[color] add a note to the documentation to specify the values of the alpha

The alpha channel is fully opaque at 255 and fully transparent at 0.

diff --git a/clutter/clutter-color.c b/clutter/clutter-color.c
index f1c55f1..8c11c92 100644 (file)
--- a/clutter/clutter-color.c
+++ b/clutter/clutter-color.c
@@ -31,6 +31,8 @@
  *
  * A #ClutterColor is expressed as a 4-tuple of values ranging from
  * zero to 255, one for each color channel plus one for the alpha.
+ *
+ * The alpha channel is fully opaque at 255 and fully transparent at 0.
  */
 
 #ifdef HAVE_CONFIG_H