WIP: Added preliminary track dragging support

src/gui/widgets/timeline/timeline-header-container.cpp

@@ -149,12 +149,17 @@ bool TimelineHeaderContainer::on_button_press_event (
     {
     case 1: // Left Click
       // Did the user press the button on an expander?
-      if(hoveringExpander != NULL)
+      if(hoveringExpander)
         {
           // Yes? The prime for a release event
           clickedExpander = hoveringExpander;
           queue_draw();
         }
+      else if(hoveringTrack)  // Is the user hovering on a track
+        {
+          
+        }
+        
       break;
       
     case 3: // Right Click
@@ -186,6 +191,8 @@ bool TimelineHeaderContainer::on_button_press_event (
 bool TimelineHeaderContainer::on_button_release_event (
   GdkEventButton* event)
 {
+  TimelineLayoutHelper &layout = timelineWidget.layoutHelper;
+  
   // Did the user release the button on an expander?
   if(clickedExpander != NULL)
     {
@@ -194,8 +201,12 @@ bool TimelineHeaderContainer::on_button_release_event (
         clickedExpander->get_expanded() ? Track::Collapse : Track::Expand);
       clickedExpander.reset();
       
-      timelineWidget.layoutHelper.update_layout();
+      layout.update_layout();
     }
+    
+  // Has the user been dragging?
+  if(layout.get_dragging_track())
+    layout.end_dragging_track();
 
   return Container::on_button_release_event(event);    
 }
@@ -204,31 +215,50 @@ bool TimelineHeaderContainer::on_motion_notify_event (
   GdkEventMotion* event)
 {
   REQUIRE(event != NULL);
-
-  // Hit test the rectangle
-  shared_ptr<timeline::Track> header =
-    timelineWidget.layoutHelper.header_from_point(
-    Gdk::Point(event->x, event->y));
   
-  if(header)
-  {
-    const optional<Gdk::Rectangle> rect =
-      get_expander_button_rectangle(header);
+  const bool result = Container::on_motion_notify_event(event);  
+  
+  const Gdk::Point point(event->x, event->y);
+  TimelineLayoutHelper &layout = timelineWidget.layoutHelper;
+  
+  // Are we beginning to drag a header?
+  if((event->state & GDK_BUTTON1_MASK) && hoveringTrack &&
+    !hoveringExpander && !layout.get_dragging_track())
+    {
+      layout.begin_dragging_track(hoveringTrack);
+      return result;
+    }
     
-    REQUIRE(rect);
+  // Are we currently dragging?
+  if(layout.get_dragging_track())
+    {
+      layout.drag_to_point(point);
+      return result;
+    }
+  
+  // Hit test the rectangle
+  hoveringTrack = layout.header_from_point(point);
+  
+  if(hoveringTrack)
+    {
+      const optional<Gdk::Rectangle> rect =
+        get_expander_button_rectangle(hoveringTrack);
+      
+      REQUIRE(rect);
 
-    // Are we hovering on the expander?
-    if(event->x >= rect->get_x() &&
-      event->x < rect->get_x() + rect->get_width() &&
-      event->y >= rect->get_y() &&
-      event->y < rect->get_y() + rect->get_height())
-      {
-        hoveringExpander = header;
-        queue_draw();
-      }
-  }
+      // Are we hovering on the expander?
+      if(event->x >= rect->get_x() &&
+        event->x < rect->get_x() + rect->get_width() &&
+        event->y >= rect->get_y() &&
+        event->y < rect->get_y() + rect->get_height())
+        {
+          hoveringExpander = hoveringTrack;
+          queue_draw();
+        }
+      else hoveringExpander.reset();
+    }
     
-  return Container::on_motion_notify_event(event);
+  return result;
 }
 
 void

src/gui/widgets/timeline/timeline-header-container.hpp

@@ -221,6 +221,8 @@ private:
   Gtk::Menu contextMenu;
     
   //----- User Interaction State -----//
+  boost::shared_ptr<timeline::Track> hoveringTrack;
+  
   boost::shared_ptr<timeline::Track> hoveringExpander;
   
   boost::shared_ptr<timeline::Track> clickedExpander;

src/gui/widgets/timeline/timeline-layout-helper.cpp

@@ -132,6 +132,71 @@ TimelineLayoutHelper::track_from_y(int y)
   return shared_ptr<timeline::Track>();
 }
 
+void
+TimelineLayoutHelper::begin_dragging_track(
+  boost::shared_ptr<timeline::Track> track)
+{
+  REQUIRE(track);
+  draggingTrack = track;
+  g_message("begin_dragging_track");
+  
+  // Find the track in the tree
+  const shared_ptr<model::Track> model_track = track->get_model_track();
+  REQUIRE(model_track);
+  for(draggingTrackIter = layoutTree.begin();
+    draggingTrackIter != layoutTree.end();
+    draggingTrackIter++)
+    {
+      if(*draggingTrackIter == model_track)
+        break;
+    }
+}
+
+void
+TimelineLayoutHelper::end_dragging_track()
+{
+  draggingTrack.reset();
+  clone_tree_from_sequence();
+  update_layout();
+}
+
+boost::shared_ptr<timeline::Track>
+TimelineLayoutHelper::get_dragging_track() const
+{
+  return draggingTrack;
+}
+
+void
+TimelineLayoutHelper::drag_to_point(Gdk::Point point)
+{
+  // Apply the scroll offset
+  point.set_y(point.get_y() + timelineWidget.get_y_scroll_offset());
+  
+  // Search the headers
+  TrackTree::pre_order_iterator iterator;
+  for(iterator = ++layoutTree.begin(); // ++ so we miss out the root sequence
+    iterator != layoutTree.end();
+    iterator++)
+    {
+      // Hit test the rectangle      
+      const weak_ptr<timeline::Track> track = 
+        lookup_timeline_track(*iterator);
+      const Gdk::Rectangle &rect = headerBoxes[track];
+      
+      if(point.get_x() >= rect.get_x() &&
+        point.get_x() < rect.get_x() + rect.get_width() &&
+        point.get_y() >= rect.get_y() &&
+        point.get_y() < rect.get_y() + rect.get_height())
+        {
+          // Relocate the header
+          draggingTrackIter = layoutTree.move_after(
+            iterator, draggingTrackIter);
+          update_layout();
+          return;
+        }
+    }
+}
+
 int
 TimelineLayoutHelper::get_total_height() const
 {

src/gui/widgets/timeline/timeline-layout-helper.hpp

@@ -127,6 +127,14 @@ public:
    **/
   boost::shared_ptr<timeline::Track> track_from_y(int y);
   
+  void begin_dragging_track(boost::shared_ptr<timeline::Track> track);
+  
+  void end_dragging_track();
+  
+  boost::shared_ptr<timeline::Track> get_dragging_track() const;
+  
+  void drag_to_point(Gdk::Point point);
+  
   /**
    * Returns the total height in pixels of the layout tree.
    * @remarks This function is only on returns a valid value fter
@@ -228,6 +236,10 @@ protected:
    **/
   int totalHeight;
   
+  TrackTree::pre_order_iterator draggingTrackIter;
+  
+  boost::shared_ptr<timeline::Track> draggingTrack;
+  
   /**
    * The connection to the animation timer.
    * @see begin_animation()