diff options
Diffstat (limited to 'libdimension/color.c')
| -rw-r--r-- | libdimension/color.c | 301 |
1 files changed, 125 insertions, 176 deletions
diff --git a/libdimension/color.c b/libdimension/color.c index 15c6150..4421224 100644 --- a/libdimension/color.c +++ b/libdimension/color.c @@ -28,96 +28,105 @@ const dmnsn_CIE_XYZ dmnsn_whitepoint = { .X = 0.9504060171449392, /* Standard colors */ const dmnsn_color dmnsn_black = { - .X = 0.0, - .Y = 0.0, - .Z = 0.0, + .R = 0.0, + .G = 0.0, + .B = 0.0, .filter = 0.0, .trans = 0.0 }; const dmnsn_color dmnsn_white = { - .X = 0.9504060171449392, - .Y = 0.9999085943425312, - .Z = 1.089062231497274, + .R = 1.0, + .G = 1.0, + .B = 1.0, .filter = 0.0, .trans = 0.0 }; const dmnsn_color dmnsn_red = { - .X = 0.4123808838268995, - .Y = 0.2126198631048975, - .Z = 0.0193434956789248, + .R = 1.0, + .G = 0.0, + .B = 0.0, .filter = 0.0, .trans = 0.0 }; const dmnsn_color dmnsn_green = { - .X = 0.3575728355732478, - .Y = 0.7151387878413206, - .Z = 0.1192121694056356, + .R = 0.0, + .G = 1.0, + .B = 0.0, .filter = 0.0, .trans = 0.0 }; const dmnsn_color dmnsn_blue = { - .X = 0.1804522977447919, - .Y = 0.0721499433963131, - .Z = 0.950506566412713, + .R = 0.0, + .G = 0.0, + .B = 1.0, .filter = 0.0, .trans = 0.0 }; const dmnsn_color dmnsn_magenta = { - .X = 0.5928331815716914, - .Y = 0.2847698065012106, - .Z = 0.9698500620916378, + .R = 1.0, + .G = 0.0, + .B = 1.0, .filter = 0.0, .trans = 0.0 }; const dmnsn_color dmnsn_yellow = { - .X = 0.7699537194001473, - .Y = 0.9277586509462181, - .Z = 0.1385556650845604, + .R = 1.0, + .G = 1.0, + .B = 0.0, .filter = 0.0, .trans = 0.0 }; const dmnsn_color dmnsn_cyan = { - .X = 0.5380251333180397, - .Y = 0.7872887312376337, - .Z = 1.069718735818349, + .R = 0.0, + .G = 1.0, + .B = 1.0, .filter = 0.0, .trans = 0.0 }; -/* Convert a CIE XYZ color to a dmnsn_color (actually a no-op) */ +/* 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 ret = { .X = XYZ.X, .Y = XYZ.Y, .Z = XYZ.Z, - .filter = 0.0, .trans = 0.0 }; - return ret; + 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_color ret = { + 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, - .filter = 0.0, - .trans = 0.0 - }; - return ret; -} - -dmnsn_color -dmnsn_color_from_RGB(dmnsn_CIE_RGB RGB) -{ - dmnsn_color ret = { - .X = 0.49*RGB.R + 0.31*RGB.G + 0.20*RGB.B, - .Y = 0.17697*RGB.R + 0.81240*RGB.G + 0.01063*RGB.B, - .Z = 0.00*RGB.R + 0.01*RGB.G + 0.99*RGB.B, - .filter = 0.0, - .trans = 0.0 }; - return ret; + return dmnsn_color_from_XYZ(ret); } /* Inverse function of CIE L*a*b*'s `f' function, for the reverse conversion */ @@ -135,7 +144,7 @@ dmnsn_color dmnsn_color_from_Lab(dmnsn_CIE_Lab Lab, dmnsn_CIE_XYZ white) { double fx, fy, fz; - dmnsn_color ret; + dmnsn_CIE_XYZ ret; fy = (Lab.L + 16.0)/116.0; fx = fy + Lab.a/500.0; @@ -144,10 +153,7 @@ dmnsn_color_from_Lab(dmnsn_CIE_Lab Lab, dmnsn_CIE_XYZ white) ret.X = white.X*dmnsn_Lab_finv(fx); ret.Y = white.Y*dmnsn_Lab_finv(fy); ret.Z = white.Z*dmnsn_Lab_finv(fz); - ret.filter = 0.0; - ret.trans = 0.0; - - return ret; + return dmnsn_color_from_XYZ(ret); } /* Convert a CIE L*u*v* color to a dmnsn_color, relative to the given @@ -157,7 +163,7 @@ dmnsn_color_from_Luv(dmnsn_CIE_Luv Luv, dmnsn_CIE_XYZ white) { double fy; double