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authorTavian Barnes <tavianator@gmail.com>2009-04-12 19:06:50 +0000
committerTavian Barnes <tavianator@gmail.com>2009-04-12 19:06:50 +0000
commitb9e19e076662ae5743b9c81eb238fe11204f6dbd (patch)
tree2a29279adf20a2b8291f56f341695db07e861e98 /libdimension/color.c
parent8a4f9e902cf64f97ee2f15fa3940a7cf183a27b7 (diff)
downloaddimension-b9e19e076662ae5743b9c81eb238fe11204f6dbd.tar.xz
Add some comments.
Diffstat (limited to 'libdimension/color.c')
-rw-r--r--libdimension/color.c20
1 files changed, 20 insertions, 0 deletions
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)
{