TrackPanel no longer implements other mouse wheel actions

src/tracks/ui/CommonTrackPanelCell.cpp

@@ -10,8 +10,120 @@ Paul Licameli split from TrackPanel.cpp
 
 #include "../../Audacity.h"
 #include "CommonTrackPanelCell.h"
+#include "Scrubbing.h"
+
+#include "../../Experimental.h"
 #include "../../HitTestResult.h"
+#include "../../Project.h"
+#include "../../RefreshCode.h"
+#include "../../Track.h"
+#include "../../TrackPanel.h"
+#include "../../TrackPanelMouseEvent.h"
 
 CommonTrackPanelCell::~CommonTrackPanelCell()
 {
 }
+
+unsigned CommonTrackPanelCell::HandleWheelRotation
+(const TrackPanelMouseEvent &evt, AudacityProject *pProject)
+{
+   using namespace RefreshCode;
+
+   if (pProject->GetTracks()->IsEmpty())
+      // Scrolling and Zoom in and out commands are disabled when there are no tracks.
+      // This should be disabled too for consistency.  Otherwise
+      // you do see changes in the time ruler.
+      return Cancelled;
+
+   unsigned result = RefreshAll;
+   const wxMouseEvent &event = evt.event;
+   ViewInfo &viewInfo = pProject->GetViewInfo();
+   Scrubber &scrubber = pProject->GetScrubber();
+   const auto steps = evt.steps;
+
+   if (event.ShiftDown()
+       // Don't pan during smooth scrolling.  That would conflict with keeping
+       // the play indicator centered.
+       && !scrubber.IsScrollScrubbing()
+      )
+   {
+      // MM: Scroll left/right when used with Shift key down
+      pProject->TP_ScrollWindow(
+         viewInfo.OffsetTimeByPixels(
+            viewInfo.PositionToTime(0), 50.0 * -steps));
+   }
+   else if (event.CmdDown())
+   {
+#if 0
+         // JKC: Alternative scroll wheel zooming code
+         // using AudacityProject zooming, which is smarter,
+         // it keeps selections on screen and centred if it can,
+         // also this ensures mousewheel and zoom buttons give same result.
+         double ZoomFactor = pow(2.0, steps);
+         AudacityProject *p = GetProject();
+         if( steps > 0 )
+            p->ZoomInByFactor( ZoomFactor );
+         else
+            p->ZoomOutByFactor( ZoomFactor );
+#endif
+      // MM: Zoom in/out when used with Control key down
+      // We're converting pixel positions to times,
+      // counting pixels from the left edge of the track.
+      int trackLeftEdge = pProject->GetTrackPanel()->GetLeftOffset();
+
+      // Time corresponding to mouse position
+      wxCoord xx;
+      double center_h;
+      if (scrubber.IsScrollScrubbing()) {
+         // Expand or contract about the center, ignoring mouse position
+         center_h = viewInfo.h + (pProject->GetScreenEndTime() - viewInfo.h) / 2.0;
+         xx = viewInfo.TimeToPosition(center_h, trackLeftEdge);
+      }
+      else
+      {
+         xx = event.m_x;
+         center_h = viewInfo.PositionToTime(xx, trackLeftEdge);
+      }
+      // Time corresponding to last (most far right) audio.
+      double audioEndTime = pProject->GetTracks()->GetEndTime();
+
+      // When zooming in in empty space, it's easy to 'lose' the waveform.
+      // This prevents it.
+      // IF zooming in
+      if (steps > 0)
+      {
+         // IF mouse is to right of audio
+         if (center_h > audioEndTime)
+            // Zooming brings far right of audio to mouse.
+            center_h = audioEndTime;
+      }
+
+      viewInfo.ZoomBy(pow(2.0, steps));
+
+      double new_center_h = viewInfo.PositionToTime(xx, trackLeftEdge);
+      viewInfo.h += (center_h - new_center_h);
+
+      result |= FixScrollbars;
+   }
+   else
+   {
+#ifdef EXPERIMENTAL_SCRUBBING_SCROLL_WHEEL
+      if (scrubber.IsScrubbing()) {
+         scrubber.HandleScrollWheel(steps);
+         evt.event.Skip(false);
+      }
+      else
+#endif
+      {
+         // MM: Scroll up/down when used without modifier keys
+         double lines = steps * 4 + mVertScrollRemainder;
+         mVertScrollRemainder = lines - floor(lines);
+         lines = floor(lines);
+         auto didSomething = pProject->TP_ScrollUpDown((int)-lines);
+         if (!didSomething)
+            result |= Cancelled;
+      }
+   }
+
+   return result;
+}

src/tracks/ui/CommonTrackPanelCell.h

@@ -20,13 +20,21 @@ class AUDACITY_DLL_API CommonTrackPanelCell /* not final */
    : public TrackPanelCell
 {
 public:
-   CommonTrackPanelCell() {}
+   CommonTrackPanelCell()
+      : mVertScrollRemainder(0.0)
+   {}
 
    virtual ~CommonTrackPanelCell() = 0;
 
    virtual Track *FindTrack() = 0;
 
 protected:
+   unsigned HandleWheelRotation
+      (const TrackPanelMouseEvent &event,
+      AudacityProject *pProject) override;
+
+private:
+   double mVertScrollRemainder;
 };
 
 #endif