JPH01234892A - Method for displaying character string in graphic image plane - Google Patents

Abstract

PURPOSE:To improve the handling for character display by giving one optional character in a character string to be displayed the front start address of a specific area according to the corresponding character code, and transferring a font pattern from the address to a specified location in a graphic display memory. CONSTITUTION:Character front data 11 are stored in the specific area of a rewritable memory 10 in the order of character code corresponding to characters, and character font data B0l-B15l corresponding to, for example, a lower-case English letter l represent a character front 10 by 16 bytes from a start address 12. Then a one-byte front pattern read out to the high-order digits of the arithmetic register of a processor is shifted right logically by 0-7 bits to perform two-byte transfer, so that a character string beings to be displayed from an optional dot position. Consequently, the character string can be displayed freely and repeatedly during a character string display procedure and the display position is optional in a display dot area, so the handling for the character display is improved greatly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for displaying character strings, and more particularly to a method for displaying character strings on a graphic screen suitable for simultaneous hard copying of a graphic screen and characters.

[Conventional technology]

Conventionally, one character string has been displayed by writing character codes and character attributes into a text (character) display memory. Furthermore, in order to display on a graphic screen, it is necessary to develop a character font in a display memory, and each time the character font is displayed, it is read out by a system call from a font read-only memory.

[Problem to be solved by the invention]

On a text screen, character display positions are fixed, for example, 80 characters x 25 lines, and it is impossible to display characters at arbitrary positions and with arbitrary spacing. On the other hand, the graphic screen is a dot map, and characters can be displayed in any position, but it is necessary to expand the character font, and to obtain a single character font, generally a system call must be used. It took a considerable amount of time to process.

The purpose of the present invention is to display characters at any position,
By shortening the display time, the usability of character display is improved.

[Means to solve the problem]

The first purpose is achieved by developing a character string as a font pattern group on a graphic screen, and the second purpose is achieved by transferring a single character font, which has been developed and placed in a fixed area of a rewritable memory, to a display memory. The goal of speeding up is achieved.

[Effect]

As characters, consider alphanumeric kana characters representing a character font of 8×16 dots. A character font for one character represents 8 horizontal dots as a 1-byte bit pattern, and 1 from top to bottom.
It is expressed in 6 patterns, or 16 bytes. If the dot configuration of the graphic screen is 640 x 400 dots I, the display memory will be 80 x 400 by 1-, and moving 8 dots horizontally will modify the display memory address by 1 byte, and moving 1 dot vertically will modify the display memory address by 80 bytes. There must be. Therefore, it is not possible to directly specify the display position of a character on the graphic screen with a precision of 8 dots or less, and it is necessary to shift the dot pattern of the character phono 1- to be displayed over 2 bytes. Therefore,
The 1-byte font pattern read into the upper part of the calculation register of the processing unit is logically shifted to the right by 0 to 7 bits (0 is filled from the maximum digit MSB) and 2 bytes are transferred. You can start displaying the string from the dot position.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. Character font data 11 is stored in a specific area of the rewritable memory in the order of character codes (for example, ASCI I) corresponding to one character. For example, the character font data Bofl-B1512 for the lowercase English letter Q represents the character font 20 using 16 bytes from the start address 12, and this character shape is a modified standard shape.

On the other hand, in order to display an image, it is necessary to write byte data 31 corresponding to the dot pattern of the image into the display memory 30 corresponding to the pixels of the image.

The character font 20 is moved to the specified absolute coordinates of the screen (xp+
Consider the case where the image is displayed on yp). At this time, the coordinates (i, j) of the element to be displayed are 1 display memory address A I
It corresponds to J and is calculated by .

If the absolute coordinate XP is not a multiple of 8, S = X
The bit shift of p mod 8 (2) is required for the font pattern 20, and it must be converted into the pattern 25.27, for example.

This can be done by transferring the original pattern 20 to the upper byte of the calculation register and performing an S (<7) bit logical shift to the right.
A bit pattern shifted to the right by S bits is obtained.

This 2-byte data is divided into two horizontally consecutive pixels (i,
j) l (i+1.j), the specified absolute coordinates ((xp.

yp) can display the character font.

The address below one font line (one byte) on the display memory is 80 bytes later, as shown in equation (1).

