JPH06210901A - Font cache controlling system - Google Patents

Abstract

PURPOSE:To enable a font to be provided in a short time by a method wherein when a modified font is not registered in a font cache memory, a bit map data of a font prior to executing the modification is searched for an modified to be used. CONSTITUTION:A font cache memory 8 in which a bit map data prepared from an outline data of a font is registered, is provided. When the requested font exists in the memory 8, it is taken out to be used. When it does not exist, the bit map data prepared reading the outline data is used. Then, an item concerning modification is provided in a use record of the memory 8, and besides a means for performing modification of the font is provided. When the modified font is not registered in the memory 8, the bit map data of the font prior to executing modification is searched for, and qualified to be used. Consequently, the bit map data of the modified font can be provided at high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a font cache control system for providing fonts to a printer or the like at high speed.

[0002]

2. Description of the Related Art In order to provide fonts to a printer at high speed, in addition to a large-capacity storage device that stores outline data (vector data) of all fonts, a small-capacity cache that can be read out at high speed. A font cache system is known in which a memory is provided, and bitmap data of frequently used fonts is temporarily stored therein and provided from there.

FIG. 4 is a diagram showing the configuration of such a font cache system. In FIG. 4, 1 is a font cache system, 2 is a CPU (central processing unit), 3 is an address bus, 4 is a data bus, and 5 is a ROM.
(Read-only memory), 6 is a work RAM (RAM ...
Random access memory), 7 is an interface, 8 is a font cache RAM, 9 is a page memory, 10 is a DMA controller (DMA ... Direct Memory Acces)
s), 11 is a SCSI controller (SCSI ... scan line, interface for hard disk), 12 is a hard disk, 13 is a host computer, 14 is a printer engine, and 17 is an interface.

The ROM 5 is for storing various programs executed by the CPU 2, and is a work RAM 6
Provides a working memory area for executing the program. All fonts are stored in the hard disk 12 in the form of outline data (vector data). Printing information (eg, character code) such as characters to be printed by the printer engine 14 is given from the host computer 13 via the interface 7.

The font corresponding to the character code is first searched in the font cache RAM 8, and if there is, it is read out and expanded in the page memory 9. If not, the outline data is read from the hard disk 12, bit map data of a desired size is generated based on the read outline data, and the bitmap data is expanded in the page memory 9. At the same time, it is stored in the font cache RAM 8. When one page of font is expanded in the page memory 9,
A print start command is sent through the interface 17 of the printer engine 14, and the DMA controller 10
After that, the print data (bitmap data) is serially sent to the printer engine 14 and printing is executed.

Initially, the font cache RAM 8
Nothing is stored in. Each time it is read from the hard disk 12, a record relating to the font is stored in the font cache RAM 8 (the structure of the record will be described later in FIG.
Will be recorded).

[Configuration of Font Cache RAM] First, the configuration of the font cache RAM 8 will be described. FIG. 6 is a diagram illustrating the overall configuration of the font cache RAM 8. In FIG. 6, 8-1 is a font search table, 8-2 is a cache area, 80 is a table division column, 81 is a used record, 82 is an empty record,
CP is a new registration pointer.

The font cache RAM 8 includes a font search table 8-1 and a cache area 8-2. Records relating to fonts such as bitmap data are registered in the cache area 8-2, and information indicating the location where the record is registered is recorded in the font search table 8-1.

The font search table 8-1 is divided into the same number of partitions as the number of font codes, and one specific font code is associated with one specific partition. For example, for the font code representing the character A, a section called a table section column 80 is assigned.

If the font A is registered in the cache area 8-2, information indicating the registered location (address) is written in the table section column 80. When a plurality of fonts having the same font code are registered, one of the registered locations is written. If not registered, not written (Nu
ll)).

In the cache area 8-2, the portion with dots is a portion used for registering a record relating to the font read from the hard disk 12, that is, a portion of a used record. The part without dots is the part of the empty record that is not used as such. The straight line drawn horizontally indicates the record delimiter.

The new registration pointer CP is a pointer that indicates the position when a record relating to a font is newly registered, and is advanced in the cache area 8-2 in a ring direction in a certain direction. When the constant direction is changed from the top to the bottom in FIG. 6, the lowermost end is advanced to the uppermost end.

