sigmoidal-contrast: prevent argument out of range and remove unnecessary ClampToQuantum

[imagemagick] / MagickCore / gem.c

diff --git a/MagickCore/gem.c b/MagickCore/gem.c
index 64608bc357b787c3ac8b966f821624ab5259a734..0d6ee4036608c33b8c52fe23ac95424f52888739 100644 (file)
--- a/MagickCore/gem.c
+++ b/MagickCore/gem.c
@@ -1012,3 +1012,61 @@ MagickPrivate size_t  GetOptimalKernelWidth(const double radius,
 {
   return(GetOptimalKernelWidth1D(radius,sigma));
 }
+\f
+/*
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%                                                                             %
+%                                                                             %
+%                                                                             %
+%   I n v e r s e s R G B C o m p a n d o r                                   %
+%                                                                             %
+%                                                                             %
+%                                                                             %
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+%  InversesRGBCompandor() removes the gamma function from a sRGB pixel.
+%
+%  The format of the InversesRGBCompandor method is:
+%
+%      double InversesRGBCompandor(const double pixel)
+%
+%  A description of each parameter follows:
+%
+%    o pixel: the pixel.
+%
+*/
+MagickExport double InversesRGBCompandor(const double pixel)
+{
+  if (pixel <= (0.0404482362771076*QuantumRange))
+    return(pixel/12.92);
+  return(QuantumRange*pow((QuantumScale*pixel+0.055)/1.055,2.4));
+}
+\f
+/*
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%                                                                             %
+%                                                                             %
+%                                                                             %
+%   s R G B C o m p a n d o r                                                 %
+%                                                                             %
+%                                                                             %
+%                                                                             %
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+%  sRGBCompandor() adds the gamma function to a sRGB pixel.
+%
+%  The format of the sRGBCompandor method is:
+%
+%      double sRGBCompandor(const double pixel)
+%
+%  A description of each parameter follows:
+%
+%    o pixel: the pixel.
+%
+*/
+MagickExport double sRGBCompandor(const double pixel)
+{
+  if (pixel <= (0.0031306684425005883*QuantumRange))
+    return(12.92*pixel);
+  return(QuantumRange*(1.055*pow(QuantumScale*pixel,1.0/2.4)-0.055));
+}