refactor zoom smothing into TimelineViewWindow

src/gui/widgets/timeline-widget.cpp

@@ -41,9 +41,7 @@ namespace widgets {
 const int TimelineWidget::TrackPadding = 1;
 const int TimelineWidget::HeaderWidth = 150;
 const int TimelineWidget::HeaderIndentWidth = 10;
-const double TimelineWidget::ZoomIncrement = 1.25; // Not currently used
-const double TimelineWidget::ZoomSmoothing = 9.0;
-const int64_t TimelineWidget::MaxScale = 30000000; // 30 Million
+
 
 TimelineWidget::TimelineWidget(shared_ptr<timeline::TimelineState> source_state)
   : Table(2, 2)

src/gui/widgets/timeline-widget.hpp

@@ -278,20 +278,10 @@ protected:
   bool update_tracks_frozen;
    
   /* ===== Constants ===== */
-public:
-  /**
-   * The maximum scale for timeline display.
-   * @remarks At MaxScale, every pixel on the timeline is equivalent
-   * to 30000000 lumiera::Time increments.
-   */ 
-  static const int64_t MaxScale;
-  static const double ZoomSmoothing;
-  
 protected:
   static const int TrackPadding;
   static const int HeaderWidth;
   static const int HeaderIndentWidth;
-  static const double ZoomIncrement;
 
   friend class timeline::TimelineBody;
   friend class timeline::TimelineHeaderContainer;

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

@@ -31,6 +31,14 @@ namespace gui {
 namespace widgets {
 namespace timeline {
 
+/* == public constants == */
+  
+const int64_t TimelineViewWindow::MaxScale = 30000000; // 30 Million
+const double TimelineViewWindow::ZoomIncrement = 1.25; // Not currently used
+const double TimelineViewWindow::ZoomSmoothing = 9.0;
+
+
+
 TimelineViewWindow::TimelineViewWindow (Offset offset, int64_t scale)
   : timeOffset(offset)
   , timeScale(scale)
@@ -67,7 +75,7 @@ TimelineViewWindow::set_time_scale(int64_t scale)
 void
 TimelineViewWindow::set_time_scale(double ratio)
 {
-  int64_t max = TimelineWidget::MaxScale;
+  int64_t max = MaxScale;
   int64_t min = 1;
 
   if(ratio <= 0.0)
@@ -84,19 +92,28 @@ TimelineViewWindow::set_time_scale(double ratio)
    set_time_scale((int64_t)(ratio * max));
 }
 
+double
+TimelineViewWindow::get_smoothed_time_scale()  const
+{
+  double linear_scale ( 1.0 / MaxScale * timeScale);
+
+  // reverse the effect of zoom scale smoothing
+  return pow (linear_scale, (1.0 / ZoomSmoothing));
+}
+
 void
 TimelineViewWindow::zoom_view(int point, double time_scale_ratio)
 {
   // Apply the smoothing factor
-  int64_t new_time_scale(pow (time_scale_ratio, TimelineWidget::ZoomSmoothing)
-                         * double(TimelineWidget::MaxScale));
+  int64_t new_time_scale(pow (time_scale_ratio, ZoomSmoothing)
+                         * double(MaxScale));
 
   /* Prevent Zooming in To Close and Far */
   if(new_time_scale < 1)
     new_time_scale = 1;
 
-  if(new_time_scale > TimelineWidget::MaxScale)
-    new_time_scale = TimelineWidget::MaxScale;
+  if(new_time_scale > MaxScale)
+    new_time_scale = MaxScale;
 
   // The view must be shifted so that the zoom is centred on the cursor
   TimeVar newStartPoint = timeOffset + TimeValue(point * (timeScale - new_time_scale));

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

@@ -54,6 +54,16 @@ using lib::time::Offset;
 class TimelineViewWindow
 {
 public:
+    
+  /**
+   * The maximum scale for timeline display.
+   * @remarks At MaxScale, every pixel on the timeline is equivalent
+   * to 30000000 lumiera::Time increments.
+   */ 
+  static const int64_t MaxScale;
+  static const double ZoomSmoothing;
+  static const double ZoomIncrement;
+  
  
   /**
    * @param offset The initial view offset.
@@ -95,6 +105,10 @@ public:
    */
   void set_time_scale(int64_t time_scale);
   void set_time_scale(double ratio);
+  
+  /** get the current time scale with zoom smoothing applied */
+  double get_smoothed_time_scale()  const;
+  
   /**
    * Zooms the view in or out as by a number of steps while keeping a 
    * given point on the timeline still.

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

@@ -102,21 +102,10 @@ TimelineZoomScale::wireTimelineState (shared_ptr<TimelineState> currentState,
 void
 TimelineZoomScale::on_timeline_state_changed (shared_ptr<TimelineState> newState)
 {
-                                     /////////////////////////////TICKET #861 : part of that could be a library routine!
   REQUIRE (newState);
   timelineState = newState;
   
-  int64_t current_scale =
-      getViewWindow().get_time_scale();
-
-  double linear_scale =
-      (double) current_scale / (double) TimelineWidget::MaxScale;
-
-  /* We have to Revese the Smoothing */
-  double new_relative_scale =
-      pow(linear_scale,(1.0 / TimelineWidget::ZoomSmoothing));
-
-  adjustment.set_value(new_relative_scale);
+  adjustment.set_value (getViewWindow().get_smoothed_time_scale());
 }
 
 void