Add a section of a cubic Bézier curve described by the three given control points to the current path.
psdocResource identifier of the postscript file as returned by ps_new().
x1x-coordinate of first control point.
y1y-coordinate of first control point.
x2x-coordinate of second control point.
y2y-coordinate of second control point.
x3x-coordinate of third control point.
y3y-coordinate of third control point.