TrackPanel no longer implements the zoom tool...

... Also changed the behavior of drawing of dashed lines: make them
disappear when they approach close enough that right-up will zoom out,
not in.

mac/Audacity.xcodeproj/project.pbxproj

@@ -1239,6 +1239,7 @@
 		5EF17C231D1F0A690090A642 /* ScrubbingToolBar.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 5EF17C211D1F0A690090A642 /* ScrubbingToolBar.cpp */; };
 		5EF958851DEB121800191280 /* InconsistencyException.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 5EF958831DEB121800191280 /* InconsistencyException.cpp */; };
 		5E73963B1DAFD82D00BA0A4D /* PopupMenuTable.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 5E7396391DAFD82D00BA0A4D /* PopupMenuTable.cpp */; };
+		5E73963E1DAFD86000BA0A4D /* ZoomHandle.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 5E73963C1DAFD86000BA0A4D /* ZoomHandle.cpp */; };
 		8406A93812D0F2510011EA01 /* EQDefaultCurves.xml in Resources */ = {isa = PBXBuildFile; fileRef = 8406A93712D0F2510011EA01 /* EQDefaultCurves.xml */; };
 		8484F31413086237002DF7F0 /* DeviceManager.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 8484F31213086237002DF7F0 /* DeviceManager.cpp */; };
 		AA0084191EA8C6E70070CCE3 /* TracksBehaviorsPrefs.cpp in Sources */ = {isa = PBXBuildFile; fileRef = AA0084181EA8C6E70070CCE3 /* TracksBehaviorsPrefs.cpp */; };
@@ -3075,6 +3076,8 @@
 		5EF958841DEB121800191280 /* InconsistencyException.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = InconsistencyException.h; sourceTree = "<group>"; };
 		5E7396391DAFD82D00BA0A4D /* PopupMenuTable.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = PopupMenuTable.cpp; sourceTree = "<group>"; };
 		5E73963A1DAFD82D00BA0A4D /* PopupMenuTable.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = PopupMenuTable.h; sourceTree = "<group>"; };
+		5E73963C1DAFD86000BA0A4D /* ZoomHandle.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = ZoomHandle.cpp; sourceTree = "<group>"; };
+		5E73963D1DAFD86000BA0A4D /* ZoomHandle.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ZoomHandle.h; sourceTree = "<group>"; };
 		82FF184D13CF01A600C1B664 /* dBTable.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = dBTable.cpp; path = sbsms/src/dBTable.cpp; sourceTree = "<group>"; };
 		82FF184E13CF01A600C1B664 /* dBTable.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = dBTable.h; path = sbsms/src/dBTable.h; sourceTree = "<group>"; };
 		82FF184F13CF01A600C1B664 /* slide.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = slide.cpp; path = sbsms/src/slide.cpp; sourceTree = "<group>"; };
@@ -5729,12 +5732,14 @@
 				5E1512681DB0010C00702E29 /* TrackControls.cpp */,
 				5E15126A1DB0010C00702E29 /* TrackUI.cpp */,
 				5E15126B1DB0010C00702E29 /* TrackVRulerControls.cpp */,
+				5E73963C1DAFD86000BA0A4D /* ZoomHandle.cpp */,
 				5E1512671DB0010C00702E29 /* CommonTrackPanelCell.h */,
 				5E74D2DE1CC4429700D88B0B /* EditCursorOverlay.h */,
 				5E74D2E01CC4429700D88B0B /* PlayIndicatorOverlay.h */,
 				5E74D2E21CC4429700D88B0B /* Scrubbing.h */,
 				5E1512691DB0010C00702E29 /* TrackControls.h */,
 				5E15126C1DB0010C00702E29 /* TrackVRulerControls.h */,
+				5E73963D1DAFD86000BA0A4D /* ZoomHandle.h */,
 			);
 			path = ui;
 			sourceTree = "<group>";
@@ -7748,6 +7753,7 @@
 				28D540060FD1912A00FA7C75 /* CommandBuilder.cpp in Sources */,
 				28D540070FD1912A00FA7C75 /* CommandHandler.cpp in Sources */,
 				28D540080FD1912A00FA7C75 /* ScriptCommandRelay.cpp in Sources */,
+				5E73963E1DAFD86000BA0A4D /* ZoomHandle.cpp in Sources */,
 				28DB34790FDC2C5D0011F589 /* ResponseQueue.cpp in Sources */,
 				28DABFBE0FF19DB100AC7848 /* RealFFTf.cpp in Sources */,
 				2800FE370FF32566005CA9E5 /* MidiIOPrefs.cpp in Sources */,

