JPH02304596A - Character data generator - Google Patents

Abstract

PURPOSE:To express characters of high definition without raising the cost by expanding compressed data, which is obtained by compressing character data, by a data expanding means. CONSTITUTION:Compressed data obtained by subjecting character data from a storage means 13 to compression processing is expanded by a data expanding means 17 to output character data corresponding to respective dots constituting a character. Consequently, the storage capacity of the storage means 13 is reduced because the storage means 13 requires only the storage capacity to store compressed data obtained by compressing character data. Thus, unnecessary increase of the storage capacity of the storage means is prevented to express characters of high definition without raising the cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a character data generation device suitably implemented in, for example, a personal computer or a word processor.

[Conventional technology]

Personal computers, word processors, etc.
In order to display characters such as letters on a display device such as a CRT (cathode ray tube) or print them out on a printing device, a so-called font memory is provided that stores the dot patterns of multiple characters as bit images. In response to a predetermined character code corresponding to each character, the bit image of the character corresponding to this character code is read from the font memory and provided to a display device, etc., thereby realizing character display. There is.

A configuration for generating character data represented by the bit image is shown in FIG. ROM (read-only memory) provided as font memory
For example, as shown in FIG. 3, a bit image of a character composed of 16x16 dots is stored, and data "l" is stored in correspondence to a filled dot.
is memorized, and the data ``0'' is memorized corresponding to the unfilled dots.Such data is memorized between multiple characters, and the JIS code etc. input from line 2 is memorized. Character data represented by the bit image of the character stored at the address corresponding to the character code is derived on line 3. This succession of character data consists of 1947 bits consisting of 16 dots arranged in the row direction for each character. In order to specify the line to be output, the ROM
A scan address signal is input to I via line 4.

In each character, scan addresses 0 to 15 are 1st line f1 to 16th line/! 16, and by giving a character code from line 2 and giving a scan address signal sequentially pointing to scan addresses 0 to 15 from line 4, the character data corresponding to the character code can be changed to the first Lines are sequentially derived from line 11 to line 3 one by one.

[Problem to be solved by the invention]

In the conventional configuration as described above, all the patterns of each character are stored as focused images, so for example, if one character is composed of 64 x 64 dots and a high-definition character is to be expressed, R.O.
MI requires 16 times as much storage capacity as when one character is composed of 16x16 dots. As described above, in the conventional configuration, a ROM 1 having a large storage capacity is required for high-definition expression, resulting in problems such as high cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a character data generation device that solves the above-mentioned technical problems and allows high-definition character expression to be realized without increasing costs.

[Means to solve the problem]

The character data generation device of the present invention includes a storage means in which compressed data obtained by performing compression processing on character data is stored, and the compressed data is read out in response to input of a character code; The present invention is characterized by comprising a data decompression means for decompressing and outputting the character data corresponding to the character code.

[Effect]

According to the configuration of the present invention, the compressed data obtained by performing compression processing on the character data from the storage means is expanded by the data expansion means, thereby outputting character data corresponding to each dot forming the character. Therefore, since the storage means only needs a storage capacity capable of storing compressed data obtained by compressing character data, the storage capacity is reduced, thereby contributing to cost reduction. Furthermore, even if each character is made up of many dots in order to express the character with high precision, the storage capacity of the storage means will not become unnecessarily large, and therefore high-definition character expression will be possible at a reduced cost. This is achieved without causing an increase in

〔Example〕

FIG. 1 is a block diagram showing the basic configuration of a character data generation device according to an embodiment of the present invention. This character data generator is configured to derive character data on line 12 in response to a character code inputted on line 11, and has a memory in which compressed data obtained by performing compression processing on the character data is stored. ROM (read only memory) 13 as a means,
and a data decompression section 17 that decompresses the compressed data and outputs the character data. The character data is data equivalent to the character data derived on line 3 in the conventional configuration shown in FIG. 2, and is composed of a plurality of dots arranged in a matrix as shown in FIG. 3, for example. Insert the character you created into each dot.
: It is expressed as data (“0” or “1”) corresponding to I.

The ROM 13 stores data representing a plurality of characters such as letters. In this embodiment, the data representing this character is compressed data obtained by subjecting the character data to compression processing such as Modified Huffman method (hereinafter referred to as "rMH method"), or the character data which is not subjected to this compression processing. . That is, only characters whose data length is shortened by the compression process are stored in the ROM 13 as compressed data subjected to the compression process.

