| 摘要 |
PURPOSE:To plot a circle at high speed by deciding the position of a 1st point and 2nd point which decide the side of a polygon for approximating a polygon from the center point of the circle to be plotted and the length, then plotting the line connecting the 1st point and the 2nd point as a line thickened for just the amount of thickness of the line of the circle at a counter direction of the circle. CONSTITUTION:A processor 31 for plotting reads out the content of a memory 32 and executes processing. A circle plotting program 321, a cosine table 322 and radius angle correspondence table 323 are stored in the memory 32. The position of the 1st point for deciding the side of the polygon to approximate the polygon is decided from the center point of the circle to be plotted and the length, and the position of the 2nd point for deciding the side is decided from the center point of the circle to be plotted and the first term length. The two points are connected, and the thick line which is a line parallel to the 1st line connected between the 1st point and 2nd point and is sandwiched with the line decided by a line segment separated by the thickness of the line of the circle in the direction of the center of the circle, is plotted. Thus, when executing the polygon approximation to a circular arc of an arbitrary line width, vertex processing becomes unnecessary, and the processing can be executed at high speed. |
