Re: color-complement for defface

[Ted Zlatanov <tzz@lifelogs.com>]

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(patches?  we don't need no steenkin' patches!)

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=== modified file 'doc/lispref/display.texi'
--- doc/lispref/display.texi	2011-01-31 23:54:50 +0000
+++ doc/lispref/display.texi	2011-03-10 19:03:48 +0000
@@ -2057,6 +2057,21 @@
 black-and-white displays, certain shades of gray are implemented by
 stipple patterns.
 
+You may want to set the foreground automatically in some cases using
+the @code{color-complement} and @code{color-rgb-to-hex} functions from
+the @code{color.el} library.  Here's an example:
+
+@example
+(defface myface
+  (let ((color "red"))
+    `((((class color) (background light))
+       (:foreground ,color))
+      (((class color) (background dark))
+        (:foreground ,(apply 'color-rgb-to-hex (color-complement color))))
+      (t nil)))
+  "My face.")
+@end example
+
 @item :background
 Background color, a string.  The value can be a system-defined color
 name, or a hexadecimal color specification.  @xref{Color Names}.