| 摘要 |
PURPOSE:To reduce the burden of a processor and to improve the processing speed by setting lengths of the longer axis and the shorter axis and positional information of the center point of an ellipse merely to describe the ellipse. CONSTITUTION:A processor 1 sets a length 2A of the longer axis, a length 2B of the shorter axis, and center position information which are given from a host device to a value A register 10, a value B register 11, and a center value register 12 respectively and starts a value X counter 15. A comparing circuit 13 compares values of the value A register 10 and the value B register 11 with each other, and the inclination direction of a tangent 20 of the ellipse is determined by the comparison result and is sent to an inclination table 14. The inclination table 14 sends constants (a), (b), and (c) constituting equations of the tangent, which are stored preliminarily in a value Y calculating circuit 16, on a basis of a value X transmitted from the value X counter 15 to calculate (x) and (y) coordinate values. |
