JPH0432977A - Plotting device and image display system - Google Patents

Abstract

PURPOSE:To facilitate movement to picking or clipping detection operation by placing plotting operation in a temporary stop state (pause state) in response to the detection of picking or clipping. CONSTITUTION:The plotting device 12 is equipped with a host bus interface unit 13, an instruction fetch unit 14, a plotting unit 15, and a graphic bus interface unit 16. When the picking is detected, the pause state is entered. Therefore, when picking detection operation is performed again after the picking is detected, a CPU 1 only cancels the pause state of the plotting device 12 and need not reactuate the plotting device 12. Consequently, when the picking detection operation is performed again after the picking is detected, the movement to this operation is facilitated.

Description

[Detailed Description of the Invention] [Summary] Regarding a drawing device that executes a drawing command to draw on an image memory, after detecting picking or clipping, it is necessary to shift to picking or clipping detection operation again. The object of the present invention is to provide a means for detecting picking or clipping, and a drawing operation in response to detection of picking or clipping by the means. and a means for temporarily stopping the operation.

[Field of Industrial Application] The present invention relates to a drawing device that executes a drawing command to draw on an image memory, and an image display system configured using such a drawing device.

[Prior Art] Conventionally, an image display system, the main part of which is shown in FIG. 7, has been proposed.

In the figure, 1 is a central processing unit (CPU), 2 is an instruction memory, 3 is a drawing device, 4 is an image memory, 5 is a serial/parallel converter, and 6 is a CRT. In this image display system, The drawing command is stored in the instruction memory 2 and executed by the drawing device 3, and is stored in the image memory 4.
and is displayed on the CRT 6 via the serial/parallel converter 5.

In addition, such an image display system has a picking function, that is, one of the graphic primitives in the image already displayed on the CRT 6 (an image drawn by combining graphic primitives such as lines, circles, rectangles, etc.). It has a function that the user can specify and pick up using a mouse or the like.

FIG. 8 is a diagram for explaining such picking. In the figure, 7.8 is a straight line drawn on the CRT 6, 9 is a cursor, and when the picking mode is set, a predetermined width is set based on the point specified by the mouse, that is, the center of the cursor 9. The area (the area surrounded by the broken line .

In this case, the drawing device 3 is set to a mode in which it only performs coordinate calculations and does not perform drawing on the image memory 4, and then
When the instructions stored in the instruction memory 2 are executed sequentially from the first address and the instruction of a graphic primitive whose line segment is drawn in the picking area 10 is executed, this is detected and the status provided inside the instruction is detected. Control was such that a flag was set and an interrupt was issued to the CPU 1 to notify the CPU 1 that picking had been detected, and then the process directly proceeded to the next instruction.

[Problems to be Solved by the Invention] However, if the drawing device 3 is a drawing device that fetches instructions by itself or a drawing device that has a large capacity buffer and can preload instructions, C.P.U.I.
There is a problem in that the instruction moves to the next instruction before checking the instruction in which picking has been detected, and the instruction in which picking has been detected cannot be confirmed.

Therefore, in such a case, due to the configuration of the drawing device 3, a method may be considered in which the processing is stopped (ended) after the command that detects picking. According to this method, in a case like the example in FIG. 8, the CPUI can confirm the picked instruction.

However, if such a method is adopted, for example,
As shown in the figure, when picking is to be performed for a circle 11, other graphic primitives, such as a straight line 7, are included in the picking area 10, and
The command list stored in the command memory 2 contains 1 yen.
If the command to draw the straight line 7 is stored as an earlier address than the command to draw the straight line 7, an inconvenience will occur. That is, in such a case, the straight line 7 is first detected as a picking target, and this is examined by the CPU, but
Since straight line 7 is not subject to picking, the CPU
It is necessary to restart the drawing device 3 and have the drawing device 3 detect the figure (circle 11) to be picked, and when restarting the drawing device 3, complicated processing must be executed. A problem arises.

FIG. 10 is a flowchart for explaining this problem in more detail, and shows the operations of the CPU 1 and the drawing device 3.

First, when the picking mode is set, the first address of the command list stored in the command memory 2 is set in the address counter, and the drawing device 3 is activated. The drawing device 3 fetches an instruction from the instruction memory 2 and executes it. However, in this case, the mode is set such that only coordinate calculation is performed and no drawing is performed on the image memory 4.

Here, when the drawing device 3 detects picking, that is, executes an instruction to draw a line segment in the picking area, it sets a picking flag in a status register provided therein and interrupts the CPUI. hand,
It notifies the CPUI that picking has been detected, and the subsequent processing ends.

The CPU reads the status register and current command register in the drawing device 3, determines whether or not it is an instruction to be picked, and if it is an instruction to be picked, ends the detection process. On the other hand, if the instruction is not the one you want to pick, check the number of instructions pre-loaded into the drawing device 3, read the address counter, calculate the address for restarting the drawing device 3, and read that address into the address counter. , and restart the drawing device 3.