src/Makefile.am

@@ -582,6 +582,8 @@ audacity_SOURCES = \
 	tracks/ui/TrackUI.cpp \
 	tracks/ui/TrackVRulerControls.cpp \
 	tracks/ui/TrackVRulerControls.h \
+	tracks/ui/ZoomHandle.cpp \
+	tracks/ui/ZoomHandle.h \
 	widgets/AButton.cpp \
 	widgets/AButton.h \
 	widgets/ASlider.cpp \

src/TrackPanel.cpp

@@ -1146,7 +1146,6 @@ void TrackPanel::HandleInterruptedDrag()
       case IsSoloing:
       case IsMinimizing:
       case IsPopping:
-      case IsZooming:
          sendEvent = false;
 
       default:
@@ -1298,7 +1297,6 @@ bool TrackPanel::HandleEscapeKey(bool down)
          pMixerBoard->Refresh();
    }
       break;
-   case IsZooming:
    case IsVZooming:
    //case IsAdjustingSample:
       break;
@@ -1779,9 +1777,6 @@ void TrackPanel::SetCursorAndTipByTool( int tool,
    case slideTool:
       SetCursor(unsafe ? *mDisabledCursor : *mSlideCursor);
       break;
-   case zoomTool:
-      SetCursor(event.ShiftDown()? *mZoomOutCursor : *mZoomInCursor);
-      break;
    case drawTool:
       if (unsafe)
          SetCursor(*mDisabledCursor);
@@ -4057,88 +4052,6 @@ double TrackPanel::OnClipMove
 }
 
 
-///  This method takes care of our different zoom
-///  possibilities.  It is possible for a user to just
-///  "zoom in" or "zoom out," but it is also possible
-///  for a user to drag and select an area that he
-///  or she wants to be zoomed in on.  We use mZoomStart
-///  and mZoomEnd to track the beggining and end of such
-///  a zoom area.  Note that the ViewInfo member
-///  mViewInfo actually keeps track of our zoom constant,
-///  so we achieve zooming by altering the zoom constant
-///  and forcing a refresh.
-void TrackPanel::HandleZoom(wxMouseEvent & event)
-{
-   if (event.ButtonDown() || event.LeftDClick()) {
-      HandleZoomClick(event);
-   }
-   else if (mMouseCapture == IsZooming) {
-      if (event.Dragging()) {
-         HandleZoomDrag(event);
-      }
-      else if (event.ButtonUp()) {
-         HandleZoomButtonUp(event);
-      }
-   }
-}
-
-/// Zoom button down, record the position.
-void TrackPanel::HandleZoomClick(wxMouseEvent & event)
-{
-   if (mCapturedTrack)
-      return;
-
-   const auto foundCell = FindCell(event.m_x, event.m_y);
-   mCapturedTrack = foundCell.pTrack;
-   mCapturedRect = foundCell.rect;
-   if (foundCell.type != CellType::Track || !(mCapturedTrack = foundCell.pTrack))
-      return;
-
-   SetCapturedTrack(mCapturedTrack, IsZooming);
-
-   mZoomStart = event.m_x;
-   mZoomEnd = event.m_x;
-}
-
-/// Zoom drag
-void TrackPanel::HandleZoomDrag(wxMouseEvent & event)
-{
-   const int left = GetLeftOffset();
-   const int right = GetSize().x - kRightMargin - 1;
-
-   mZoomEnd = event.m_x;
-
-   if (event.m_x < left) {
-      mZoomEnd = left;
-   }
-   else if (event.m_x > right) {
-      mZoomEnd = right;
-   }
-
-   if (IsDragZooming()) {
-      Refresh(false);
-   }
-}
-
-/// Zoom button up
-void TrackPanel::HandleZoomButtonUp(wxMouseEvent & event)
-{
-   if (mZoomEnd < mZoomStart)
-      std::swap(mZoomStart, mZoomEnd);
-
-   if (IsDragZooming())
-      DragZoom(event, GetLeftOffset());
-   else
-      DoZoomInOut(event, GetLeftOffset());
-
-   mZoomEnd = mZoomStart = 0;
-
-   SetCapturedTrack(NULL);
-
-   MakeParentRedrawScrollbars();
-   Refresh(false);
-}
-
 /// Determines if drag zooming is active
 bool TrackPanel::IsDragZooming(int zoomStart, int zoomEnd)
 {
@@ -4153,41 +4066,6 @@ bool TrackPanel::IsMouseCaptured()
 }
 
