| 摘要 |
<p>PURPOSE:To control the hierarchizing display of plural windows at a high speed. CONSTITUTION:Output image data memory 8 is provided with words equivalent to the number of picture elements constituting an output image, and pixel data for expressing the color of the picture element is stored in it. Output image control data memory 10 is provided with the words equivalent to the number of picture elements constituting the output image, and information required for control is stored in it, and it is composed of a RAM with fast access speed. An output image memory control part 12 performs the read/write control of the pixel data and the discharge control of the pixel data from a periodical serial port on the output image data memory 8, and the read/write control of control data on the output image control data memory 10, etc. A pixel data write decision part 19 decides whether or not the write of the pixel data on the output image data memory 8 is permitted based on designation information at every picture element read out on to an output image control data bus 11 and representing whether or not the write should be permitted.</p> |
