| 摘要 |
PURPOSE:To shorten a painting-out time by moving along the sides of a polygon, projecting the respective sides on X and Y axes, and deciding a convex polygon based on the number of times of changes in the moving direction on the axis. CONSTITUTION:A process move along a polygon 1 in the sequence of apexes P1, P2, P3,... PN, and P1, and the respective sides are projected on the X and Y axes. Next the number of times of changes in the moving direction of the sides projected on the X and Y axes is checked, when the number of times of the changes is, for example, <=2 for the both X axis and Y axis, the graphic is decided as the convex polygon in the painting-out processing. Thus by checking only the number of times of the changes in the side direction and deciding the convex polygon without executing a multiplying processing, the painting-out processing time can be shortened. |
