JPH03240098A - Font cache system for outline font - Google Patents

Abstract

PURPOSE:To utilize a small cache memory effectively even when a Japanese sentence which contains many characters is handled by storing HIRAGANA (cursive form of Japanese syllabary), KATAKANA (square form of Japanese syllabary), and numbers which are quantitatively high in use frequency in a cache memory. CONSTITUTION:When a receiver 1 receives print data from a host computer, a command analysis part 2 analyzes its commands and supplies character control information and character codes to a plotting part 3. The plotting part 3 accesses the font cache memory 8 when there are character codes on the font cache memory 8 to read a corresponding dot matrix font, which is written in the bit map memory 4. Thus, the dot matrix font of some of the HIRAGANA, KATAKANA, numbers, and symbols is developed on the memory 8 to eliminate the need for the development of characters by about 71%, and the development on the memory 4 can be speeded up; and the memory 8 can be constituted with small capacity and effective use becomes possible.

Description

[Detailed description of the invention] [Table of contents] Overview Industrial field of application Prior art (Figure 4) Means for solving the problem to be solved by the invention (Figure 1) Working example (a) 1 Explanation of Embodiments (Figures 2 and 3) (b) Explanation of Other Embodiments Effects of the Invention [Summary] Outline font data is stored in a font memory, and the outline font data is developed into a dot matrix font. Regarding the font caching method for outline fonts in which dot matrix fonts are expanded in the cache memory in advance for Japanese output devices that output fonts, it is possible to make effective use of the small amount of cache memory even when handling Japanese that contains a large number of characters. The purpose of this is to prevent the configuration from becoming complicated, and includes a memory that stores outline font data, a character development section that develops the outline font data in the memory into a dot matrix font, and bits into which the dot matrix font is written. It has a map memory, an output unit that outputs the contents of the bitmap memory, and a cache memory that stores the dot matrix font, and the characters stored in the cache memory are stored in the dot matrix font from the cache memory. In this Japanese language output device, among the Japanese fonts, hiragana, katakana, and numeric dot matrix fonts were stored in the cache memory.

[Industrial application field]

The present invention provides a Japanese output device that stores outline font data in a font memory, develops the outline font data into a dot matrix font, and outputs the output. Regarding font cache method.

When an output device such as a printer receives a character string represented by a character code from the host, it outputs a dot matrix font (character pattern) that corresponds to the character code.
must be generated and output on the printing section or display section.

The method for generating this dot matrix font is to store outline font data, which is character outline information, in the font memory, draw (expand) the outline of the character based on the outline font data, and then create the dot matrix font. Outline font technology is used to generate fonts.

A Japanese output device using such outline font technology is expected to speed up the development of Japanese characters.

[Conventional technology]

FIG. 4 is an explanatory diagram of the prior art.

In the printer that uses the Japanese outline font shown in FIG. ) and the character code are given to the drawing section (control section) 3.

The drawing section 3 supplies the character code and character control information such as enlargement specification to the character expansion section 6.

The outline font memory 7 stores the position of a desired point (
The character development unit 6 draws the outline of the character based on the outline information (outline data) corresponding to the character code, and then develops the inside of the outline to fill it in. A dot matrix font as shown in FIG. 4(C) is created.

This dot matrix font is written into a specified position in the bitmap memory 4 under the control of the drawing section 3. When the desired dot matrix font is written into the bitmap memory 4, the contents of the bitmap memory 4 are written into the printing section. 5
printed by.

This outline font provides characters with relatively smooth outlines, and can be easily enlarged, rotated, whitened, etc.

As described above, although outline fonts have excellent printing quality, they have the disadvantage that they take time to develop and the printing speed is slow.

For this reason, a font cache technique has been proposed in which a cache memory is provided to store the developed dot matrix font, and the characters in the cache memory are obtained from the cache memory, for example in Japanese Patent Laid-Open No. 1-188354. has been done.

The following methods were used to cache fonts in this cache memory.

■ Store all expanded fonts in cache memory.

