| 摘要 |
PROBLEM TO BE SOLVED: To execute display even if a polygon is lying horizontally or on a straight line during the rotation of the polygon by detecting the leftmost point and the rightmost point of the polygon based on data which is read and transferring them to a display device. SOLUTION: An edge side retrieval device 101 inputs a polygon side from outside end judges whether the polygon side is the left edge side or the right edge side of whether the start of the polygon side becomes the leftmost point or the rightmost point. Edge side data is stored on a left edge side memory 103 and a right edge side memory 104, leftmost point data in a leftmost point memory 107 and rightmost point data in a rightmost memory 108 in accordance with a judged result. Wherever data are stored in the memories 103 and 108, the left edge counter 105 and the right edge counter 106 are increased by one. An edge side transfer device 102 transfers left edge side data and right edge side data, which are read from the left edge side memory 103, the right edge side memory 104, the leftmost point memory 107 and the rightmost point memory 108, to a raster division device. |