uprime, unprime, vprime, vnprime; - dmnsn_color ret; + dmnsn_CIE_XYZ ret; fy = (Luv.L + 16.0)/116.0; @@ -169,9 +175,20 @@ dmnsn_color_from_Luv(dmnsn_CIE_Luv Luv, dmnsn_CIE_XYZ white) 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; - ret.filter = 0.0; - ret.trans = 0.0; + return dmnsn_color_from_XYZ(ret); +} +/* 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; } @@ -192,39 +209,22 @@ static double dmnsn_sRGB_Cinv(double CsRGB) { } } -/* Perform the inverse linear sRGB conversion */ -static dmnsn_color -dmnsn_linear_color_from_sRGB(dmnsn_sRGB sRGB) -{ - dmnsn_color ret = { - .X = 0.4123808838268995*sRGB.R + 0.3575728355732478*sRGB.G - + 0.1804522977447919*sRGB.B, - .Y = 0.2126198631048975*sRGB.R + 0.7151387878413206*sRGB.G - + 0.0721499433963131*sRGB.B, - .Z = 0.0193434956789248*sRGB.R + 0.1192121694056356*sRGB.G - + 0.9505065664127130*sRGB.B, - .filter = 0.0, - .trans = 0.0 - }; - return ret; -} - -/* Convert an sRGB value to a dmnsn_color */ -dmnsn_color -dmnsn_color_from_sRGB(dmnsn_sRGB sRGB) -{ - sRGB.R = dmnsn_sRGB_Cinv(sRGB.R); - sRGB.G = dmnsn_sRGB_Cinv(sRGB.G); - sRGB.B = dmnsn_sRGB_Cinv(sRGB.B); - - return dmnsn_linear_color_from_sRGB(sRGB); -} - -/* Convert a dmnsn_color to a CIE XYZ color (actually a no-op) */ +/* Convert a dmnsn_color to a CIE XYZ color */ dmnsn_CIE_XYZ dmnsn_XYZ_from_color(dmnsn_color color) { - dmnsn_CIE_XYZ ret = { .X = color.X, .Y = color.Y, .Z = color.Z }; + 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; } @@ -232,24 +232,11 @@ dmnsn_XYZ_from_color(dmnsn_color 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 = color.X/(color.X + color.Y + color.Z), - .y = color.Y/(color.X + color.Y + color.Z), - .Y = color.Y - }; - return ret; -} - -dmnsn_CIE_RGB -dmnsn_RGB_from_color(dmnsn_color color) -{ - dmnsn_CIE_RGB ret = { - .R = 2.36461384653836548*color.X + -0.89654057073966797*color.Y - + -0.46807327579869740*color.Z, - .G = -0.51516620844788796*color.X + 1.42640810385638872*color.Y - + 0.08875810459149917*color.Z, - .B = 0.00520369907523119*color.X + -0.01440816266521605*color.Y - + 1.00920446358998483*color.Z + .x = XYZ.X/(XYZ.X + XYZ.Y + XYZ.Z), + .y = XYZ.Y/(XYZ.X + XYZ.Y + XYZ.Z), + .Y = XYZ.Y }; return ret; } @@ -268,12 +255,12 @@ static double dmnsn_Lab_f(double t) { 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(color.Y/white.Y) - 16.0; - ret.a = 500.0*(dmnsn_Lab_f(color.X/white.X) - dmnsn_Lab_f(color.Y/white.Y)); - ret.b = 200.0*(dmnsn_Lab_f(color.Y/white.Y) - dmnsn_Lab_f(color.Z/white.Z)); - + 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; } @@ -282,80 +269,51 @@ dmnsn_Lab_from_color(dmnsn_color color, dmnsn_CIE_XYZ white) 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*color.X/(color.X + 15.0*color.Y + 3.0*color.Z); - unprime = 4.0*white.X/(white.X + 15.0*white.Y + 3.0*white.Z); - vprime = 9.0*color.Y/(color.X + 15.0*color.Y + 3.0*color.Z); - vnprime = 9.0*white.Y/(white.X + 15.0*white.Y + 3.0*white.Z); + 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(color.Y/white.Y) - 16.0; + 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; -} - -/* 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; - } -} - -/* Perform the linear sRGB conversion */ -static dmnsn_sRGB -dmnsn_linear_sRGB_from_color(dmnsn_color