void cpdf_curveto (int pdf document, double x1, double y1, double x2, double y2, double x3, double y3 [, int mode])
The cpdf_curveto() function draws a Bezier curve from the current point to the point (x3, y3) using (x1, y1) and (x2, y2) as control points.
The optional parameter mode determines the unit length. If it's 0 or omitted the default unit as specified for the page is used. Otherwise the coordinates are measured in postscript points disregarding the current unit.
See also cpdf_moveto(), cpdf_rmoveto(), cpdf_rlineto(), cpdf_lineto().