMode m)
   Core::instance()->undo_stack()->push(new WorkareaSetRangeCommand(GetTimelinePointsProject(), points_, r));
 }
 
+void TimeBasedWidget::PageScrollInternal(bool whole_page_scroll)
+{
+  int playhead_pos = qRound(TimeToScene(GetTime()));
+
+  int viewport_width = ruler()->width();
+  int viewport_padding = viewport_width / 16;
+
+  if (whole_page_scroll) {
+    if (playhead_pos < scrollbar()->value()) {
+      // Anchor the playhead to the RIGHT of where we scroll to
+      scrollbar()->setValue(playhead_pos - viewport_width + viewport_padding);
+    } else if (playhead_pos > scrollbar()->value() + viewport_width) {
+      // Anchor the playhead to the LEFT of where we scroll to
+      scrollbar()->setValue(playhead_pos - viewport_padding);
+    }
+  } else {
+    // Just jump in increments
+    if (playhead_pos < scrollbar()->value() + viewport_padding) {
+      scrollbar()->setValue(scrollbar()->value() - viewport_padding);
+    } else if (playhead_pos > scrollbar()->value() + viewport_width - viewport_padding) {
+      scrollbar()->setValue(scrollbar()->value() + viewport_padding);
+    }
+  }
+}
+
+bool TimeBasedWidget::UserIsDraggingPlayhead() const
+{
+  if (ruler_->IsDraggingPlayhead()) {
+    return true;
+  }
+
+  foreach (TimeBasedView* view, timeline_views_) {
+    if (view->IsDraggingPlayhead()) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
 void TimeBasedWidget::SetInAtPlayhead()
 {
   SetPoint(Timeline::kTrimIn, GetTime());

app/widget/timebased/timebasedwidget.h

@@ -121,7 +121,7 @@ protected:
 
   TimelinePoints* GetConnectedTimelinePoints() const;
 
-  void ConnectTimelineView(TimeBasedView* base);
+  void ConnectTimelineView(TimeBasedView* base, bool connect_time_change_event = true);
 
   void PassWheelEventsToScrollBar(QObject* object);
 
@@ -184,6 +184,10 @@ private:
    */
   void ResetPoint(Timeline::MovementMode m);
 
+  void PageScrollInternal(bool whole_page_scroll);
+
+  bool UserIsDraggingPlayhead() const;
+
   ViewerOutput* viewer_node_;
 
   TimeRuler* ruler_;
@@ -225,6 +229,8 @@ private slots:
    */
   void PageScrollToPlayhead();
 
+  void CatchUpScrollToPlayhead();
+
 };
 
 }

app/widget/timelinewidget/timelinewidget.cpp

@@ -124,7 +124,7 @@ TimelineWidget::TimelineWidget(QWidget *parent) :
 
     view_splitter_->addWidget(tview);
 
-    ConnectTimelineView(view);
+    ConnectTimelineView(view, false);
 
     connect(view->horizontalScrollBar(), &QScrollBar::valueChanged, ruler(), &TimeRuler::SetScroll);
     connect(view, &TimelineView::ScaleChanged, this, &TimelineWidget::SetScale);
@@ -1012,9 +1012,7 @@ void TimelineWidget::ViewTimestampChanged(int64_t ts)
   }
 
   // Update all other views
-  SetViewTimestamp(ts);
-
-  ruler()->SetTime(ts);
+  SetTimestamp(ts);
   emit TimeChanged(ts);
 }
 

app/widget/timeruler/seekablewidget.cpp

@@ -34,7 +34,8 @@ SeekableWidget::SeekableWidget(QWidget* parent) :
   time_(0),
   timeline_points_(nullptr),
   scroll_(0),
-  snap_service_(nullptr)
+  snap_service_(nullptr),
+  dragging_(false)
 {
   QFontMetrics fm = fontMetrics();
 
@@ -86,6 +87,7 @@ void SeekableWidget::mousePressEvent(QMouseEvent *event)
 {
   if (event->button() == Qt::LeftButton) {
     SeekToScreenPoint(event->pos().x());
+    dragging_ = true;
   }
 }
 
@@ -103,6 +105,8 @@ void SeekableWidget::mouseReleaseEvent(QMouseEvent *event)
   if (snap_service_) {
     snap_service_->HideSnaps();
   }
+
+  dragging_ = false;
 }
 
 void SeekableWidget::ScaleChangedEvent(const double &)

app/widget/timeruler/seekablewidget.h

@@ -42,6 +42,11 @@ public:
 
   void SetSnapService(SnapService* service);
 
+  bool IsDraggingPlayhead() const
+  {
+    return dragging_;
+  }
+
 public slots:
   void SetTime(const int64_t &r);
 
@@ -98,6 +103,8 @@ private:
 
   SnapService* snap_service_;
 
+  bool dragging_;
+
 };
 
 }