ZoomInfo.h

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/**********************************************************************
 
  Audacity: A Digital Audio Editor
 
  ZoomInfo.h
 
  Paul Licameli split from ViewInfo.h
 
**********************************************************************/
 
#ifndef __AUDACITY_ZOOM_INFO__
#define __AUDACITY_ZOOM_INFO__
 
#include <cstdint>
#include <vector>
 
class AudacityProject;
 
// See big pictorial comment in TrackPanel.cpp for explanation of these numbers
enum : int {
   // Constants related to x coordinates in the track panel
   kBorderThickness = 1,
   kShadowThickness = 1,
 
   kLeftInset = 4,
   kRightInset = kLeftInset,
   kLeftMargin = kLeftInset + kBorderThickness,
   kRightMargin = kRightInset + kShadowThickness + kBorderThickness,
 
   kTrackInfoWidth = 100 - kLeftMargin,
};
 
// The subset of ViewInfo information (other than selection)
// that is sufficient for purposes of TrackArtist,
// and for computing conversions between track times and pixel positions.
class SCREEN_GEOMETRY_API ZoomInfo /* not final */
   // Note that ViewInfo inherits from ZoomInfo but there are no virtual functions.
   // That's okay if we pass always by reference and never copy, suffering "slicing."
{
public:
   using int64 = std::int64_t;
 
   ZoomInfo(double start, double pixelsPerSecond);
   ~ZoomInfo();
 
   // Be sure we don't slice
   ZoomInfo(const ZoomInfo&) PROHIBITED;
   ZoomInfo& operator= (const ZoomInfo&) PROHIBITED;
 
   int vpos;                    // vertical scroll pos
 
   double h;                    // h pos in secs
 
protected:
   double zoom;                 // pixels per second
 
public:
   // do NOT use this once to convert a pixel width to a duration!
   // Instead, call twice to convert start and end times,
   // and take the difference.
   // origin specifies the pixel corresponding to time h
   double PositionToTime(int64 position,
      int64 origin = 0
      , bool ignoreFisheye = false
   ) const;
 
   // do NOT use this once to convert a duration to a pixel width!
   // Instead, call twice to convert start and end positions,
   // and take the difference.
   // origin specifies the pixel corresponding to time h
   int64 TimeToPosition(double time,
      int64 origin = 0
      , bool ignoreFisheye = false
   ) const;
 
   // This always ignores the fisheye.  Use with caution!
   // You should prefer to call TimeToPosition twice, for endpoints, and take the difference!
   double TimeRangeToPixelWidth(double timeRange) const;
 
   double OffsetTimeByPixels(double time, int64 offset, bool ignoreFisheye = false) const
   {
      return PositionToTime(offset + TimeToPosition(time, ignoreFisheye), ignoreFisheye);
   }
 
   int GetWidth() const { return mWidth; }
   void SetWidth( int width ) { mWidth = width; }
 
   int GetVRulerWidth() const { return mVRulerWidth; }
   void SetVRulerWidth( int width ) { mVRulerWidth = width; }
   int GetVRulerOffset() const { return kTrackInfoWidth + kLeftMargin; }
 
   // The x-coordinate of the start of the displayed track data
   int GetLeftOffset() const
      { return GetVRulerOffset() + GetVRulerWidth() + 1; }
   // The number of pixel columns for display of track data
   int GetTracksUsableWidth() const
   {
      return
         std::max( 0, GetWidth() - ( GetLeftOffset() + kRightMargin ) );
   }
 
   // Returns the time corresponding to the pixel column one past the track area
   // (ignoring any fisheye)
   double GetScreenEndTime() const
   {
      auto width = GetTracksUsableWidth();
      return PositionToTime(width, 0, true);
   }
 
   bool ZoomInAvailable() const;
   bool ZoomOutAvailable() const;
 
   static double GetDefaultZoom()
   { return 44100.0 / 512.0; }
 
 
   // Limits zoom to certain bounds
   void SetZoom(double pixelsPerSecond);
 
   // This function should not be used to convert positions to times and back
   // Use TimeToPosition and PositionToTime and OffsetTimeByPixels instead
   double GetZoom() const;
 
   static double GetMaxZoom( );
   static double GetMinZoom( );
 
   // Limits zoom to certain bounds
   // multipliers above 1.0 zoom in, below out
   void ZoomBy(double multiplier);
 
   struct Interval {
      int64 position; double averageZoom; bool inFisheye;
      Interval(int64 p, double z, bool i)
         : position(p), averageZoom(z), inFisheye(i) {}
   };
   typedef std::vector<Interval> Intervals;
 
   // Find an increasing sequence of pixel positions.  Each is the start
   // of an interval, or is the end position.
   // Each of the disjoint intervals should be drawn
   // separately.
   // It is guaranteed that there is at least one entry and the position of the
   // first entry equals origin.
   // @param origin specifies the pixel position corresponding to time ViewInfo::h.
   void FindIntervals
      (double rate, Intervals &results, int64 width, int64 origin = 0) const;
 
   enum FisheyeState {
      HIDDEN,
      PINNED,
 
      NUM_STATES,
   };
   FisheyeState GetFisheyeState() const
   { return HIDDEN; } // stub
 
   // Return true if the mouse position is anywhere in the fisheye
   // origin specifies the pixel corresponding to time h
   bool InFisheye(int64 /*position*/, int64 = 0) const
   {return false;} // stub
 
   // These accessors ignore the fisheye hiding state.
   // Inclusive:
   int64 GetFisheyeLeftBoundary(int64 = 0) const
   {return 0;} // stub
   // Exclusive:
   int64 GetFisheyeRightBoundary(int64 = 0) const
   {return 0;} // stub
 
   int mWidth{ 0 };
   int mVRulerWidth{ 36 };
};
 
#endif