diff options
Diffstat (limited to 'libdimension/color.c')
| -rw-r--r-- | libdimension/color.c | 308 |
1 files changed, 16 insertions, 292 deletions
diff --git a/libdimension/color.c b/libdimension/color.c index 0af063f..24a4574 100644 --- a/libdimension/color.c +++ b/libdimension/color.c @@ -24,12 +24,6 @@ */ #include "dimension.h" -#include <math.h> /* For pow(), sqrt() */ - -/* sRGB white point (CIE D50) */ -const dmnsn_CIE_XYZ dmnsn_whitepoint = { .X = 0.9504060171449392, - .Y = 0.9999085943425312, - .Z = 1.089062231497274 }; /* Standard colors */ const dmnsn_color dmnsn_black = { @@ -103,252 +97,19 @@ const dmnsn_color dmnsn_cyan = { .trans = 0.0 }; -bool -dmnsn_color_is_black(dmnsn_color color) -{ - return color.R == 0.0 && color.G == 0.0 && color.B == 0.0; -} - -/* Convert an sRGB color to a dmnsn_color (actually a no-op) */ -dmnsn_color -dmnsn_color_from_sRGB(dmnsn_sRGB sRGB) -{ - dmnsn_color ret = { - .R = sRGB.R, - .G = sRGB.G, - .B = sRGB.B, - .filter = 0.0, - .trans = 0.0 - }; - 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: - * - * { 12.92*Clinear, Clinear <= 0.0031308 - * Csrgb = { 1/2.4 - * { (1.055)*Clinear - 0.055, Clinear > 0.0031308 - */ - if (Clinear <= 0.0031308) { - return 12.92*Clinear; - } else { - return 1.055*pow(Clinear, 1.0/2.4) - 0.055; - } -} - -/* Convert a CIE XYZ color to a dmnsn_color */ -dmnsn_color -dmnsn_color_from_XYZ(dmnsn_CIE_XYZ XYZ) -{ - dmnsn_color color = { - .R = 3.2410*XYZ.X - 1.5374*XYZ.Y - 0.4986*XYZ.Z, - .G = -0.9692*XYZ.X + 1.8760*XYZ.Y + 0.0416*XYZ.Z, - .B = 0.0556*XYZ.X - 0.2040*XYZ.Y + 1.0570*XYZ.Z, - .filter = 0.0, - .trans = 0.0 - }; - color.R = dmnsn_sRGB_C(color.R); - color.G = dmnsn_sRGB_C(color.G); - color.B = dmnsn_sRGB_C(color.B); - return color; -} - -/* Convert a CIE xyY color to a dmnsn_color */ -dmnsn_color -dmnsn_color_from_xyY(dmnsn_CIE_xyY xyY) -{ - dmnsn_CIE_XYZ ret = { - .X = xyY.Y*xyY.x/xyY.y, - .Y = xyY.Y, - .Z = xyY.Y*(1.0 - xyY.x - xyY.y)/xyY.y, - }; - return dmnsn_color_from_XYZ(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; - } else { - return 108.0*(t - 16.0/116.0)/841.0; - } -} - -/* 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) -{ - double fx, fy, fz; - dmnsn_CIE_XYZ ret; - - fy = (Lab.L + 16.0)/116.0; - fx = fy + Lab.a/500.0; - fz = fy - Lab.b/200.0; - - ret.X = white.X*dmnsn_Lab_finv(fx); - ret.Y = white.Y*dmnsn_Lab_finv(fy); - ret.Z = white.Z*dmnsn_Lab_finv(fz); - return dmnsn_color_from_XYZ(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) -{ - double fy; - double uprime, unprime, vprime, vnprime; - dmnsn_CIE_XYZ ret; - - fy = (Luv.L + 16.0)/116.0; - - unprime = 4.0*white.X/(white.X + 15.0*white.Y + 3.0*white.Z); - uprime = Luv.u/Luv.L/13.0 + unprime; - vnprime = 9.0*white.Y/(white.X + 15.0*white.Y + 3.0*white.Z); - vprime = Luv.v/Luv.L/13.0 + vnprime; - - ret.Y = white.Y*dmnsn_Lab_finv(fy); - ret.X = ret.Y*9.0*uprime/vprime/4.0; - ret.Z = ret.Y*(12.0 - 3*uprime - 20*vprime)/vprime/4.0; - return dmnsn_color_from_XYZ(ret); -} - -/* Convert a dmnsn_color to an sRGB color (actually a no-op) */ -dmnsn_sRGB -dmnsn_sRGB_from_color(dmnsn_color color) -{ - dmnsn_sRGB sRGB = { .R = color.R, .G = color.G, .B = color.B }; - return sRGB; -} - -/** 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 - * follows: - * - * { Csrgb/12.92, Csrgb <= 0.04045 - * Clinear = { 1/2.4 - * { ((Csrgb + 0.055)/1.055) , Csrgb > 0.04045 - */ - if (CsRGB <= 0.040449936) { - return CsRGB/12.92; - } else { - return pow((CsRGB + 0.055)/1.055, 2.4); - } -} - -/* Convert a dmnsn_color to a CIE XYZ color */ -dmnsn_CIE_XYZ -dmnsn_XYZ_from_color(dmnsn_color color) -{ - color.R = dmnsn_sRGB_Cinv(color.R); - color.G = dmnsn_sRGB_Cinv(color.G); - color.B = dmnsn_sRGB_Cinv(color.B); - - dmnsn_CIE_XYZ ret = { - .X = 0.4123808838268995*color.R + 0.3575728355732478*color.G - + 0.1804522977447919*color.B, - .Y = 0.2126198631048975*color.R + 0.7151387878413206*color.G - + 0.0721499433963131*color.B, - .Z = 0.0193434956789248*color.R + 0.1192121694056356*color.G - + 0.9505065664127130*color.B, - }; - return ret; -} - -/* Convert a dmnsn_color to a CIE xyY color */ -dmnsn_CIE_xyY -dmnsn_xyY_from_color(dmnsn_color color) -{ - dmnsn_CIE_XYZ XYZ = dmnsn_XYZ_from_color(color); - dmnsn_CIE_xyY ret = { - .x = XYZ.X/(XYZ.X + XYZ.Y + XYZ.Z), - .y = XYZ.Y/(XYZ.X + XYZ.Y + XYZ.Z), - .Y = XYZ.Y - }; - 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); - } else { - return 841.0*t/108.0 + 4.0/29.0; - } -} - -/* 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) -{ - dmnsn_CIE_XYZ XYZ = dmnsn_XYZ_from_color(color); - dmnsn_CIE_Lab ret; - - ret.L = 116.0*dmnsn_Lab_f(XYZ.Y/white.Y) - 16.0; - ret.a = 500.0*(dmnsn_Lab_f(XYZ.X/white.X) - dmnsn_Lab_f(XYZ.Y/white.Y)); - ret.b = 200.0*(dmnsn_Lab_f(XYZ.Y/white.Y) - dmnsn_Lab_f(XYZ.Z/white.Z)); - 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) -{ - dmnsn_CIE_XYZ XYZ = dmnsn_XYZ_from_color(color); - double uprime, unprime, vprime, vnprime; - dmnsn_CIE_Luv ret; - - uprime = 4.0*XYZ.X / (XYZ.X + 15.0*XYZ.Y + 3.0*XYZ.Z); - unprime = 4.0*white.X / (white.X + 15.0*white.Y + 3.0*white.Z); - vprime = 9.0*XYZ.Y / (XYZ.X + 15.0*XYZ.Y + 3.0*XYZ.Z); - vnprime = 9.0*white.Y / (white.X + 15.0*white.Y + 3.0*white.Z); - - ret.L = 116.0*dmnsn_Lab_f(XYZ.Y/white.Y) - 16.0; - ret.u = 13.0*ret.L*(uprime - unprime); - ret.v = 13.0*ret.L*(vprime - vnprime); - return ret; -} - /* Greyscale color intensity */ double dmnsn_color_intensity(dmnsn_color color) { - dmnsn_sRGB sRGB = dmnsn_sRGB_from_color(color); - return 0.2126198631048975*sRGB.R + 0.7151387878413206*sRGB.G - + 0.0721499433963131*sRGB.B; + return 0.2126198631048975*color.R + 