 
-///  This actually sets the Zoom value when you're done doing
-///  a drag zoom.
-void TrackPanel::DragZoom(wxMouseEvent & event, int trackLeftEdge)
-{
-   double left = mViewInfo->PositionToTime(mZoomStart, trackLeftEdge);
-   double right = mViewInfo->PositionToTime(mZoomEnd, trackLeftEdge);
-   double multiplier = (GetScreenEndTime() - mViewInfo->h) / (right - left);
-   if (event.ShiftDown())
-      multiplier = 1.0 / multiplier;
-
-   mViewInfo->ZoomBy(multiplier);
-
-   mViewInfo->h = left;
-}
-
-/// This handles normal Zoom In/Out, if you just clicked;
-/// IOW, if you were NOT dragging to zoom an area.
-/// \todo MAGIC NUMBER: We've got several in this method.
-void TrackPanel::DoZoomInOut(wxMouseEvent & event, int trackLeftEdge)
-{
-   double center_h = mViewInfo->PositionToTime(event.m_x, trackLeftEdge);
-
-   const double multiplier =
-      (event.RightUp() || event.RightDClick() || event.ShiftDown())
-      ? 0.5 : 2.0;
-   mViewInfo->ZoomBy(multiplier);
-
-   if (event.MiddleUp() || event.MiddleDClick())
-      mViewInfo->SetZoom(ZoomInfo::GetDefaultZoom()); // AS: Reset zoom.
-
-   double new_center_h = mViewInfo->PositionToTime(event.m_x, trackLeftEdge);
-
-   mViewInfo->h += (center_h - new_center_h);
-}
-
 /// Vertical zooming (triggered by clicking in the
 /// vertical ruler)
 void TrackPanel::HandleVZoom(wxMouseEvent & event)
@@ -6536,9 +6414,6 @@ try
    case IsMinimizing:
       HandleMinimizing(event);
       break;
-   case IsZooming:
-      HandleZoom(event);
-      break;
    case IsAdjustingLabel:
       // Reach this case only when the captured track was label
       HandleGlyphDragRelease(static_cast<LabelTrack *>(mCapturedTrack), event);
@@ -7010,9 +6885,6 @@ void TrackPanel::HandleTrackSpecificMouseEvent(wxMouseEvent & event)
             if (!unsafe)
                HandleSlide(event);
             break;
-         case zoomTool:
-            HandleZoom(event);
-            break;
          case drawTool:
             if (!unsafe)
                HandleSampleEditing(event);
@@ -7067,10 +6939,7 @@ int TrackPanel::DetermineToolToUse( ToolsToolBar * pTtb, const wxMouseEvent & ev
    int trackKind = pTrack->GetKind();
    currentTool = selectTool; // the default.
 
