JPH07219510A - On-screen display device - Google Patents

Abstract

PURPOSE:To provide the device capable of making an on-screen display of display information such as character information together with its background information without increasing the capacity of an image memory. CONSTITUTION:This on-screen device, capable of adding the background information to the display information such as the character information and expand and display them on the screen, is equipped with a 1st storage means 7 which stores the graphic pattern of the display information and the pattern of the background information, 2nd and 3rd storage means 5 and 4 which stores codes for reading the patterns out, a code specification means 1, pattern read means 1, 6, and 7 corresponding to specified codes, a background pattern storage means 10 which stores the read pattern of the background information, a 1st conversion means 8 which converts the read pattern of the display information into image information, a 2nd information conversion means 11 which converts the read pattern of the background information into an image, and a display control means 9 which makes an on-screen display of the image information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-screen display device for expanding and displaying display information such as character information and graphic information on a screen such as a television or video.
In particular, the present invention relates to an on-screen display device that can display background information by adding it to the display information.

[0002]

2. Description of the Related Art Generally, when various kinds of display information are to be displayed on-screen on a screen such as a television or a video, a character generator ROM and a video RAM are provided.
An on-screen IC with a type of image memory is used. When the display information is character information, the character code stored in the video RAM is used to read the character pattern to be displayed on-screen from the character patterns stored in the character generator ROM, and this is read. It is controlled so as to be converted into image data and output as a signal at a predetermined position on the screen.

On the other hand, in the case where a personal computer or the like displays graphic information on the screen, which can be expressed in a much more detailed manner than the character information, the graphic information is handled as a group of pixels, and individual graphic information is displayed on the screen. Control for expanding and displaying the pixels is performed. in this case,
The above character generator ROM is not used, and the graphic pattern information is stored in the video RAM together with the color information as a bit map graphic.

On the other hand, Japanese Patent Application No. 5-269178 discloses an on-screen display that enables coloring on a pixel-by-pixel basis and, at the same time, realizes on-screen display of graphic information at a low cost by reducing the memory capacity. A device has been proposed. FIG. 8 is a block diagram showing a basic circuit configuration for displaying on-screen graphic information, and specifically shows an example of the configuration of the on-screen display device proposed in Japanese Patent Application No. 5-269178. ing. According to this circuit configuration, on-screen display of graphic information is performed as follows. That is, in the CPU, the code of the graphic pattern to be displayed on-screen on the screen is transferred to the video RA through the address changeover switch.
Store in M. Then, the code of the corresponding graphic pattern is read from the video RAM according to the read address generated by the read address generator.

On the other hand, in the graphic pattern ROM,
A graphic pattern composed of X pixels and Y pixels is stored in the horizontal and vertical directions of the screen together with color information. The code of the graphic pattern read from the video RAM and the read address generated by the read address generator are stored. Thus, the vertical read address of the graphic pattern ROM is created. Then, according to the read address, the graphic pattern data having the color information read from the graphic pattern ROM is converted into three image data R, G, B by the color conversion table for each pixel, and further, the display control circuit. At, the processing necessary for the screen display is performed by a control signal such as a changeover switch SW for display ON / OFF, blanking, and superimpose display, and the information is displayed as on-screen display information on a television screen or the like.

Now, let us consider using the above-mentioned circuit configuration to display a screen called so-called "wallpaper" in which a certain graphic pattern is used as a background and characters and figures are displayed on the background. . FIG. 9 is an explanatory diagram showing the wallpaper display function of displaying the background image on the screen together with the character or graphic image. That is, in (a), “AB
The character string "CDEFG ..." is displayed. Further, in (b), a background image (shown by hatching in the figure) that is the background of the display character string is displayed on the entire display screen. Then, in (c), the background image shown in (b) serves as a so-called wallpaper, and the display character string shown in (a) is superimposed and displayed on the background image.

[0007]

However, when the above-mentioned wallpaper display function is to be realized with the circuit configuration shown in FIG. 8, the following problems occur. That is, for the area on the display screen where the graphic or character is not displayed, it is sufficient to display only the background pattern on the screen by the same method as the conventional method for displaying a character or graphic on the screen. For the rectangular area on the on-screen screen for displaying, a new graphic pattern in which the background pattern to be the background image is embedded must be created in the pixels forming the background portion of the character or graphic pattern.

