void pdf_curveto (int pdf document, double x1, double y1, double x2, double y2, double x3, double y3)
The PDF_curveto() function draws a Bezier curve from the current point to the point (x3, y3) using (x1, y1) and (x2, y2) as control points.
See also PDF_moveto(), PDF_lineto(), PDF_stroke().