-   if (event.ButtonIsDown(wxMOUSE_BTN_RIGHT) || event.RightUp()){
+   if (trackKind == Track::Time){
-      currentTool = zoomTool;
-   }
-   else if (trackKind == Track::Time){
       currentTool = envelopeTool;
    } else if( trackKind == Track::Label ){
       currentTool = selectTool;
@@ -7473,8 +7342,7 @@ void TrackPanel::DrawEverythingElse(wxDC * dc,
    if (mUIHandle)
       mUIHandle->DrawExtras(UIHandle::Cells, dc, region, clip);
 
-   if ((mMouseCapture == IsZooming || mMouseCapture == IsVZooming) &&
+   if (mMouseCapture == IsVZooming && IsDragZooming()
-       IsDragZooming()
        // note track zooming now works like audio track
        //#ifdef USE_MIDI
        //       && mCapturedTrack && mCapturedTrack->GetKind() != Track::Note

src/TrackPanel.h

@@ -515,16 +515,8 @@ protected:
    static void AddClipsToCaptured
       ( ClipMoveState &state, Track *t, double t0, double t1 );
 
-   // AS: Handle zooming into tracks
-   virtual void HandleZoom(wxMouseEvent & event);
-   virtual void HandleZoomClick(wxMouseEvent & event);
-   virtual void HandleZoomDrag(wxMouseEvent & event);
-   virtual void HandleZoomButtonUp(wxMouseEvent & event);
-
    static bool IsDragZooming(int zoomStart, int zoomEnd);
    virtual bool IsDragZooming() { return IsDragZooming(mZoomStart, mZoomEnd); }
-   virtual void DragZoom(wxMouseEvent &event, int x);
-   virtual void DoZoomInOut(wxMouseEvent &event, int x);
 
    virtual void HandleVZoom(wxMouseEvent & event);
    virtual void HandleVZoomClick(wxMouseEvent & event);
@@ -902,7 +894,6 @@ public:
       IsMinimizing,
       WasOverCutLine,
       IsPopping,
-      IsZooming,
 #ifdef EXPERIMENTAL_MIDI_OUT
       IsVelocitySliding,
 #endif

src/toolbars/ToolsToolBar.cpp

@@ -89,6 +89,8 @@ ToolsToolBar::ToolsToolBar()
 
    mMessageOfTool[envelopeTool] = _("Click and drag to edit the amplitude envelope");
    mMessageOfTool[drawTool] = _("Click and drag to edit the samples");
+
+   // TODO:  Why not mention middle click to zoom normal on Windows too?
 #if defined( __WXMAC__ )
    mMessageOfTool[zoomTool] = _("Click to Zoom In, Shift-Click to Zoom Out");
 #elif defined( __WXMSW__ )
@@ -96,6 +98,7 @@ ToolsToolBar::ToolsToolBar()
 #elif defined( __WXGTK__ )
    mMessageOfTool[zoomTool] = _("Left=Zoom In, Right=Zoom Out, Middle=Normal");
 #endif
+
    mMessageOfTool[slideTool] = _("Click and drag to move a track in time");
    mMessageOfTool[multiTool] = wxT(""); // multi-mode tool
 

src/tracks/ui/TrackUI.cpp

@@ -9,6 +9,7 @@ Paul Licameli split from TrackPanel.cpp
 **********************************************************************/
 
 #include "../../Track.h"
+#include "../../TrackPanelMouseEvent.h"
 #include "TrackControls.h"
 #include "TrackVRulerControls.h"
 
@@ -16,8 +17,10 @@ Paul Licameli split from TrackPanel.cpp
 #include "../../Project.h"
 #include "../../toolbars/ToolsToolBar.h"
 
+#include "ZoomHandle.h"
+
 HitTestResult Track::HitTest
-(const TrackPanelMouseEvent &,
+(const TrackPanelMouseEvent &event,
  const AudacityProject *pProject)
 {
    const ToolsToolBar * pTtb = pProject->GetToolsToolBar();
@@ -25,10 +28,12 @@ HitTestResult Track::HitTest
    const bool isMultiTool = pTtb->IsDown(multiTool);
    if (!isMultiTool) {
       switch (pTtb->GetCurrentTool()) {
+      case zoomTool:
+         return ZoomHandle::HitAnywhere(event.event, pProject);
+
       case selectTool:
       case envelopeTool:
       case drawTool:
-      case zoomTool:
       case slideTool:
       default:
          // cases not yet implemented
@@ -40,9 +45,8 @@ HitTestResult Track::HitTest
    // Replicate some of the logic of TrackPanel::DetermineToolToUse
    HitTestResult result;
 
