Define a base class that will be useful for several track control buttons

src/tracks/ui/ButtonHandle.cpp

@@ -0,0 +1,111 @@
+/**********************************************************************
+
+Audacity: A Digital Audio Editor
+
+ButtonHandle.cpp
+
+Paul Licameli
+
+**********************************************************************/
+
+#include "ButtonHandle.h"
+#include "../../HitTestResult.h"
+#include "../../Project.h"
+#include "../../RefreshCode.h"
+#include "../../Track.h"
+#include "../../TrackPanelMouseEvent.h"
+#include "../ui/TrackControls.h"
+
+ButtonHandle::ButtonHandle(int dragCode)
+   : mDragCode(dragCode)
+{
+}
+
+ButtonHandle::~ButtonHandle()
+{
+}
+
+HitTestPreview ButtonHandle::HitPreview()
+{
+   // No special message or cursor
+   return {};
+}
+
+UIHandle::Result ButtonHandle::Click
+(const TrackPanelMouseEvent &evt, AudacityProject *)
+{
+   const wxMouseEvent &event = evt.event;
+   using namespace RefreshCode;
+   if (!event.Button(wxMOUSE_BTN_LEFT))
+      return Cancelled;
+
+   // Come here for left click or double click
+   if (mRect.Contains(event.m_x, event.m_y)) {
+      mpTrack = static_cast<TrackControls*>(evt.pCell)->GetTrack();
+      TrackControls::gCaptureState = mDragCode;
+      // Toggle visible button state
+      return RefreshCell;
+   }
+   else
+      return Cancelled;
+}
+
+UIHandle::Result ButtonHandle::Drag
+(const TrackPanelMouseEvent &evt, AudacityProject *)
+{
+   const wxMouseEvent &event = evt.event;
+   using namespace RefreshCode;
+   const int newState =
+      mRect.Contains(event.m_x, event.m_y) ? mDragCode : 0;
+   if (TrackControls::gCaptureState == newState)
+      return RefreshNone;
+   else {
+      TrackControls::gCaptureState = newState;
+      return RefreshCell;
+   }
+}
+
+HitTestPreview ButtonHandle::Preview
+(const TrackPanelMouseEvent &, const AudacityProject *)
+{
+   // No special message or cursor
+   return {};
+}
+
+UIHandle::Result ButtonHandle::Release
+(const TrackPanelMouseEvent &evt, AudacityProject *pProject,
+ wxWindow *pParent)
+{
+   using namespace RefreshCode;
+   Result result = RefreshNone;
+   const wxMouseEvent &event = evt.event;
+   if (TrackControls::gCaptureState) {
+      TrackControls::gCaptureState = 0;
+      result = RefreshCell;
+   }
+   if (mpTrack && mRect.Contains(event.m_x, event.m_y))
+      result |= CommitChanges(event, pProject, pParent);
+   return result;
+}
+
+UIHandle::Result ButtonHandle::Cancel(AudacityProject *pProject)
+{
+   using namespace RefreshCode;
+   if (TrackControls::gCaptureState) {
+      TrackControls::gCaptureState = 0;
+      return RefreshCell;
+   }
+   else
+      return RefreshNone;
+}
+
+void ButtonHandle::OnProjectChange(AudacityProject *pProject)
+{
+   if (! pProject->GetTracks()->Contains(mpTrack)) {
+      mpTrack = nullptr;
+      mRect = {};
+   }
+
+   UIHandle::OnProjectChange(pProject);
+}
+

src/tracks/ui/ButtonHandle.h

@@ -0,0 +1,63 @@
+/**********************************************************************
+
+Audacity: A Digital Audio Editor
+
+ButtonHandle.h
+
+Paul Licameli
+
+**********************************************************************/
+
+#ifndef __AUDACITY_BUTTON_HANDLE__
+#define __AUDACITY_BUTTON_HANDLE__
+
+#include "../../UIHandle.h"
+
+class wxMouseEvent;
+#include <wx/gdicmn.h>
+
+class Track;
+
+class ButtonHandle /* not final */ : public UIHandle
+{
+   ButtonHandle(const ButtonHandle&) = delete;
+   ButtonHandle &operator=(const ButtonHandle&) = delete;
+
+protected:
+   explicit ButtonHandle(int dragCode);
+   virtual ~ButtonHandle();
+
+   // This new abstract virtual simplifies the duties of further subclasses.
+   // This class will decide whether to refresh the clicked cell for button state
+   // change.
+   // Subclass can decide to refresh other things and the results will be ORed.
+   virtual Result CommitChanges
+      (const wxMouseEvent &event, AudacityProject *pProject, wxWindow *pParent) = 0;
+
+   // For derived class to define hit tests
+   static HitTestPreview HitPreview();
+
+   Result Click
+      (const TrackPanelMouseEvent &event, AudacityProject *pProject) override;
+
+   Result Drag
+      (const TrackPanelMouseEvent &event, AudacityProject *pProject) override;
+
+   HitTestPreview Preview
+      (const TrackPanelMouseEvent &event, const AudacityProject *pProject)
+      override;
+
+   Result Release
+      (const TrackPanelMouseEvent &event, AudacityProject *pProject,
+       wxWindow *pParent) override;
+
+   Result Cancel(AudacityProject *pProject) override;
+
+   void OnProjectChange(AudacityProject *pProject) override;
+
+   wxRect mRect {};
+   Track *mpTrack {};
+   const int mDragCode;
+};
+
+#endif