JP2605609B2 - Dot display processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of temporarily storing a dot pattern of a graphic to be displayed in a video RAM, reading out the video RAM, displaying the video RAM on a display device, and displaying the data.
When a dot is represented by a plurality of bits of a video RAM, the present invention relates to a dot display processing device for writing data of one dot to a plurality of bits of a video RAM.

[0002]

2. Description of the Related Art When displaying on a CRT or a liquid crystal display device,
The display is performed by writing a dot pattern of an image to be displayed in a video memory and repeatedly reading out the video memory at high speed. In this case, the display dot which is the minimum unit of display may be represented by a plurality of bits of the video memory. For example, there is a case in which display is performed with 3 × 3 bits (one dot having a width of 3 bits in the X-axis direction and a width of 3 bits in the Y-axis direction) of the video memory as one dot. In this case, it is necessary to write the same data to 3 × 3 = 9 bits of the video memory. The process of determining which nine bits in the video memory each dot to be displayed corresponds to and writing the same data to these nine bits is conventionally performed by software, and thus requires a considerable amount of time. There was a problem of doing.

As a prior art for solving a problem similar to the present invention, there is an invention disclosed in Japanese Patent Application Laid-Open No. 61-107384, entitled "Display Device". This is an invention for processing a bit pattern of a font memory representing a character pattern to display a character pattern having a wider line width (so-called bold) than the character pattern represented by the original font memory. Even in this case, since the processing is performed by software, there is a problem in that the processing time becomes longer.

[0004]

As described above, in the conventional dot display processing device, when one dot is to be displayed by a plurality of bits, the dot display process requires a lot of time. Also, as the size of one dot becomes larger, the number of bits of the video memory to which one dot data is to be written becomes larger, so that there is a problem that a longer time is required for writing.

The present invention has been made to solve such a problem. When one dot of a display is displayed by a plurality of bits in a video memory, a plurality of bits corresponding to one dot of the display are displayed. It is an object of the present invention to provide a dot display processing device capable of writing bits into a video memory at high speed.

[0006]

The dot display processing apparatus according to the present invention prepares a bit pattern table for each bit number (n) of one dot in the X-axis direction, and determines the position of the dot in the X-axis direction. Write from this table by
The bit pattern is read and written to the video memory in one operation. That is, in detail, the present invention
Means for determining the coordinate position of the display dot to be displayed, and the coordinate position of the word (the jth number from the 0th number) on one line of the video RAM Means for determining whether the bit corresponds to the k-th bit counting from the number), each of which is prepared for each value of n,
The n-bit long line pattern with the start position shifted
A pattern table having i sets of bit patterns having a length of 1 or 2 words, from the pattern data table ,
n of the table corresponding to the value of n
Of the start position corresponding to the value of k when the
Read the bit pattern representing the line pattern and read
The bit pattern of the video RAM
Each of the m lines in the Y-axis direction starting from
Means for writing to the j-th word when the j-th word is determined by the determining means.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. A CPU 1 controls each unit according to a program stored in a program RAM 6 and stores data in the middle using a work RAM 7. The embodiment shown in FIG. 1 removes a variation in the size of a line caused by hand-drawing a hand-drawn figure and sets the size of one dot to a predetermined number of bits.
In an example utilizing the present invention, data handwritten on the tablet 2 is input from the handwriting input control unit 3 to the video RAM 4 and displayed on the display device 5.

FIG. 2 is a flowchart showing the operation of the apparatus shown in FIG. 1. In FIG. 2, S1 to S4 indicate respective processing steps. FIG. 3 shows an example of a dot to be displayed. In this example, the dot size is 3 bits in the X-axis direction,
The Y-axis direction has three bits. Hereinafter, FIG.
The operation of the apparatus of the present invention will be described with respect to the example shown in FIG. When dots are written by hand on the tablet 2, an accurate square as shown in FIG. 3 (if the unit dimensions in the X-axis direction and the Y-axis direction in FIG. 3 are the same, the hatched portion in FIG. ) Cannot be written. However, the coordinate position of the handwritten dot is determined by the tablet 2 and sent to the handwriting input control unit 3.

