DRAWING PROCESSOR

PURPOSE:To obtain the drawing processor which has a fast drawing speed and is inexpensive by displaying effective data between data of an image memory and a display memory, pixel by pixel. CONSTITUTION:Base image data are developed in an image memory (VRAM) 108, and the display memory (SRAM) 110 is provided and display data to be superimposed are developed. Then the drawing processor is provided with a display address generating circuit 112 for the display memory 110, a display detecting circuit 116 which detects whether or not there are the display data to be superimposed, and a selector circuit 117 which is controlled with its output signal. The output of the display detecting circuit 116 is connected to a D/A converter 118 with a look-up table, which is switched with the output signal of the display detecting circuit 116. Further, a horizontal and a vertical synchronizing signal are used to initialize the display address generating circuit 112, and the selector circuit 117 selects and sends effective data between the data of the VRAM 108 and SRAM 110 to the D/A converter 118, so that the data are displayed on a video monitor 120.