| 摘要 |
PURPOSE:To attain simple and rapid drawing by providing a drawing device for a clipping memory, detecting an intersecting point of a drawn vector with an optional clipping graphic frame at the time of drawing the graphic and deciding whether the drawn points exist in the inside or outside of the graphic. CONSTITUTION:A drawing deciding circuit 22 receives a starting point address of a drawing vector from a vector drawing circuit 5, and when a starting bit is drawing OFF, a starting point address is collated with the same position address in a clipping image memory 21, the starting point is decided whether it is included in the inside or outside of the clipping graphic frame and a drawing flag for determining the existence of drawing is set up. A value '1' or '0' is respectively set up in case of inside or outside, and when an intersecting point counter is entered into a graphic after counting one count of ON OFF and OFF ON, a flag is checked, and at the time of '1', drawing processing is executed. In case of '0', the drawing point of the next drawing vector is checked, the ON/OFF change from the immediately preceding bit is checked, and at the time of the OFF ON change in the odd number of times and ON OFF change in the even number of times, the drawing flag is inverted. At the time of flag '1', drawing in the image memory 7 is displayed. Said operation is repeated until the end of drawing. |