In the handwriting input control unit 3, the processing of step S1 in FIG. 2 is performed, and the coordinate position sent from the tablet 2 is converted into an address of the video RAM 4. In the example shown in FIG. 3, X = 2 and Y = 0. The X-axis direction, in the case where divided into for example 16 bits each word is, X = 2
Is 3 in the word (j = 0) of the first address in the X-axis direction.
Means a bit of th (k = 2). Next, the process proceeds to S2, referring to the pattern data table corresponding to n = 3 in FIG. 4, and outputting data 3800 (H) corresponding to k = 2.
Get. However, (H) indicates that the display is in hexadecimal.

Next, the flow shifts to S3, where data 3800 is written in the video RAM at the position of X = 0, Y = 0. The next S
In step 4, the same data is written at each position of X = 0, Y = 1; X = 0, Y = 2. As a result of this writing, the video RAM
4 is as follows: 0011100... 0011100... 0011100... 00000000...... The display shown is obtained.

The structure of the table shown in FIG. 4 is easy.
That is, if one dot has a width of n bits in the X-axis direction (n = 3 in FIG. 4), as shown in FIG.
The words may be divided into four groups of four bits, and the bit pattern of each group may be read in hexadecimal. For example, k
In the case of = 5, the first bit is set to 0, and the fifth, sixth, and seventh bits are set to "1".

FIG. 4 shows only the contents of the table up to k = 7, but up to k = 15. Where k = 14
If k and k = 15, it is necessary to write the word at the next address. Therefore, it is necessary to store the data and execute the writing process.

FIG. 5 shows the contents of the pattern data table corresponding to n = 5. FIG. 5 also has a table up to k = 15, where k = 12, k = 13, k = 14, and k = 15. Must also be written in the word at the following address: Although the present invention has been described with reference to the numerical examples 1 and 2, it is apparent that the present invention is not limited to these numerical examples.

[0014]

As described above, the dot display processing device according to the present invention, when writing the same dot data to a plurality of bits of the video RAM, writes the data with reference to a previously created pattern data table. Therefore, there is an effect that the writing time can be sufficiently reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the apparatus of FIG.

FIG. 3 is a diagram for explaining the operation of the device of FIG. 1;

FIG. 4 is an explanatory diagram showing an example of a pattern data table.

FIG. 5 is an explanatory diagram showing another example of the pattern data table.

[Explanation of symbols]

 Reference Signs List 1 CPU 2 tablet 3 handwriting input control unit 4 video RAM 5 display device 6 program RAM 7 work RAM

Claims (3)

(57) [Claims] 1. A storing graphic dot pattern representing a (including a character) to the video RAM, the reading out the video RAM when cormorants line graphic display, X-axis direction of the n (n is an arbitrary natural number of the video RAM ) bit, wherein when the vertical Y-axis direction of the m (m in the X-axis to display one dot shapes with a natural number) bits, bits for displaying a dot
When the pattern data is one word i bits (i is a natural
In dot display processing unit to be written into video RAM by the word unit consisting of a number), means for determining the coordinate position of the display dot to be displayed, the ordinal number of the word on one line of the coordinate position is the video RAM (first Means for deciding the number of a bit (counted from the 0th to jth) which corresponds to the jth bit (counted from the 0th to kth), each bit being adjusted for each value of n Start position
1 representing a shifted n-bit long line pattern or
A pattern table having i sets of bit patterns having a length of two words, and from the pattern data table ,
Table is determined to be k-th by the determining means.
The line pattern of the start position corresponding to the value of k in the case is displayed.
Read the bit pattern, and read the read bit pattern.
To the Y-axis starting from the line in the video RAM.
Each of the m lines in the direction
means for writing to the j-th word when determined to be the j-th, a dot display processing device. 2. The method according to claim 1, wherein said one word comprises 16 bits and n = 3.
The said pattern data table corresponding to, k = 0,
For each of 1 , 2 , 3 , 4 , 5 , 6 , 7 ,... , Four hexadecimal digits, E000, 7000, 3800, 1C
00,0E00,0700,0380,01C0 , ...
2. The dot display processing device according to claim 1 , wherein? Is stored. 3. The one word is composed of 16 bits, and n = 5.
The said pattern data table corresponding to, k = 0,
For 1, 2, 3, 4, 5, 6, and 7, each of four digits 1
Hexadecimal, F800, 7C00, 3E00, 1F00, 0
2. The dot display processing device according to claim 1 , wherein F80 , 07C0 , 03E0 , 01F0 ,... Are stored.