Add battery shape/picture

src/Color.hs

@@ -79,6 +79,10 @@ normalizeColor (V4 r g b a) = V4 (f r) (f g) (f b) (f a)
   where
     f = min 1 . max 0
 
+mixColorsFrac :: Color -> Color -> Float -> Color
+{-# INLINE mixColorsFrac #-}
+mixColorsFrac c1 c2 x = mixColors x (1-x) c1 c2
+
 mixColors :: Float -> Float -> Color -> Color -> Color
 {-# INLINE mixColors #-}
 mixColors rata ratb (V4 r0 g0 b0 a0) (V4 r2 g2 b2 a2) =