yet another refactoring

[cpPlugins.git] / lib / cpExtensions / Algorithms / RGBToHSVFunction.h

diff --git a/lib/cpExtensions/Algorithms/RGBToHSVFunction.h b/lib/cpExtensions/Algorithms/RGBToHSVFunction.h
new file mode 100644 (file)
index 0000000..b10f295
--- /dev/null
+++ b/lib/cpExtensions/Algorithms/RGBToHSVFunction.h
@@ -0,0 +1,87 @@
+// -------------------------------------------------------------------------
+// @author Leonardo Florez-Valencia (florez-l@javeriana.edu.co)
+// -------------------------------------------------------------------------
+
+#ifndef __CPEXTENSIONS__ALGORITHMS__RGBTOHSVFUNCTION__H__
+#define __CPEXTENSIONS__ALGORITHMS__RGBTOHSVFUNCTION__H__
+
+#include <cmath>
+#include <limits>
+#include <vnl/vnl_math.h>
+
+#include <itkRGBPixel.h>
+
+namespace cpExtensions
+{
+  namespace Algorithms
+  {
+    /**
+     */
+    template< class P >
+    struct RGBToHSVFunction
+    {
+      typedef RGBToHSVFunction      Self;
+      typedef P                     TOutPixel;
+      typedef typename P::ValueType TValue;
+
+      template< class Tr, class Tg, class Tb >
+      P operator()( const Tr& r, const Tg& g, const Tb& b ) const
+        {
+          static const double mVal =
+            double( std::numeric_limits< TValue >::max( ) );
+          static const double _0 = double( 0 );
+          static const double _1 = double( 1 );
+          static const double _2 = double( 2 );
+          static const double _3 = double( 3 );
+          static const double _2pi = _2 * double( vnl_math::pi );
+
+          P hsv;
+
+          double R = double( r );
+          double G = double( g );
+          double B = double( b );
+          double sRGB = R + G + B;
+          double RG = R - G;
+          double RB = R - B;
+          double GB = G - B;
+
+          // Hue
+          double A = std::sqrt( ( RG * RG ) + ( RB * GB ) );
+          if( A != _0 )
+            A = std::acos( ( RG + RB ) / ( _2 * A ) );
+          A /= _2pi;
+          hsv[ 0 ] = TValue( mVal * ( ( G >= B )? A: _1 - A ) );
+
+          // Saturation
+          if( sRGB != _0 )
+          {
+            double C = ( G < R )? G: R;
+            C        = ( B < C )? B: C;
+            hsv[ 1 ] = TValue( mVal * ( _1 - ( ( _3 * C ) / sRGB ) ) );
+          }
+          else
+            hsv[ 1 ] = TValue( 0 );
+
+          // Value
+          hsv[ 2 ] = TValue( sRGB / _3 );
+          return( hsv );
+        }
+
+      template< class C >
+      TOutPixel operator()( const itk::RGBPixel< C >& rgb ) const
+        {
+          return(
+            this->operator()(
+              rgb.GetRed( ), rgb.GetGreen( ), rgb.GetBlue( )
+              )
+            );
+        }
+    };
+
+  } // ecapseman
+
+} // ecapseman
+
+#endif // __CPEXTENSIONS__ALGORITHMS__RGBTOHSVFUNCTION__H__
+
+// eof - $RCSfile$