| 摘要 |
<p>METHOD AND APPARATUS FOR CONTROLLING THE DISPLAY OF A COMPUTER GENERATED RASTER GRAPHIC SYSTEM Method and apparatus for controlling the display of a raster scan color cathode ray tube. m e tube is provided with an orthogonal array of picture elements (pixels) with each picture element having a unique binary address. An addressable memory having memory locations with addresses corresponding to those of the picture element has stored in such memory locations an address of a location in a color look-up memory for an alphanumeric color, for a graphic color and priority signals. In the color look-up memory at the addressed locations is stored binary signals representing the color and intensity of a pixel. In synchronism with the raster scan of the picture elements of the cathode ray tube, there is read from the memory graphic-color addresses, alphanumeric color addresses and priority signals for each pixel. One of the addresses, either the graphic or alphanumeric, is applied to the color look-up memory, with the address that is applied being determined by the binary priority signals. The binary color signals stored at the addressed color look-up memory location represent varying intensities of a plurality of predetermined colors. The color signals are converted by a digital to analog converter into analog signals which are applied to the color cathode ray tube to control the color and intensity of each pixel as it is scanned.</p> |
