JPH0216598A - Color display system - Google Patents

Abstract

PURPOSE:To reduce the load on a host process and to reduce an increase of hardware for the color display of a cursor by providing a specific display control part. CONSTITUTION:A display control part 3 writes cursor patterns 104 and 106 in cursor pattern latches 6-0 and 6-1 in, for example, a horizontal blanking period. The display control part 3 reads memory planes 2-0-2-3 at the time corresponding to a raster scan on a display 8 and reads the contents of the cursor pattern latches 6-0 and 6-1 corresponding to a cursor display position. Further, the display control part 3 controls a color look-up table 4 and a color look-up table 7 for cursor display into enabled states respectively corresponding to read pieces of binary information 106 and 107. Consequently, the load on the host processor is reduced and the hardware quantity of the cursor pattern latches, etc., is reducible.

Description

[Detailed Description of the Invention] (Summary) A color display is performed using a plurality of memory planes and a color look-up table that is accessed based on information read from the current memory plane. Concerning a color display system that displays the cursor in color as necessary.

The purpose of this invention is to reduce the load on a host processor when displaying a cursor in color, and to reduce the increase in hardware required to display a cursor in color.

In addition to providing cursor pattern latches that are smaller in number than the plurality of memory planes mentioned above to enable read/write control by the display control unit, the cursor pattern latches are
The configuration includes a color look-up table for cursor display that is accessed based on information read from the pattern latch.

[Industrial application field]

The present invention includes a plurality of memory planes and the memory planes.
The present invention relates to a color display system that includes a color look-up table that is accessed based on information read from a plane, performs color display, and displays a cursor in color as necessary.

It is desired to display a cursor indicating a bit position in color on a display capable of displaying in color in a manner that follows the movement of a pointing device.

[Conventional technology]

The following measures have been taken to display the cursor in color on a color bit map display.

3 and 4 show conventional examples, respectively. Code 1 in the diagram
is a host processor, 2 is a memory plane, 3 is a display control unit, 4 is a color look-up table, 5
6 represents a digital-to-analog converter, 6 represents a cursor pattern latch, and 9 represents a multiplexer.

The number of memory planes 2 shown corresponds to the number of colors that can be simultaneously produced on one screen. For example, if four memory planes 2 are prepared as shown in the figure, the number of colors that can be simultaneously produced on one screen is 16.

The host processors have their respective memory planes 'l
- on top, information is written and refreshed with a bit image corresponding to the image displayed by the display. The display control section 3.

As images are displayed on the display according to raster scanning, the contents of four memory planes are read out all at once in the case shown in one figure, and output as 4-bit information.

In the case shown in FIG. 3, the host processor 1 generates a display image including a cursor image that is displayed in one color, and writes it into the memory planes 2-0 to 2-3.
The display control unit 3 reads the contents of each memory plane and performs a color look-up as 94-bit information.
Supply to table 4. In the color look-up table 4, the 4-bit information is used as an address to access the RAM having 24 storage locations. The contents of the RAM include, for example, 24 bits of information for each storage location. 4 from memory plane 2-1
In response to the readout of the bit information, 24-bit information in one-to-one correspondence with the 4-bit information is read out from the RAM and sent to the digital-to-analog converter 5.
is supplied to The above 24-bit information is 2, for example, R, G.
.

Eight bits are prepared corresponding to each of B. To do this, specify 256 colors for R, 256 colors for G, and 256 colors for B. I can do it.

Therefore, the number of colors that can be produced simultaneously on one screen is limited to 16 when there are four memory planes 2, but each of the 16 colors can be preset from among 224 colors. It can be specified.

In the case shown in FIG. 4, cursor pattern latches 6-0 to 6-3 are prepared so that one display control section 3 can perform read/write control. Then, regarding the cursor pattern written by the host processor 1 on the memory plane 2-i, the 1 display control unit 3 transfers the cursor pattern to the cursor pattern latches 6-0 to 6 during the display retrace period, for example. -3 Lunch on top. In this state, information is read out from the memory plane 2-i in response to raster scanning on the display, but when the display control unit 3 reaches the raster scanning position where the cursor should be displayed, cursor pattern
The contents of latches 6-0 to 6-3 are read to control multiplexer 9. That is, information from memory planes 2-0 to 2-3 and information from cursor pattern latches 60 to 6-3 are selected. The output from multiplexer 9 is directed to a color look up table 4.

[Problem to be solved by the invention]

In the case shown in FIG. 3 above, the load on the host processor 1 becomes large. Especially as the number of memory planes 2i increases and the number of types of cursor color display (the number of types on one screen) increases.

Also, as the cursor movement speed increases, the host
The load on processor l becomes extremely large.

In the case shown in FIG. 4, the load on the host processor 1 is reduced compared to the case shown in FIG. Requires i. The multiplexer 9 also selects the information from the two memory planes 2-0 and the cursor pattern latch 6-0, and selects the information from the memory plane 2-1 and the cursor pattern latch 6-1. Select the information from...
It is necessary to select information from memory plane 2-3 and information from cursor pattern latch 6-3;
As the number of memory planes 2-1 increases, the amount of hardware increases.

An object of the present invention is to reduce the load on a host processor when displaying a cursor in color, and to reduce the increase in hardware for displaying a cursor in color.

[Means to solve the problem]

FIG. 1 shows a principle diagram of the present invention, FIG. 1(A) is a configuration diagram, and FIG. 1(B) is an explanatory diagram.

