func rCubicCurveTo(path draw2d.PathBuilder, dcx1, dcy1, dcx2, dcy2, dx, dy float64) {
x, y := path.LastPoint()
path.CubicCurveTo(x+dcx1, y+dcy1, x+dcx2, y+dcy2, x+dx, y+dy)
}
func rLineTo(path draw2d.PathBuilder, x, y float64) {
x0, y0 := path.LastPoint()
path.LineTo(x0+x, y0+y)
}
func rQuadCurveTo(path draw2d.PathBuilder, dcx, dcy, dx, dy float64) {
x, y := path.LastPoint()
path.QuadCurveTo(x+dcx, y+dcy, x+dx, y+dy)
}
