JPH04293179A - Plotting circuit - Google Patents

Abstract

PURPOSE:To execute the plotting whose limited number of hues and number of lightness are increased by compressing remarkably a hardware scale of a frame memory and a color pallet. CONSTITUTION:From a CPU 10, a plotting instruction 100 containing hue data and a plotting instruction 101 containing hightness data are supplied to a graphic processor 11 and a graphic processor 12, respectively. From the graphic processor 11, hue data 102 is outputted, and from the graphic processor 12, lightness data 103 is outputted, and they are supplied to a frame memory 13, respectively. Hue data 104 and lightness data 105 read out of the frame memory 13 are inputted to a color pallet 14 by a TV scanning system, and display color data 106 is outputted and displayed thereby.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing circuit, and more particularly to a drawing circuit for drawing and displaying color images.

0002

[Prior Art] Conventionally, in this type of drawing circuit, color data was specified to the drawing circuit by specifying red data, green data, and blue data respectively, which was not suitable for increasing the number of hues. However, when there is a limited number of hues and it is desired to select a large number of brightness values for each hue, there is a problem in that the scale of the hardware becomes large.

For example, when specifying red data with 4 bits, green data with 4 bits, and blue data with 4 bits, totaling 12 bits, the number of displayed colors will be 12 bits = 4096 colors, but the brightness of a single color will be 4 bits. = This means that only 16 levels can be selected.

However, among various systems, there are systems in which there is a strong desire to select a limited number of hues and a large number of brightnesses for each hue, rather than a large number of hues.

For example, in systems where the display screen must be constantly monitored, it is undesirable to increase the number of hues from the viewpoint of fatigue, and many systems use a limited number of hues. For example, if you try to obtain 64 levels in a single color using the conventional method, the total will be 18 bits: 6 bits of red data, 6 bits of green data, and 6 bits of blue data, and the corresponding frame memory will also require 18 frame memories (1 bit/sheet). Become.

[0006]Also, the color palette for converting the output of the frame memory into the final color data is usually composed of a RAM, but the input or address of this RAM is also 18
Bits and 256K words are required, resulting in a very large scale.

[0007]

[Problems to be Solved by the Invention] In the conventional drawing circuit described above, the color data specified for the drawing circuit is red data,
Since this method specifies green data and blue data separately, there is a drawback that the scale of the hardware becomes significantly large when it is desired to select a large number of brightnesses for each hue with a limited number of hues.

SUMMARY OF THE INVENTION An object of the present invention is to provide a drawing circuit that eliminates the above-mentioned drawbacks, reduces the scale of hardware, and can significantly increase the number of brightnesses with a limited number of hues.

[0009]

[Means for Solving the Problems] The drawing circuit of the present invention has a frame memory in one-to-one correspondence with a display screen, writes drawing data in the frame memory, and reads and displays the drawing data using a TV scanning method. , a graphics processor for writing hue data into the frame memory, a graphics processor for writing brightness data into the frame memory, a frame memory for storing data from the two graphics processors, and a TV scanning method from the frame memory. It is configured to include a color palette for converting read hue data and brightness data into display color data.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. The embodiment shown in FIG. 1 includes a CPU 10 as a central processor, a graphics processor 11 for writing hue data into a frame memory,
A graphics processor 12 for writing brightness data into a frame memory, a frame memory 13, and a color palette 1 for converting hue data and brightness data read from the frame memory 13 using a TV scanning method into display color data.
It consists of 4.

Next, the operation of this embodiment will be explained.

A drawing command 100 including hue data and a drawing command 101 including brightness data from the CPU 10 respectively cause a graphic processor 11 to write hue data 102 to the frame memory and a graphic processor 12 to write brightness data 103 to the frame memory. will be forwarded to.

Hue data 104 and brightness data 105 read from the frame memory are each input to the color palette 14 using the TV scanning method.

The color palette 14 generates final display color data 106 based on the input hue data and brightness data.
Output. For example, if the hue data 104 is 6 bits and the brightness data is 6 bits, there are 64 hues, and 64 levels of brightness can be selected for each hue. In this case, only 12 frame memories and 4K words are required for the color palette, which means that the amount of the frame memory is 2/3, and the amount of the color palette is 1/64, compared to the prior art described above.

[0016]

[Effects of the Invention] As explained above, the present invention is configured to process hue data and brightness data separately, so that there is a demand for selecting a large number of brightness values for each hue with a limited number of hues. This has the effect of making it possible to significantly reduce the hardware scale of the frame memory and color palette in a system with strong performance.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

[Explanation of symbols]

10 CPU 11 Graphic processor 12 Graphic processor 13 Frame memory 14 Color palette 100 Drawing command 101 including hue data
Drawing command 102 including brightness data Hue data 103 Brightness data 104 Hue data 105 Brightness data 106 Display color data

Claims (1)

[Claims] 1. A graphic for writing hue data to the frame memory in a drawing circuit that has a frame memory in one-to-one correspondence with a display screen, writes drawing data to the frame memory, reads out and displays it using a TV scanning method. a processor, a graphics processor for writing brightness data into a frame memory, a frame memory for storing data from the two graphic processors, and display color data for hue data and brightness data read out from the frame memory by a TV scanning method. A drawing circuit characterized by comprising: a color palette for converting into a color palette;