JPH0417460B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to a buffer control method for an input/output device, and particularly to a receive buffer control method for receiving and temporarily holding information to be output from a host computer, etc. .

(b) Technical background In order to make administrative, technical, and other visible materials easier to understand, it is desirable to use figures, graphs, tables, and so-called natural pictures in addition to letters. many. In response to such demands, display devices and printers that are capable of displaying not only certain coded characters but also so-called dot images are increasingly being used.

(c) Prior art and problems In general, printers that can display dot images can directly handle encoded character data, graphic data encoded using a vector method, etc., and output dots from the printer, etc. Image data consisting of a bit string is input from a host computer, etc., and after being developed into a screen buffer as a dot image for one page, it is output.
Therefore, a receiving buffer is required to temporarily hold the various input data mentioned above.

By the way, for example, if you fill an A4 sheet of paper with only dot images, you will need at least 600,000 bytes of dot information, and even more dots are required for high-quality display, so the buffer is It is necessary to meet the demand, but on the other hand, due to the demand for lower cost input/output devices, the amount of buffer is kept to the minimum necessary.

Information received from a host computer, etc. can begin to be expanded on the screen before all the information necessary to output one page is gathered, and information that has been expanded usually does not need to be saved. Batsuhua does not need to hold all the information. In such a case, the capacity of the receiving buffer required to output one page is relatively small, so two pages of information are received alternately, and while the contents of one area of the receiving buffer are being expanded, the other area is being expanded. By receiving other pages into the area, the efficiency and speed of output processing can be increased.

However, in other cases, a printing format is required in which data such as the same characters, graphics, images, etc. are written in a plurality of different output forms (hereinafter, such a printing format is referred to as multicopy).
Typical such requests can be found in various documents.

In the case of such an output format, if a buffer is used in the above method, the previously received information will not be saved, so the same data will need to be transmitted from the host computer twice as many times as there are different output formats. . Therefore, in this case, it is preferable to use a buffer control method that can store all the information for one page for the necessary period of time and use it repeatedly for expansion to the screen buffer. There is no suitable buffer control method that is economically satisfactory.

(d) Object of the invention Therefore, the object of the present invention is to solve the above-mentioned conventional problems and to provide a buffer that can be adapted to both a replacement buffer system and a buffer system suitable for multi-copy using one type of buffer. To provide a control method.

(e) Structure of the Invention The object is to provide a buffer control method for an input/output device that receives input information in a buffer, expands the input information on the buffer, and generates output information.
In accordance with the output format designation received with the input information, in the case of the first output format, the predetermined reception area of the buffer is divided into two, and each of the input information is divided into two different pages of the output information. Divide the information and receive it alternately,
Each received input information is sequentially overwritten in each divided reception area, and in the case of the second output format, 1
This is achieved by a buffer control method characterized in that the input information is received as the output information of the page, and the received input information is held using the entire reception area. be able to.

(f) Embodiments of the Invention The flow of data related to the present invention will be explained with reference to FIG. Reference numeral 10 denotes a printer device which is an example of an input/output device to which the present invention is applied, and is connected to a host computer 11 by a line 12. An interface control circuit 18 within the printer device 10 controls data exchange with the host. This interface may be any standard interface for transmitting data in a byte-serial or bit-serial manner as is known in the art.

The printer device 10 is generally controlled by a microprocessor 13 according to a program stored in a read-only memory 14.

Information to be output to the printer 24 is stored in the receiving buffer 16 from the host computer via the line 12 and the interface control circuit 18. The information sent from the host computer consists of control information 1, such as specifying the output format, and the following data, as illustrated in Figure 2, and the data consists of various data 3, 5, 7, etc. that should be output to the printer. . They are,
This is all or part of the data for configuring one page of output.

The processor 13 develops the character data, graphic data, image data, and form overlay data of the received data on the screen buffer 20 based on the control information of the received information on the reception buffer 16. Screen buffer 20 is a memory that holds bit patterns that directly correspond to dot images output by the printer. In the expansion process, the received character data is converted into a bit pattern by the character generator memory 19, and then stored in the memory 20.
will be forwarded to. Graphic data encoded as geometric graphic elements such as vectors are converted into bit patterns on the memory 20 in a manner similar to character data. The form overlay data is generally transferred from the host and stored in the buffer 16 in advance, and its contents are encoded in the same way as the graphic data, forming the so-called form of output. For example, the saved form overlay data is numbered and
Which form overlay data is to be used is specified in the control information included in the input information from the host.

