Abstract: A window clipping method and device for processing data with arbitrarily shaped clipping windows, wherein arbitrarily shaped clipping windows and graphic data are stored in separate bit mapped memories, employing a graphic processor and a controller. The drawing graph is drawn only inside the clipping window, and patterns of the clipping window can also be mixed with the graph. Intersection calculations of the drawing graph and the boundary of the clipping window are not employed.

Abstract: A method of generating hollow multistroke characters. First and second bit maps are created using border and interior data from a polygon fill drawing a first stroke. Data from the polygon fill drawing a second stroke is processed in a RMW LOGIC utilizing data signals from the first and second bit maps to modify the two bit maps. When completed the second bit map contains a depiction of the interiors of the strokes employed to create the character. When completed the first bit map contains a depiction of all of the borders of all of these strokes except those portions of the borders residing in the same addresses as the addresses of interior depiction in the second bit map. The character is made legible by displaying the first bit map on a cathode ray tube.