Patch idea from Debian, but modified considerably in implementation:

introduce a new colour in Slant (COL_FILLEDSQUARE) which is used for
the background of any grid square that has a diagonal line in it.
This makes it easier to spot the one square on a giant board you
forgot to fill in, but on the other hand I found it to look very
strange and disconcerting. So I've set the colour to be identical to
COL_BACKGROUND by default, and users who like the idea can enable it
by environment variable or by local patch.

[originally from svn r8930]

1 files changed, 4 insertions, 2 deletions

diff --git a/misc.c b/misc.c
index 4215e47..fe41332 100644
--- a/misc.c
+++ b/misc.c
@@ -187,8 +187,10 @@ void game_mkhighlight_specific(frontend *fe, float *ret,
     }
 
     for (i = 0; i < 3; i++) {
-        ret[highlight * 3 + i] = ret[background * 3 + i] * 1.2F;
-        ret[lowlight * 3 + i] = ret[background * 3 + i] * 0.8F;
+	if (highlight >= 0)
+	    ret[highlight * 3 + i] = ret[background * 3 + i] * 1.2F;
+	if (lowlight >= 0)
+	    ret[lowlight * 3 + i] = ret[background * 3 + i] * 0.8F;
     }
 }