TrackPanel still draws Miminize and Close, but no longer handles...

clicks on them...

... also implemented ESC key for those drags

src/tracks/ui/TrackButtonHandles.cpp

@@ -0,0 +1,126 @@
+/**********************************************************************
+
+Audacity: A Digital Audio Editor
+
+TrackButtonHandles.cpp
+
+Paul Licameli split from TrackPanel.cpp
+
+**********************************************************************/
+
+#include "TrackButtonHandles.h"
+
+#include "../../HitTestResult.h"
+#include "../../Project.h"
+#include "../../RefreshCode.h"
+#include "../../Track.h"
+#include "../../TrackPanel.h"
+
+MinimizeButtonHandle::MinimizeButtonHandle()
+   : ButtonHandle{ TrackPanel::IsMinimizing }
+{
+}
+
+MinimizeButtonHandle::~MinimizeButtonHandle()
+{
+}
+
+MinimizeButtonHandle &MinimizeButtonHandle::Instance()
+{
+   static MinimizeButtonHandle instance;
+   return instance;
+}
+
+UIHandle::Result MinimizeButtonHandle::CommitChanges
+(const wxMouseEvent &, AudacityProject *pProject, wxWindow*)
+{
+   using namespace RefreshCode;
+
+   if (mpTrack)
+   {
+      mpTrack->SetMinimized(!mpTrack->GetMinimized());
+      if (mpTrack->GetLink())
+         mpTrack->GetLink()->SetMinimized(mpTrack->GetMinimized());
+      pProject->ModifyState(true);
+
+      // Redraw all tracks when any one of them expands or contracts
+      // (Could we invent a return code that draws only those at or below
+      // the affected track?)
+      return RefreshAll | FixScrollbars;
+   }
+
+   return RefreshNone;
+}
+
+HitTestResult MinimizeButtonHandle::HitTest
+(const wxMouseEvent &event, const wxRect &rect)
+{
+   wxRect buttonRect;
+   TrackInfo::GetMinimizeRect(rect, buttonRect);
+
+   if (buttonRect.Contains(event.m_x, event.m_y)) {
+      Instance().mRect = buttonRect;
+      return {
+         HitPreview(),
+         &Instance()
+      };
+   }
+   else
+      return {};
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+CloseButtonHandle::CloseButtonHandle()
+   : ButtonHandle{ TrackPanel::IsClosing }
+{
+}
+
+CloseButtonHandle::~CloseButtonHandle()
+{
+}
+
+CloseButtonHandle &CloseButtonHandle::Instance()
+{
+   static CloseButtonHandle instance;
+   return instance;
+}
+
+UIHandle::Result CloseButtonHandle::CommitChanges
+(const wxMouseEvent &, AudacityProject *pProject, wxWindow*)
+{
+   using namespace RefreshCode;
+   Result result = RefreshNone;
+
+   if (mpTrack)
+   {
+      pProject->StopIfPaused();
+      if (!pProject->IsAudioActive()) {
+         // This pushes an undo item:
+         pProject->RemoveTrack(mpTrack);
+         // Redraw all tracks when any one of them closes
+         // (Could we invent a return code that draws only those at or below
+         // the affected track?)
+         result |= Resize | RefreshAll | FixScrollbars | DestroyedCell;
+      }
+   }
+
+   return result;
+}
+
+HitTestResult CloseButtonHandle::HitTest
+(const wxMouseEvent &event, const wxRect &rect)
+{
+   wxRect buttonRect;
+   TrackInfo::GetCloseBoxRect(rect, buttonRect);
+
+   if (buttonRect.Contains(event.m_x, event.m_y)) {
+      Instance().mRect = buttonRect;
+      return {
+         HitPreview(),
+         &Instance()
+      };
+   }
+   else
+      return {};
+}