| 摘要 |
PURPOSE:To calculate an integer coordinate point belonging to an inside area at high speed by storing the next edge list element at a position away from an edge list element preparing position, for which a previously stored Y coordinate is L, only for f(K). CONSTITUTION:A processor 1 stores a calculated XY coordinate apex string in a memory 3 (for XY coordinate apex string storage) and previously calculates the f(K) as 'the number of intersections between the side of a polygon and the horizontal straight line of Y=K.' Based on the apex string of the polygon stored in the memory 3, a line segment generator 7 generates edge list elements composed of 'the coordinates of intersections between the side of the polygon and the horizontal straight line of Y=K' and 'Wn obtained at the intersection' in a certain order so as to trace all the sides of the polygon with one stroke. In the process of storing the edge list elements successively generated by the line segment generator 7 in a memory 5 (for edge list storage), the next edge list element is stored at the position away from the storing position of the previously stored edge list element having the Y coordinate of K only for the f(K) calculated by the line segment generator 7. Thus, the processing can be accelerated. |
