JPH079197Y2 - Drawing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a drawing device installed in a CRT display device of a computer system for drawing graphics and the like, and particularly to improve cursor drawing processing.

<Prior Art> Generally, a drawing apparatus for drawing graphics or the like performs a drawing operation according to a drawing command included in a drawing request sequentially transmitted from a host computer.

The same applies to the cursor drawing for instructing the position chart on the CRT display screen, and when the drawing command in the drawing request transmitted from the host computer is the cursor drawing request, the cursor drawing is performed.

<Problems to be Solved by the Invention> In the conventional drawing device as described above, when the host computer sends a drawing request larger than the capability of the drawing device,
It takes time to wait until the cursor is actually drawn after the host computer sends the cursor drawing request,
There was a delay in the cursor display and movement.

The present invention aims to solve such a problem,
It is an object of the present invention to obtain a drawing device which does not delay time by speeding up the reaction of cursor movement.

<Means for Solving the Problems> The present invention, which has solved the above problems, is a writing apparatus that performs a drawing operation in response to a drawing request successively given from a host computer, and a cursor position buffer writable from the host computer, A cursor drawing unit that draws a cursor according to a value in the cursor position buffer; a FIFO (First In First Out) memory that sequentially stores the drawing requests;
A drawing device provided with a request interpreting unit that fetches the drawing request from the FIFO memory, interprets a command, activates the corresponding process, and activates the cursor drawing unit at the end of the process or when there is no drawing request. is there.

<Operation> The drawing apparatus of the present invention operates as follows.

When drawing requests from the host computer are sequentially stored in the FIFO and read, and the processing corresponding to the drawing command is completed,
Alternatively, the cursor is drawn when there is no drawing request.

<Embodiment> FIG. 1 is a block diagram showing the configuration of a drawing apparatus embodying the present invention.

The host computer 1 issues a drawing request to draw the drawing device 2 of the present invention.
This drawing request is given to the FIFO (First In First O
ut) Stored in the memory 21. The request interpreting unit 22 sequentially reads the drawing requests stored in the FIFO 21, and activates the corresponding processing among the processing p ₁ , p ₂ , ..., Pn corresponding to the drawing command in the drawing request. Then, every time each processing is completed, the cursor drawing unit 23 is activated. The cursor drawing unit 23 takes out the cursor position from the cursor position buffer 24 holding the cursor position and draws the cursor on the CRT display device 3.

The host computer 1 can set the cursor position in the cursor position buffer 24.
When writing to, lock it. When the cursor position buffer 24 is locked, the cursor drawing unit
23 cannot read this cursor position buffer 24 and cursor drawing is not performed.

FIG. 2 is a flow chart showing the operation of the device of the present invention shown in FIG. 1, which will be described below.

The host computer 1 sequentially sends drawing requests, and the FIFO 21 stores the drawing requests.

The request interpretation unit 22 reads the drawing request accumulated in the FIFO 21.

If the FIFO 21 is empty, the locked position of the cursor position buffer 24 is checked and if not locked, the cursor position is taken out, the cursor drawing unit 23 is activated, and cursor drawing is executed.

If the FIFO 21 is not empty, interpret the read drawing request and perform the corresponding processing ( _one of p ₁ , p ₂ , ..., pn processing)
To start.

When this process ends, the cursor position is taken out by checking the locked state of the cursor position buffer 24, and the cursor drawing is executed.

Then, the next drawing request from the FIFO 21 is read again, and the same processing is repeated.

As described above, the device of the present invention performs cursor drawing each time the drawing request is sequentially read from the FIFO 21 and the corresponding processing is completed, or when there is no drawing request, and the cursor drawing issued from the host computer 1 waits. There is no such thing.

That is, the above operation will be summarized as follows.
There are three cases of (1), (2), and (3).
(1) When the cursor position is set while processing a drawing request: The request interpreter 22 extracts the drawing request from the FIFO 21 and interprets it, and performs the processing corresponding to the request. In the meantime, when the cursor position in the cursor position buffer 24 is changed by the host computer 1 or the like, the cursor drawing unit 23 reads the cursor position from the cursor position buffer 24 when the processing corresponding to this request is completed. To draw the cursor. (2) When the cursor drawing unit 23 is activated while the host computer 1 is setting the cursor position Even if the cursor drawing unit 23 tries to extract the cursor position of the cursor position buffer 24, the host computer 1 is writing. Therefore, the cursor position buffer 24 is locked and the cursor position cannot be read. At this time, the cursor 21 is not drawn, and the FIFO 21 or the next drawing request is fetched and processed. After that, the operation is the same as (1).

(3) When there is no drawing request and the cursor position is set by the host computer 1. There is no drawing request to be processed, and cursor drawing is performed as soon as the lock of the cursor position buffer 24 is released.

As described above, no matter what the state of the drawing device,
Cursor drawing is executed immediately.

<Effect of device> Even when a large number of drawing requests that cannot be processed are received from the host computer, cursor drawing can be performed with the highest priority. Therefore, when moving the cursor using a device such as a mouse. Even in this case, the cursor can be moved at high speed while executing another drawing operation.

[Brief description of drawings]

FIG. 1 is a block diagram of a drawing device embodying the present invention, and FIG. 2 is a flow chart showing the operation of the device of the present invention. 1 ... Host computer, 2 ... Drawing device, 21 ... FIFO memory, 22 ... Request interpreting unit, 23 ... Cursor drawing unit, 24 ...
Cursor position buffer, 3 ... CRT display device.

Claims (1)

[Scope of utility model registration request] 1. A drawing apparatus for performing a drawing operation in response to a drawing request successively given from a host computer, and a cursor position buffer writable by the host computer and a cursor drawing for drawing a cursor according to a value in the cursor position buffer. Section and FI that sequentially stores the drawing request
FO (First In First Out) memory and fetches the drawing request from this FIFO memory, interprets the command and activates the corresponding process, and activates the cursor drawing unit at the end of the process or when there is no drawing request. A drawing device provided with a request interpretation unit.