Merge with git+ssh://cvs.ucw.cz/projects/sherlock/GIT/sherlock.git

[libucw.git] / images / color.h

diff --git a/images/color.h b/images/color.h
index 28daa822141bff1cef63e27655b8a6d272aff866..ec3cd4afd99e928f88baef9f8bafa3a0712d3d5c 100644 (file)
--- a/images/color.h
+++ b/images/color.h
@@ -15,6 +15,9 @@
  *     - SIMD should help to speed up conversion of large arrays
  *     - maybe try to generate a long switch in color_conv_pixel()
  *       with optimized entries instead of access to interpolation table
+ *     - most of multiplications in srgb_to_luv_pixels can be replaced
+ *       with tables lookup... tests shows almost the same speed for random
+ *       input and cca 40% gain when input colors fit in CPU chache
  */
 
 #ifndef _IMAGES_COLOR_H
@@ -56,6 +59,7 @@ extern u32 srgb_to_luv_tab3[20 << SRGB_TO_LUV_TAB3_SIZE];
 void srgb_to_luv_init(void);
 void srgb_to_luv_pixels(byte *dest, byte *src, uns count);
 
+/* L covers the interval [0..255]; u and v are centered to 128 and scaled by 1/4 in respect of L */
 static inline void
 srgb_to_luv_pixel(byte *dest, byte *src)
 {