Creates a shading, which can be used by ps_shfill or ps_shading_pattern.
The color of the shading can be in any color space except for pattern.
Resource identifier of the postscript file as returned by ps_new.
The type of shading can be either radial or axial. Each shading starts with the current fill color and ends with the given color values passed in the parameters c1 to c4 (see ps_setcolor for their meaning).
- x0, x1, y0, y1
The coordinates x0, y0, x1, y1 are the start and end point of the shading. If the type of shading is radial the two points are the middle points of a starting and ending circle.
- c1, c2, c3, c4
See ps_setcolor for their meaning.
If the shading is of type radial the optlist must also contain the parameters r0 and r1 with the radius of the start and end circle.
Returns the identifier of the pattern or false on failure.