WIP: Added keep-above code

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

@@ -183,7 +183,7 @@ bool TimelineHeaderContainer::on_button_release_event (
   
   // Has the user been dragging?
   if(layout.get_dragging_track())
-    layout.end_dragging_track();
+    end_drag();
 
   return Container::on_button_release_event(event);    
 }
@@ -208,7 +208,7 @@ bool TimelineHeaderContainer::on_motion_notify_event (
   if((event->state & GDK_BUTTON1_MASK) && hoveringTrack &&
     !layout.get_dragging_track())
     {
-      layout.begin_dragging_track(mousePoint);
+      begin_drag();      
       return result;
     }
     
@@ -400,6 +400,66 @@ TimelineHeaderContainer::lookup_timeline_track(
   return timeline_track;
 }
 
+void
+TimelineHeaderContainer::begin_drag()
+{
+  TimelineLayoutHelper &layout = timelineWidget.layoutHelper;
+  
+  shared_ptr<timeline::Track> dragging_track =
+    layout.begin_dragging_track(mousePoint);
+  ENSURE(dragging_track); // Something strange has happened if we
+                          // were somehow not hovering on a track
+
+  const TimelineLayoutHelper::TrackTree::pre_order_iterator node =
+    layout.iterator_from_track(dragging_track->get_model_track());
+  set_keep_above_recursive(node, true);
+}
+
+void
+TimelineHeaderContainer::end_drag()
+{ 
+  TimelineLayoutHelper &layout = timelineWidget.layoutHelper;
+  
+  shared_ptr<timeline::Track> dragging_track =
+    layout.get_dragging_track();
+  ENSURE(dragging_track); // Something strange has happened if we
+                          // were somehow not dragging on a track  
+
+  const TimelineLayoutHelper::TrackTree::pre_order_iterator node =
+    layout.iterator_from_track(dragging_track->get_model_track());
+  set_keep_above_recursive(node, false);
+  
+  layout.end_dragging_track();
+}
+
+void
+TimelineHeaderContainer::set_keep_above_recursive(
+  TimelineLayoutHelper::TrackTree::iterator_base node,
+  const bool keep_above)
+{
+  TimelineLayoutHelper::TrackTree::pre_order_iterator iter;
+  
+  const TimelineLayoutHelper::TrackTree &layout_tree =
+    timelineWidget.layoutHelper.get_layout_tree();
+    
+  shared_ptr<timeline::Track> timeline_track =
+    lookup_timeline_track(*node);
+  REQUIRE(timeline_track);
+
+  Glib::RefPtr<Gdk::Window> window =
+    timeline_track->get_header_widget().get_window();
+  ENSURE(window); // Something strange has happened if there was no
+                  // window
+  window->set_keep_above(keep_above);
+  
+  for(iter = layout_tree.begin(node);
+    iter != layout_tree.end(node);
+    iter++)
+    {
+      set_keep_above_recursive(iter, keep_above);
+    }
+}
+
 void
 TimelineHeaderContainer::begin_scroll_slide(int scroll_slide_rate)
 {

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

@@ -29,6 +29,7 @@
 #define HEADER_CONTAINER_HPP
 
 #include "../../gtk-lumiera.hpp"
+#include "timeline-layout-helper.hpp"
 
 namespace gui {
   
@@ -182,6 +183,15 @@ private:
   boost::shared_ptr<timeline::Track> lookup_timeline_track(
     boost::shared_ptr<model::Track> model_track);
     
+  void begin_drag();
+  
+  
+  void end_drag();
+  
+  void set_keep_above_recursive(
+    TimelineLayoutHelper::TrackTree::iterator_base node,
+    const bool keep_above);
+    
   /**
    * Begins, or continues a scroll slide at a given rate
    * @param scroll_slide_rate The distance to slide every timer event

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

@@ -128,13 +128,13 @@ TimelineLayoutHelper::track_from_y(int y)
   return shared_ptr<timeline::Track>();
 }
 
-bool
+shared_ptr<timeline::Track>
 TimelineLayoutHelper::begin_dragging_track(
   const Gdk::Point &mouse_point)
 {
   draggingTrack = header_from_point(mouse_point);
   if(!draggingTrack)
-    return false;
+    return shared_ptr<timeline::Track>();
     
   const Gdk::Rectangle &rect = headerBoxes[draggingTrack];
   dragStartOffset = Gdk::Point(
@@ -142,19 +142,11 @@ TimelineLayoutHelper::begin_dragging_track(
     mouse_point.get_y() - rect.get_y() +
       timelineWidget.get_y_scroll_offset());
   
-  // Find the track in the tree
   const shared_ptr<model::Track> model_track =
     draggingTrack->get_model_track();
-  REQUIRE(model_track);
-  for(draggingTrackIter = layoutTree.begin();
-    draggingTrackIter != layoutTree.end();
-    draggingTrackIter++)
-    {
-      if(*draggingTrackIter == model_track)
-        break;
-    }
+  draggingTrackIter = iterator_from_track(model_track);
     
-  return true;
+  return draggingTrack;
 }
 
 void
@@ -212,6 +204,22 @@ TimelineLayoutHelper::is_animating() const
   return animating;
 }
 
+TimelineLayoutHelper::TrackTree::pre_order_iterator
+TimelineLayoutHelper::iterator_from_track(
+  boost::shared_ptr<model::Track> model_track)
+{
+  REQUIRE(model_track);
+  
+  TrackTree::pre_order_iterator iter;
+  for(iter = layoutTree.begin(); iter != layoutTree.end(); iter++)
+    {
+      if(*iter == model_track)
+        break;
+    }
+    
+  return iter;
+}
+
 void
 TimelineLayoutHelper::update_layout()
 {

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

@@ -127,7 +127,8 @@ public:
    **/
   boost::shared_ptr<timeline::Track> track_from_y(int y);
   
-  bool begin_dragging_track(const Gdk::Point &mouse_point);
+  boost::shared_ptr<timeline::Track>
+    begin_dragging_track(const Gdk::Point &mouse_point);
   
   void end_dragging_track();
   
@@ -144,6 +145,16 @@ public:
   int get_total_height() const;
   
   bool is_animating() const;
+
+  /**
+   * A utility function which finds the iterator of a track in the
+   * layout tree.
+   * @param model_track The model track to look for.
+   * @return Returns the model iterator of layoutTree.end() if no
+   * iterator was found.
+   **/
+  TrackTree::pre_order_iterator iterator_from_track(
+    boost::shared_ptr<model::Track> model_track);
   
 protected: