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add CMYK conversion matrices to colorspace-tools

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hunterk 2017-03-13 14:31:40 -05:00
parent 47e7583af8
commit a414020804
1 changed files with 32 additions and 9 deletions
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41
misc/colorspace-tools.h
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@ -75,7 +75,7 @@ vec3 XYZtoSRGB(vec3 XYZ)
return XYZ * m;
}
vec3 RGBtoYUV(vec3 RGB)
vec3 RGBtoYUV(vec3 RGB)
{
const mat3x3 m = mat3x3(
0.2126, 0.7152, 0.0722,
@ -85,7 +85,7 @@ vec3 XYZtoSRGB(vec3 XYZ)
return RGB * m;
}
vec3 YUVtoRGB(vec3 YUV)
vec3 YUVtoRGB(vec3 YUV)
{
const mat3x3 m = mat3x3(
1.000, 0.000, 1.28033,
@ -124,7 +124,7 @@ vec3 XYZtoYxy(vec3 XYZ)
return Yxy;
}
vec3 YxytoXYZ(vec3 Yxy)
vec3 YxytoXYZ(vec3 Yxy)
{
vec3 XYZ;
XYZ.g = Yxy.r;
@ -134,7 +134,30 @@ vec3 XYZtoYxy(vec3 XYZ)
return XYZ;
}
// Converting pure hue to RGB
// RGB <-> CMYK conversions require 4 channels
vec4 RGBtoCMYK(vec3 RGB){
float Red = RGB.r;
float Green = RGB.g;
float Blue = RGB.b;
float Black = min(1.0 - Red, min(1.0 - Green, 1.0 - Blue));
float Cyan = (1.0 - Red - Black) / (1.0 - Black);
float Magenta = (1.0 - Green - Black) / (1.0 - Black);
float Yellow = (1.0 - Blue - Black) / (1.0 - Black);
return vec4(Cyan, Magenta, Yellow, Black);
}
vec3 CMYKtoRGB(vec4 CMYK){
float Cyan = CMYK.x;
float Magenta = CMYK.y;
float Yellow = CMYK.z;
float Black = CMYK.w;
float Red = 1.0 - min(1.0, Cyan * (1.0 - Black) + Black);
float Green = 1.0 - min(1.0, Magenta * (1.0 - Black) + Black);
float Blue = 1.0 - min(1.0, Yellow * (1.0 - Black) + Black);
return vec3(Red, Green, Blue);
}
// Converting pure hue to RGB
vec3 HUEtoRGB(float H)
{
float R = abs(H * 6.0 - 3.0) - 1.0;
@ -182,14 +205,14 @@ vec3 HSVtoRGB(vec3 c)
}
// conversion from NTSC RGB Reference White D65 ( color space used by NA/Japan TV's ) to XYZ
vec3 NTSC(vec3 c)
vec3 NTSC(vec3 c)
{
vec3 v = vec3(pow(c.r, 2.2), pow(c.g, 2.2), pow(c.b, 2.2)); //Inverse Companding
return RGBtoXYZ(v);
}
// conversion from XYZ to sRGB Reference White D65 ( color space used by windows )
vec3 sRGB(vec3 c)
// conversion from XYZ to sRGB Reference White D65 ( color space used by windows )
vec3 sRGB(vec3 c)
{
vec3 v = XYZtoSRGB(c);
v = DecodeGamma(v, 2.4); //Companding
@ -197,8 +220,8 @@ vec3 HSVtoRGB(vec3 c)
return v;
}
// NTSC RGB to sRGB
vec3 NTSCtoSRGB( vec3 c )
// NTSC RGB to sRGB
vec3 NTSCtoSRGB( vec3 c )
{
return sRGB(NTSC( c ));
}