Fix color addition.

1 files changed, 34 insertions, 37 deletions

diff --git a/libdimension/color.c b/libdimension/color.c
index 9243a19..25a6826 100644
--- a/libdimension/color.c
+++ b/libdimension/color.c
@@ -21,33 +21,30 @@
 #include "dimension.h"
 #include <math.h> /* For pow() */
 
-dmnsn_CIE_XYZ whitepoint = { 0.9505, 1, 1.089 };
+/* sRGB white point (D50) */
+dmnsn_CIE_XYZ whitepoint = { .X = 0.9504060171449392,
+                             .Y = 0.9999085943425312,
+                             .Z = 1.089062231497274 };
 
 dmnsn_color
 dmnsn_color_from_XYZ(dmnsn_CIE_XYZ XYZ)
 {
-  dmnsn_color ret;
-  ret.X = XYZ.X;
-  ret.Y = XYZ.Y;
-  ret.Z = XYZ.Z;
-  ret.filter = 0.0;
-  ret.trans  = 0.0;
+  dmnsn_color ret = { .X = XYZ.X, .Y = XYZ.Y, .Z = XYZ.Z,
+                      .filter = 0.0, .trans = 0.0 };
   return ret;
 }
 
 dmnsn_color
 dmnsn_color_from_xyY(dmnsn_CIE_xyY xyY)
 {
-  dmnsn_color ret;
-  ret.X = xyY.Y*xyY.x/xyY.y;
-  ret.Y = xyY.Y;
-  ret.Z = xyY.Y*(1.0 - xyY.x - xyY.Y)/xyY.y;
-  ret.filter = 0.0;
-  ret.trans  = 0.0;
+  dmnsn_color 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;
 }
 
-static double Lab_finv(double t) {
+static double dmnsn_Lab_finv(double t) {
   if (t > 6.0/29.0) {
     return t*t*t;
   } else {
@@ -65,9 +62,9 @@ dmnsn_color_from_Lab(dmnsn_CIE_Lab Lab, dmnsn_CIE_XYZ white)
   fx = fy + Lab.a/500.0;
   fz = fy - Lab.b/200.0;
 
-  ret.X = white.X*Lab_finv(fx);
-  ret.Y = white.Y*Lab_finv(fy);
-  ret.Z = white.Z*Lab_finv(fz);
+  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 ret;
 }
@@ -86,14 +83,14 @@ dmnsn_color_from_Luv(dmnsn_CIE_Luv Luv, dmnsn_CIE_XYZ white)
   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*Lab_finv(fy);
+  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 ret;
 }
 
-static double sRGB_Cinv(double CsRGB) {
+static double dmnsn_sRGB_Cinv(double CsRGB) {
   /*
    * If C represents R, G, and B, then the Clinear values are now found as
    * follows:
@@ -115,9 +112,9 @@ dmnsn_color_from_sRGB(dmnsn_sRGB sRGB)
   double Rlinear, Glinear, Blinear; /* Linear RGB values - no gamma */
   dmnsn_color ret;
 
-  Rlinear = sRGB_Cinv(sRGB.R);
-  Glinear = sRGB_Cinv(sRGB.G);
-  Blinear = sRGB_Cinv(sRGB.B);
+  Rlinear = dmnsn_sRGB_Cinv(sRGB.R);
+  Glinear = dmnsn_sRGB_Cinv(sRGB.G);
+  Blinear = dmnsn_sRGB_Cinv(sRGB.B);
 
   /*
    * Now, the linear conversion.  Expressed as matrix multiplication, it looks
@@ -142,20 +139,20 @@ dmnsn_color_from_sRGB(dmnsn_sRGB sRGB)
 dmnsn_CIE_XYZ
 dmnsn_XYZ_from_color(dmnsn_color color)
 {
-  dmnsn_CIE_XYZ ret = { color.X, color.Y, color.Z };
+  dmnsn_CIE_XYZ ret = { .X = color.X, .Y = color.Y, .Z = color.Z };
   return ret;
 }
 
 dmnsn_CIE_xyY
 dmnsn_xyY_from_color(dmnsn_color color)
 {
-  dmnsn_CIE_xyY ret = { color.X/(color.X + color.Y + color.Z),
-                        color.Y/(color.X + color.Y + color.Z),
-                        color.Y };
+  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;
 }
 
-static double Lab_f(double t) {
+static double dmnsn_Lab_f(double t) {
   if (t > 216.0/24389.0) {
     return pow(t, 1.0/3.0);
   } else {
@@ -168,9 +165,9 @@ dmnsn_Lab_from_color(dmnsn_color color, dmnsn_CIE_XYZ white)
 {
   dmnsn_CIE_Lab ret;
 
-  ret.L = 116.0*Lab_f(color.Y/white.Y) - 16.0;
-  ret.a = 500.0*(Lab_f(color.X/white.X) - Lab_f(color.Y/white.Y));
-  ret.b = 200.0*(Lab_f(color.Y/white.Y) - Lab_f(color.Z/white.Z));
+  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));
 
   return ret;
 }
@@ -186,14 +183,14 @@ dmnsn_Luv_from_color(dmnsn_color color, dmnsn_CIE_XYZ white)
   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);
 
-  ret.L = 116.0*Lab_f(color.Y/white.Y) - 16.0;
+  ret.L = 116.0*dmnsn_Lab_f(color.Y/white.Y) - 16.0;
   ret.u = 13.0*ret.L*(uprime - unprime);
   ret.v = 13.0*ret.L*(vprime - vnprime);
 
   return ret;
 }
 
-static double sRGB_C(double Clinear) {
+static double dmnsn_sRGB_C(double Clinear) {
   /*
    * If C represents R, G, and B, then the sRGB values are now found as follows:
    *
@@ -226,9 +223,9 @@ dmnsn_sRGB_from_color(dmnsn_color color)
   Glinear = -0.9692*color.X + 1.8760*color.Y + 0.0416*color.Z;
   Blinear =  0.0556*color.X - 0.2040*color.Y + 1.0570*color.Z;
 
-  ret.R = sRGB_C(Rlinear);
-  ret.G = sRGB_C(Glinear);
-  ret.B = sRGB_C(Blinear);
+  ret.R = dmnsn_sRGB_C(Rlinear);
+  ret.G = dmnsn_sRGB_C(Glinear);
+  ret.B = dmnsn_sRGB_C(Blinear);
 
   return ret;
 }
@@ -243,8 +240,8 @@ dmnsn_color_add(dmnsn_color color1, dmnsn_color color2)
   Lab2 = dmnsn_Lab_from_color(color2, whitepoint);
 
   Lab.L = Lab1.L + Lab2.L;
-  Lab.a = (Lab1.L*Lab1.a + Lab2.L*Lab2.a)/Lab.L;
-  Lab.b = (Lab1.L*Lab1.b + Lab2.L*Lab2.b)/Lab.L;
+  Lab.a = Lab1.a + Lab2.a;
+  Lab.b = Lab1.b + Lab2.b;
 
   ret = dmnsn_color_from_Lab(Lab, whitepoint);
   ret.filter = (Lab1.L*color1.filter + Lab2.L*color2.filter)/Lab.L;