As described above, in the conventional image drawing system shown in FIG. 7, when picking is detected, the drawing bag f3 may have to be restarted, which requires complicated processing. Such complicated processing may also be required in the clipping mode when detecting an instruction to draw a figure to be clipped.

In view of this, the present invention provides a system that allows the transition to the picking or clipping detection operation to be easily performed when it is necessary to transition to the picking or clipping detection operation again after detecting picking or clipping. The purpose of the present invention is to provide a drawing device and an image display system.

[Means for Solving the Problems] A drawing device according to the present invention improves a drawing device that executes a drawing command to draw on an image memory, and includes means for detecting picking or clipping; and means for temporarily stopping the drawing operation (hereinafter referred to as a pause state) in response to detection of picking or clipping by this means.

Further, the image display system according to the present invention includes a central processing unit, a command memory that stores drawing commands supplied from the central processing unit, and a command memory that executes the drawing command and performs drawing on the image memory. and a display device that displays images drawn in an image memory.

[Operation] The drawing device of the present invention is configured to enter a pause state when picking or clipping is detected.

Therefore, when configuring an image display system using the drawing device of the present invention like the image display system of the present invention, when picking or clipping is detected and then the picking or clipping detection operation is performed again, C.P.
For U, it is sufficient to release the pose state of the drawing device, and there is no need to restart the drawing device. Therefore, when the picking or clipping detection operation is performed again after detecting picking or clipping, the transition to the picking or clipping detection operation can be easily performed.

[Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 6. In FIG. 1, parts corresponding to those in FIG. 7 are given the same reference numerals, and redundant explanation thereof will be omitted.

FIG. 1 is a block diagram showing the main parts of an embodiment of the present invention. In this embodiment, the drawing device 12 includes a host bus interface unit 13, an instruction fetch unit 14, and a drawing unit 15. and a graphic bus interface unit 16. Note that this drawing device 12 can be configured as one chip.

Here, the host bus interface unit 13 is a unit for interfacing with the host (CPU 1, instruction memory 2), and as shown in FIG.
It has registers such as , and a pause signal generation circuit that generates a pause (stop at negative time) signal PAUSE.

As shown in FIG. 3, the pause signal generation circuit includes a flip-flop 19 and a decoder 20. When a picking detection signal PICK, which will be described later, is supplied to a set terminal S of the flip-flop 19, Outputs a pause signal PAUSE, and also sends a signal from the cpui to the decoder 20.
When a logic "0" and a write instruction signal WRITE are supplied as data together with an address to select the decoder 2, the decoder 2
0 to the reset terminal R of the flip-flop 19.
0'' to reset the flip-flop 19 and negate the pause signal PAUSE.

The instruction fetch unit 14 is a unit that calculates addresses for fetching instructions and controls fetch operations, and includes a current command register 21, a current address register 22, and the like. Note that the device is configured to pause upon assertion of the pause signal PAUSE.

Further, the drawing unit 15 includes a drawing pre-processing section 23 and a raster processing section 24, as shown in FIG. The drawing preprocessing unit 23 decodes the instructions fetched by the instruction fetch unit 14, that is, the instructions fetched by the instruction fetch unit 14 (macro instructions for drawing triangles, circles, etc.) are sent to the raster processing unit 24. This part performs preprocessing necessary for the raster processing unit 24, such as decoding it into basic commands (commands for drawing straight lines, points, etc.) necessary for the raster processing unit 24. Note that the drawing preprocessing section 23 is configured to interrupt instruction processing upon assertion of the picking detection signal PICK, and enter a state of waiting for the next instruction upon assertion of the pause signal PAUSE.

Furthermore, the raster processing section 24 is a section that performs actual drawing processing such as linear interpolation and logical operations based on basic commands sent from the drawing preprocessing section 23.
al differential analyzer)
unit 25, address calculation unit 26, and access control unit 27
, a logic operation section 28 , and a picking processing section 29 .

Here, the DDA section 25 is a section that calculates movement information based on basic commands sent from the drawing preprocessing section 23 and various information such as the start point and end point of a straight line.

Further, the address calculation section 26 is a section that calculates the next address to be accessed based on the movement information supplied from the DDA section 25, and controls the access control section 27, the logic operation section 28, and the like. Note that the picking detection signal PI
It is configured to interrupt processing upon assertion of CK.

Furthermore, the access control section 27 is a section that sends the address supplied from the address calculation section 26 to the graphic bus interface unit 16 and requests access.

Further, the logical operation section 28 is a section that performs logical operations on the data taken in from the image memory 4 and the data created internally to create data to be written into the image memory 4.