[Structure of Record] FIG. 7 is a diagram for explaining the structure of a used record and an empty record. Figure 7
(B) shows the structure of the empty record 82. "Free flag" which means that it is free is written in this,
"Free size" indicating the size of the area of the empty record is described.

FIG. 7A shows the structure of the usage record 81. The usage record 81 includes an area for recording information on font attributes and an area for recording bitmap data. The information on font attributes includes, for example, font type (eg, Mincho font, Gothic font), font code (character code, etc.), font size (vertical length, horizontal length), number of hits, same code NE.
There are an XT pointer, a same code BEFORE pointer, and the like. In FIG. 7A, as an example of the bitmap data,
"A" is shown.

The number of hits is the number of times this font has been used while the pointer circulating in a fixed direction in the cache area 8-2 makes a round.

The "same code NEXT pointer" and the "same code BEFORE pointer" are stored in the font cache RAM 8 when a plurality of fonts having the same code are registered, before the usage record 81 is used. And a pointer indicating the location of a record used later. That is, the same code BEFORE pointer indicates the location of the font hit by the same code as the used record 81 after hit. The same code NEXT pointer indicates the location of the font hit by the same code as the used record 81 before hit.

By tracing the same code NEXT pointer and the same code BEFORE pointer, fonts of the same code registered in the font cache RAM 8 can be searched one after another and the order of hits can be known. Since it can be seen that fonts having the same code are connected in a chain through these pointers, so to speak, a "search chain" is formed. The latest hit will be at the top of the search chain.

[Search Chain] FIG. 8 is a diagram for explaining the search chain. Numerals correspond to those of FIG. 6, R ₄ ~
R ₇ has the same font code (assumed to be the font code of the letter A), but the font type is different (“A ₁ ”, “A ₂ ”, “A ₃ ”, and “A ₄ ” in the figure are , Which indicates that the font type is different) represents a record. ~ Indicates the rank of the freshness of the hit (rank of latest hit). Record R ₄ is the latest hit record.

When paying attention to the record R ₅ of the order, the location of the record R ₄ which is hit after this is written in the same code NEXT pointer thereof, and the record R ₄ which is hit before that is written in the same code BEFORE pointer. ₆ locations are written.

[Operation] Next, the control operation of the font cache system configured as described above will be described with reference to the flowchart of FIG. Step 1 ... When the font code to be printed is received from the host computer 13, the font search table 8-
By checking the table division column defined in 1 corresponding to the font code, it is checked whether the font of the font code is registered in the cache area 8-2. If not registered, step 7
Then, the outline data is read from the hard disk 12, converted into bitmap data, and newly registered in the font cache RAM 8.

Step 2 ... If it is registered, the record (used record) is accessed. Now, suppose that what is sought is the record R ₆ in FIG. Further, the font code is set to "A". In the table division column 80 defined corresponding to the font code A in the font search table 8-1, the font code A
The location of the record R ₄ located at the head () of the search chain in the record group of is written, so first access it.

Step 3 ... By looking at the items shown in FIG. 7A of the accessed record R ₄ , it is checked whether or not the font type, size, etc. of the font currently requested match.

Step 4 ... If the result matches the desired one, the record is positioned at the head of the search chain. The meaning of being located at the head of the search chain will be described with reference to FIG. First, the top of the search chain (hit recency order) is the position of the record accessed next time from the font search table 8-1 among the plurality of records linked by the search chain. A dotted arrow in FIG. 8 indicates a record accessed from the font search table 8-1.
In FIG. 8A, the record R ₄ is recorded in the table division column 80.
The location of is written.

If the record hit in step 3 of FIG. 5 is record R ₆ instead of record R ₄ ,
In step 4, as shown in FIG. 8B, the record R ₆ is positioned at the position of hit recency rank in the search chain. Along with this, the hit recency of other records is changed to record R ₄ and record R ₅ to the order.

Specifically, the contents of the table division column 80 are rewritten so as to indicate the location of the record R ₆ .
Since the contents of the table partition column 80 are represented by, for example, about 4 bytes, the time required for this rewriting is extremely short.
In addition, the same code NEXT pointer and the same code BEFORE in each record are changed according to the change of hit recency order.
Rewrite the pointer if necessary. Incidentally, the same code NEXT pointer record R ₆ of the rewritten to represent the location of records R _4, the same code BEFORE pointer record R _4, and to represent the location of records R ₆ rewriting To be
NEXT pointer of record R ₅ , BEFORE of R ₇
The pointer is also rewritten to connect the records R ₅ and R ₇ to each other.

