JPS6188296A - Crt display for computer system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention mainly relates to a CRT display method in which a graphic image and text characters are displayed in a superimposed manner on a CRT screen in a personal computer system, and more specifically, to a CRT display method in which a graphic image and text characters are displayed in a superimposed manner on a CRT screen in a personal computer system. This invention relates to a CRT display method that displays images in an overlapping manner.

<Prior Art> In a conventional personal computer system, graph ink images and text characters are displayed in a superimposed manner on a CRT screen using a configuration as shown in the block diagram of FIG. That is, in the conventional CRT display system, graphics Rc B I, J Rg, Gg
, Bg are introduced through the pallet circuit 20,
R introducing text lICl3 signals Rt, Gt, Bt
GB data selector 10, text RGB signal Rt,
NO as a selection gate circuit operated by Gt and Bt
Since it is equipped with an R gate 30, when text RGB signals Rt, ct, and Bt are input to the RGB data selector 10, N.

1 (a selection signal is output from the gate 30, and this selection signal causes the RGB data selector lO to select the text R.
The GB signals R1, Gt, Bt are selected, the output is switched from the graphic RGB signals Rg, Gg, Bg to the text RGB signals, and the text l-RG B signals R1, Gt, Bt are sent to the CRT. , text characters will be displayed superimposed on the graphic image at desired locations.

By the way, when a graphic image and a text character are displayed side-by-side, and both images are bright in color, you may want to convert the color of the text character to black and display it in order to make the text character easier to see. However, in the conventional system, such a display could not be made. This is because if you try to display a black text character superimposed on a graphic image, this black text character will cut all of the text RGB signals Rt, Gt, and Bt that correspond to the image, that is, the color code of each signal will be cut. is formed by setting all to "0", so this black text R
For GB signals R1, GL, Bt, NOR gate 3
0 does not output a selection signal, and the RGB data selector IO does not select the text RGB signals Rt, Gt, Bt. Therefore, the black text rLGB signals Rt, Gt, Bt
is determined to be transparent to the graphic RGB signals Rg, Gg, and Bg, and a graphic image is displayed at the location corresponding to the black text character.
Black text characters are not displayed at all.

As mentioned above, in the conventional CRT display method, it is not possible to display black text characters on the CR7 screen by superimposing them on the graphic image, and the form of expression of superimposition is limited, so it is necessary to create an easy-to-read screen. It was inconvenient to do so.

<Object of the Invention> The present invention has been made in view of the above-mentioned problems, and it is possible to display black text characters on a CRT screen by superimposing them on a graphic image, thereby achieving easy-to-see superposition. The purpose is to facilitate screen formation.

<Configuration of the Invention> In order to achieve the above object, the present invention provides graphic R
An RGB data selector which introduces a Gr3 signal and a text RGB signal and selects one of the RGB signals by a selection signal and outputs it to Cr1T; A selection gate circuit that outputs a selection signal to the data selector is provided for each text RGB signal, and each text RGB signal and a black display signal are introduced, and when the black display signal is not manually generated, each text RG
The present invention is characterized in that it includes a 3@ black conversion gate circuit that sends the B signal to the RGB data selector and cuts off the text RGB signal when the black display signal is input.

<Example> Hereinafter, the present invention will be explained in detail with reference to an example shown in the drawings.

(a) First Embodiment FIG. 1 is a block diagram showing the configuration of the CRT display system of the present invention. In the figure, reference numeral 1 is an IIGB data selector, one of which input terminals B receives graphic RGB signals Rg and G.
When g and Bg are input through the pallet circuit 2,
Text RGB signals Rt, Gt, B are input to the other input terminal A.
t is input, and one of R is selected by a selection signal described later.
Select GB signal and connect output terminal Y to CRT (not shown)
Output to.

3 is N as a selection gate circuit that outputs the selection signal.
At the OR gate, the text RG [3 signals Rt, Gt, Bt
Introducing one of the text RGB signals Rt.

When Gt and Bt are input, the RGB data selector I
A selection signal is sent to the input terminal S of. In this example,
When the selection signal in the It G B data selector l is at a high level, the graphic RGB signals J, Gg,
When Bg is selected and output, and the selection signal is at low level, the text RGB signals Rt, Gt, and Bt are selected and output. 4 (
4r, 4g, 4b) are black conversion gate circuits A
At the ND gate, each text RGB signal 1tL, Gt, B
Text RG B signal R
t, G', and Bt signals and a black display signal sb are introduced, and when the black display signal sb is not input, each text RGB
The signals Rt, Gt, and Bt are connected to the RG 13 data selector! When the black display signal sb is input manually, the text RGB signals Rt, ct, and Bt are cut off, that is, the text RG
B signal Rt.

