ZenithalProjections.h

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//     ____   ______ __
//    / __ \ / ____// /
//   / /_/ // /    / /
//  / ____// /___ / /___   PixInsight Class Library
// /_/     \____//_____/   PCL 2.7.0
// ----------------------------------------------------------------------------
// pcl/ZenithalProjections.h - Released 2024-06-18T15:48:54Z
// ----------------------------------------------------------------------------
// This file is part of the PixInsight Class Library (PCL).
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// ----------------------------------------------------------------------------
 
#ifndef __PCL_ZenithalProjections_h
#define __PCL_ZenithalProjections_h
 
 
#include <pcl/Defs.h>
 
#include <pcl/ProjectionBase.h>
 
/*
 * Based on original work contributed by Andrés del Pozo.
 */
 
namespace pcl
{
 
// ----------------------------------------------------------------------------
 
class PCL_CLASS ZenithalProjectionBase : public ProjectionBase
{
protected:
 
   ZenithalProjectionBase()
   {
      m_theta0 = 90;
   }
 
   ZenithalProjectionBase( const ZenithalProjectionBase& ) = default;
 
   virtual ProjectionBase* Clone() const override = 0;
 
   virtual IsoString ProjCode() const override = 0;
 
   virtual IsoString Identifier() const override = 0;
 
   virtual IsoString Name() const override = 0;
 
protected:
 
   bool Project( DPoint& pW, const DPoint& pN ) const noexcept override
   {
      double rTheta = GetRTheta( pN );
      double sinTheta, cosTheta;
      SinCos( Rad( pN.x ), sinTheta, cosTheta );
      pW.x =  rTheta * sinTheta;
      pW.y = -rTheta * cosTheta;
      return true;
   }
 
   bool Unproject( DPoint& pN, const DPoint& pW ) const noexcept override
   {
      pN.x = Deg( ArcTan( pW.x, -pW.y ) );
      pN.y = GetTheta( Sqrt( pW.x*pW.x + pW.y*pW.y ) );
      return true;
   }
 
   virtual double GetRTheta( const DPoint& np ) const = 0;
   virtual double GetTheta( double rTheta ) const = 0;
};
 
// ----------------------------------------------------------------------------
 
class PCL_CLASS ZenithalEqualAreaProjection: public ZenithalProjectionBase
{
public:
 
   ZenithalEqualAreaProjection() = default;
 
   ZenithalEqualAreaProjection( const ZenithalEqualAreaProjection& ) = default;
 
   ProjectionBase* Clone() const override
   {
      return new ZenithalEqualAreaProjection( *this );
   }
 
   IsoString ProjCode() const override
   {
      return "ZEA";
   }
 
   IsoString Identifier() const override
   {
      return "ZenithalEqualArea";
   };
 
   IsoString Name() const override
   {
      return "Zenithal Equal Area";
   }
 
   bool CheckBrokenLine( const DPoint& cp1, const DPoint& cp2 ) const noexcept override
   {
      DPoint np1 = m_sph.CelestialToNative( cp1 );
      DPoint np2 = m_sph.CelestialToNative( cp2 );
      return Min( Mod( Abs( np1.x - np2.x - 360 ), 360.0 ),
                  Mod( Abs( np1.x - np2.x + 360 ), 360.0 ) ) < 180*Sin( Rad( 45 + (np1.y + np2.y)/2/2 ) );
   }
 
private:
 
   double GetRTheta( const DPoint& np ) const override
   {
      return 2 * Deg( Sin( Rad( (90 - np.y)/2 ) ) );
   }
 
   double GetTheta( double rTheta ) const override
   {
      return 90 - 2*Deg( ArcSin( Rad( rTheta )/2 ) );
   }
};
 
// ----------------------------------------------------------------------------
 
class PCL_CLASS StereographicProjection: public ZenithalProjectionBase
{
public:
 
   StereographicProjection() = default;
 
   StereographicProjection( const StereographicProjection& ) = default;
 
   ProjectionBase* Clone() const override
   {
      return new StereographicProjection( *this );
   }
 
   IsoString ProjCode() const override
   {
      return "STG";
   }
 
   IsoString Identifier() const override
   {
      return "Stereographic";
   };
 
   IsoString Name() const override
   {
      return "Stereographic";
   }
 
   bool CheckBrokenLine(const DPoint& cp1, const DPoint& cp2) const noexcept override
   {
      return true;
   }
 
private:
 
   double GetRTheta( const DPoint& np ) const override
   {
      return 2 * Deg( Tan( Rad( (90 - np.y)/2 ) ) );
   }
 
   double GetTheta( double rTheta ) const override
   {
      return 90 - 2*Deg( ArcTan( Rad( rTheta )/2 ) );
   }
};
 
// ----------------------------------------------------------------------------
 
} // pcl
 
#endif   // __PCL_ZenithalProjections_h
 
// ----------------------------------------------------------------------------
// EOF pcl/ZenithalProjections.h - Released 2024-06-18T15:48:54Z