Thanks for replying. I was specifying this through a new command line flag, which I defined as follows:
newtype Background = Background (Maybe (Colour Double))
instance Parseable Background where
parser = Opt.option (Opt.str >>= aux) $ mconcat [
, Opt.help "Background color"
aux :: String -> Opt.ReadM Background
aux "none" = return $ Background Nothing
aux str = Background . Just . fromAlphaColour <$> readHexColor str
and which I then use as follows
backgroundRect :: Background -> Diagram B
backgroundRect (Background background) =
rect (20 * nodeDiameter) (14 * nodeDiameter)
# lwO 0
# maybe id fc background
I worked around the problem by adding a border around the rendered animation (so that the difference between the animation and rest of background on which I was showing it wasn't so obvious).
Curious little problem! :)