-   if (isMultiTool) {
+   if (isMultiTool)
-      // To do: special hit tests
+      result = ZoomHandle::HitTest(event.event, pProject);
-   }
 
    return result;
 }

src/tracks/ui/ZoomHandle.cpp

@@ -0,0 +1,212 @@
+/**********************************************************************
+
+Audacity: A Digital Audio Editor
+
+ZoomHandle.cpp
+
+Paul Licameli split from TrackPanel.cpp
+
+**********************************************************************/
+
+#include "../../Audacity.h"
+#include "ZoomHandle.h"
+
+#include <algorithm>
+#include "../../MemoryX.h"
+
+#include <wx/dc.h>
+#include <wx/event.h>
+#include <wx/gdicmn.h>
+
+#include "../../HitTestResult.h"
+#include "../../Project.h"
+#include "../../RefreshCode.h"
+#include "../../TrackPanelMouseEvent.h"
+#include "../../toolbars/ToolsToolBar.h"
+#include "../../ViewInfo.h"
+#include "../../../images/Cursors.h"
+
+///  This class takes care of our different zoom
+///  possibilities.  It is possible for a user to just
+///  "zoom in" or "zoom out," but it is also possible
+///  for a user to drag and select an area that he
+///  or she wants to be zoomed in on.  We use mZoomStart
+///  and mZoomEnd to track the beginning and end of such
+///  a zoom area.  Note that the ViewInfo
+///  actually keeps track of our zoom constant,
+///  so we achieve zooming by altering the zoom constant
+///  and forcing a refresh.
+
+ZoomHandle::ZoomHandle()
+{
+}
+
+ZoomHandle &ZoomHandle::Instance()
+{
+   static ZoomHandle instance;
+   return instance;
+}
+
+HitTestPreview ZoomHandle::HitPreview
+   (const wxMouseEvent &event, const AudacityProject *pProject)
+{
+   static auto zoomInCursor =
+      ::MakeCursor(wxCURSOR_MAGNIFIER, ZoomInCursorXpm, 19, 15);
+   static auto zoomOutCursor =
+      ::MakeCursor(wxCURSOR_MAGNIFIER, ZoomOutCursorXpm, 19, 15);
+   const ToolsToolBar *const ttb = pProject->GetToolsToolBar();
+   return {
+      ttb->GetMessageForTool(zoomTool),
+      (event.ShiftDown() ? &*zoomOutCursor : &*zoomInCursor)
+   };
+}
+
+HitTestResult ZoomHandle::HitAnywhere
+(const wxMouseEvent &event, const AudacityProject *pProject)
+{
+   return { HitPreview(event, pProject), &Instance() };
+}
+
+HitTestResult ZoomHandle::HitTest
+(const wxMouseEvent &event, const AudacityProject *pProject)
+{
+   if (event.ButtonIsDown(wxMOUSE_BTN_RIGHT) || event.RightUp())
+      return HitAnywhere(event, pProject);
+   else
+      return {};
+}
+
+ZoomHandle::~ZoomHandle()
+{
+}
+
+UIHandle::Result ZoomHandle::Click
+(const TrackPanelMouseEvent &evt, AudacityProject *)
+{
+   const wxMouseEvent &event = evt.event;
+   if (event.ButtonDown() || event.LeftDClick()) {
+      /// Zoom button down, record the position.
+      mZoomStart = event.m_x;
+      mZoomEnd = event.m_x;
+      mRect = evt.rect;
+   }
+   return RefreshCode::RefreshNone;
+}
+
+UIHandle::Result ZoomHandle::Drag
+(const TrackPanelMouseEvent &evt, AudacityProject *)
+{
+   const wxMouseEvent &event = evt.event;
+   const int left = mRect.GetLeft();
+   const int right = mRect.GetRight();
+
+   mZoomEnd = event.m_x;
+
+   if (event.m_x < left) {
+      mZoomEnd = left;
