| 摘要 |
PURPOSE:To make it possible to rapidly and accurately execute the painting-out of a polygon in any of a replace mode and an EOR mode by providing the graphic generator with a start point generator, an end point generator, a start point data buffer, an end point data buffer, a start point comparator, an end point comparator, and two selectors. CONSTITUTION:In the case of painting out a polygon by a trapezoidal dividing method, a start point and an end point selected by the start point comparator 12 and the end point comparator 13 in trapezoid painting-out starting line and a starting point and an end point generated from the starting point generator 6 and the end point generator 7 from the succeeding line are selected by the selectors 14, 15. The selected start and end points are painted out, and in a trapezoid painting-out end line, the start point and end point data buffers 10, 11 store the data generated from the generators 6, 7 and a write controller 17 inhibits writing in a frame memory 18. Thereby, the painting-out of a polygon can be rapidly and accurately executed in any of the replace mode and the EOR mode (rastor operation mode for writing data to be newly written while operating exclusive OR between the new data and already written data). |
