carrow makes a arrow with a curved line lcarrow x1 y1 x2 y2 x3 y3 [linewidth] [arrowidth] [arrowheight] [color] [opacity] rcarrow x1 y1 x2 y2 x3 y3 [linewidth] [arrowidth] [arrowheight] [color] [opacity] ucarrow x1 y1 x2 y2 x3 y3 [linewidth] [arrowidth] [arrowheight] [color] [opacity] dcarrow x1 y1
(w io.Writer, s []string, linenumber int)