Step 5: The value of the number of hits written in the hit record is incremented by 1 from the hit this time.

Step 6 ... If they do not match, it is checked whether there is another record connected by the search chain. If so, go back to step 2 to access it. If not, it must be ordered from the hard disk 12 and newly registered in the font cache RAM 8. For Figure 8 (b), but will access the records R ₅ hits recency ranking to the next record R _4, font type, the size does not yet match, repeating the steps 3 and 4 again, hits The record R ₆ of the latest order is accessed, and finally the desired one is reached (hit).

Step 7 ... If there is no desired font even after searching the search chain, the outline data is read from the hard disk 12 to the work RAM 6. Step 8 ... Convert the read outline data into bitmap data.

Step 9 ... It is checked whether the data size of the converted bitmap data is a predetermined value or less (eg, 2 kilobytes or less). This check is for deciding whether to register in the font cache RAM 8. If the data size is too large, it will occupy a large area of the font cache RAM 8 and will not be registered. By the way, 400/600 dpi
In a high-resolution printer such as the above, since the memory capacity per character is large, it is decided not to cache bitmap data of a font larger than a predetermined size.

Step 10 ... If the data size is less than a predetermined value, it is registered in the font cache RAM 8. Step 11 ... Transfers the bitmap data of the hit record or the newly developed bitmap data to the page memory 9. This bitmap data is used for printing by the printer engine 14.

A conventional document relating to such a font cache control system is, for example, Japanese Patent Laid-Open No. 61-6.
There are 3884 and Japanese Patent Laid-Open No. 64-88660.

[0032]

[Problems to be Solved by the Invention]

(Problem) When a font obtained by modifying a certain font is requested, in the conventional font cache control method,
Unless there is exactly the same font as the requested font in the font cache RAM 8, the outline data must be read out and converted into bitmap data, so it takes time to provide the font. there were.

(Explanation of Problems) The font modification process is, for example, a process of rotating a certain font as a whole, making it bold, making it a bag character, or making it italic. . FIG. 3 is a diagram showing a font obtained by rotating the font "A" 90 degrees to the left.

When such a rotated font is requested, even if the font "A" is registered, it is not used. Unless the exact same font is registered in the font cache RAM 8, a time-consuming procedure of reading out outline data and converting it into bitmap data must be performed.

Incidentally, it takes about 10 ms to access the hard disk for reading the outline data, and about 3 to 30 ms to convert it to bitmap data. Such length of time is an obstacle when trying to make the printer even faster.
An object of the present invention is to solve the above problems.

[0036]

In order to solve the above-mentioned problems, the present invention has a font cache memory for registering bitmap data created from font outline data, and the requested font is in the font cache memory. If the font cache control method uses the bitmap data created by reading out the outline data and using it if there is no font modification control item in the record used in the font cache memory, and the font modification process If the font subjected to the modification processing is not registered in the font cache memory, the bitmap data of the font before the modification processing is searched for and used for modification.

[0037]

[Operation] In the font cache control method that uses a font cache memory that stores bitmap data, when a font modified from a certain font is requested, the font that is the same as that of Look in cache memory. If not found, the present invention searches for a font before the modification processing. If there is, a desired modification process is performed by the modification process means. This makes it possible to obtain the outline data in a shorter time than when the outline data is read and the bitmap data is created.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, if a font which is a source of modification processing is registered in the font cache RAM 8, a font subjected to modification processing is created by utilizing it. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Although there are various types of font modification processing as described above, the case of rotation as shown in FIG. 3 will be described here as an example.

FIG. 2 is a diagram showing the structure of a used record in this embodiment, but an item related to decoration processing (in this case, "character direction") is also provided as an item of attribute information of the used record. The “character direction” represents the rotation angle from the normal posture. The overall hardware configuration of the font cache system is the same as that shown in FIG. 4, and a description thereof will be omitted. Next, the operation of the present invention will be described.

FIG. 1 is a flow chart for explaining the operation of the font cache control system of the present invention. The description of the same steps as those in the flowchart of FIG. 5 will be simplified. Step 1 ... Assume that the host computer 13 requests to print the font "A" rotated 90 ° to the left as shown in FIG. Font search table 8
By checking the table division column defined corresponding to the font code in -1, it is checked whether the font of the font code is registered in the cache area 8-2.