Image data is originally a bit pattern that directly corresponds to the output dots, but since it is a large amount of data, it is usually compressed and encoded during transmission and storage. The compression method may be one of various known run-length codes or a simplified form thereof, such as replacing consecutive bits of the same code with short codes. The processor 13 restores the compressed image data on the buffer 16 to the original bit pattern and places it on the screen buffer 20. The screen buffer 20 is assumed to have a development area of two pages, and its usage will be described later.

When one page of output bit patterns is completed on the screen buffer 20, the processor 13 commands the
Printer control circuit 22 drives printer 24 according to information on screen buffer 20.

An example of arrangement of received data on the reception buffer 16 is shown in FIG. Block 30 is a storage area for form overlay data received and stored in advance;
Block 32 is a receiving area for control information such as printing. Blocks 34 and 35 are receiving areas for graphic data, 36 and 37 are receiving areas for character data, and 38 and 39 are receiving areas for image data, and blocks 34, 36, and 38 or 35, 37, and 39 are receiving data corresponding to one page of output data, respectively. Therefore, two pages of data can coexist. here 3
For the graphic and character data 4 to 37, all the data for one page usually fits into each one block area, but the image data cannot fit into the block 38 or 39. Therefore, when block 38 is filled with received data, processor 13 transfers it to screen buffer 2.
0 on one page, and in the meantime, the screen buffer 2
The image data to be expanded to the other page of 0 is requested from the host computer, and block 39 receives the image data. In this way, the next received data is written into the block that has been expanded, and the previous data is lost, but two pages of screens are constructed in parallel on the screen buffer 20.

When the processor 13 identifies multi-copy designation based on the control information received by the block 32, the area of the reception buffer 16 is designated as shown in FIG. 4 to receive subsequent data. In Figure 4,
Blocks 30a, 30b and 32 are the same form overlay data and control information as in FIG.
Block 40 receives one page of graphic data, and block 42 receives the same page of character data. They correspond to blocks 34 and 36, respectively, in FIG.

The remaining area of the buffer 16 is used as a block 44 to receive image data. This area is the combined area of blocks 36 to 39 in Figure 3, so if the size of the output screen is limited to a level that does not cause any practical problems (for example, A4 size or less),
All image data for one page can be stored in block 44 at one time.

In multi-copy designation, two or more form overlay data numbers are designated by the control information. The processor 13 processes blocks 40 and 42.
and 44 are combined with specified form overlay data, for example, the data of block 30a, one page of output is developed on the screen buffer 20 and output to the printer. Then block 4 again
The data of blocks 0, 42, and 44 and, for example, the data of block 30b are expanded to the screen buffer 20.
In this way, multiple types of print output can be sequentially developed on the screen buffer 20 using the same data.

(g) Effect of the invention As is clear from the above explanation, if the present invention is applied to a buffer such as a printer device, by using one relatively small capacity memory as a buffer, it is possible to achieve the same output format as the normal output format. Since the buffering method can be adapted to both multi-copy output formats, it becomes possible to economically construct a high-performance input/output device.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating the configuration of an input/output device, FIG. 2 is a diagram illustrating an example of the format of information transmitted from a host computer, and FIGS. 3 and 4 are diagrams illustrating area allocation of a receiving buffer. In the figure, 10 is a printer device, 11 is a host computer, 13 is a processor, 14 is a read-only memory, 16 is a reception buffer, 18 is an interface control circuit, 20 is a screen buffer, 22 is a printer control circuit, and 24 is a printer. be.

Claims (1)

[Scope of Claims] 1. In a buffer control method for an input/output device that receives input information in a buffer and generates output information by expanding the input information on the buffer, the output is received along with the input information. In accordance with the format designation, in the case of the first output format, the predetermined reception area of the buffer is divided into two, and each input information to be output information on two different pages is divided and received alternately. , sequentially overwrite each of the received input information in each of the divided reception areas, and in the case of the second output format, receive the input information to be the output information of one page, and A buffer control system, characterized in that the buffer control system is configured to hold information using the entire reception area.