Further, the picking processing section 29 includes a coordinate calculation section 30, a picking area designation register 31, and a comparison circuit 32. Here, the coordinate calculation unit 30 calculates DD
This is a part that calculates the coordinates for drawing based on the movement information supplied from the A part 25. Further, the picking area designation register 31 stores coordinates indicating the picking area. The comparison circuit 32 compares the coordinates output from the coordinate calculation unit 30 with the coordinates stored in the picking area designation register 31, and if the coordinates output from the coordinate calculation unit 30 are within the picking area, picking is performed. A detection signal PICK is output, and this picking detection signal PIC
It is configured to supply K to the host bus interface unit 13, the drawing preprocessing section 23, and the address calculation section 26.

Also, graphic bus interface unit 1
6 is a unit for interfacing with the image memory 4 and a CRT control circuit (not shown).

Next, referring to FIG. 6, the operation when picking detection is performed will be described.

First, when the picking mode is set, the CPU 1
The first address of the command list stored in the command memory 2 is set in the address counter, and the drawing device 12 is activated. Then, the drawing device 12 fetches the instruction from the instruction memory 2 and executes it. However, in this case,
The mode is set such that only coordinate calculation is performed and no drawing is performed on the image memory 4.

Here, when an instruction to draw a line segment in the picking area is executed, that is, when picking is detected, the picking signal PICK is asserted, and the PICK of the status register 17 of the host bus interface unit 13 is asserted.
The (picking) flag 17A is set, an interrupt is issued to the CPUI, and the instruction fetch unit 14 and drawing unit 15 are placed in a pause state.

On the other hand, the CPU can know that picking has been detected by receiving an interrupt from the drawing device 12 or by reading the status register 17 (see FIG. 2) of the host bus interface unit 13, and can also know that picking has been detected.
Current command register 2 that holds the code of the currently executing or last executed instruction in unit 14
1 (see Figure 4) and the current address register 22 that holds the address where the code of that instruction was fetched.
The picked instruction can be known by reading (see FIG. 4). At this point, it is determined whether or not the instruction is to be started, and if it is, the processing is aborted and the ABRT (abort) bit 18A of the control register 18 of the host bus interface unit 13 is set to logic "1". By writing, the drawing device 12 is also instructed to abort. vice versa,
If the instruction for which picking is detected is not the instruction to be picked, CPtJl sets PAUS (
Pause) Writing a logic "o" to bit 18B releases the pause state of drawing device 12. Here, the drawing device 12 again fetches the instruction from the instruction memory 2, restarts the operation of executing the instruction, and repeats the above-described operation.

As described above, in this embodiment, the drawing device 12 is
Since the CPU is configured to enter a pause state when picking is detected, when the picking detection operation is performed again after detecting picking, the CPU
It is sufficient to release the pose state, and there is no need to restart the drawing device 12. Therefore, when the picking detection operation is performed again after picking is detected, the transition to this operation can be easily performed.

In the above embodiment, the case where picking detection is performed is described, but it can also be applied to the case where clipping detection is performed and a drawing command for drawing outside the drawing area is detected, and in this case. , the picking area designation register 31 (see FIG. 5) may be used as a clipping area designation register, and the clipping detection signal CLIP may be obtained at the output terminal of the comparison circuit 32.

[Effects of the Invention] As described above, the drawing device of the present invention is configured to enter a pause state when picking or clipping is detected. When configuring an image display system using a drawing device, after detecting picking or clipping, when performing a picking or clipping detection operation again, it is sufficient for the CPU to release the pose state of the drawing device. Since there is no need to restart the drawing device, when the picking or clipping detection operation is performed again after detecting picking or clipping, the transition to the picking or clipping detection operation can be easily performed.

[Brief explanation of the drawing]

The first section is a block diagram showing a main part of an embodiment of the present invention, FIG. 2 is a block diagram showing an example of registers included in a host bus interface unit, and FIG. 3 is a block diagram showing an example of registers included in a host bus interface unit. A block diagram showing the pause signal generation circuit built into the unit; FIG. 4 is a block diagram showing an example of registers included in the instruction fetch unit; FIG. 5 is a block diagram showing the main parts of the drawing unit; FIG. 6 is a flowchart for explaining the operation of an embodiment of the present invention, FIG. 7 is a block diagram showing main parts of a conventional image display system, FIG. 8 is a diagram for explaining picking, and FIG. 9 is a diagram for explaining picking. The figure is a diagram for explaining the problems that the conventional example has, and FIG. 10 is a flowchart for explaining the problems that the conventional example has. 1...CPU 2...Memory for instructions 3.12...Drawing device 4...Memory for images 5...Serial/parallel converter 6...CRT

Claims (2)

[Claims] (1) A drawing device that executes a drawing command to draw on an image memory, which includes means for detecting picking or clipping, and suspending the drawing operation in response to detection of picking or clipping by the means. What is claimed is: 1. A drawing device comprising: means for changing the state. (2) The drawing device according to claim 1, comprising: a central processing unit; a command memory for storing a drawing command supplied from the central processing unit; and a drawing device for executing the drawing command to draw on an image memory. , and a display device that displays the image drawn in the image memory.