It takes a lot of time and effort to create a new composite pattern by combining such a character / graphic pattern and a background pattern, and a plurality of background patterns are provided for the same character / graphic pattern. If this is done, it will be necessary to create a composite pattern for each background, so pattern data will increase and RO
This leads to an increase in M capacity.

The present invention has been made in order to solve such a problem, and can easily display display information such as character information together with background information thereof on the on-screen without increasing the capacity of the image memory. It is an object to provide an on-screen display device capable of displaying.

[0010]

In order to achieve the above object, the invention according to claim 1 adds background information to display information such as character information and develops and displays it on an on-screen screen. An on-screen display device capable of performing the above-mentioned display information and background information on the on-screen screen as an aggregate of X pixels in the horizontal direction of the screen and Y pixels in the vertical direction. First storage means for storing the respective fixed graphic pattern information having 2 ^N pieces of color information, and a predetermined pattern in the graphic pattern information for the display information stored in the first storage means are designated. A second storage means for storing a rewritable designated code for storing the rewritable designation code, and a portion of the graphic pattern information about the background information stored in the first storage means. And a third storage means for storing a rewritable designation code for designating the pattern, and a predetermined pattern to be displayed from the graphic pattern information stored in the first storage means. Code specifying means for specifying a corresponding code in the first storage means, and a predetermined pattern corresponding to the code specified by the code specifying means from the graphic pattern information stored in the first storage means. Pattern reading means for reading the background information, background pattern storing means for storing a predetermined pattern for the background information read by the pattern reading means, and a predetermined pattern for the display information read by the pattern reading means on an on-screen screen. First conversion means for converting into image information for display, and the background pattern Second conversion means for converting a predetermined pattern of background information stored in the storage means into image information for displaying on an on-screen screen; and display information obtained by the first and second conversion means. Combining image information about background information,
And a display control means for controlling the display at a predetermined position on the on-screen screen.

The invention according to claim 2 is the invention according to claim 1, wherein the code designating means further comprises the designating code for the display information stored in the second storing means and the code. It is characterized in that the third storage means is provided with a code read switching means for switching the reading of the designated code for the background information stored.

The invention according to claim 3 is the invention according to claim 1 or claim 2, wherein the pattern reading means comprises a first horizontal synchronizing period which is one scanning period of the display screen. During the next second horizontal sync period,
After the lapse of the first horizontal synchronization period and before the start of the on-screen display period, a predetermined pattern of the background information stored by the first storage means is read out.

The invention according to claim 4 is the invention according to claim 3, wherein the background pattern storage means stores background information read by the pattern reading means during the on-screen display period. It is characterized by holding a predetermined pattern. In addition, claim 5
The invention according to claim 4 is the invention according to claim 4, wherein the display control means, during the on-screen display period,
White information that the image information about the display information has,
The display information and the background information are combined as image information by replacing the background information with the image information.

[0014]

According to the above structure, in the present on-screen display device, it is possible to add background information to display information such as character information and expand and display it on the on-screen screen. The display information and the background information are both treated as an X pixel group in the horizontal direction of the screen and a Y pixel group in the vertical direction of the screen, and further, each fixed pixel information having 2 ^N color information per pixel. Is stored in the first storage means as the graphic pattern information.

Further, a rewritable designation code for designating a predetermined pattern in the graphic pattern information of the display information stored by the first storage means is stored by the second storage means. Furthermore, the first
A rewritable designation code for designating a predetermined pattern in the graphic pattern information about the background information stored by the storage means is stored in the third storage means.

Next, in order to select a predetermined pattern to be displayed from the graphic pattern information stored in the first storage means, the corresponding code is assigned to the first storage means by the code designating means. It is specified. In this case, the code designating means includes a code reading switching means for switching the reading of each of the designated code for the display information stored in the second storage means and the designated code for the background information stored in the third storage means. A corresponding designated code is provided to the first storage means through the code read switching means.

Subsequently, from the graphic pattern information stored in the first storage means, the predetermined pattern corresponding to the code designated by the code designating means is read by the pattern reading means. In this case, the pattern reading means is between a first horizontal synchronization period which is one scanning period on a display screen such as a television screen and a second horizontal synchronization period which is the next, and the first horizontal synchronization period has elapsed. After doing
In a period before entering the on-screen display period, a predetermined pattern of background information is read out.

The predetermined pattern of the background information read by the pattern reading means is stored by the background pattern storage means. In this case, the background pattern storage means holds a predetermined pattern of the background information to be stored during the on-screen display period. Subsequently, the predetermined pattern of the display information read by the pattern reading means is converted into image information by the first converting means in order to be displayed on the on-screen screen. Also, the predetermined pattern for the background information stored by the background pattern storage means is
In order to be displayed on the on-screen screen,
It is converted into image information by the second conversion means.

The display information and the image information about the background information obtained by the first and second conversion means are combined by the display control means and further displayed at a predetermined position on the on-screen screen. Is controlled. In this case, the display control unit replaces the white information included in the image information about the display information with the image information about the background information during the on-screen display period so that the display information and the background information are combined. Has become.

As a result of the above, on the on-screen screen,
A so-called wallpaper display in which background information is added to display information such as character information is realized in a pixel unit in a colorful and expressive manner.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a block diagram showing a basic circuit configuration of an on-screen display device according to the present invention.
This on-screen display device displays on-screen graphic information including a CPU 1, a read address generator 2, an address changeover switch 3, a video RAM 5, a graphic pattern ROM 7, a color conversion table 8 and a display control circuit 9. In addition to the basic circuit required for displaying, a background register 4 required for displaying a background pattern on-screen, a background / character / graphic data switching switch 6, a background pattern storage unit 10,
A background color conversion table 11 is further added and configured.

The graphic pattern ROM 7 includes graphic pattern data (character / graphic pattern data) in which graphic information such as characters / graphics to be displayed on-screen on a screen of a television, a video or the like and background information thereof include color information. And background pattern data). Also,
The video RAM 5 stores a character / graphic pattern code serving as a read address for the character / graphic pattern data stored in the graphic pattern ROM 7.

Next, according to the circuit configuration shown in the figure, a specific circuit operation when background information is added to graphic information such as characters and figures and on-screen display will be described. The CPU 1 specifies an address (indicated by an arrow as a CPU address in the drawing) with respect to the video RAM 5, outputs CPU data, and controls writing and reading of a character / graphic pattern code.

Further, in the read address generator 2, the video RAM 5 is synchronized with the final screen refresh.
And in both memories of graphic pattern ROM7,
A read address is supplied to the background pattern storage unit 10. When the character / graphic pattern code stored in the video RAM 5 is rewritten, the address changeover switch 3 is used to change the address.

On the other hand, the CPU 1 stores the background pattern code (including the color designation code) in the background register 4 when the background information is added to the graphic information such as characters and figures for on-screen display. This background pattern code is read out through the background / character / graphic data switching switch 6 when reading the background pattern data from the graphic pattern ROM 7, and becomes the read address of the graphic pattern ROM 7.

In reading the background pattern data (which will be described in detail with reference to FIG. 4), the read address generator 2 generates a read address in the screen vertical direction for each scanning line on the on-screen screen. The background pattern data read from the graphic pattern ROM 7 in accordance with the read address is sent to and stored in the background pattern storage unit 10.
Further, the background pattern data held therein is read by the screen horizontal direction address supplied from the read address generator 2, supplied to the background color conversion table 11 and colored, and is supplied to the display control circuit 9 as image data. Sent.

In the on-screen display (described in detail in FIG. 5), character / graphic pattern data is read from the graphic pattern ROM 7 according to the graphic pattern code (including the color designation code) read from the video RAM 5. The read character / figure pattern data is further supplied to the color conversion table 8 and converted into image data. Then, the image data is sent to the next display control circuit 9.

In the display control circuit 9, with respect to the image data of the character / graphic pattern sent from the color conversion table 8, in the rectangular area on the on-screen screen that the image data occupies, for the pixel to be the background image, the background color is set. The image data of the background pattern sent from the conversion table 11 is replaced and displayed. When there is no character / graphic pattern data to be displayed on-screen, the background pattern is controlled to be displayed.

If a plurality of background color conversion tables 11 are provided and one of the background color conversion tables is designated by the background pattern code, the same character / graphic pattern is represented by different colors. It is also possible to display the background information displayed on the screen. In addition, it is possible to provide a plurality of background patterns, and in this case, the background image can be changed, so that the expressive power can be further enhanced.

FIG. 2 is a schematic diagram showing an example of creating a background composite pattern displayed on the on-screen screen by the circuit configuration shown in FIG. Here, there are a total of 64 pixels of 8 pixels in the horizontal direction and 8 pixels in the vertical direction of the on-screen screen.
The character / graphic pattern shown in (a) and the background pattern shown in (b) are combined with respect to a rectangular area made up of pixels,
The example which produces the synthetic pattern shown to (c) is shown.

Now, assuming that the coordinates of the pixel are represented as (i, j), in (a), (2, 4), (2, 5)
And (3,3), (3,6) and (4,2), (4
7), (5,2), (5,7), (6,2),
(6,3), (6,4), (6,5), (6,6),
A total of 16 pixels (6, 7), (7, 2), and (7, 7) (display pixels are shown in black in the figure).
Form the character / graphic pattern shown in the figure.

Similarly, in (b), (1, 3),
(1,6) and (2,2), (2,5), (2,8)
And (3,1), (3,4), (3,7), and (4
3), (4, 6) and (5, 2), (5, 5), (5
8), (6,1) (6,4), (6,7), (7,
3), (7, 6) and (8, 2), (8, 5), (8,
A total of 21 pixels (8) (display pixels are shown with spots in the figure) form a background pattern consisting of several lines running in the diagonal direction shown in the figure.

In (c), a combined pattern is formed by combining the character / graphic pattern shown in (a) and the background pattern shown in (b). In this case, pixels (2, 5) that are common to the patterns (a) and (b),
For the four pixels (5, 2), (6, 4), and (6, 7), the pattern of (a) is preferentially selected and displayed.

In this way, the wallpaper display function is realized by synthesizing the character / graphic pattern and the background pattern. The background pattern data stored in the graphic pattern ROM 7 is composed of M × N pixels in the horizontal and vertical directions of the on-screen screen (however, M and N are arbitrary integers of 1 or more) and displayed. The control circuit 9 reads the horizontal pattern for each horizontal line on the on-screen screen and combines it with the character / graphic pattern.

FIG. 3 is a timing chart showing the timing of reading the background pattern data from the graphic pattern ROM 7 shown in FIG. In the present embodiment, as described above, since the character / graphic pattern data and the background pattern data are both stored in the graphic pattern ROM 7, the CPU 1 adjusts the read timing of each data. Specifically, as shown in the figure, the background pattern data used in the line is read immediately after the horizontal synchronizing signal and before the actual video data is displayed, and the background pattern storage unit is read. The read data is held in 10. continue,
When the actual video data comes, the character / graphic pattern data to be displayed on-screen during the on-screen display period is read from the graphic ROM 7, converted into image data together with the background pattern data that has already been read and held, and post-synthesized. On-screen display of composite image.

FIG. 4 is an explanatory diagram showing a background pattern data reading process from the graphic pattern ROM 7 shown in FIG. First, the CPU 1 writes the background pattern code n in the background register 4. Further, the graphic pattern ROM 7 is designated by graphic pattern data (code numbers 0, 1, ...) Of a character / figure having a pixel configuration corresponding to x pixels in the horizontal direction and y pixels in the vertical direction of the on-screen screen. Background pattern data (designated by the code number n) having the same pixel configuration is stored. Therefore, by the switching operation of the background / character / graphic data switching switch 6, the background pattern code n held in the background register 4 is supplied to the graphic pattern ROM 7, and the background pattern data is read.

When reading the background pattern data, the read address (C, L) is supplied from the read address generator 2 to the graphic pattern ROM 7. That is, the horizontal position x of one pixel to be read (in the figure, the pixel "b" is shown as an example) among the pixels forming the background pattern data is given by x = C / X, and the vertical position y is also given. Is given by y = L / X. Therefore,
The background pattern data is read according to the read address (C, L).

