ZoomInfo.cpp

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/**********************************************************************
 
  Audacity: A Digital Audio Editor
 
  ZoomInfo.cpp
 
  Paul Licameli split from ViewInfo.cpp
 
**********************************************************************/
 
#include "ZoomInfo.h"
 
#include <cassert>
#include <cmath>
 
namespace {
static const double gMaxZoom = 6000000;
static const double gMinZoom = 0.001;
}
 
ZoomInfo::ZoomInfo(double start, double pixelsPerSecond)
   : vpos(0)
   , h(start)
   , zoom(pixelsPerSecond)
{
}
 
ZoomInfo::~ZoomInfo()
{
}
 
double ZoomInfo::PositionToTime(int64 position,
   int64 origin
   , bool // ignoreFisheye
) const
{
   return h + (position - origin) / zoom;
}
 
 
auto ZoomInfo::TimeToPosition(double projectTime,
   int64 origin
   , bool // ignoreFisheye
) const -> int64
{
   double t = 0.5 + zoom * (projectTime - h) + origin ;
   if( t < INT64_MIN )
      return INT64_MIN;
   if( t > INT64_MAX )
      return INT64_MAX;
   t = floor( t );
   return t;
}
 
// This always ignores the fisheye.  Use with caution!
// You should prefer to call TimeToPosition twice, for endpoints, and take the difference!
double ZoomInfo::TimeRangeToPixelWidth(double timeRange) const
{
   return timeRange * zoom;
}
 
bool ZoomInfo::ZoomInAvailable() const
{
   return zoom < gMaxZoom;
}
 
bool ZoomInfo::ZoomOutAvailable() const
{
   return zoom > gMinZoom;
}
 
double ZoomInfo::GetZoom( ) const { return zoom;};
 
double ZoomInfo::GetAbsoluteOffset(double offset) const
{
   return std::floor(0.5 + h * zoom + offset);
}
 
double ZoomInfo::GetMaxZoom()
{
   return gMaxZoom;
};
double ZoomInfo::GetMinZoom( ) { return gMinZoom;};
 
void ZoomInfo::SetZoom(double pixelsPerSecond)
{
   zoom = std::max(gMinZoom, std::min(gMaxZoom, pixelsPerSecond));
// DA: Avoids stuck in snap-to
#ifdef EXPERIMENTAL_DA
   // Disable snapping if user zooms in a long way.
   // Helps stop users be trapped in snap-to.
   // The level chosen is in sample viewing range with samples
   // still quite close together.
   if( zoom > (gMaxZoom * 0.06  ))
   {
      AudacityProject * project = GetActiveProject();
      if( project )
         project->OnSnapToOff();
   }
#endif
}
 
void ZoomInfo::ZoomBy(double multiplier)
{
   SetZoom(zoom * multiplier);
}
 
void ZoomInfo::FindIntervals(
   Intervals& results, int64 width, int64 origin) const
{
   results.clear();
   results.reserve(2);
 
   const int64 rightmost(origin + (0.5 + width));
   assert(origin <= rightmost);
   {
      results.push_back(Interval(origin, zoom, false));
   }
 
   if (origin < rightmost)
      results.push_back(Interval(rightmost, 0, false));
   assert(!results.empty() && results[0].position == origin);
}