Define a new starting point in the vector list for the following polygon defined by calls to AreaDraw(). The last polygon is closed if it wasn't closed by the user and the new starting points are added to the vector collection matrix.
INPUTS
rp
pointer to a valid RastPort structure with a pointer to the previously initilized AreaInfo structure.
x
x-coordinate of the starting-point in the raster
y
y-coordinate of the starting-point in the raster
RESULT
error - 0 for success -1 if the vector collection matrix is full