FIG. 4 shows the flow of processing for displaying a character string as an image at arbitrary character intervals. When the display procedure 70 starts, first, calculation processing 71 of equation (1) is performed, and the character code of one character in the character string is read out in order from the beginning. S' = (S+d) mod 8 by the 1-pixel address A to which the character font is to be transferred and the specified character dot spacing d
- Perform processing 72 to calculate the shift amount given by (3).

The processing 75 for one line of the character font is the same as described above, and if it is not finished, the one character end determination 85 is performed.
The transfer destination address is incremented by +80 and the process returns to the next font data processing 75. Processing 80 performs a logical operation with the bar (screen) on which characters are to be displayed, for example, AND, according to attributes given as display conditions.

It is an operation such as OR or XOR, and determines the combination state with memory data for two pixels at the transfer destination.

While the character string end determination 90 is negative, process 7 for the next character.
Repeat step 2.

FIG. 3 is a flowchart showing the system and program functions necessary for the operation of this embodiment.

Figure 2 is an example of transfer data processing for subscript small letters (8 x 8 font), and the font data B052 to Btasz in the rewritable memory size are character font 20.
However, if the font is transferred from the start address 17 of font reading, a character font 23 that has been moved upward is obtained.

If these font data are transferred to a designated location in the display memory, they can be used selectively like subscripts 42 and 43 in display screen construction.

The font read address can be specified using the attribute for the character string, and the address calculation of the transfer destination pixel is uniformly simple.

Although not mentioned in the above explanation, the display color of the character phono is transferred sequentially or simultaneously to the display memory of the three screens corresponding to the three primary colors (RGB), depending on the specified color. This is possible by doing the following.

According to this embodiment, character fonts of any pattern or color can be displayed at any position on one display screen, at any character spacing, and therefore it is possible to display a screen displaying a mixture of graphic images and characters. This can be done very effectively.

〔Effect of the invention〕

According to the present invention, a specific Greek letter or symbol image can be stored in a specific area of a rewritable memory and displayed any number of times during a character string display procedure.

Furthermore, since the display position can be arbitrary within the display dot area, the usability of character display is greatly improved.

The character string display method described here is based on a high-level language such as BAS.
IC machine language subroutines and PAS (AL procedures) are created by users as software.

Since it can be used, there is no need to modify conventional hardware parts.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of one embodiment of the present invention, FIG. 2 is another explanatory diagram of the embodiment, and FIGS. 3 and 4 are flowcharts of data processing in the present invention. 10... Rewritable memory, 20... Character font, 25.27... Font data, 30... Image quality display memory, 40... Display screen, 41-43...
Image display characters, 50... Preparation work, 60... Condition specification work, 70... Execution procedure, 80... Logical operation,
85.90...Judgment. To agent and patent attorney Muscle Ogawa: ”> (...゛10th (0,3'IQ+ (+, clogged---UIM, 5MM
]House 2-Figure 4-1 Utsu 4δ Guan 3

Claims (1)

[Claims] 1. Character fonts are developed in advance in the order of character codes in a specific area of a rewritable memory, and the font start address of the specific area is determined from the character code corresponding to any one character of the character string to be displayed. A method for displaying a character string on a graphic screen, characterized in that a font pattern is transferred from the address to a specified position in a graphic display memory. 2. In the method described in item 1, at the time of system startup, the character font is read from the read-only memory, and appropriate modifications are made to the font of any read character, or any font pattern is assigned to the undefined character code, A method of displaying character strings on a graphic screen characterized by expanding them to a specific area of rewritable memory. 3. In the method described in item 1 or 2, when transferring the font pattern, perform a logical negation operation on the font pattern itself and/or a logical operation with the dot pattern existing in the display memory corresponding to the display screen position. A method of displaying strings on a graphic screen featuring 4. In the method described in Items 1 to 3, when transferring the font pattern, the 1-byte font pattern read into the register is shifted to the right by up to 7 bits and transferred to the display memory location as a 2-byte pattern. A method for displaying character strings on a graphic screen, characterized in that character strings can be displayed at any screen position and with any spacing by performing a logical sum operation with existing dot patterns. 5. In the method described in paragraphs 1 to 4, by moving the read start address of font data for any small character stored in a specific area of the rewritable memory from the beginning, the display vertical position of the small character is changed. A method for displaying character strings on a graphic screen characterized by making them variable.