Move class ZoomInfo to separate files

src/ZoomInfo.cpp

@@ -0,0 +1,123 @@
+/**********************************************************************
+
+  Audacity: A Digital Audio Editor
+
+  ZoomInfo.cpp
+
+  Paul Licameli split from ViewInfo.cpp
+
+**********************************************************************/
+
+#include "ZoomInfo.h"
+
+#include "prefs/GUISettings.h"
+
+namespace {
+static const double gMaxZoom = 6000000;
+static const double gMinZoom = 0.001;
+}
+
+ZoomInfo::ZoomInfo(double start, double pixelsPerSecond)
+   : vpos(0)
+   , h(start)
+   , zoom(pixelsPerSecond)
+{
+   UpdatePrefs();
+}
+
+ZoomInfo::~ZoomInfo()
+{
+}
+
+void ZoomInfo::UpdatePrefs()
+{
+   dBr = gPrefs->Read(ENV_DB_KEY, ENV_DB_RANGE);
+}
+
+/// Converts a position (mouse X coordinate) to
+/// project time, in seconds.  Needs the left edge of
+/// the track as an additional parameter.
+double ZoomInfo::PositionToTime(wxInt64 position,
+   wxInt64 origin
+   , bool // ignoreFisheye
+) const
+{
+   return h + (position - origin) / zoom;
+}
+
+
+/// STM: Converts a project time to screen x position.
+wxInt64 ZoomInfo::TimeToPosition(double projectTime,
+   wxInt64 origin
+   , bool // ignoreFisheye
+) const
+{
+   double t = 0.5 + zoom * (projectTime - h) + origin ;
+   if( t < wxINT64_MIN )
+      return wxINT64_MIN;
+   if( t > wxINT64_MAX )
+      return wxINT64_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::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
+   (double /*rate*/, Intervals &results, wxInt64 width, wxInt64 origin) const
+{
+   results.clear();
+   results.reserve(2);
+
+   const wxInt64 rightmost(origin + (0.5 + width));
+   wxASSERT(origin <= rightmost);
+   {
+      results.push_back(Interval(origin, zoom, false));
+   }
+
+   if (origin < rightmost)
+      results.push_back(Interval(rightmost, 0, false));
+   wxASSERT(!results.empty() && results[0].position == origin);
+}