Make colors less abstract.

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);
 }