JPH0768844A - Letter pattern generating mechanism - Google Patents

Abstract

PURPOSE:To contrive the reduction of the capacity of a letter pattern generating mechanism and the high-speed processing of the same mechanism by a method wherein only letter patterns, whose using frequency is low, are compressed while letter patterns, whose using frequency is high, are not compressed. CONSTITUTION:A character generator (hereinafter abbreviated to C. G.) 4 is constituted of a part 4a, storing letter pattern as a non-compressed bit image data, and another part 4b, storing the letter patterns as compressed bit image data. On the other hand, a compressed letter judging means 1 judges whether the letter pattern of the letter is stored in the C. G. 4 as the bit image data of compressed form or not from an inputted letter code. Further, a compessed bit image defreezing means 3 reads out the bit image data of compressed form from the C. G. 4 and restores (defreezes) it into non-compressed bit image data. A bit image reading means 2 reads the non-compressed bit image data out of the C. G. 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a character pattern generating mechanism used in a printing device or a display device of a computer system, and more particularly to compression of bit image data.

[0002]

2. Description of the Related Art A conventional character pattern generating mechanism is composed of a character generator (hereinafter abbreviated as CG) which stores a character pattern as a bit image and a reading means thereof. Due to the increase, C.I. G. Capacity is increasing. Therefore, C.I. G.
In order to reduce the capacity of the C. G. There is also a character pattern generation mechanism including a means for reading the data and restoring (decompressing) the bit image before compression.

Next, this conventional character pattern generating mechanism will be described with reference to the drawings. FIG. 3 is a functional block diagram of a conventional character pattern generation mechanism.

The character pattern generating mechanism of the conventional example is a character generator (CG) 34 that stores a bit image in a compressed form of a character pattern, and the data is read out and restored to a bit image before compression ( Defrosting means 33 for defrosting).

Next, the operation of the conventional character pattern generating mechanism will be described with reference to the drawings.

FIG. 4 is a flow chart for explaining the operation of the conventional character pattern generating mechanism.

3 and 4, C.I. G. 34 includes
The character pattern of every character is stored as a compressed bit image in compressed form. To obtain a character pattern of a character, a character code is first input to the character pattern generation mechanism (step 41). The decompression means 33 extracts the compressed bit image corresponding to the input character code as C.I.
G. It is read from 34 (step 42) and restored (decompressed) to the bit image before compression (step 43). The decompressed bit image is output as a character pattern from the character pattern generation mechanism (step 44).

[0008]

In the conventional character pattern generating mechanism described above, when the bit image is not compressed, the C.I. G. However, when compressing a bit image, it is necessary to restore the compressed bit image to the bit image before it is compressed, so compared to the case where the bit image is not compressed. ,
It has a drawback that the processing time becomes long.

[0009]

The character pattern generating mechanism of the present invention comprises a portion for storing a character pattern as uncompressed bit image data and a portion for storing a character pattern as bit image data in a compressed form. C. G. And C. as bit image data in which the character pattern of the character is compressed from the input character code. G. The compressed character determining means for determining whether or not the bit image data in the compressed form is stored in C.I. G. The compressed bit image decompressing means for reading (decompressing) the uncompressed bit image data and the uncompressed bit image data.
G. And a bit image reading means for reading from.

[0010]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a functional block diagram of an embodiment of a character pattern generating mechanism according to the present invention, and FIG. 2 is a flow chart for explaining the operation of the character pattern generating mechanism of this embodiment.

Referring to FIG. 1, the character pattern generating mechanism of this embodiment has a bit image data storage unit 4 for storing character patterns as uncompressed bit image data.
a and a character generator (CG) 4 including a compressed bit image data storage unit 4b for storing bit image data in a compressed form of a character pattern.
And C. as bit image data in which the character pattern of the character is compressed from the input character code. G. Four
Compressed character judging means 1 for judging whether or not it is stored in
And bit image data in a compressed form as C.I. G. A compressed bit image decompressing means 3 for decompressing (decompressing) the bit image data in an uncompressed state.
The uncompressed bit image data is C.I. G. 4 and bit image reading means 2 for reading.

Next, description will be given with reference to the drawings on the assumption that the character pattern generating mechanism of this embodiment is used in a Kanji printer.

1 and 2, the character generator 4 stores a character pattern of Chinese characters in the compressed bit image data storage unit 4b as a compressed bit image in a compressed form, and stores characters other than Chinese characters (Hiragana, Katakana, etc.). It is assumed that the character pattern is stored in the bit image data storage section 4a as an uncompressed bit image.

In order to obtain a character pattern of a character to be printed, a character code is first input to the character pattern generating mechanism (step 11). The compressed character determination means 1 determines whether the input character code is a kanji code or not (step 12). If the input character code is a Kanji code, the compressed character determination means 1 transfers it to the compressed bit image decompression means 3. G. An instruction is issued to read the compressed bit image data from 4 (step 13). The compressed bit image decompression means 3 is a C.I. G.
The compressed bit image data read from No. 4 is restored (decompressed) to the bit image before compression (step 14).
The decompressed bit image is output as a character pattern from the character pattern generation mechanism (step 15).

If the input character code is not a Kanji code, the compressed character judgment means 1 transfers the C.D. G. An instruction is issued to read the uncompressed bit image data from 4 (step 16). C. G. The bit image data read from No. 4 is directly output as a character pattern from the character pattern generation mechanism (step 15).

In the case of this embodiment, only the character patterns of Chinese characters are compressed. G. The capacity of the Chinese character pattern stored in the C.I. G. Since it occupies about 80% of the whole, when the compression rate is 70%, C.I. G. As compared with the case of not compressing, the capacity of [(1-0.8) + 0.8 × 0.7] ÷ 1 = 76% is sufficient.

In general documents, characters other than Chinese characters are generally used more than Chinese characters. Here, when decompressing a compressed character and when it is not compressed. Assuming that the processing time ratio when reading a character pattern as it is is 1: 1.5 and the usage frequency ratio of kanji and non-kanji characters is 2: 3, the processing time (throughput) of this embodiment is the same for all characters. When the processing time (throughput) when the pattern is compressed is 100%, 87
% Processing time will suffice.

[0019]

As described above, the character pattern generating mechanism of the present invention compresses only the character patterns that are used infrequently and does not compress the character patterns that are used frequently, so that all the character patterns are C. than when not compressed. G. Requires less space, and processing time (throughput) is better than when compressing all character patterns
Has the effect of being short.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an embodiment of a character pattern generation mechanism according to the present invention.

FIG. 2 is a flowchart for explaining the operation of the character pattern generation mechanism of this embodiment.

FIG. 3 is a functional block diagram of a conventional character pattern generation mechanism.

FIG. 4 is a flowchart for explaining the operation of a conventional character pattern generation mechanism.

[Explanation of symbols]

 1 Compressed character judging means 2 Bit image reading means 3 Compressed bit image decompressing means 4 Character generator (CG) 4a Bit image data storage section 4b Compressed bit image data storage section 33 Decompression means 34 Character generator (CG)

Claims (1)

[Claims] 1. A character generator comprising a part for storing a character pattern as uncompressed bit image data and a part for storing the character pattern as bit image data in a compressed form, and a character based on an input character code. And a compressed character determining means for determining whether or not the character pattern is stored in the character generator as compressed bit image data, and the compressed bit image data is read from the character generator and is not compressed. Character pattern generation, comprising: compressed bit image decompressing means for decompressing (decompressing) bit image data in a state; and bit image reading means for reading the uncompressed bit image data from the character generator. mechanism.