Review the new TimelineZoomScale widget code

src/gui/panels/timeline-panel.cpp

@@ -124,6 +124,7 @@ TimelinePanel::TimelinePanel (workspace::PanelManager &panel_manager,
 
   zoomIn          .set_tooltip_text(_("Zoom in"));
   zoomOut         .set_tooltip_text(_("Zoom out"));
+  zoomScale       .set_tooltip_text(_("Adjust timeline zoom scale"));
 
   // Setup the timeline widget
   shared_ptr<Sequence> sequence          ///////////////////////////////TICKET #796

src/gui/widgets/timeline/timeline-body.cpp

@@ -264,7 +264,7 @@ TimelineBody::on_motion_notify_event(GdkEventMotion *event)
           {
             TimelineViewWindow &window = view_window();
             
-                                   /////////////////////////////TICKET# 795 : don't reach in from outside and manipulate internals of the timeline view!
+                                   /////////////////////////////TICKET #795 : don't reach in from outside and manipulate internals of the timeline view!
                                    /////////////////////////////            : either encapsulate this entirely here, or leave it to the timeline view!            
             const int64_t scale = window.get_time_scale();
             window.set_time_offset(beginShiftTimeOffset

src/gui/widgets/timeline/timeline-view-window.cpp

@@ -38,20 +38,20 @@ TimelineViewWindow::TimelineViewWindow (Offset offset, int64_t scale)
 }
 
 Offset
-TimelineViewWindow::get_time_offset() const      /////////////////////TODO: this function shouldn't be accessible from outside
+TimelineViewWindow::get_time_offset() const      /////////////////////TICKET #795: this function shouldn't be accessible from outside
 {
   return Offset (timeOffset);
 }
 
 void
-TimelineViewWindow::set_time_offset(TimeValue const& offset) /////////TODO: this function shouldn't be accessible from outside
+TimelineViewWindow::set_time_offset(TimeValue const& offset) /////////TICKET #795: this function shouldn't be accessible from outside
 {
   timeOffset = offset;
   changedSignal.emit();
 }
 
 int64_t
-TimelineViewWindow::get_time_scale() const       /////////////////////TODO: this function shouldn't be accessible from outside
+TimelineViewWindow::get_time_scale() const       /////////////////////TICKET #795: this function shouldn't be accessible from outside
 {
   return timeScale;
 }
@@ -64,21 +64,11 @@ TimelineViewWindow::set_time_scale(int64_t scale)
 }
 
 void
-TimelineViewWindow::zoom_view(int point, int64_t zoom_scale)
+TimelineViewWindow::zoom_view(int point, int64_t new_time_scale)
 {
-  int64_t new_time_scale = zoom_scale;
-
   // Limit zooming in too close
   if(new_time_scale < 1) new_time_scale = 1;
 
- /* Not sure if this is still needed. MRF
-  *  // Nudge zoom problems caused by integer rounding
-  if(new_time_scale == timeScale && zoom_size < 0)
-    new_time_scale++;
-  */
-  
-  // Limit to Min and Max scale code moved to timeline-zoom-scale.cpp
-
   // The view must be shifted so that the zoom is centred on the cursor
   TimeVar newStartPoint = get_time_offset();
   newStartPoint += TimeValue(point * (timeScale - new_time_scale));

src/gui/widgets/timeline/timeline-view-window.hpp

@@ -98,10 +98,10 @@ public:
   /**
    * Zooms the view in or out as by a number of steps while keeping a 
    * given point on the timeline still.
-   * @param zoom_size The number of steps to zoom by. The scale factor
-   * is 1.25^(-zoom_size).
+   * @param new_time_scale The number of steps to zoom by. The scale factor
+   * is 1.25^(-new_time_scale).
    */
-  void zoom_view(int point, int64_t zoom_size);
+  void zoom_view(int point, int64_t new_time_scale);
   
   /**
    * Scrolls the view horizontally as a proportion of the view area.

src/gui/widgets/timeline/timeline-zoom-scale.cpp

@@ -33,12 +33,27 @@ class TimelineWidget;
 namespace timeline {
 
 /**
- * TODO: The initial adjustment value needs to
+ * @todo The initial adjustment value needs to
  * match what the TimelineViewWindow's actual timeScale
  * Value is. TimelineViewWindow::get_time_scale() is
  * currently a public method, but will soon be private.
  * Maybe TimelineViewWindow can have a zoom_adjustment
  * that gets passed to this widget's Constructor?
+ * 
+ * @todo actually there is a more involved problem.
+ * The TimelineWidget maintains a TimelineState, which in turn
+ * owns the TimelineViewWindow. Now, the problem is: when we
+ * switch to another Sequence (View), then this TimelineState
+ * gets switched too, causing also a entirely different TimelineViewWindow
+ * to become effective. Thus
+ * - how can we managed to be notified from that switch?
+ * - problem is: TimelineZoomScale widget is owned by the TimelinePannel.
+ *   Likewise, TimelineWidget is owned by the TimelinePannel. But the
+ *   state handling/switching logic is embedded within TimelineWidget
+ * - and finally: how can we translate the actual scale (in time units),
+ *   as maintained within TimelineViewWindow, back into the adjustment
+ *   used here (which uses a relative scale 0...1.0 ) 
+ * 
  */
 
 TimelineZoomScale::TimelineZoomScale()