■ Detects the frequency of use of each font during printing and stores frequently used fonts in cache memory.

■ Character type specified by the operator in advance (JISI, etc.)
is stored in cache memory.

[Problem to be solved by the invention]

However, in the conventional method (■), all used characters are stored in the cache memory, which requires a large capacity cache memory.In addition, characters that are not used frequently are also stored in the cache memory. There was also a problem in that the cache memory could not be used effectively.

In addition, in the conventional method (■), the actual frequency of use is detected, so the cache memory can be used effectively, but in order to detect the frequency of use of each character, a counter is required for each character, and the number of characters is 7000. When dealing with Japanese, 7
In addition to the problem that 000 counters are required and the configuration for detecting the frequency of use becomes complicated, lowering the value for detecting the frequency of use requires a large capacity of the cache memory, making it difficult to use the cache memory effectively. If the detection value is increased, the number of characters stored in the cache memory becomes too small, reducing the effectiveness of the cache memory by half, making it difficult to detect the frequency of use.

Furthermore, in the conventional method (■), specifying a detailed character type depends on the subjectivity of the operator, and cache memory cannot necessarily be used effectively. There was a problem in that a large capacity memory was required.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a font cache method for outline fonts that can effectively utilize a small amount of cache memory and prevent the configuration from becoming complicated even when Japanese characters containing a large number of characters are handled. shall be.

[Means to solve the problem]

FIG. 1 is a diagram showing the principle of the present invention.

As shown in FIG. 1, the present invention comprises a memory 7 that stores outline font data, a character development section 6 that develops the outline font data in the memory into a dot matrix font, and bits into which the dot matrix font is written. It has a map memory 4, an output unit 5 that outputs the contents of the bitmap memory 4, and a cache memory 8 that stores the dot matrix font, and the characters stored in the cache memory 8 are stored in the cache memory 8. In this Japanese language output device, the cache memory 8 stores dot matrix fonts for hiragana, katakana, and numbers among the Japanese fonts.

[Effect]

The present invention qualitatively investigated the printed content of Japanese documents and found that hiragana, katakana, and numbers account for the majority (about 2/3) of the Japanese characters.

Therefore, hiragana, katakana, which are qualitatively frequently used,
The numbers are stored in cache memory 8.

Furthermore, since the Japanese language has 83 hiragana characters, 86 katakana characters, and 10 numeric characters, for a total of 179 characters, the capacity of the cache memory 8 can be small.

Therefore, in order to increase the expansion speed of the conventional technology, the cache memory must be made larger, and conversely, if the cache memory is made smaller, the expansion speed becomes slower. Also, the deployment speed can be increased.

Furthermore, since it is not necessary to detect the actual frequency of use, problems caused by detecting the frequency of use, complication of the configuration, difficulty in detection, etc. can be solved.

〔Example〕

(a) Description of one embodiment FIG. 2 is a configuration diagram of an embodiment of the present invention.

In the figure, the same parts as shown in Figures 1 and 4 are:
They are indicated by the same symbols, and 9a is an address/data bus that outputs printing codes etc. from the drawing unit 3 to the character expansion unit 6 and font cache memory 8. 9b is a data bus that connects the character expansion unit 6 to the character expansion unit 6. From bitmap memory 4
, for transferring the dot matrix font developed in the font cache memory 8.

FIG. 3 is a detailed explanatory diagram of the present invention.

The font memory 7 stores outline data (outline information) of over 7000 Japanese characters shown in FIG. 3(A).

On the other hand, the cache memory 8 stores some fonts of hiragana, katakana, numbers, and symbols shown in FIG. 3(B) developed using outline data.

We did this because we investigated various documents and found that 27% of the printed content was in kanji, 37% in hiragana, and 27% in katakana.
, 3% were numbers, 2% were alphabets, and 4% were symbols.

Japanese has 83 hiragana characters and 86 katakana characters.
The numbers are 10 characters long, and the main symbols are 20 characters long. There are 199 characters in total.

