| 摘要 |
PURPOSE:To form the painted out graphic of a polygon having a complicate concave form without calculating the intersections of the respective sides ad and a horizontal scanning line by providing a vertex string extracting means and a removed vertex string extracting means. CONSTITUTION:The vertex string composed only of convex vertexes obtained by removing concave vertexes and local convex vertexes from the vertex string of an initially inputted polygon is extracted by the vertex string extracting means 104 and a polygon area formed by the extracted vertex string is coated out by a polygon coating out means 111. The removed concave vertex or the like has two adjacent vertexes added in the vicinity by the removed vertex string extracting means 106 to from a new vertex string and it is held by a stack 108. At this time, an extracted vertex string identification flag is inverted and applied. Then, the new vertex string is inputted to the vertex string extracting means 104 from the stack 108, a similar processing is carried out to erase already coated data or coat out by background data and this processing is repeated until the stack 108 is simplified. Thereby, the painted out processing of the polygon of the concave form is simplified. |
