From b9e19e076662ae5743b9c81eb238fe11204f6dbd Mon Sep 17 00:00:00 2001 From: Tavian Barnes Date: Sun, 12 Apr 2009 19:06:50 +0000 Subject: Add some comments. --- libdimension/color.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'libdimension/color.c') diff --git a/libdimension/color.c b/libdimension/color.c index e2a4df9..5a685c1 100644 --- a/libdimension/color.c +++ b/libdimension/color.c @@ -26,6 +26,7 @@ const dmnsn_CIE_XYZ dmnsn_whitepoint = { .X = 0.9504060171449392, .Y = 0.9999085943425312, .Z = 1.089062231497274 }; +/* Convert a CIE XYZ color to a dmnsn_color (actually a no-op) */ dmnsn_color dmnsn_color_from_XYZ(dmnsn_CIE_XYZ XYZ) { @@ -34,6 +35,7 @@ dmnsn_color_from_XYZ(dmnsn_CIE_XYZ XYZ) return ret; } +/* Convert a CIE xyY color to a dmnsn_color */ dmnsn_color dmnsn_color_from_xyY(dmnsn_CIE_xyY xyY) { @@ -44,6 +46,7 @@ dmnsn_color_from_xyY(dmnsn_CIE_xyY xyY) return ret; } +/* Inverse function of CIE L*a*b*'s `f' function, for the reverse conversion */ static double dmnsn_Lab_finv(double t) { if (t > 6.0/29.0) { return t*t*t; @@ -52,6 +55,8 @@ static double dmnsn_Lab_finv(double t) { } } +/* Convert a CIE L*a*b* color to a dmnsn_color, relative to the given + whitepoint. */ dmnsn_color dmnsn_color_from_Lab(dmnsn_CIE_Lab Lab, dmnsn_CIE_XYZ white) { @@ -71,6 +76,8 @@ dmnsn_color_from_Lab(dmnsn_CIE_Lab Lab, dmnsn_CIE_XYZ white) return ret; } +/* Convert a CIE L*u*v* color to a dmnsn_color, relative to the given + whitepoint. */ dmnsn_color dmnsn_color_from_Luv(dmnsn_CIE_Luv Luv, dmnsn_CIE_XYZ white) { @@ -94,6 +101,7 @@ dmnsn_color_from_Luv(dmnsn_CIE_Luv Luv, dmnsn_CIE_XYZ white) return ret; } +/* Inverse function of sRGB's `C' function, for the reverse conversion */ static double dmnsn_sRGB_Cinv(double CsRGB) { /* * If C represents R, G, and B, then the Clinear values are now found as @@ -110,6 +118,7 @@ static double dmnsn_sRGB_Cinv(double CsRGB) { } } +/* Convert an sRGB value to a dmnsn_color */ dmnsn_color dmnsn_color_from_sRGB(dmnsn_sRGB sRGB) { @@ -140,6 +149,7 @@ dmnsn_color_from_sRGB(dmnsn_sRGB sRGB) return ret; } +/* Convert a dmnsn_color to a CIE XYZ color (actually a no-op) */ dmnsn_CIE_XYZ dmnsn_XYZ_from_color(dmnsn_color color) { @@ -147,6 +157,7 @@ dmnsn_XYZ_from_color(dmnsn_color color) return ret; } +/* Convert a dmnsn_color to a CIE xyY color */ dmnsn_CIE_xyY dmnsn_xyY_from_color(dmnsn_color color) { @@ -156,6 +167,7 @@ dmnsn_xyY_from_color(dmnsn_color color) return ret; } +/* CIE L*a*b*'s `f' function */ static double dmnsn_Lab_f(double t) { if (t > 216.0/24389.0) { return pow(t, 1.0/3.0); @@ -164,6 +176,8 @@ static double dmnsn_Lab_f(double t) { } } +/* Convert a dmnsn_color to a CIE L*a*b* color, relative to the given + whitepoint */ dmnsn_CIE_Lab dmnsn_Lab_from_color(dmnsn_color color, dmnsn_CIE_XYZ white) { @@ -176,6 +190,8 @@ dmnsn_Lab_from_color(dmnsn_color color, dmnsn_CIE_XYZ white) return ret; } +/* Convert a dmnsn_color to a CIE L*u*v* color, relative to the given + whitepoint */ dmnsn_CIE_Luv dmnsn_Luv_from_color(dmnsn_color color, dmnsn_CIE_XYZ white) { @@ -194,6 +210,7 @@ dmnsn_Luv_from_color(dmnsn_color color, dmnsn_CIE_XYZ white) return ret; } +/* sRGB's `C' function */ static double dmnsn_sRGB_C(double Clinear) { /* * If C represents R, G, and B, then the sRGB values are now found as follows: @@ -209,6 +226,7 @@ static double dmnsn_sRGB_C(double Clinear) { } } +/* Convert a dmnsn_color to an sRGB color */ dmnsn_sRGB dmnsn_sRGB_from_color(dmnsn_color color) { @@ -234,6 +252,7 @@ dmnsn_sRGB_from_color(dmnsn_color color) return ret; } +/* Add two colors in a perceptually correct manner, using CIE L*a*b*. */ dmnsn_color dmnsn_color_add(dmnsn_color color1, dmnsn_color color2) { @@ -254,6 +273,7 @@ dmnsn_color_add(dmnsn_color color1, dmnsn_color color2) return ret; } +/* Find the perceptual difference between two colors, using CIE L*a*b*. */ double dmnsn_color_difference(dmnsn_color color1, dmnsn_color color2) { -- cgit v1.2.3