# File lib/rvg/pathdata.rb, line 94
            def smooth_curveto(abs, x2, y2, x, y, *coords)
                @path << sprintf("%s%g,%g %g,%g ", (abs ? 'S' : 's'), x2, y2, x, y)
                # "multiple sets of coordinates may be specified to draw a polybezier"
                add_points(4, *coords)
            end