If only these characters are developed in advance as a font cache in the cache memory 8, 71% of the characters in the above-mentioned document can be obtained directly from the cache memory 8.

If you obtain a dot matrix font directly from the cache memory 8, you can develop it on the bitmap memory 4 more than 50 times faster than when you obtain a dot matrix font from the outline font memory 7. can be considered to be 50 times faster.

Therefore, the development speed of the total bitmap memory including kanji characters is improved about three times that of the conventional method.

Moreover, it is only necessary to develop a small number of characters (199 characters) in the cache memory 8, and the cache memory 8 can be used efficiently with a small capacity.

Next, the operation of the embodiment shown in FIG. 2 will be explained.

Prior to printing, when the power is turned on, the drawing section 3
commands to expand some characters of hiragana, katakana, numbers, and symbols.

The character development section 6 reads out these outline font data from the outline font memory 7, develops it into a dot matrix font, and transfers it to the font cache memory 8 for storage.

Next, when the receiving section 1 receives print data from the unprinted data, the command analyzing section 2 analyzes the command and provides character control information and a character code to the drawing section 3.

The drawing unit 3 stores the character code in the font cache memory 8.
If not, the character code is given to the character development section 6 via the bus 9a, and the
The outline font data corresponding to the character code is read from the font, developed into a dot matrix font, and written into the bitmap memory 4 via the bus 9b.

Conversely, if the character code is in the font cache memory 8, the drawing unit 3 accesses the font cache memory 8 via the bus 9a, reads out the corresponding dot matrix font, and stores it in the bitmap memory 4 via the bus 9b.
write to.

In this way, some dot matrix fonts for hiragana, katakana, numbers, and symbols that are qualitatively frequently used are expanded in the cache memory 8, which eliminates the need to expand approximately 71% of the characters, resulting in faster processing. Since it is possible to expand into a bitmap memory, and only 199 characters of dot matrix fonts need to be stored in the cache memory 8, the cache memory 8 can be configured with a small capacity and can be used effectively.

Further, unlike the conventional method, it is not necessary to detect the frequency of use for each character, so a complicated configuration for detecting the frequency of use is not required, and the difficulty in detection can be solved.

As a result, the most frequently used fonts can be stored in the cache memory, speeding up development time, and making effective use of the small amount of cache memory.

(t)) Description of other embodiments In the embodiments described above, a portion of hiragana, katakana, numbers, and symbols were stored in the cache memory, but it is also possible to store only hiragana, katakana, and numbers, or even all of the alphabet. Or you may add a part.

Furthermore, although hiragana and other characters are expanded and stored in the cache memory when the power is turned on, the cache memory may also be configured with ROM (read-only memory) and store dot matrix fonts such as hiragana. The font memory 7 and the cache memory 8 may be configured as an integrated memory.

Although the present invention has been described above using examples, the present invention can be modified in various ways according to the gist of the present invention, and these are not excluded from the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, characters that are qualitatively used frequently are cached in the font, so the development speed of Japanese outline fonts can be maximized with a small amount of cache memory, and the cache memory can be maximized. It has the effect of being able to be used effectively.

[Brief explanation of drawings]

Figure 1 is a diagram of the principle of the present invention. FIG. 2 is a configuration diagram of an embodiment of the present invention. FIG. 3 is a detailed explanatory diagram of the present invention, FIG. 4 is an explanatory diagram of the prior art. In the figure, 4-bitmap memory, 5-output section; 6-Character expansion part, 7-Font memory, 8-Cache memory.

Claims (1)

[Scope of Claims] A memory (7) that stores outline font data, a character development section (6) that develops the outline font data in the memory into a dot matrix font, and a bitmap memory into which the dot matrix font is written. (4), and an output unit (
5) and a cache memory (8) for storing the dot matrix font, and characters stored in the cache memory (8) obtain the dot matrix font from the cache memory (8). A font cache method for outline fonts in a Japanese language output device, characterized in that the cache memory (8) stores Japanese fonts such as hiragana, katakana, and numeric dot matrix fonts.