JPH06274148A - Character generating device - Google Patents

Abstract

PURPOSE:To speedily output a dot pattern that a vector font is expanded into even unless the dot pattern of an output requested character is registered in a font cache memory. CONSTITUTION:A retrieval means 41 retrieves the dot pattern of the character requested to be outputted in the font cache memory and outputs it. An expanding means 80 expands the vector font of the output requested character into the dot pattern and outputs it in parallel to the retrieving operation by the retrieval means 41. A selecting means 42 outputs the dot pattern when the dot pattern is outputted from the retrieval means 41 or outputs the dot pattern that the vector font is expanded into by the expanding means 80 unless the dot pattern is outputted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a character generator, and more particularly to a font cache memory for expanding and registering graphic data (vector font) of a character or the like expressed in vector format into dot format data. Regarding the character generator.

[0002]

2. Description of the Related Art In recent years, a character generator used in a Japanese word processor or the like represents one character by combining vector data because of the advantage that the contour can be printed smoothly even if the character is greatly enlarged. Vector fonts are widely adopted.

In a vector font, a dot pattern can be generated by performing vector calculation on vector data corresponding to a character code for which printing is requested to draw the outline of the font and fill the inside of the outline.

The use of the character data represented in the vector format has the advantage that high quality characters can be obtained, but on the other hand, there is the problem that it takes time to develop the character data in the dot format.

In order to solve this problem, once expanded dot format character data is registered in the font cache memory, and when the same character is requested later, the data in the font cache memory is reused for high speed. A technique of outputting a document to a computer has been developed. For example, the IPSJ journal Vol. 31, No. 1, it is discussed as "high-quality Japanese character high-speed output method".

[0006]

In the above-mentioned prior art, when a character print request or display request is made, the font cache memory is searched first, and the dot pattern corresponding to the output request character is not registered in the font cache memory. Only when it is found that, the expansion instruction is given at this point, and the vector font is read out from the font ROM and the expansion processing is executed.

Therefore, if the dot pattern of the output request character is not registered in the font cache memory, there is a problem in that it takes an extra time to output the character by the time for searching the font cache memory.

An object of the present invention is to solve the above-mentioned problems of the prior art and to promptly output a dot pattern developed from a vector font even when the dot pattern of an output request character is not registered in the font cache memory. To provide the character generator.

[0009]

In order to achieve the above object, the present invention comprises a font cache memory for registering a dot pattern developed from a vector font, and the registered dot pattern is read from the font cache memory and re-registered. In the character generator to be used, a retrieval means for retrieving the dot pattern of the character requested to be output from the font cache memory, and an expansion for developing the vector font of the character required to be output into a dot pattern in parallel with the retrieval It is characterized in that it is provided with a means and a selection means for selectively outputting one of the searched dot pattern and the expanded dot pattern according to the search result.

[0010]

According to the above configuration, regardless of whether the character requested to be output is registered or not registered in the font cache memory, the expansion operation of the character from the vector font is performed in parallel with the search operation. Therefore, even if the output request character is not registered in the font cache memory, the dot pattern of the character can be quickly output.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 2 is a block diagram of a character generator which is an embodiment of the present invention.

In the figure, the host computer 1 is
A character code and a font selection instruction are sequentially generated. The input interface 2 exchanges various data and control signals between the host computer 1 and the character generator.

The input buffer memory 3 temporarily stores the character code and font selection instruction sent from the host computer 1. The character pattern generator 8 develops a vector font corresponding to the character code into a dot pattern. The dot pattern output from the character pattern generator 8 is registered in the font cache memory 7.

In the frame buffer memory 5, the dot pattern already registered in the font cache memory 7 and the dot pattern developed from the vector font by the character pattern generator 8 are image-developed at the position corresponding to the print position command from the CPU 4. Then, the image data for one page is formed. The completed image data for one page is transferred to the output device 6 and displayed on a screen or printed out on recording paper.

The character pattern generator 8 includes a font R
An OM 81, a character pattern generating CPU 82, and a character pattern memory 83. The CPU 82 uses a font ROM for a vector font corresponding to a character code.
It is read from 81 and developed as a dot pattern on the character pattern memory 83.

FIG. 1 is a block diagram for explaining the function of the present invention. In the font cache memory 7, a large number of graphic data such as characters developed from vector fonts are registered as dot patterns. Search means 41
Is a function of the CPU 4, and searches the font cache memory 7 for a dot pattern of a character for which an output is requested and outputs it.

The expanding means 80 has a function equivalent to that of the character pattern generator 8 and expands the vector font of the output request character into a dot pattern and outputs it in parallel with the searching operation by the searching means 41.

The selecting means 42 is a function of the CPU 4, and outputs the dot pattern if the searching means 41 outputs the pattern. If the dot pattern is not output, the expanding means 80 expands it from the vector font. Output the dot pattern.