Set G L, B t to [1-level. This black display signal sb is for converting at least one of the text l-RGB signals Rt, Gt, and Bt into black and displaying it as a black text character, and in this embodiment, it is in the active state at a low level. The signal is CP
It is generated and output by an instruction U (not shown).

Next, the operation of the above configuration will be explained. If the black display signal sb is not input to each AND gate 4r, 4g, 4b,
That is, when the black display signal sb is at a high level, R
Graphic RGB signal Rg to GB data selector 1,
With Gg and Bg being manually operated, if any of the text RGB signals RL, Gt, and Bt are sent in, the ANDNO gate r, 4 g.

At 4h, the black display signal sb is at a high level, so the text RGB signals Rt, Gt, and Bt pass through the AND gates 4r, 4g, and 4b without being blocked.
Manually enter B data selector I. Text RGB at the same time
Since the signals Rt, Gt, and Bt are input to the NOR gate 3, a low-level selection signal is output from the NOR gate 3, and this selection signal causes the RGB data selector l
The text RGB signals Rt, Gt, Bt are selected, and the output is the text RGB signal RE from the graphic RGB signals Rg, Gg, Bg.

Switches to Gt and Bt. As a result, text characters are displayed on the CR7 screen in the desired locations of the graphic image.

Here, when a low level black display signal sh is input to the AND gates 4r, 4g, and 4b, each text Rcn signal [
IL, GL, and BL are these A N D gates 4r and 4g.

4b, and the I(CB data selector 1 receives the text I-RGB signals Rt, GL, BE at low level. On the other hand, the text RGB signal Rt
. selected, the output switches from the graphic RGB signals Rg, Gg, Bg to the text RGB signals Rt, Gt, Bt. At this time, as described above, each text RG B signal nt, c
Since t, Bt are at low level, these low level text RGB signals R1, Gt, Bt are It G
The low level text RGB signals R1, Gt,
Bt causes black text characters to be superimposed and displayed on the CRT screen at required locations on the graphic image.

As mentioned above, the black display signal sb is generated and outputted according to a command from the CPU, and the method of generation and the configuration of the generation circuit are not particularly limited, but the generation circuit will be embodied and one embodiment will be described below. In each embodiment, the same +14 component as in the embodiment shown in FIG. 1 is designated by the same reference numeral.

(B) Second Embodiment FIG. 2 is a block diagram of a second embodiment in which a latch circuit and a black display data selector generate and output a black display signal sb. In addition to the example components, there is also a latch circuit 5 that latches data signals from the CPU, the output of the latch circuit 5, and text RGB.
Signals Rt, Gt.

It has a black display data selector 6 that introduces Bt. The black display data selector 6 outputs a black display signal sb from an output terminal W in response to the data signals DO to 7 input through the latch circuit 5 and the text RGB signals Rt, Gt, BL. If the value of 110 to 7 is "0", the black display signal sb is not output,
When the value of data signal DO~7 is “B”, black display signal sb
Output. The correspondence relationship between the input signal and the output signal is as shown in Appendix Table 1. As is clear from Table 1, the text R manually input to the data selector 6 for black display
By supplying required data signals DO to 7 to the data selector 6 in response to the G B signals nt, ct, and Bt, text characters of any color are converted to black and displayed.

A data bus of the CPU is connected to the input terminal of the latch circuit 5, and a data signal from the data bus is latched into the latch circuit 5 according to a command from the CPU.

(Leaving space below) This appendix* <Table 1> Human power signal 1 output I BL IRtiGt 10 1W l
Operation-1-1-1-II 1 No black display 0 10 10 1DO=O1l 1 No black display (only graphics displayed) 0 10 10
1DO=li0 1 No black display (only graphics displayed) + 10 10 1DI=oll 1
Do not display black + 101 Oi old = 1101 Text blue becomes black 0 11 10 1D2 = ol
l l No black display O11101D2=10
1 Text red becomes black 1 11 jo
1D3=ol l + Do not display black l Mouth IQ ID3=I10 1 Text magenta becomes black 0 10 Mouth jD4=011 1 Do not display black 0 10 II :D4=l10 1 Text green becomes black 1 10 II +D5
=flll l No black display 1 ;o 1+
D5=l10 1 Yellow text becomes black 0 11 II tD6=Qll l No black display OII II 1D6=l10 1
Text yellow becomes black 11111 ■? =Gii
Do not display black l II jl 'D? =1
'0 1 White text becomes black (hereinafter referred to as margin) (c) Third embodiment Figure 3 shows a block diagram of the third embodiment in which a black display signal sb is generated and output by a memory and a black display data selector. The figure shows, in addition to the components of the first embodiment shown in FIG. RGB signal R1,G
t, and a black display data selector 6 that introduces BE.