+   }
+   else if (event.m_x > right) {
+      mZoomEnd = right;
+   }
+
+   // Refresh tracks ALWAYS.  Even if IsDragZooming() becomes false, make the
+   // dashed lines disappear. -- PRL
+   return RefreshCode::RefreshAll; // (IsDragZooming() ? RefreshAllTracks : RefreshNone),
+}
+
+HitTestPreview ZoomHandle::Preview
+(const TrackPanelMouseEvent &evt, const AudacityProject *pProject)
+{
+   return HitPreview(evt.event, pProject);
+}
+
+UIHandle::Result ZoomHandle::Release
+(const TrackPanelMouseEvent &evt, AudacityProject *pProject,
+ wxWindow *)
+{
+   const wxMouseEvent &event = evt.event;
+   ViewInfo &viewInfo = pProject->GetViewInfo();
+   if (mZoomEnd < mZoomStart)
+      std::swap(mZoomStart, mZoomEnd);
+
+   const int trackLeftEdge = mRect.x;
+   if (IsDragZooming())
+   {
+      ///  This actually sets the Zoom value when you're done doing
+      ///  a drag zoom.
+      double left = viewInfo.PositionToTime(mZoomStart, trackLeftEdge);
+      double right = viewInfo.PositionToTime(mZoomEnd, trackLeftEdge);
+
+      double multiplier =
+         (viewInfo.PositionToTime(mRect.width) - viewInfo.PositionToTime(0)) /
+         (right - left);
+      if (event.ShiftDown())
+         multiplier = 1.0 / multiplier;
+
+      viewInfo.ZoomBy(multiplier);
+
+      viewInfo.h = left;
+   }
+   else
+   {
+      /// This handles normal Zoom In/Out, if you just clicked;
+      /// IOW, if you were NOT dragging to zoom an area.
+      /// \todo MAGIC NUMBER: We've got several in this method.
+      const double center_h =
+         viewInfo.PositionToTime(event.m_x, trackLeftEdge);
+
+      const double multiplier =
+         (event.RightUp() || event.RightDClick() || event.ShiftDown())
+         ? 0.5 : 2.0;
+      viewInfo.ZoomBy(multiplier);
+
+      if (event.MiddleUp() || event.MiddleDClick())
+         viewInfo.SetZoom(ZoomInfo::GetDefaultZoom()); // AS: Reset zoom.
+
+      const double new_center_h =
+         viewInfo.PositionToTime(event.m_x, trackLeftEdge);
+
+      viewInfo.h += (center_h - new_center_h);
+   }
+
+   mZoomEnd = mZoomStart = 0;
+
+   using namespace RefreshCode;
+   return RefreshAll | FixScrollbars;
+}
+
+UIHandle::Result ZoomHandle::Cancel(AudacityProject*)
+{
+   // Cancel is implemented!  And there is no initial state to restore,
+   // so just return a code.
+   return RefreshCode::RefreshAll;
+}
+
+void ZoomHandle::DrawExtras
+(DrawingPass pass, wxDC * dc, const wxRegion &, const wxRect &panelRect)
+{
+   if (pass == Cells) {
+      // PRL: Draw dashed lines only if we would zoom in
+      // for button up.
+      if (!IsDragZooming())
+         return;
+
+      wxRect rect;
+
+      dc->SetBrush(*wxTRANSPARENT_BRUSH);
+      dc->SetPen(*wxBLACK_DASHED_PEN);
+
+      rect.x = std::min(mZoomStart, mZoomEnd);
+      rect.width = 1 + abs(mZoomEnd - mZoomStart);
+      rect.y = -1;
+      rect.height = panelRect.height + 2;
+
+      dc->DrawRectangle(rect);
+   }
+}
+
+bool ZoomHandle::IsDragZooming() const
+{
+   const int DragThreshold = 3;// Anything over 3 pixels is a drag, else a click.
+   return (abs(mZoomEnd - mZoomStart) > DragThreshold);
+}

