A graphical computing system comprising a control unit and a set of edge processing units. The control unit (a) receives a surface primitive, (b) transfers edge specifying information for each edge of the surface primitive to a corresponding one of the edge processing units, and (c) transfers a horizontal address CX and a vertical address CY of a current pixel to the edge processing units. Each of the edge processing units computes trimming information for the current pixel with respect to the corresponding edge using the horizontal address CX and vertical address CY. The trimming information specifies a portion of the corresponding edge which intersects the current pixel. The control unit collects the trimming information from the edge processing units and transmits an output packet including the addresses CX and CY of the current pixel along with the collected trimming information.