JPH05158453A - Character retrieving system - Google Patents

Abstract

PURPOSE:To speed up the retrieval of character expansion tables by preparing cache tables for each character size as character expansion destination address tables. CONSTITUTION:Characters are read out from a character storage memory 2, each size of the characters is expanded in an expansion pattern storage memory 3 and cache tables 5 for each character size, which summarize character expansion destination addresses at each character size, are formed as the tables for retrieving the expanded characters. When a request is issued for a desired size of character, the tables 5 are retrieved for each character size, the desired size is retrieved, the table, which contains the size characters, is retrieved, the address of the desired character is read out, that size character is read out from the table 3 and that character is expanded in an output memory 4. Since the number of the kinds of character sizes is small, the retrieval of the desired size is performed in a short time and since the number of the tables 5 equals to only the number of the expanded characters, the retrieval of the desired character is performed in a short time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a character retrieval system for an output device, such as a vector font, which develops a character having a standard size to a desired size and retrieves and outputs the developed character.

[0002]

2. Description of the Related Art Fonts used for displays and printers are bitmap fonts for storing characters as bit patterns, vector fonts for storing characters as vector information, and information for the start and length of black portions of characters. There is a run length font.

FIG. 2 shows an example of a bitmap font. If the character size is different, a bitmap font is required for each size. FIG. 3 shows an example of a kind of outline font of a vector font. The outline font represents the outer shape (outline) of a character by a straight line or a curve, and holds the coordinates of each straight line or curve as data. (B) shows the retained data. The outline font holds the coordinate data of the characters of the standard size, and characters of different sizes can be obtained by enlarging or reducing the standard size, so it requires less memory area than the bitmap font. There are features.

When a vector font such as an outline font is used, a character of a standard size is expanded into a character of a desired size in a memory, and when the character and its size are designated, the expanded memory is displayed. It is necessary to search for a character of a specified size. A cache control method is often used for this search. This is a method of creating a cache table indicating whether or not a character of a standard size has been expanded on a memory and searching this cache table.

FIG. 4 is a diagram showing a character output cache control system and a general control system. As an example, when printing or displaying the same character, for example, four A characters in succession, (a)
In the cache control method shown in (4), if the output is expanded once in the required character size on the memory, four characters can be printed continuously by the data, and high speed can be realized.
(B) is a case where the cache control method is not used, and four characters are developed on the memory one by one and printed one by one. For this reason, the output speed of the characters becomes slow.

FIG. 5 is a diagram showing an example of character search when the cache control method is used. Characters of a standard size are stored in the character storage memory 2. The expansion pattern storage memory 3 stores data in which the character sizes of the character storage memory 2 are expanded into characters of various sizes. The cache table 1 is a table of characters and sizes expanded in the expansion pattern storage memory 3 and addresses of expansion destinations. The original character pattern storage address is the character storage memory 2
The address of the character in the table is indicated, and the character indicated by this address is stored in the address indicated by the expansion destination address in the table according to the expanded size.

For example, the character "wealth" is stored at the address 20001000 of the character storage memory 2, and this "wealth" is stored.
Is expanded to 20, 50, 12, 15, 54, and 24 points, and stored at the position indicated by the expansion destination address. The output memory 4 searches the cache table 1 for an output-requested character to obtain an expansion destination address, reads it from the expansion pattern storage memory 3, and stores it.

Next, the operation will be described. The cache table 1 is searched for whether the output-requested character has been expanded in the expansion pattern storage memory 3, and if the corresponding character has been expanded, that character is expanded in the output memory 4. If the character has not been expanded, the character storage memory 2 is searched, and the character is extracted and expanded into the expansion pattern storage memory 3 in the required size and output to the output memory 4 and the cache memory 1 is updated based on this data.

[0009]

As shown in FIG. 5, in the cache table, characters of a plurality of sizes are collected for each character. Therefore, it is necessary to search for the expanded character size, and the search often takes a very long time. For this reason, in an extreme case, the cache control may warp the search time.

The present invention has been made in view of the above problems, and an object thereof is to provide a character table for each character size to speed up cache search.

[0011]

FIG. 1 shows the principle of the present invention. A character is read from the character storage memory 2 and the character of each size is expanded in the expansion pattern storage memory 3. The table used to search the expanded character is a character that collects the expansion destination address of the character according to the character size. The size-based cache table 5 is created. The retrieved character is expanded in the output memory 4.

[0012]

When a request for a character of a desired size is issued, the character size cache table 5 is first searched for by character size, then the desired size is searched, and then the character table of that size is searched for and the desired character is searched. Read the address of the character,
A character of that size is read from the expansion pattern storage memory 3 and expanded in the output memory 4. Since there are few types of character size, the search for the desired size is performed in a short time, and then the desired character is searched from the table of that size. Since this table has only the number of expanded characters, You can search in a short time.

The character size cache table 5
If there is no desired size in the text, or if there is a size but there is no desired character in the expanded character address table of that size, the desired character is read from the character storage memory 2 and the expanded pattern storage memory 3 with the desired size is read. To the output memory 4, and at the same time, the character size cache table 5 is updated with this size or a character of this size. This allows subsequent searches for this character to be performed quickly.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 6 shows a cache table, and FIG. 7 shows a character storage memory 2, a developed pattern storage memory 3 and an output memory 4. Character size table 6 for cache table
And the expansion destination information table 7 for each character size. The character size table 6 shows the character size and the address of the expansion destination information table 7 in which the character of each character size is expanded. The expansion destination information table 7 shows the address of each character on the character storage memory 2 and the address at which the character at that address is expanded in the expansion pattern storage memory 3.

Next, the operation will be described. When the character expansion is requested, first, the character size table 6 shown in FIG. 6 is searched. Therefore, if the address value is written in the start address information of the character size for which the expansion request is made, there is a possibility that the corresponding character has been expanded. Therefore, the expansion destination information table 7 indicated by the start address information is searched.

Next, it is searched whether or not the address on the character storage memory 2 of the character for which the expansion request is made is in the character address information of the expansion destination information table 7. If there is information on the corresponding character address in this search, the character pattern is transferred (developed) from the expansion pattern storage memory 3 to the output memory 4 in accordance with the expansion address corresponding to that address.

If the corresponding size is not in the character size table 6 or the corresponding character address is not in the expansion destination information table 7, the corresponding character is read from the character storage memory 2 and the desired character in the desired size is read. Is expanded and stored in the expansion pattern storage memory 3 and output to the output memory 4, and the character size table 6 and the expansion destination information table 7 are updated.

As is apparent from the above description, according to the present invention, the processing time required for searching the cache table can be greatly reduced by creating the character expansion destination address table for each character size of the cache table. , The processing of the entire character expansion can be speeded up.

[Brief description of drawings]

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

FIG. 2 is a diagram showing an example of a bitmap font.

FIG. 3 is a diagram showing an example of an outline font.

FIG. 4 is a comparative explanatory diagram of a cache control method and a case where the cache control method is not used.

FIG. 5 is a diagram illustrating a conventional cache control method.

FIG. 6 is a diagram showing a cache table of the embodiment.

FIG. 7 is a diagram showing a storage example of a character storage memory, a developed pattern storage memory, and an output memory according to the embodiment.

Claims (1)

[Claims] 1. When a character having a predetermined size is expanded from a character having a standard size on a memory and the size and the character are used as a table, a desired character and the size are requested, the table is searched and the memory is searched. A character search method for extracting a character expanded above, wherein the table is a table in which characters are collected for each character size.