src/tracks/ui/ZoomHandle.h

@@ -0,0 +1,66 @@
+/**********************************************************************
+
+Audacity: A Digital Audio Editor
+
+ZoomHandle.h
+
+Paul Licameli split from TrackPanel.cpp
+
+**********************************************************************/
+
+#ifndef __AUDACITY_ZOOM_HANDLE__
+#define __AUDACITY_ZOOM_HANDLE__
+
+#include "../../UIHandle.h"
+
+class wxMouseEvent;
+#include <wx/gdicmn.h>
+
+struct HitTestResult;
+
+class ZoomHandle final : public UIHandle
+{
+   ZoomHandle();
+   ZoomHandle(const ZoomHandle&) = delete;
+   ZoomHandle &operator=(const ZoomHandle&) = delete;
+   static ZoomHandle& Instance();
+   static HitTestPreview HitPreview
+      (const wxMouseEvent &event, const AudacityProject *pProject);
+
+public:
+   static HitTestResult HitAnywhere
+      (const wxMouseEvent &event, const AudacityProject *pProject);
+   static HitTestResult HitTest
+      (const wxMouseEvent &event, const AudacityProject *pProject);
+
+   virtual ~ZoomHandle();
+
+   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 DrawExtras
+      (DrawingPass pass,
+       wxDC * dc, const wxRegion &updateRegion, const wxRect &panelRect)
+      override;
+
+private:
+   bool IsDragZooming() const;
+
+   int mZoomStart{}, mZoomEnd{};
+   wxRect mRect{};
+};
+
+#endif

win/Projects/Audacity/Audacity.vcxproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" ToolsVersion="12.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup Label="ProjectConfigurations">
     <ProjectConfiguration Include="Debug|Win32">
@@ -243,6 +243,7 @@
     <ClCompile Include="..\..\..\src\tracks\ui\TrackControls.cpp" />
     <ClCompile Include="..\..\..\src\tracks\ui\TrackUI.cpp" />
     <ClCompile Include="..\..\..\src\tracks\ui\TrackVRulerControls.cpp" />
+    <ClCompile Include="..\..\..\src\tracks\ui\ZoomHandle.cpp" />
     <ClCompile Include="..\..\..\src\UIHandle.cpp" />
     <ClCompile Include="..\..\..\src\UndoManager.cpp" />
     <ClCompile Include="..\..\..\src\UserException.cpp" />
@@ -501,6 +502,7 @@
     <ClInclude Include="..\..\..\src\TranslatableStringArray.h" />
     <ClInclude Include="..\..\..\src\UserException.h" />
     <ClInclude Include="..\..\..\src\tracks\ui\TrackControls.h" />
+    <ClInclude Include="..\..\..\src\tracks\ui\ZoomHandle.h" />
     <ClInclude Include="..\..\..\src\tracks\timetrack\ui\TimeTrackVRulerControls.h" />
     <ClInclude Include="..\..\..\src\tracks\ui\TrackVRulerControls.h" />
     <ClInclude Include="..\..\..\src\UIHandle.h" />

win/Projects/Audacity/Audacity.vcxproj.filters

@@ -950,6 +950,9 @@
     <ClCompile Include="..\..\..\src\tracks\ui\TrackControls.cpp">
       <Filter>src\tracks\ui</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\..\src\tracks\ui\ZoomHandle.cpp">
+      <Filter>src\tracks\ui</Filter>
+    </ClCompile>
     <ClCompile Include="..\..\..\src\tracks\timetrack\ui\TimeTrackControls.cpp">
       <Filter>src\tracks\timetrack\ui</Filter>
     </ClCompile>
@@ -1894,6 +1897,9 @@
     <ClInclude Include="..\..\..\src\tracks\ui\TrackControls.h">
       <Filter>src\tracks\ui</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\..\src\tracks\ui\ZoomHandle.h">
+      <Filter>src\tracks\ui</Filter>
+    </ClInclude>
     <ClInclude Include="..\..\..\src\tracks\timetrack\ui\TimeTrackControls.h">
       <Filter>src\tracks\timetrack\ui</Filter>
     </ClInclude>