In data compression processing using the MH method, black dots (filled dots in Figure 3) and white dots (
A run-length code is created corresponding to each consecutive number of unfilled dots in Figure 3, but in this MH method, the data length after compression processing is not necessarily shorter than the data length before compression processing. In other words, if black or white dots are continuous, the compression rate will be high, but if black dots and white dots appear alternately, the run length will be adjusted according to the number of changes between white dots and black dots. Because the sign is created, we end up with
On the contrary, the data length becomes long. Therefore, in this embodiment, for a character where (data M before compression) - (data amount after compression) > 0, the storage area 13a of the ROM 13 is
The compressed data subjected to the compression processing is stored in the storage area 13b of the ROM 13 for characters where (data before compression - (data after compression iF)) < 0.
The character data without compression processing is stored as is.

The character code from line 11 is given to address generator 14 which specifies the address of ROM 13 in accordance with this manually inputted character code. This address generation unit 14 determines whether data representing a character corresponding to the input character code is compressed and stored in the ROM 13, and based on the determination result, the storage area 13a or the storage area 13b of the ROM 13. An address signal AI is applied from line 15 to . The determination result in the address generation section 14 is set as a flag Fl.
The data is supplied to a data decompression unit 17 that decompresses the compressed data from the OM 13 and decodes it into character data.

The address signal A1 from the address generation section is sent to the storage area 13.
When the address of address a is specified, compressed data for l characters stored in the storage area 13a and corresponding to the manually inputted character code is inputted via the address signal A1 and the line 18 from the data decompression section 17. The address signal A2 is applied from the line 16 to the data expansion section 17 based on the address signal A2.

The data decompression section 17 decodes the compressed data based on an internally provided compressed data decompression table 17a, and creates character data corresponding to 21 for each dot composing the character. This character data is
Based on the scan address signal SA (equivalent to the scan address signal from line 4 in FIG. 2) inputted from line 19 and given to data expansion unit 17 via line 20, a plurality of dots are arranged in the row direction. configured 1
Every 947 minutes of data is output from line 21 to line 12.

When the address generation unit 14 determines that the data representing the character corresponding to the input character code is stored in the ROM 13 without being compressed, the address generation unit 14 stores the input data in the storage area 13b. address signal A1 representing the address where character data corresponding to the character code is stored;
is derived on line 15. As a result, ROM13
Based on the scan address signal SA from line 19, the character data is derived from line 22 to line 12 one line at a time.

The character data derived on line 12 is
It is applied to display devices such as cathode ray tubes (cathode ray tubes) and liquid crystal displays, and printing devices.

As described above, in this embodiment, the ROM 13 stores character data for each character and compressed data obtained by compressing the character data, whichever has a smaller amount of data. The decompression unit 17 performs data decompression processing to decode the data into character data corresponding to each dot constituting the character, and then outputs the data.

As a result, the ROM 13 can store data for generating many characters with a small storage capacity, and as a result, for example, one character can be made up of many dots to enhance the character's expression. Even if high definition is desired, the ROM 13 does not require an unnecessarily large storage capacity; this effect becomes greater as the number of dots constituting one character increases.

Furthermore, even when representing each character in multiple fonts such as Gothic and Mincho, it is possible to store data representing characters corresponding to each font in the ROM 13, which has a relatively small storage capacity. It becomes possible. In this way, high-definition expression and expression of a wide variety of characters can be realized at low cost using a ROM with a relatively small storage capacity.

In the embodiments described above, the MH method was used as an example of character data compression processing, but any other compression method may be used for this compression processing.

(Effects of the Invention) As described above, according to the character data generation device of the present invention, the compressed data obtained by performing compression processing on the character data from the storage means is expanded by the data expansion means, thereby forming a character. Character data corresponding to each dot is output.Therefore, since the storage means only needs a storage capacity capable of storing compressed data obtained by compressing the character data, the storage capacity is reduced and this This can contribute to cost reduction.Furthermore, even when each character is composed of many dots in order to express the character in high definition, the storage capacity of the storage means does not become unnecessarily large. Therefore, high-definition character expression can be achieved without increasing costs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of a character data generator according to an embodiment of the present invention, FIG. 2 is a block diagram showing the basic configuration of a conventional technique, and FIG. It is an explanatory diagram showing a constituted character. 13... ROM (storage means), 17... data expansion unit

Claims (1)

[Scope of Claim] A character data generation device that generates a character composed of a plurality of dots arranged in a matrix as character data corresponding to each dot, wherein compressed data obtained by performing compression processing on the character data is stored, and the character data is A storage means for reading the compressed data in response to input of a code, and a data decompression means for decompressing the compressed data read from the storage means and outputting the character data corresponding to the character code. A character data generator characterized by: