JPH0749766A - Display device for mixture of character and graphics - Google Patents

Abstract

PURPOSE:To display character and graphics patterns together with a small display memory capacity and less load on a CPU for display with respect to the display device where characters and graphics are displayed together. CONSTITUTION:A memory 23 for display where codes of characters and codes of graphics patterns are mixed and stored with information indicating characters or graphics, a character pattern ROM 25 where character patterns to be addressed by these codes are stored, and a graphics pattern memory 26 where graphics patterns in row units which have the same number of picture elements as characters in the vertical direction and can be freely set in character units in the horizontal direction are stored are provided. The character pattern and the graphics pattern outputted from them are displayed together based on information indicating characters or graphics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device for displaying characters such as characters and graphics such as images in a mixed manner.

[0002]

2. Description of the Related Art In recent years, a mixed display device of characters and graphics has been indispensable for personal computers and information terminals.

An example of the conventional mixed display device of characters and graphics will be described below with reference to the drawings.

FIG. 5 shows a schematic configuration of a general example of a conventional mixed display device of characters and graphics.
FIG. 6 is a conceptual diagram for explaining the operation thereof. Figure 5
In FIG. 6, 1 is a CPU that controls the display device,
A system memory 2 stores a control program and data for the display device. 3 is a text RAM for storing codes for displaying characters. Reference numeral 4 is a character character pattern ROM storing a character pattern. 5
Is an address conversion unit that converts the data from the text RAM 3 into the address of the character lactate pattern ROM 4. Reference numeral 6 is a graphics RAM for storing a graphics pattern for displaying graphics. Reference numeral 7 is a display address generation unit that generates an address for displaying the text RAM 3 and the graphics RAM 6. 8
Is the character character pattern ROM 4 and graphics R
A display combining unit that combines display pattern data from AM6. Reference numeral 9 is a display such as a television, a CRT, an LCD or the like, which performs a display according to the display signal from the display composition unit 8.
The operation of the mixed display device of characters and graphics configured as described above will be described below.

First, regarding the conventional example shown in FIGS. 5 and 6,
In order to display a character such as a character, the CPU 1 writes a code corresponding to the character to be displayed by the program of the system memory 2 and attributes such as color information and reverse display in an area corresponding to the screen of the text RAM 3. At the time of display, the code sequentially output from the text RAM 3 is converted into an address of the character pattern ROM 4 by the address conversion unit 5, and the character pattern data of the character pattern ROM 4 designated by the address is output. On the other hand, in order to display graphics, a graphics pattern is written in the graphics RAM 6 from the CPU 1 by the program of the system memory 2. At this time, the graphics pattern to be written may be stored in the system memory 2. At the time of display, the data of the graphics pattern is sequentially output. In the display synthesizing section 8, the character pattern data is processed such as a display color based on the attribute information output from the text RAM 3 at the same time as the code for deriving the character pattern, and the character pattern data is synthesized with the graphics pattern data to synthesize the character and the graphics. After being converted into mixed display signals, they are displayed on the display 9.

As described above, in FIG. 5 and FIG. 6, mixed display is realized by a method in which characters are stored as code data and graphics are directly stored in separate memories as graphics pattern data and combined. .

[0007]

However, the above-mentioned configuration is suitable for a display device in which characters and graphics used in a personal computer or the like can be freely set, but a display in which a graphics pattern is fixed is displayed. Since the graphics RAM uses a large amount of memory in the device, the cost is high, and it is necessary to write the graphics pattern from the CPU.
There was a problem that the load on the In view of the above problems, the present invention provides a display device having a small display memory configuration and reducing the load of the CPU on the display, and displaying mixedly a free character and a fixed graphics pattern. To aim.

[0008]

In order to solve the above problems, a mixed display device of characters and graphics according to the present invention stores a display memory for storing character codes and graphics pattern codes and a character pattern. Character pattern ROM, and a graphics pattern memory that stores a graphics pattern memory in which the vertical direction has the same number of pixels as the character and the horizontal direction can be freely set in character units in line units, and display composition for synthesizing the character and graphics It has a structure called a section.

[0009]

According to the present invention, with the above-described structure, the fixed graphics pattern is stored in advance in the graphics pattern memory instead of the conventional method in which the CPU writes the graphics pattern to the graphics RAM and displays it. By mixing the code data corresponding thereto with the character code and writing them in the display memory, mixed display of characters and graphics is realized. Since the characters and graphics only write the code, the load on the CPU can be greatly reduced as compared with the conventional example in which the character and the graphics are code and the graphics pattern is written. Further, in the conventional example, the graphics pattern to be written in the graphics RAM is stored in another memory,
Since it is stored in the graphics pattern memory and used directly as display data, the actual graphics RA
This means that M is omitted.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mixed display device of characters and graphics according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of a character and graphics mixed display device according to an embodiment of the present invention, and FIG. 2 is a conceptual diagram for explaining the operation thereof. 1 and 2, reference numeral 21 is a CPU that controls the display device, and 22 is a system memory that stores a control program and data for the display device. Reference numeral 23 is a display memory for storing character codes and graphics pattern codes. Reference numeral 24 is a display address generation unit that generates an address for display in the display memory 23. A character pattern ROM 25 stores a character pattern. Reference numeral 26 is a graphics pattern memory in which a vertical direction has the same number of pixels as the character and a horizontal direction has a line-by-line graphic pattern which can be freely set in character units. An address conversion unit 27 converts the code data output from the display memory 23 into the addresses of the character pattern ROM 25 and the graphics pattern memory 26. Reference numeral 28 is a display combining unit that combines the display pattern data from the character pattern ROM 25 and the graphics pattern memory 26. Reference numeral 29 is a display such as a television, a CRT, an LCD or the like, which performs a display according to the display signal from the display composition unit 28. The operation of the character and graphics mixed display device configured as described above will be described below with reference to FIGS. 1 and 2.

