| 摘要 |
PURPOSE:To simplify the constitution of a generating circuit for the paint-out pattern of a polygon by deciding whether the cross points between each side of the polygon or its extended line and a scanning line exist inside a circumcircle or a circumoval of the polygon. CONSTITUTION:The number N of angles of a regular polygon is fed to a counter 2, and this counter is actuated as an N-notation counter. A cross point calculator 3 accepts the output of the N-notation counter 2 as equation numbers of sides of the polygon and also receives the scanning line number (n) from a display device to calculate the cross points between the scanning line and each side of the polygon or its extended line. This calculated cross point is decided by a cross point decider 4 whether the cross point is inside a circumcircle of the polygon. The result of this decision is latched to latch circuits 7 and 8. The outputs of the circuits 7 and 8 are supplied to a comparator 9 and multiplexers 10 and 11. Then the start and end points of said cross point are delivered from multiplexers 10 and 11. |
