| 摘要 |
PURPOSE:To quickly paint out a polygon in the case of desired EO fill as well as NZ fill by taking trapezoid fill as a processing base and repeating a simple processing independently of the complexity of the original polygon. CONSTITUTION:The polygon painting-out system consists of a CPU 1, a main storage 2, a bit map memory 3, and a display controller 4. Data in a rectangular area, namely, a winding number (WN) value is read with one picture element as the unit, and binary output '0' is obtained when the WN value is '0', and binary output '1' is obtained when it is not '0', and data is written in a desired position on the bit map memory in accordance with the output value '1'/'0'. The operation is performed in the case of a non-zero winding number rule (NZ fill). In the case of an even/odd winding number rule (EO fill), '0' is outputted for the even WB and '1' is outputted for the odd WN at the time of binarizing the WN value. Thus, the polygon is quickly filled by both of rules of EO fill and NZ fill. |