Further, the read address generator 2 supplies a horizontal read address x to the background pattern storage section 10. Therefore, in the background pattern storage unit 10, with respect to the background pattern data read from the graphic pattern ROM 7, the horizontal position x is 1 from 0 to X.
The line pattern is stored. FIG. 5 is an explanatory diagram showing an on-screen display process by the circuit configuration shown in FIG. First, the CPU 1 writes the graphic pattern code n in the video RAM 5. This graphic pattern code n is a graphic pattern ROM
It is a read code of the character / graphic pattern data stored in 7. When changing the contents of the video RAM 5, the CPU data and the CPU address are changed.

Next, the graphic pattern code n is read from the video RAM 5 by the CPU data according to the read address (C, L) supplied from the read address generator 2 to the video RAM 5 via the address changeover switch 3. It is supplied to the graphic pattern ROM 7. From the read address generator 2,
The read address (C, L) is supplied to the graphic pattern ROM 7. Then, in accordance with the read address (C, L), the character / graphic pattern data designated by the graphic pattern code n is read out and supplied to the color conversion table 8.

The color conversion table 8 converts the character / graphic pattern data read for each pixel into image data for on-screen display. Here, an example is shown in which the corresponding pixel data “a” (horizontal position x, vertical position y) is read from the graphic pattern ROM 7 and converted into image data “A”. Also, at the same time,
The background pattern data stored in the background pattern storage unit 10 described above is supplied to the background color conversion table 11 and converted into image data on the background. Here, an example is shown in which the background pattern data “b” (horizontal position x) is converted into image data “B”.

The character / graphic pattern image data “A” supplied from the color conversion table 8 and the background pattern image data “B” supplied from the background color conversion table 11 are supplied to the display control circuit 9. Are synthesized. In this case, if the image data “A” of the character / graphic pattern is a transparent color (or white), the image data “B” of the background pattern is controlled to be output.

FIG. 6 is a flow chart showing a main process for on-screen display and a one-line display process executed by the on-screen display device according to the present invention. First, in the main process, the graphic pattern code is written to the video RAM 5 (S1) and the background pattern code is written to the background register 4 (S2) during the vertical blanking period of screen scanning. Subsequently, the display processing routine for one line is executed during one screen scan (S3). When the scanning of one screen is completed (Yes in S4),
The process moves to step S1 to move to the display process for the next screen. Next, the one-line display process of step S3 in the above-mentioned main process will be described. In the 1-line display process, the background pattern data in the graphic pattern ROM 7 is selected by the background pattern code (S11), and the read position in the background pattern is determined by the read address supplied from the read address generator 2 ((S11)). S12). Then, the background pattern data read from the graphic pattern ROM 7 is stored at the current horizontal position in the background pattern storage unit 10 (S13). Then, it is confirmed whether or not the background pattern for one line is stored (S14). The processes from step S11 to step S14 described above are performed during the background pattern reading period shown in FIG.

When it is confirmed that the background pattern for one line is stored (Yes in S14), the on-screen display processing is confirmed while confirming whether or not one line is displayed (S16). , During the on-screen display period shown in FIG. 3 (S15). FIG. 7 is a flowchart showing the on-screen display processing routine (S15) in the flowchart shown in FIG. First, the characters stored in the graphic pattern ROM 7
Video R which is the read address of figure pattern data
The graphic pattern code stored in AM5 is read (S21). Next, the character / graphic pattern data in the graphic pattern ROM 7 is selected by the read code from the video RAM 5 (S22). Also,
At the same time, the read address in the character / graphic pattern is determined by the read address supplied from the read address generator 2 (S23).

Subsequently, image data (color data) of three colors (R, G, B) corresponding to the character / graphic pattern data read from the graphic pattern ROM 7 is taken out from the color conversion table 8 (S24). In parallel with this, the background pattern data at the current horizontal position in the background pattern storage unit 10 is read (S25), and the image data (color data) corresponding to the read background pattern data is converted into the background color conversion table 11 (S2
6).

