(face_color_gray_p): Colors close to black count as gray.

1 files changed, 12 insertions, 7 deletions

diff --git a/src/xfaces.c b/src/xfaces.c
index aa32c84b297..49ba6d334ec 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -1477,7 +1477,9 @@ tty_color_name (f, idx)
 
 
 /* Return non-zero if COLOR_NAME is a shade of gray (or white or
-   black) on frame F.  The algorithm is taken from 20.2 faces.el.  */
+   black) on frame F.
+
+   The criterion implemented here is not a terribly sophisticated one.  */
 
 static int
 face_color_gray_p (f, color_name)
@@ -1488,12 +1490,15 @@ face_color_gray_p (f, color_name)
   int gray_p;
 
   if (defined_color (f, color_name, &color, 0))
-    gray_p = ((abs (color.red - color.green)
-               < max (color.red, color.green) / 20)
-              && (abs (color.green - color.blue)
-                  < max (color.green, color.blue) / 20)
-              && (abs (color.blue - color.red)
-                  < max (color.blue, color.red) / 20));
+    gray_p = (/* Any color sufficiently close to black counts as grey.  */
+              (color.red < 5000 && color.green < 5000 && color.blue < 5000)
+              ||
+              ((abs (color.red - color.green)
+                < max (color.red, color.green) / 20)
+               && (abs (color.green - color.blue)
+                   < max (color.green, color.blue) / 20)
+               && (abs (color.blue - color.red)
+                   < max (color.blue, color.red) / 20)));
   else
     gray_p = 0;