Snap.h

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/**********************************************************************
 
  Audacity: A Digital Audio Editor
 
  Snap.h
 
  Dominic Mazzoni
 
  Create one of these objects at the beginning of a click/drag.
  Then, given a time corresponding to the current mouse cursor
  position, it will tell you the closest place to snap to.
 
**********************************************************************/
 
#ifndef __AUDACITY_SNAP__
#define __AUDACITY_SNAP__
 
#include <vector>
#include <wx/defs.h>
#include "ComponentInterfaceSymbol.h"
 
class AudacityProject;
class Track;
class TrackList;
class ZoomInfo;
class wxDC;
 
const int kPixelTolerance = 4;
 
class SnapPoint
{
public:
   explicit
   SnapPoint(double t_ = 0.0, const Track *track_ = nullptr)
      : t(t_), track(track_)
   {
   }
 
   double t;
   const Track *track;
};
 
using SnapPointArray = std::vector < SnapPoint > ;
 
struct SnapResults {
   double timeSnappedTime{ 0.0 };
   double outTime{ 0.0 };
   wxInt64 outCoord{ -1 };
   bool snappedPoint{ false };
   bool snappedTime{ false };
 
   bool Snapped() const { return snappedPoint || snappedTime; }
};
 
class AUDACITY_DLL_API SnapManager
{
public:
   SnapManager(const AudacityProject &project,
               SnapPointArray candidates,
               const ZoomInfo &zoomInfo,
               bool noTimeSnap = false,
               int pixelTolerance = kPixelTolerance);
 
   SnapManager(const AudacityProject &project,
               const TrackList &tracks,
               const ZoomInfo &zoomInfo,
               SnapPointArray candidates = {},
               bool noTimeSnap = false,
               int pixelTolerance = kPixelTolerance);
 
   ~SnapManager();
 
   // The track may be NULL.
   // Returns true if the output time is not the same as the input.
   // Pass rightEdge=true if this is the right edge of a selection,
   // and false if it's the left edge.
   SnapResults Snap(Track *currentTrack,
             double t,
             bool rightEdge);
   
   // The two coordinates need not be ordered:
   static void Draw( wxDC *dc, wxInt64 snap0, wxInt64 snap1 );
 
private:
 
   void Reinit();
   void CondListAdd(double t, const Track *track);
   double Get(size_t index);
   wxInt64 PixelDiff(double t, size_t index);
   size_t Find(double t, size_t i0, size_t i1);
   size_t Find(double t);
   bool SnapToPoints(Track *currentTrack, double t, bool rightEdge, double *outT);
 
private:
 
   const AudacityProject *mProject;
   const ZoomInfo *mZoomInfo;
   int mPixelTolerance;
   bool mNoTimeSnap;
   
   double mEpsilon{ 1 / 44100.0 };
   SnapPointArray mCandidates;
   SnapPointArray mSnapPoints;
 
   // Info for snap-to-time
   bool mSnapToTime{ false };
 
   Identifier mSnapTo {};
   double mRate{ 0.0 };
   NumericFormatSymbol mFormat{};
};
 
#endif