The operation of this embodiment will now be described with reference to the flow chart of FIG.

In step S10, it is determined whether or not there is a font selection instruction sent from the host computer 1,
When the CPU 4 detects the instruction, step S
In 11, the character code sent from the host computer 1 is received together with the font selection instruction.

In step S12, the CPU 4, which has received the font selection instruction and the character code, starts a search for the font cache memory 7 and, at the same time, outputs a development command to the character pattern generator 8.

In step S13, the dot pattern corresponding to the character code is searched, and if the dot pattern is already registered in the font cache memory 7,
In step S14, the dot pattern is read from the font cache memory 7.

In step S15, the read dot pattern is image-developed at a predetermined position on the frame buffer memory 5 in response to the print position command from the CPU 4. In step S16, the CPU 4 outputs a development stop command to the character pattern generator 8.

On the other hand, in the character pattern generator 8 which has received the expansion instruction in step S12, step S19
At, the character pattern generating CPU 82 reads out a vector font corresponding to the character code from the font ROM 81. In step S20, C for character pattern generation
The PU 82 develops the vector font into a dot pattern on the character pattern memory 83.

In step S21, it is determined whether or not there is the expansion stop command output in step S15 when the dot pattern of the output request character is already registered in the font cache memory 7.

If the expansion stop command is not output, it is determined in step S22 whether the expansion of the vector font into the dot pattern on the character pattern memory 83 is completed, and when the expansion is completed, in step S23. ,
The dot pattern developed on the character pattern memory 83 is image-developed at a predetermined position on the frame buffer memory 5 in response to a print position command from the CPU 4. In step S24, the dot pattern developed on the character pattern memory 83 is stored in the font cache memory 7.

In step S25, it is determined whether the image development for one page is completed, and if it is not completed,
Returning to step S10, the next output request character is accepted. In step S26, the dot pattern for one page that has been image-developed on the frame buffer memory 5 is transferred to the output device 6 for display output or print output.

When the expansion stop command is detected in step S21 during the expansion, the character pattern generating CP is generated.
U82 immediately stops the deployment operation, and at the same time, performs step S
At 30, the character pattern memory 83 is cleared, and the process waits for the next expansion instruction. Note that the character pattern memory 83 uses a memory with a clear end stop so that the character pattern memory 83 is cleared to zero by a reset signal from the CPU 82.

As described above, according to the present embodiment, the search operation for the character requested to be output from the font cache memory 7 and the expansion operation in the character pattern generator 8 are executed in parallel. As a result, even if the desired dot pattern is not registered in the font cache memory 7, the desired dot pattern can be output in a short time.

In this embodiment, after the development of the vector font into the dot pattern is completed (step S22),
The pattern is image-developed at a predetermined position on the frame buffer 5 (step S23) and then registered in the font cache memory 7 (step S24). And C
Since the PU 4 transfers the developed dot pattern directly from the character pattern memory 83 to the frame buffer 5, while the character pattern generating CPU 84 is performing the process of step S24 in the background,
The CPU 4 can execute the processing of the next character, and the processing time can be further shortened.

Further, although the number of the character pattern generators 8 is one in this embodiment, a plurality of character pattern generators may be provided so that different character expansions can be executed in parallel. good.

[0032]

As described above, according to the present invention, the following effects can be achieved. (1) Since the expansion operation and the search operation for the output requested character are executed in parallel, even if the desired dot pattern is not registered in the font cache memory,
A desired dot pattern can be output in a short time. (2) The dot pattern expanded from the vector font is registered in the font cache memory after expanding the image at the expected position on the frame buffer.
By processing the registration in the font cache memory in the background, it becomes possible to further reduce the time required to generate a character.

[Brief description of drawings]

FIG. 1 is a functional block diagram of the present invention.

FIG. 2 is a block diagram of a character generator that is an embodiment of the present invention.

FIG. 3 is a flow chart for explaining the operation of the present invention.

[Explanation of symbols]

1 ... Host computer, 2 ... Input interface,
3 ... Input buffer memory, 4 ... CPU, 5 ... Frame buffer memory, 6 ... Output device, 7 ... Font cache memory, 8 ... Character pattern generator, 41 ... Search means, 4
2 ... Selection means, 80 ... Development means, 81 ... Font RO
M, 82 ... Character pattern generating CPU, 83 ... Character pattern memory

Claims (1)

[Claims] 1. A character generator which comprises a font cache memory for registering a dot pattern expanded from a vector font, and which reads a registered dot pattern from the font cache memory and reuses the dot pattern of a character requested to be output. Search means for searching from the font cache memory; expanding means for expanding the vector font of the character requested to be output into a dot pattern in parallel with the search operation; and a searched dot pattern according to the search result, and A character generation device comprising: a selection unit that selectively outputs one of the developed dot patterns.