Similar to the second embodiment, the black display data selector 6 outputs a black display signal sb from the output terminal W in response to the input data signals Dθ to 7 and the text RGB signals Rt, Gt, BE. The correspondence relationship between the input signal and the output signal is the same as that shown in Table 1 of the attached table.

A data output terminal of a memory 7 is connected to the input terminal of the black display data selector 6, and the data output terminal of the memory 7 is also connected to a data bus of the CPU. CPt
The more J can write arbitrary data to the memory 7, the more it can read the contents of the memory 7, which allows the CPU to confirm which color text character is converted to black. .

(d) Fourth embodiment Figure 4 shows the latch circuit and comparator for the black display signal s.
This is a block diagram of a fourth embodiment configured to generate and output CP.
A launch circuit 8 that latches the data signal from U, and the output of the latch circuit 8 and the text RGB signals Rt, G.
It has a comparator 9 which introduces t and Bt and compares them. The comparator 9 outputs a black display signal sb when the output of the latch circuit 8 and the text RGB signals rtt, ct, and Bt match. This comparator 9 is a 4-bit comparator, and one input terminal A1-4 is always supplied with a high-level signal for the text RGB signal, and the other input terminal B1-4 is supplied with the text RGB signal Rt, Gt, The data signal corresponding to Bt is input with a ring for displaying black. (1
Continued from page 7 () Table 2 of this appendix Input signal 1 114 1B3 1B2 1BI l
Operation 1 io 10 II l
Text blue becomes black 1 10 11 10
1 Text red becomes black 1 10 1
1 II l Text magenta becomes black+
if 10 io i Text green becomes black l il io il 1
Text turns yellow or black + :+ u
:o i Text yellow becomes black 11111
The white text becomes black (hereinafter referred to as the margin). This black bit is a high level and active signal.

The correspondence between the input signal and the output signal of the comparator 9 is as shown in Table 2 of the attached table.

The latch circuit 8 is connected to the CPLI data bus and latches data signals from the CPU at predetermined timing.

<Effects of the Invention> As described above, according to the present invention, the text RGB signal inputted to the black conversion gate circuit is cut off and becomes low level by the black display signal generated and output by the CPU instruction, and this becomes the RGB Since the low level text RGB signals are sent to the CRT through the data selector, black text characters are displayed on the CRTli surface superimposed at desired locations on the graphic image.

Therefore, the range of overlapping expression forms is expanded, and when both the graphic image and the text character are bright colors, displaying the text character in black can make the overlapping display screen easier to see. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the CRT display system of the present invention, FIG. 2 is a block diagram of the second embodiment, FIG. 3 is a block diagram of the third embodiment, FIG. 4 is a block diagram of the fourth embodiment, FIG. 5 is a block diagram of a conventional CRT display system. 1...ROB data selector, 2...Palette circuit, 3...Selection gate circuit (NOR gate), 4 (4
r, 4g. 4b)...Black conversion gate circuit (AND gate), 5
...Latch circuit, 6...Data selector for black display, 7...Memory, 8...Latch circuit, 9...Comparator.

Claims (4)

[Claims] (1) An RGB data selector that introduces a graphic RGB signal and a text RGB signal, selects one of the RGB signals using a selection signal, and outputs it to the CRT, and an RGB data selector that introduces a text RGB signal and outputs either text RGB signal to the CRT.
A selection gate circuit outputs a selection signal to the RGB data selector when a signal is input, and a selection gate circuit is provided for each text RGB signal and introduces each signal of the text RGB signal and a black display signal, and when no black display signal is input, a selection gate circuit is provided for each text RGB signal. A CRT display method for a computer system, comprising three black conversion gate circuits that send text RGB signals to the RGB data selector and cut off the text RGB signals when a black display signal is input. (2) In the CRT display system of the computer system according to claim 1, there is provided a latch circuit that latches the data signal from the CPU, and black display data that introduces the output of the latch circuit and the text RGB signal. selector, wherein the black display signal is generated and outputted by the black display data selector in correspondence with a data signal and a text RGB signal. (3) In the CRT display system of the computer system according to claim 1, a memory in which writing/reading is performed according to address designation of the CPU;
a data selector for black display that introduces a data signal read from the memory and a text RGB signal;
A CRT display method for a computer system, characterized in that the black display data selector generates and outputs data corresponding to GB signals. (4) In the CRT display method of a computer system according to claim 1, a latch circuit that latches a data signal from a CPU, and an output of the latch circuit and a text RGB signal are introduced and compared. 1. A CRT display system for a computer system, comprising: a comparator that outputs the black display signal from the comparator when an output of a latch circuit matches a text RGB signal.