Step 2 ... If registered, the record (used record) is accessed. Step 3: Check whether the font matches the desired font.

Step 4 If the desired record matches, the record is positioned at the head of the search chain. Along with this, the NEXT pointer and the BEFORE pointer are rewritten as appropriate. Step 5 ... The value of the number of hits written in the hit record is incremented by 1 since this hit.

Step 6 ... If they do not match, it is checked whether there is another record connected by the search chain. If so, go back to step 2 to access it. Here, the one that exactly matches the font in which “A” is rotated 90 ° to the left is searched for. Step 7 ... If there is no exact match, the process returns to the first record in the search chain.

Step 8 ... This time, the search criteria are changed and each record in the search chain is hit again. The standard at that time is the font in the state before the modification processing. In the case of this example, the font is the one that is desired when rotated.

Step 9 ... Look at the item relating to the attribute of the accessed record and check whether the font type and size match. Step 10 ... If they do not match, it is checked whether there is another record connected by the search chain. If so, go back to step 8 to try.

Step 11 ... If there is a match (for example, if there is a record as shown in FIG. 2), the bitmap data of the record is changed to the left (90 ° left in the request direction). Direction). The time required to simply rotate the bitmap data is about 1 ms in terms of software (about 1 ms if hardware for rotation processing is provided).
It is about 00 μs). This time is the time to read out the outline and convert it to bitmap data (about 3 to 3
It is much shorter than 0 ms). Therefore, the font can be provided at high speed.

Step 12 ... Even if the search chain is searched,
If there is no font in the state before modification processing,
Outline data is read from the hard disk 12 to the work RAM 6. Step 13 ... Converts the read outline data into bitmap data.

Step 14 ... It is checked whether the data size of the converted bitmap data is a predetermined value or less (eg, 2 kilobytes or less). This check is for deciding whether to register in the font cache RAM 8. If the data size is too large, it will occupy a large area of the font cache RAM 8 and will not be registered.

Step 15 ... If the data size is less than a predetermined value (eg, 2 kilobytes or less), it is registered in the font cache RAM 8. Step 16 ... Transfers the bitmap data of the hit record or the newly developed bitmap data to the page memory 9. This bitmap data is used for printing by the printer engine 14.

The case where a font subjected to the modification processing of rotation is requested has been described above. However, when a font subjected to another modification processing is requested, it is similarly provided in a shorter time than the case of creating from outline data. You can do it.

[0051]

As described above, according to the font cache control method of the present invention, when there is no font that has been modified for a certain font, the font before the modification is searched. Then, if there is, a desired modifying process is performed by the modifying process means. This makes it possible to provide the font in a shorter time than reading out the outline data and creating the bitmap data.

[Brief description of drawings]

FIG. 1 is a flowchart for explaining the operation of the font cache control system of the present invention.

FIG. 2 is a diagram showing the structure of a usage record in the present invention.

FIG. 3 is a diagram showing an entirely rotated font.

FIG. 4 is a diagram showing a configuration of a font cache system.

FIG. 5 is a flowchart illustrating an operation in a conventional font cache control method.

FIG. 6 is a diagram illustrating an overall configuration of a font cache RAM.

FIG. 7 is a diagram for explaining the structure of used records and empty records.

FIG. 8 is a diagram illustrating a search chain.

[Explanation of symbols]

1 ... Font cache system, 2 ... CPU, 3 ... Address bus, 4 ... Data bus, 5 ... ROM, 6 ... Work RAM, 7 ... Interface, 8 ... Font cache RAM, 8-1 ... Font search table, 8-2 ... cache area, 9 ... page memory, 10 ... DMA controller, 11 ... SCSI controller, 12 ... hard disk, 13 ... host computer, 14 ... printer engine, 17 ... interface, 80 ... table partition column, 81 ... used record, 82 ... Empty record, CP ...
New registration pointer, R _{1 to} R ₆ ... Record

Claims (1)

[Claims] 1. A font cache memory is provided for registering bitmap data created from font outline data. If the requested font is in the font cache memory, it is taken out and used. If not, outline data is used. In a font cache control method that uses bitmap data created by reading, the items used for modification processing are provided in the records used in the font cache memory, and means for performing font modification processing is provided. If the font is not registered in the memory, the font cache control method is characterized in that the bitmap data of the font before the modification processing is searched for and modified and used.