Uses segment data management manner and this management manner the clipping treatment manner

摘要

PURPOSE:To improve a practicality by operating a high speed processing by a simple managing constitution. CONSTITUTION:A graphic constituted of clip paths is trapezoid-divided by a horizontal lines passing through vertexes and intersected points (S1). Then, the leading address of a clip segment memory 16 is set at a segment memory pointer (smp) (S2). The segment of a valid clip area is searched, and registered in a clip segment memory (S3). Then, the processings of the steps S1-S3 are repeated until the entire clip paths can be trapezoid divided (S4). When the entire clip paths are trapezoid-divided, the graphic constituted of plotting paths is trapezoid-divided by the horizontal lines passing through the vertexes and the intersected points (S5). The segments of the plotting paths being the right and left sides of the trapezoid surrounded by the two horizontal lines are prepared, and the clipping segments are taken out from the clipping data so that the mapping of the trapezoid can be operated (S6). Then, the mapping of the entire trapezoids surrounded by the two horizontal lines is operated (S7), and this is repeated until the entire graphic constituted of the plotting paths can be trapezoid-divided (S8).