cairo-mesh-pattern-set-control-point (pattern point-num x y)

pattern -- a cairo-pattern-t instance
point-num -- an unsigned integer with the control point to set the position for
x -- the double float x coordinate of the control point
y -- the double float y coordinate of the control point

Set an internal control point of the current patch.

Valid values for point-num are from 0 to 3 and identify the control points as explained for the function cairo-pattern-create-mesh. If pattern is not a mesh pattern then pattern will be put into an error status with a status of :pattern-type-mismatch. If point-num is not valid, pattern will be put into an error status with a status of :invalid-index. If pattern has no current patch, pattern will be put into an error status with a status of :invalid-mesh-construction.