| 摘要 |
PURPOSE:To paint out with a high accuracy a graphic in which a circular are and an elliptical arc have been mixed, by dividing the circular arc by an angle of a multiple of 45 degrees, and also, dividing the elliptical arc by an angle of a multiple of 90 degrees and a point in which an inclination of a tangent is + or -1, and executing the same processing as that of a segment. CONSTITUTION:A radius and the center of a given circular arc are derived, and thereafter, the circular arc is divided by an angle of a multiple of 45 degrees. With regard to the respective circular arcs which have been divided, whether they are convex upward or convex downward is checked, and it is stored together with coordinate values of a start point and en end point. A log diameter, a short diameter and the center of a given elliptical arc are derived, and thereafter, the elliptical arc is divided by an angle of a multiple of 90 degrees and a point in which an inclination of a tangents is + or -1. With regard to the respective elliptical are which have been divided, whether they are convex upward or convex upward or convex down ward is checked, and it is stored together with coordinate values of a start point and an end point. The segment, circular arc and elliptical arc are rearranged by a coordinate of an end point. A horizontal segment i cut off. The segment, circular arc and elliptical arc being not horizontal are rearranged so that the end point whose (y) coordinate is smaller is arranged in small order. The segment, circular arc and elliptical arc which do not cross a scanning line on a screen are cut off. |
