JPH0113110B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a video effect device such as a personal computer capable of displaying a text screen and a graphic screen.

BACKGROUND ART Conventionally, in personal computers and the like that can display a text screen and a graphic screen, when a text screen such as characters is superimposed on the graphic screen, the characters become difficult to see.

Purpose The purpose of the present invention is to solve the above-mentioned technical problem,
To provide a video effect device that makes characters and the like on a text screen easier to see by creating shading display on them.

Embodiment FIG. 1 is a block diagram showing the electrical configuration included in a personal computer according to an embodiment of the present invention. A video RAM (random access memory) 1 for temporarily storing a red color signal for a graphic screen is connected to a terminal 1B of a data selector circuit 5. A video RAM 2 for temporarily storing a green color signal for graphics is connected to a terminal 2B of the data selector circuit 5. A video RAM 3 for temporarily storing a blue color signal for graphics is connected to a terminal 3B of the data selector circuit 5. In the video RAM 4 for the text screen displaying characters, the terminal 4R is connected to the input terminal of the NOT gate 6 and the terminal 1A of the data selector circuit 5. Video RAM4 terminal 4G for text screen
is connected to the input terminal of the NOT gate 7 and the terminal 2A of the data selector circuit 5. Terminal 4B of video RAM 4 for text screen is connected to an input terminal of NOT gate 8 and terminal 3A of data selector circuit 5.

The output terminal of NOT gate 6, the output terminal of NOT gate 7, and the output terminal of NOT gate 8 are connected,
The connection point 7a is connected to the input terminal of the NOT gate 9 and one end of the resistor R1, respectively. Resistance R
A voltage of 5V is applied to the other end of 1 through line 11. The output terminal of NOT gate 9 is resistor R
2 to line l1 and OR gate 1
Connected to one input terminal of 0. Further, the output terminal of the NOT gate 9 is connected to the terminal A of the one-shot multivibrator 18. OR gate 1
The other input terminal of 0 is connected to the output terminal of the one-shot multivibrator 18. The output terminal of the OR gate 10 is the AND gate 14 to 16.
is connected to one input terminal of the Terminal Rext/Cext of one-shot multivibrator 18 is connected to line 11 via resistor R3 and variable resistor R7, and to terminal Cext of one-shot multivibrator 18 via capacitor C1.

In the data selector circuit 5, the output terminal 1Y
is connected to the other input terminal of AND gate 14 via NOT gate 11, and output terminal 2Y is connected to NOT
The output terminal 3Y is connected to the other input terminal of the AND gate 15 via the gate 12, and the output terminal 3Y is connected to the other input terminal of the AND gate 16 via the NOT gate 13. The output terminal of the NOT gate 11 is given a voltage of 5V through a resistor R4, the output terminal of the NOT gate 12 is given a voltage of 5V through a resistor R5, and the output terminal of the NOT gate 13 is given a voltage of 5V through a resistor R6.
A voltage of 5V is applied via. AND gate 14
The outputs of -16 are connected to output terminals 19-21.

The operation of this circuit will be explained below with reference to the waveform diagram of FIG. The video RAM 1 temporarily stores a color signal that produces a red color on a graphic screen displayed on a cathode ray tube of a personal computer.
Similarly, the video RAM 2 temporarily stores a color signal representing the green color of a graphic screen displayed on a cathode ray tube, and the video RAM 3 temporarily stores a color signal representing the blue color of a graphic screen displayed on a cathode ray tube. Video RAM 4 temporarily stores text screen characters of the personal computer. The data select circuit 5 includes video RAM 1 to
The color signal of the graphic screen from 3 is connected to terminal 1Y~
This circuit selects whether to send the color signal of the text screen from the video RAM 4 to the terminals 1Y to 3Y. Data selector circuit 5
Red, green, and blue color signals representing a graphic screen or a text screen are sent from terminals 1Y to 3Y, respectively. Since this color signal is activated at a low level, it is inverted by NOT gates 11-13. The outputs of NOT gates 11-13 are color signals for the graphics screen and text screen of an ordinary personal computer.

Color signals for displaying text characters from the video RAM 4 are given to the input terminals of NOT gates 6 to 8, respectively, and red color signals, green color signals, and blue color signals are output from the output terminals of NOT gates 6 to 8. A combined color signal is sent out. The composite signal is
It is applied to terminal A of one-shot multivibrator 18 via NOT gate 9. The one-shot multivibrator 18 generates a one-shot pulse at the falling edge of the signal from the NOT gate 9. The pulse width of this one-shot pulse determines the width of the character shadow and can be adjusted by variable resistor R7. However, "shadow" refers to a shaded display. The output of OR gate 10 is for preventing character shadows from covering the right-hand adjacent character on the text screen, and is applied to one input end of AND gates 14-16. AND
The other inputs of gates 14-16 are provided with color signals from a graphics or text screen. A color signal and its shadow signal are sent out from the output terminals of the AND gates 14-16.

In FIG. 2, the text characters "FE" are superimposed on the blue portion A1 of the graphic screen. Also, the character shadow A2 is attached to the right back of this character "FE". Taking this case as an example, the operation of the circuit shown in FIG. 1 will be explained. The red color signal from the NOT gate 11 becomes a pulse signal P4 as shown in FIG. 24. The green color signal from the NOT gate 12 becomes a pulse signal P5 as shown in FIG. The blue color signal from the NOT gate 13 becomes a pulse signal P6 as shown in FIG. 26. The text character (R+G+B) signal applied to terminal A of the one-shot multivibrator 18 becomes the pulse signal P1 shown in FIG. A signal P2 shown in FIG. 2 is sent out from the output terminal of the one-shot multivibrator 18.
The OR gate 10 takes the logical sum of the signal P1 and the signal P2, and sends out the signal P3 shown in FIG. 2.
The AND gate 14 performs a logical product of the pulse signal P3 and the pulse signal P4, and sends out a pulse signal P7. The AND gate 15 takes the logical product of the pulse signal P3 and the pulse signal P5, and outputs the logical product of the pulse signal P8.
Send out. AND gate 16 receives pulse signal P
3 and the pulse signal P6, and sends out the pulse signal P9. These pulse signals P7 to P
9 is the text character "FE" as shown in Figure 2
These are red, green, and blue color signals with the character shadow A2 attached.

Effects As described above, according to the present invention, by providing a screen in which a text screen is superimposed on a graphics screen with a means for displaying shading on the characters on the text screen, the text becomes easier to see.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the electrical configuration of an embodiment of the present invention, and FIG. 2 is a waveform diagram for explaining the operation of the block diagram in FIG. 1-4...Video random access memory, 5...Data selector circuit, 6-9, 11-
13...NOT gate, 10...OR gate, 14
~16...AND gate, C1...capacitor,
R1-R6...Resistor, R7...Variable resistor.

Claims (1)

[Claims] 1. Video for text screen displaying characters, etc.
In a device that is equipped with a RAM and a video RAM for a graphics screen that displays figures, etc., and displays a text screen superimposed on the graphics screen, shadow display is performed based on the output signal from the video RAM for the text screen. a shadow signal generation means for generating a signal; a first gate means for obtaining an OR output of an output signal obtained from the text screen video RAM and a shadow signal obtained from the shadow signal generation means; a second gate means for obtaining an AND output of the output signal obtained from the gate means and the output signal obtained from the graphic screen video RAM, and is characterized in that it displays shading on characters, etc. on the text screen. Video effect equipment.