Then, it is confirmed whether or not the image data of the character / graphic pattern is transparent (S27). If it is transparent (Yes in S27), the background image data is displayed on the on-screen screen. If it is not transparent and is not transparent (No in S27), the image data of the character / graphic pattern is output on the same screen (S29).

[0046]

As described above, according to the present invention, the graphic pattern ROM corresponding to the first storage means stores the graphic pattern for the background, and the on-screen display device can be realized by adding and changing the simple circuit configuration. , It is possible to provide a wallpaper display function for adding background information to on-screen display information such as character information. Further, in terms of apparatus cost, almost no increase in cost is brought about, and since various on-screen displays are realized, the expressive power of on-screen display is greatly improved compared to the conventional case.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic circuit configuration of an on-screen display device according to the present invention.

FIG. 2 is a schematic diagram showing an example of creating a background composite pattern displayed on the on-screen screen by the circuit configuration shown in FIG.

3 is a timing chart showing the timing of reading background pattern data from the graphic pattern ROM 7 shown in FIG.

FIG. 4 is an explanatory diagram showing a process of reading background pattern data from the graphic pattern ROM 7 shown in FIG.

5 is an explanatory diagram showing an on-screen display process by the circuit configuration shown in FIG.

FIG. 6 is a main process for on-screen display executed by the on-screen display device according to the present invention and 1
It is a flowchart which shows a line display process.

7 is a flowchart showing an on-screen display processing routine in the flowchart shown in FIG.

FIG. 8 is a block diagram showing a basic circuit configuration for displaying on-screen graphic information.

FIG. 9 is an explanatory diagram showing a wallpaper display function of displaying a background image on a screen together with a character or graphic image.

[Explanation of symbols]

 1 CPU 2 Read Address Generator 3 Address Change Switch 4 Background Register 5 Video RAM 6 Background / Character / Figure Data Change Switch 7 Graphic Pattern ROM 8 Color Conversion Table 9 Display Control Circuit 10 Background Pattern Storage 11 Background Color Conversion Table

Claims (5)

[Claims] 1. An on-screen display device capable of adding background information to display information such as character information and expanding and displaying the information on an on-screen screen, wherein the display information and the background information are displayed horizontally on a screen. A first pixel is developed on the on-screen screen as a pixel group of X in the direction and Y in the vertical direction, and is further stored as fixed graphic pattern information having 2 ^N color information for each pixel. Storage means; second storage means for storing a rewritable designation code for designating a predetermined pattern in the graphic pattern information of the display information stored in the first storage means; A third storing a rewritable designation code for designating a predetermined pattern in the graphic pattern information about the background information stored in the storage means. Storage means and code designating means for designating a corresponding code to the first storage means in order to select a predetermined pattern to be displayed from the graphic pattern information stored in the first storage means. A pattern reading means for reading a predetermined pattern corresponding to a code designated by the code designating means from the graphic pattern information stored by the first storing means, and background information read by the pattern reading means. Background pattern storage means for storing a predetermined pattern; first conversion means for converting a predetermined pattern of display information read by the pattern reading means into image information for displaying on an on-screen screen; and the background On-screen the specified pattern for the background information stored by the pattern storage means. Second conversion means for converting into image information to be displayed on a screen, and the first conversion means.
And display control means for synthesizing the display information obtained by the second conversion means and the image information about the background information and displaying the synthesized information at a predetermined position on the on-screen screen. On-screen display device. 2. The code designating means further comprises the second
2. The code read switching means for switching the reading of the designated code for the display information stored in the storage means of the above and the designated code for the background information stored in the third storage means. On-screen display device. 3. The pattern reading means is arranged between a first horizontal synchronization period which is one scanning period of a display screen and a second horizontal synchronization period which is the next period, and which is the lapse of the first horizontal synchronization period. 3. The on-screen display device according to claim 1 or 2, wherein a predetermined pattern of background information stored in the first storage unit is read out in a period before the start of the on-screen display period. . 4. The on-screen display device according to claim 3, wherein the background pattern storage means holds a predetermined pattern of the background information read by the pattern reading means during the on-screen display period. . 5. The display control unit replaces the white information included in the image information about the display information with the image information about the background information during the on-screen display period to replace the display information with the display information. The on-screen display device according to claim 4, wherein background information is combined as image information.