X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=images%2Fcolor.c;h=80f48294c86c0db14d7d5fe925a365c6469208ef;hb=9c00dfe809b9ac03c1cbe8a233812f486f64ddcb;hp=e6846605681d45a4c955f30192113370445a542c;hpb=35d602a8f8676b8988eca13086c63f2026c1b952;p=libucw.git

diff --git a/images/color.c b/images/color.c
index e6846605..80f48294 100644
--- a/images/color.c
+++ b/images/color.c
@@ -11,8 +11,61 @@
 
 #include "sherlock/sherlock.h"
 #include "lib/math.h"
+#include "images/images.h"
 #include "images/color.h"
 
+struct color color_black = { .color_space = COLOR_SPACE_GRAYSCALE };
+struct color color_white = { .c = { 255 }, .color_space = COLOR_SPACE_GRAYSCALE };
+
+inline void
+color_put_grayscale(byte *dest, struct color *color)
+{
+  switch (color->color_space)
+    {
+      case COLOR_SPACE_GRAYSCALE:
+	dest[0] = color->c[0];
+	break;
+      case COLOR_SPACE_RGB:
+	dest[0] = rgb_to_gray_func(color->c[0], color->c[1], color->c[2]);
+	break;
+      default:
+	ASSERT(0);	
+    }
+}
+
+inline void
+color_put_rgb(byte *dest, struct color *color)
+{
+  switch (color->color_space)
+    {
+      case COLOR_SPACE_GRAYSCALE:
+	dest[0] = dest[1] = dest[2] = color->c[0];
+	break;
+      case COLOR_SPACE_RGB:
+	dest[0] = color->c[0];
+	dest[1] = color->c[1];
+	dest[2] = color->c[2];
+	break;
+      default:
+	ASSERT(0);	
+    }
+}
+
+void
+color_put_color_space(byte *dest, struct color *color, enum color_space color_space)
+{
+  switch (color_space)
+    {
+      case COLOR_SPACE_GRAYSCALE:
+	color_put_grayscale(dest, color);
+	break;  
+      case COLOR_SPACE_RGB:
+	color_put_rgb(dest, color);	
+	break;
+      default:
+	ASSERT(0);	
+    }
+}
 
 /********************* EXACT CONVERSION ROUTINES **********************/
 
@@ -31,6 +84,21 @@ srgb_to_xyz_slow(double xyz[3], double srgb[3])
   xyz[2] = SRGB_XYZ_ZR * a[0] + SRGB_XYZ_ZG * a[1] + SRGB_XYZ_ZB * a[2];
 }
 
+/* XYZ to sRGB */
+void
+xyz_to_srgb_slow(double srgb[3], double xyz[3])
+{
+  double a[3];
+  a[0] =  3.2406 * xyz[0] + -1.5372 * xyz[1] + -0.4986 * xyz[2];
+  a[1] = -0.9689 * xyz[0] +  1.8758 * xyz[1] +  0.0415 * xyz[2];
+  a[2] =  0.0557 * xyz[0] + -0.2040 * xyz[1] +  1.0570 * xyz[2];
+  for (uns i = 0; i < 3; i++)
+    if (a[i] > 0.0031308)
+      srgb[i] = 1.055 * pow(a[i], 1 / 2.4) - 0.055;
+    else
+      srgb[i] = 12.92 * a[i];
+}
+
 /* XYZ to CIE-Luv */
 void
 xyz_to_luv_slow(double luv[3], double xyz[3])
@@ -52,6 +120,23 @@ xyz_to_luv_slow(double luv[3], double xyz[3])
    }
 }
 
+/* CIE-Luv to XYZ */
+void
+luv_to_xyz_slow(double xyz[3], double luv[3])
+{
+  double var_u = luv[1] / (13 * luv[0]) + (4 * REF_WHITE_X / (REF_WHITE_X + 15 * REF_WHITE_Y + 3 * REF_WHITE_Z));
+  double var_v = luv[2] / (13 * luv[0]) + (9 * REF_WHITE_Y / (REF_WHITE_X + 15 * REF_WHITE_Y + 3 * REF_WHITE_Z));
+  double var_y = (luv[0] + 16) / 116;
+  double pow_y = var_y * var_y * var_y;
+  if (pow_y > 0.008856)
+    var_y = pow_y;
+  else
+    var_y = (var_y - 16 / 116) / 7.787;
+  xyz[1] = var_y;
+  xyz[0] = -(9 * xyz[1] * var_u) / ((var_u - 4) * var_v - var_u * var_v);
+  xyz[2] = (9 * xyz[1] - 15 * var_v * xyz[1] - var_v * xyz[0]) / (3 * var_v);
+}
+
 
 /***************** OPTIMIZED SRGB -> LUV CONVERSION *********************/