Expose colour_mix() to backends (and others)

Quite a few backends currently generate colours by multiplying the
foreground colour by a fraction, effectively mixing it with black.  On a
black background, this might be reasonably replaced by mixing the
background colour with white, but that's rather arithmetically fiddly.
Happily, I already have a function for that and just need to expose it.

1 files changed, 1 insertions, 2 deletions

diff --git a/misc.c b/misc.c
index aaabb39..c4c4b69 100644
--- a/misc.c
+++ b/misc.c
@@ -207,8 +207,7 @@ static float colour_distance(const float a[3], const float b[3])
                        (a[2]-b[2]) * (a[2]-b[2]));
 }
 
-static void colour_mix(const float src1[3], const float src2[3],
-                       float p, float dst[3])
+void colour_mix(const float src1[3], const float src2[3], float p, float dst[3])
 {
     int i;
     for (i = 0; i < 3; i++)