First, in FIG. 1, the CPU 21 is controlled by a program in the system memory 22, and at the address corresponding to the display position of the display memory 23, the character code and the graphic pattern code, and the character color information. Write attribute data such as blink, blink, or reverse display. Also, in the data to be written, determination information "C" or "G" indicating whether the code is a character or graphics is also written. For convenience of description, the character is "C" and the graphic is "G".

At the time of display, the display address generator 24
Since the address corresponding to the display position of the screen and the read timing are given to the display memory 23, the display memory 23 outputs the data of the indicated address. This data is character or graphics code and attribute data written by the CPU 21, and the address conversion unit 27 converts this code into the addresses of the character pattern ROM 25 and the graphics pattern memory 26. The character pattern ROM 25 outputs the character pattern data of that address, and the graphics pattern memory 26 outputs the graphics pattern data of that address. In the display synthesizing unit 28, the character pattern data is processed such as a display color based on the information of the attribute output from the text RAM 23 at the same time as the code for deriving the character pattern, and finally it is judged whether the character or the graphic is the previous character or graphics. A character pattern or a graphics pattern is selected based on the information, converted into a display signal, and then the character and graphics are mixedly displayed on the display 29.

In FIG. 2, each part corresponds to FIG. The display screen is represented by a matrix (x, y) in which one character is a unit. The relationship between the display 29 and the display memory 23 is as shown in FIG.
One display memory area (two bytes for convenience of explanation) is allocated to one matrix of 9. Here, in the area of the display memory 23 corresponding to the matrix (1, 1) of the display 29, the code of the character "A" and the attribute data such as color information and the information "C" indicating that it is a character are displayed. Write, then matrix (2,
In the area of the display memory 23 corresponding to 1), the code of the character "F" and the attribute data such as color information and "C" are written. On the other hand, in the area of the display memory 23 corresponding to the matrix (M, N) of the display 29, the code of the graphics pattern-1 (hereinafter referred to as GP1) and the information "G" indicating that it is graphics.
Write. Nothing is written in the areas of the display memory 23 corresponding to the subsequent matrix (M + 1, N) to matrix (M + m, N), and the initial setting state [00, 00] is set. It should be noted that the initial setting state [00,00] is used here because this data can be identified as data that is not a character and used to minimize writing from the CPU. Other data may be used as long as the data satisfies the above condition. Next, the next matrix (M + m + 1, N) in which the region of GP1 is completed
A character "F" code, an attribute, and information "C" indicating that the character is a character are written in. Go to the next row, and display pattern 23 (hereinafter GP) in the display memory 23 corresponding to the matrix (M, N + 1).
2) and the information "G" indicating that it is graphics. In this way, the display memory 23 stores one screen of characters and graphics codes and attributes, and information "C" or "G" indicating whether they are characters or graphics.
Write.

