| 摘要 |
PURPOSE:To make a processing speed fast and to make even a small memory capacity sufficient by, when write data are changed, reading the changed write data. CONSTITUTION:When write data (DATA) are written to a first FIFO memory 19, even a second write clock (WCLK 2) is inputted to a clear terminal (CL) of a flip-flop 24, the flip-flop 24 is reset in response to the input, and a rewrite flag is set. In such a case, until the flag to indicate that the write data are changed is set, namely, in the area of the same write data, the write data are not read, only start point and end point coordinates are read, they are outputted to an image memory side, and the area of the same write data is plotted by the rewrite of the write data once. When the flag is set, the new write data are read first, the luminance and color of a straight line are designated, and thereafter, the start point and end point coordinates are written to the image memory. Thus, the processing time is made short. |