0.7151387878413206*color.G + + 0.0721499433963131*color.B; } /* Add two colors */ dmnsn_color dmnsn_color_add(dmnsn_color c1, dmnsn_color c2) { - dmnsn_sRGB sRGB1 = dmnsn_sRGB_from_color(c1); - dmnsn_sRGB sRGB2 = dmnsn_sRGB_from_color(c2); - - dmnsn_sRGB sRGB = { - .R = sRGB1.R + sRGB2.R, - .G = sRGB1.G + sRGB2.G, - .B = sRGB1.B + sRGB2.B - }; - - dmnsn_color ret = dmnsn_color_from_sRGB(sRGB); + dmnsn_color ret = dmnsn_new_color(c1.R + c2.R, c1.G + c2.G, c1.B + c2.B); double n1 = dmnsn_color_intensity(c1), n2 = dmnsn_color_intensity(c2); if (n1 + n2 != 0.0) { @@ -363,34 +124,23 @@ dmnsn_color_add(dmnsn_color c1, dmnsn_color c2) dmnsn_color dmnsn_color_mul(double n, dmnsn_color color) { - dmnsn_sRGB sRGB = dmnsn_sRGB_from_color(color); - sRGB.R *= n; - sRGB.G *= n; - sRGB.B *= n; - - dmnsn_color ret = dmnsn_color_from_sRGB(sRGB); - ret.filter = color.filter; - ret.trans = color.trans; - return ret; + color.R *= n; + color.G *= n; + color.B *= n; + return color; } /* For n in [0, 1] get the color in a gradient between c1 and c2 */ dmnsn_color dmnsn_color_gradient(dmnsn_color c1, dmnsn_color c2, double n) { - dmnsn_sRGB sRGB1 = dmnsn_sRGB_from_color(c1); - dmnsn_sRGB sRGB2 = dmnsn_sRGB_from_color(c2); - - dmnsn_sRGB sRGB = { - .R = n*(sRGB2.R - sRGB1.R) + sRGB1.R, - .G = n*(sRGB2.G - sRGB1.G) + sRGB1.G, - .B = n*(sRGB2.B - sRGB1.B) + sRGB1.B - }; - - dmnsn_color ret = dmnsn_color_from_sRGB(sRGB); - ret.filter = n*(c2.filter - c1.filter) + c1.filter; - ret.trans = n*(c2.trans - c1.trans) + c1.trans; - return ret; + return dmnsn_new_color5( + n*(c2.R - c1.R) + c1.R, + n*(c2.G - c1.G) + c1.G, + n*(c2.B - c1.B) + c1.B, + n*(c2.filter - c1.filter) + c1.filter, + n*(c2.trans - c1.trans) + c1.trans + ); } /* Filters `light' through `filter' */ @@ -433,32 +183,6 @@ dmnsn_apply_filter(dmnsn_color color, dmnsn_color filter) dmnsn_color dmnsn_color_illuminate(dmnsn_color light, dmnsn_color color) { - /* We use the sRGB primaries */ - dmnsn_sRGB sRGB1 = dmnsn_sRGB_from_color(light); - dmnsn_sRGB sRGB2 = dmnsn_sRGB_from_color(color); - - dmnsn_sRGB sRGB = { - .R = sRGB1.R*sRGB2.R, - .G = sRGB1.G*sRGB2.G, - .B = sRGB1.B*sRGB2.B - }; - - dmnsn_color ret = dmnsn_color_from_sRGB(sRGB); - ret.filter = color.filter; - ret.trans = color.trans; - return ret; -} - -/* Find the perceptual difference between two colors, using CIE L*a*b* */ -double -dmnsn_color_difference(dmnsn_color color1, dmnsn_color color2) -{ - dmnsn_CIE_Lab Lab1, Lab2; - - Lab1 = dmnsn_Lab_from_color(color1, dmnsn_whitepoint); - Lab2 = dmnsn_Lab_from_color(color2, dmnsn_whitepoint); - - return sqrt((Lab1.L - Lab2.L)*(Lab1.L - Lab2.L) - + (Lab1.a - Lab2.a)*(Lab1.a - Lab2.a) - + (Lab1.b - Lab2.b)*(Lab1.b - Lab2.b)); + return dmnsn_new_color5(light.R*color.R, light.G*color.G, light.B*color.B, + color.filter, color.trans); } |