Next, at the time of display, the display address generator 24
The display memory 23 is addressed in the order of (1, 1), (2, 1) ... According to the display address from, and the contents of the display memory 23 are output. First, the code and the attribute data corresponding to the character "A" are displayed from the display memory corresponding to the matrix (1, 1).
Is output. Of these, the code data is converted into an address of the character pattern ROM 25, and the first line of the character pattern "A" is output from the character pattern ROM 25 indicated by the address. The character pattern of "A" is processed by the display synthesizing unit 28 such as the display color and the inversion according to the attribute data that is output together with the code, and finally is output together with the code and the attribute as well. It is converted into a display signal according to the information "C" indicating that it is a character, and is displayed on the first line of the area of the matrix (1, 1) of the display 29. Subsequently, the code and attribute corresponding to "F" are output from the display memory 23 corresponding to the matrix (2, 1), and similarly, the first line of the character pattern of "F" is output from the character pattern ROM 25. It is displayed on the first line of the matrix (2,1) on the display. Similarly, the first line is displayed on the display 29 thereafter. Even if the screen of the display 29 is on the second line, the address for the display memory 23 is the same as that for the first line and the code and attributes output from the display memory 23 are the same, but the address for the character pattern ROM 25 is the same. The lower bit (4 bits in the case of a character pattern of 16 vertical pixels) is incremented by 1 and the character pattern of the second line of the character pattern ROM 25 is output and displayed. Repeating this, when the display of the 16th line ends and the 17th line is reached, the display address generation unit 24 outputs the matrix (1, 2),
The display address for (2, 2) ... Is output, and the character pattern corresponding to it is read and displayed in the same manner as above. In this way the character display progresses,
From the display memory 23 corresponding to the matrix (M, N), G
Information indicating the code and graphics corresponding to P1 "
G ”is output. Here, the code corresponding to GP1 is converted into the address of the graphics pattern memory 26 by the address conversion unit 27, and the first pattern data of GP1 is output from the graphics pattern memory 26. After being output by the display synthesizing unit 28 according to the information "G" indicating graphics and converted into a display signal,
The first pattern of GP1 is displayed on the display 29. Next, since the data output from the display memory 23 corresponding to the matrix (M + 1, N) is [00, 00], the address conversion unit 27 causes the graphics pattern corresponding to the previous matrix (M, N). The address of the memory 26 is incremented by 1, and the second pattern of GP1 is read and displayed. Repeat this until GP1 up to the repetition matrix (M + m, N)
Is displayed for one line. When the matrix (M + m + 1, N) is reached, the code of the character "F" is output from the display memory 23, so that the first line of the character pattern of "F" is displayed. When this is repeated and the next display line becomes a matrix (M, N), the display memory 2
Although the code corresponding to GP1 and the information "G" indicating the graphics are output from 3, the address for the graphics pattern memory 26 is the matrix (M + m,
The address of the graphics pattern memory 26 in (N) +1 is output, and the pattern of the second line of GP1 is read and displayed. When this is repeated and the matrix (M, N + 1) is reached, the code corresponding to GP2 and the information "G" indicating graphics are output from the display memory 23 for that, and the pattern of GP2 is read. ,Is displayed. By repeating the above, the character pattern and the graphics pattern are mixedly displayed on one screen of the display 29.

As described above, according to the present embodiment, the display memory 23 for writing the character and graphics codes in a mixed manner, the character pattern ROM 25 for storing the character pattern, and the graphics pattern memory for storing the graphics pattern. 26, and a display synthesizing unit 28 for synthesizing the character pattern and the graphics pattern, and displays the information indicating the code, the attribute and the character in the case of the character display, and the information indicating the code and the graphics in the case of the graphic display. By writing in 23, characters and graphics can be mixedly displayed at high speed with a small memory.

An example showing that display can be performed at high speed with a small memory will be described with reference to FIG. In the case of displaying a graphics pattern of 128 pixels × 128 pixels as shown in FIG. 3, in the conventional example using the graphics RAM, it is necessary to set in 1 pixel units.
In the case of 16-color display, CPU in 8KB memory
Need to write. On the other hand, in this embodiment, when the character unit of horizontal 8 pixels × vertical 16 pixels is used, the CP
It is sufficient for U to write only 16 bytes at 8 locations in the display memory, which can significantly reduce the number of times of writing and enable high-speed display. Further, the number of writings is not related to the width of the graphics pattern or the number of display colors, but is related only to the number of display lines by converting the characters of the graphics pattern.

Further, since the graphics pattern is set for each row, it does not necessarily have to be a rectangle as shown in the display 29 of FIG. 2, and a shape shown in FIG. There can be multiple graphics patterns per line.

Although the memory for storing the character pattern is the ROM in this embodiment, it may be another memory such as RAM.

As the graphics pattern memory, it is possible to store the fixed graphics pattern in a read-only memory such as a ROM, but it may be another memory such as a RAM. . In the case of a readable / writable memory such as a RAM, it is possible to connect the memory to a CPU to form a semi-fixed graphics pattern that can be rewritten at a certain timing instead of a fixed graphics pattern.

[0021]

As described above, according to the present invention, a display memory for writing a mixture of character and graphics codes, a memory for storing a character pattern, a memory for storing a line-by-line graphics pattern, and a character pattern. A display synthesis unit that synthesizes a graphic pattern with a pattern is provided. In the case of character display, the code and attributes are written, and even in the case of graphic display, only the code is written to the display memory, so that the character and graphics can be mixed at high speed with a small amount of memory. Can be displayed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a mixed display device of characters and graphics according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram for explaining an operation in the embodiment.

FIG. 3 is a diagram showing the relationship between pixels and characters of the graphics pattern in the same embodiment.

FIG. 4 is an explanatory view of the shape of a graphics pattern in the embodiment.

FIG. 5 is a schematic configuration diagram of a conventional character and graphics mixed display device.

FIG. 6 is a conceptual diagram for explaining an operation in the conventional example.

[Explanation of symbols]

 21 CPU 22 System Memory 23 Display Memory 24 Display Address Generation Unit 25 Character Pattern ROM 26 Graphics Pattern Memory 27 Address Conversion Unit 28 Display Synthesis Unit 29 Display

Claims (1)

[Claims] 1. A display memory for writing a mixture of character and graphics codes, a memory for storing a character pattern, and a row in which the vertical direction has the same number of pixels as the character and the horizontal direction can be freely set for each character. A mixed character and graphics display device comprising a memory for storing a unit graphics pattern and a display combining unit for combining the character pattern and the graphics pattern.