color) -{ - dmnsn_sRGB ret = { - .R = 3.2410*color.X - 1.5374*color.Y - 0.4986*color.Z, - .G = -0.9692*color.X + 1.8760*color.Y + 0.0416*color.Z, - .B = 0.0556*color.X - 0.2040*color.Y + 1.0570*color.Z - }; return ret; } -/* Convert a dmnsn_color to an sRGB color */ +/* Convert a dmnsn_color to an sRGB color (actually a no-op) */ dmnsn_sRGB dmnsn_sRGB_from_color(dmnsn_color color) { - dmnsn_sRGB sRGB = dmnsn_linear_sRGB_from_color(color); - - sRGB.R = dmnsn_sRGB_C(sRGB.R); - sRGB.G = dmnsn_sRGB_C(sRGB.G); - sRGB.B = dmnsn_sRGB_C(sRGB.B); - + dmnsn_sRGB sRGB = { .R = color.R, .G = color.G, .B = color.B }; return sRGB; } /* Add two colors in a perceptually correct manner, using CIE L*a*b*. */ dmnsn_color -dmnsn_color_add(dmnsn_color color1, dmnsn_color color2) +dmnsn_color_add(dmnsn_color c1, dmnsn_color c2) { - dmnsn_CIE_Lab Lab1 = dmnsn_Lab_from_color(color1, dmnsn_whitepoint); - dmnsn_CIE_Lab Lab2 = dmnsn_Lab_from_color(color2, dmnsn_whitepoint); + 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_CIE_Lab Lab = { .L = Lab1.L + Lab2.L, - .a = Lab1.a + Lab2.a, - .b = Lab1.b + Lab2.b }; + dmnsn_color ret = dmnsn_color_from_sRGB(sRGB); - dmnsn_color ret = dmnsn_color_from_Lab(Lab, dmnsn_whitepoint); /* Weighted average of transparencies by intensity */ - if (Lab.L) { - ret.filter = (Lab1.L*color1.filter + Lab2.L*color2.filter)/Lab.L; - ret.trans = (Lab1.L*color1.trans + Lab2.L*color2.trans)/Lab.L; + dmnsn_CIE_Lab Lab1 = dmnsn_Lab_from_color(ret, dmnsn_whitepoint); + dmnsn_CIE_Lab Lab2 = dmnsn_Lab_from_color(ret, dmnsn_whitepoint); + if (Lab1.L + Lab2.L) { + ret.filter = (Lab1.L*c1.filter + Lab2.L*c2.filter)/(Lab1.L + Lab2.L); + ret.trans = (Lab1.L*c1.trans + Lab2.L*c2.trans )/(Lab1.L + Lab2.L); } - return ret; } @@ -363,15 +321,14 @@ dmnsn_color_add(dmnsn_color color1, dmnsn_color color2) dmnsn_color dmnsn_color_mul(double n, dmnsn_color color) { - dmnsn_CIE_Lab Lab = dmnsn_Lab_from_color(color, dmnsn_whitepoint); - Lab.L *= n; - Lab.a *= n; - Lab.b *= n; + dmnsn_sRGB sRGB = dmnsn_sRGB_from_color(color); + sRGB.R *= n; + sRGB.G *= n; + sRGB.B *= n; - dmnsn_color ret = dmnsn_color_from_Lab(Lab, dmnsn_whitepoint); + dmnsn_color ret = dmnsn_color_from_sRGB(sRGB); ret.filter = color.filter; ret.trans = color.trans; - return ret; } @@ -394,26 +351,18 @@ dmnsn_color dmnsn_color_illuminate(dmnsn_color light, dmnsn_color color) { /* We use the sRGB primaries */ - dmnsn_sRGB sRGB1 = dmnsn_linear_sRGB_from_color(light), - sRGB2 = dmnsn_linear_sRGB_from_color(color); - - double R1 = 1.16*dmnsn_Lab_f(sRGB1.R) - 0.16, - R2 = 1.16*dmnsn_Lab_f(sRGB2.R) - 0.16, - G1 = 1.16*dmnsn_Lab_f(sRGB1.G) - 0.16, - G2 = 1.16*dmnsn_Lab_f(sRGB2.G) - 0.16, - B1 = 1.16*dmnsn_Lab_f(sRGB1.B) - 0.16, - B2 = 1.16*dmnsn_Lab_f(sRGB2.B) - 0.16; + dmnsn_sRGB sRGB1 = dmnsn_sRGB_from_color(light); + dmnsn_sRGB sRGB2 = dmnsn_sRGB_from_color(color); dmnsn_sRGB sRGB = { - .R = dmnsn_Lab_finv((R1*R2 + 0.16)/1.16), - .G = dmnsn_Lab_finv((G1*G2 + 0.16)/1.16), - .B = dmnsn_Lab_finv((B1*B2 + 0.16)/1.16) + .R = sRGB1.R*sRGB2.R, + .G = sRGB1.G*sRGB2.G, + .B = sRGB1.B*sRGB2.B }; - dmnsn_color ret = dmnsn_linear_color_from_sRGB(sRGB); + dmnsn_color ret = dmnsn_color_from_sRGB(sRGB); ret.filter = color.filter; ret.trans = color.trans; - return ret; } |