| 摘要 |
PURPOSE:To improve the processing speed, by subjecting an area between bits to a prescribed processing with respective digital differential analyzer and another digital differential analyzer each time when plotting of bit positions, which are allowed to correspond to each other preliminarily, on two different lines is terminated. CONSTITUTION:A controller 9 starts digital differential analyzers DDA-1 and DDA-2; and each time one point is plotted on a screen, it is checked whether integer values of the y-coordinate axis in both DDAs are updated by one or not. If the integer part of the y-coordinate axis in one DDA is updated, the controller 9 drives the other DDA continuously while leaving one DDA stopped. When integer parts of the y-coordinate axis in both DDAs coincide with each other, the integer part of the y-coordinate axis and x-coordinates are sent to a DDA-3 from DDA-1 and DDA-2 to start the DDA-3. Then, prescribed values are set to individual picture elements between points 4 and 5, and one segment is smeared away in the (x) direction, and one segment is plotted in the (y) direction, and the area between segments is smeared away. |