In the figure, 1 is the host processor, 2-1 is the memory
3 is a display control unit, 4 is a color look-up table, 5 is a digital-to-analog converter, 6-0
．． Reference numeral 6-1 represents a cursor pattern latch, 7 a color look-up table for cursor display, and 8 a display. Furthermore, in Fig. 1 (B), 1°O represents the display on the display, 1o1 is the cursor displayed in a different color, 102 is the display area other than the cursor, and 1o3 is the cursor excluding the cursor display. Image data, 104 is a cursor pattern in the first color, ios is a cursor pattern in the second color, 106 is binary information when the cursor pattern 104 is read in correspondence with raster scanning, 107 is 2 when read out corresponding to cursor pattern 105t-raster scan.
Represents value information.

In the case shown in FIG. 1, the cursor pattern latch 6
-j, the number of memory planes smaller than the number of memory planes 2-i is prepared.

This is because, in general, it is sufficient to have a relatively small number of MIDs for cursor display colors that are displayed simultaneously on one screen. As shown in FIG. 1(B), if it is sufficient to display a cursor 101 with an R color border, it is sufficient to display two colors, and two cursor pattern latches 6 are sufficient.

The color look-up table 7 for displaying the cursor has, for example, four storage positions in the case of the two figures shown.
It is composed of ×24 bit RAM. The color lookup table 4 shown is 16X2 in the case shown.
It consists of 4-bit RAM.

[Effect]

The display control unit 3 writes cursor patterns 104 and 105 into cursor pattern latches 6-0 and 6-1, for example, during the horizontal retrace period. 1 display control section 3,
1 memory plane (in which image data 103 is written) 2 corresponding to the raster scan on the display 8
- Read out ○ to 23 all at once, and read out the contents of cursor pattern latch 6-0.61 corresponding to the cursor display position.

Corresponding to the binary information 106, 107 successively output from the cursor pattern RAF-0, 6-, 1.

The display control unit 3 controls the color look-up table 4 and the cursor display color look-up table 7 to enable states, respectively. That is, (
i) Binary information tl106 and 107 are patterns ro and OJ
If so, the color lookup table 4 side is enabled.

(ii) The binary information 106 and 107 have the pattern “1°0
”, the color lookup table 7 side for cursor display is enabled.

Adopting the cursor pattern 104 side, (iii)
If the binary information 106 and 107 are patterns rl and IJ, the cursor display color look-up table 7 side is enabled, and then the cursor pattern 105 side is adopted.

〔Example〕

FIG. 2 shows the configuration of an embodiment of the present invention. Reference numerals 1 to 7 in the figure correspond to those in FIG. 1, and 1o-o to 10-7 represent parallel-to-serial conversion chics 11 and 12, respectively, to logic gates.

In the illustrated case, eight memory planes 2 are prepared, and 256 colors can be displayed simultaneously on one screen. In addition, in tables 4 and 7, 24-bit information is stored corresponding to each storage position, and R
256 ways about.

There are 256 colors available for G and 256 colors for B.

Shifters 10-0 through 10-7 convert information from memory planes 2-0 through 2-7, respectively, into serial data and provide it to color look-up table 4.

When the contents of the cursor pattern latches 6-0 and 6-1 are patterns ro and OJ, the display control unit 3 changes the side of the color look-up table 4 based on the output of the logic gate 11. Enable. Also, the above ro,
In cases other than O.J.

Based on the output of logic gate 12, the side of color look up table 7 for cursor display is enabled. Then, as explained with reference to FIG. 1(B),
Control is performed so that outputs corresponding to patterns rl, OJ, and "1°1" are generated. In addition, the color, look,
The output of the lookup table 4 and the output of the color lookup table 7 for cursor display are subjected to dot-OR logic corresponding to bits.

〔Effect of the invention〕

As described above, according to the third aspect of the present invention, it is possible to reduce the load on the host processor and reduce the amount of hardware such as cursor patterns and latches. In particular, since writing can be performed in the cursor pattern latch using the horizontal retrace period, it is sufficient to hold, for example, two colors of l-line corresponding to the raster scan of the cursor pattern. In addition, the color for cursor display
For the look-up table 7, it is sufficient to prepare a 4×24 bit RAM, for example.

[Brief explanation of the drawing]

FIG. 1 shows the principle of the present invention, FIG. 2 shows an embodiment of the present invention, and FIGS. 3 and 4 show conventional examples. In the figure, l is a host processor, 2 is a memory plane 53, a display control unit, 4 is a color look-up table, 5 is a digital-to-analog converter, and 6 is a cursor.
7 represents a pattern latch, 7 represents a color look up table for cursor display, and 8 represents a display. Patent applicant: BFN Co., Ltd.

Claims (1)

[Claims] A plurality of memory planes (2-i) prepared corresponding to the number of colors that can be simultaneously produced on one screen, and a plurality of memory planes (2-i) prepared from each of the plurality of memory planes (2-i). a color look-up table (4) that is accessed based on the read information; and a digital-to-analog converter that generates an analog color signal based on the output from the color look-up table (4). (5), a display control unit (3) that controls the memory plane (2-i) and the color look-up table (4), and a display control unit (3) that controls the memory plane (2-i) to display display data; A color display system having a host processor (1) in which the memory planes (2-i ) cursor pattern latches (6
-j) can be read/written by the display control unit (3), and a color look for cursor display accessed based on information read from the cursor pattern latch (6-j). The display control section (3) generates a color look-up table (7) in accordance with the display mode of the cursor.
Table (4) and the color look for the cursor display above.
A color display system characterized in that the up table (7) is selectively controlled to supply a signal to the digital-to-analog converter (5).