JPS62202280A - Drawing display device - Google Patents

Abstract

PURPOSE:To execute the present return after the simulated change at a high speed by recording a change history only concerning the difference between a simulated drawing and a present drawing at a present time point at the time of the simulated change, and returning only the changed part to present drawing information at the time of a present return. CONSTITUTION:At a host computer 1, a present drawing information storing area 3, a drawing information storing area 4 for simulation, a recording part 6 and a recording processing part 7 are provided, and at a segment buffer 5 of a graphic display 2, present drawing information is stored at the time of operation and at the time of the simulated change processing, drawing information for simulation is stored. At the time of the simulated change, the change history of the drawing information in the display 2 is recorded to the recording part 6 only concerning the difference between the simulated drawing of a present time point and the present drawing, and at the time of the present return, the recording contents of the recording part 6 are referred to and only the changed part is returned to the present drawing information. Thus, the present return after the simulated change processing is executed can be executed at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a drawing display device comprising a graphic display device connected to a host computer.

B6 Summary of the Invention The present invention provides a drawing display device having a function of managing drawing information by a host computer, displaying requested portions of the drawing information on the drawing display device, and changing the drawing information in a simulated manner. Sometimes, the change history of the drawing information in the graphic display device is recorded in the recording section only for differences between the current mock drawing and the current drawing, and when returning to the current state, the recorded contents of the recording section are referred to and only the changed parts are recorded in the current drawing. By returning to the information, it is possible to quickly return to the current state after the drawing information has been simulated changed.

C1 Problems to be solved by conventional technology and invention Maps can express information on various human activities such as local natural conditions, population facilities, and even population and economic conditions, and have been used for administrative purposes since ancient times. . It is still a country.

Local governments, fire departments, etc. use it extensively as information that forms the basis of regional planning and regional management. In addition, public companies such as electricity, telephone, and gas companies use drawings depicting their facilities on maps to plan and manage their own facilities (power lines, telephone lines, gas pipes) installed in the region. . These maps and facility maps are drawn as diagrams on paper, and the information drawn is hereinafter referred to as drawing information.

In recent years, attempts have been made to draw these drawings using computers and to process drawing information using computers.

The United States was a pioneer in this, and it has been practiced since the 1960s. Such a computer system is called a drawing information processing system. Currently, it is used by federal, state, and local governments, as well as public companies such as electricity, telephone, and gas companies, and private companies such as marketing companies.

Although Japan started research later than the United States, it has successfully absorbed the developments in technology during that time, such as databases and computer graphics, and is now showing its own development. Now, national and local governments.

In public corporations such as fire departments, electricity, telephone, gas, etc.
It can be said that we have finally reached the practical stage.

A feature of the above-mentioned drawing information processing systems is that they can all be connected to a graphic display device to display drawings. The host computer manages the drawing information and controls the graphic display device to display the requested portion of the drawing according to the operator's request. The graphic display device displays the requested portion of the drawing in response to a request from the host computer. In a drawing information processing system, the part that implements the function of displaying drawings using a host computer and a graphic display device is hereinafter referred to as a drawing display device.

The basic usage of a drawing information processing system is to perform processing step by step through interactive operations with an operator, centering on drawings displayed on a graphic display device.

Therefore, good responsiveness of the drawing display function is strongly required. However, since the host computer performs various general-purpose tasks in addition to drawing display processing, the steady load is heavy, and no performance improvement can be expected on the host computer. Rather, the steady load tends to increase due to the increase in information to be processed and the demand for higher functionality, and the display processing on the host computer becomes a burden. Therefore, in order to reduce the load on the host computer and improve the responsiveness of display processing, there is a tendency for graphics display devices to become more intelligent. In other words, the graphic display device performs most of the graphic display functions. The graphic display device having the configuration shown in FIG. 9 will be described in detail below. The definitions of abbreviations used in the following explanation are as follows.

・HIF, host interface.

・SB, , Segment buffer.

・MTX, Matrix calculator. Matrix operator.

・CLP... Clipping device.

・DDA, digital differential analyzer. Digital vector generator.

・FB, frame buffer.

・LT... Lookup table. Also known as color map.

・IM, input machine. input device.

・VIP', Video interface.

・TB...table.

・AD、、、、Address.

・Pn, , plane n. (n is an integer greater than or equal to 0) First, the graphic display device 2 has a host interface (1-IIF) for transmitting and receiving data to and from a host computer. The HIF receives various display instructions and graphic information from the host computer and transmits them to the display processor 7 (CPU). Furthermore, in response to a request from the host computer, it receives various display-related information from the CPU and transmits it to the host computer.

SB is a memory that stores graphic information in descriptive representation (numeric values, symbols). The graphic information is managed in a hierarchical structure. The lowest layer contains concrete graphic entities (display graphic shape 1 position coordinates 9 display colors, etc.). Above these, there is information on various attributes (visible attributes, detected attributes, etc.) for each graphical entity. Note that the positional coordinates of the graphic entity do not directly indicate the pixel position on the screen, but are coordinates on a virtual large screen, so-called world coordinates.

From the graphic information stored in this SB, graphic information in a range (a rectangular area determined by world coordinate values) required to be displayed is cut out.

This cutting process requires a matrix calculator (MTX) that performs parallel translation and rotation transformation of the displayed figure, a CRT monitor (
A clipping device (CR, P), etc., which removes the portion that does not extend beyond the corresponding displayable area of the CRT) is provided. Furthermore, the line segments of the graphical information of the extracted descriptive expression are
A digital differential analyzer (DDA) is prepared which expands the display position coordinates into 0N10FF information of the corresponding frame buffer (F B ) J2 bits.

The FB is a memory having bits corresponding to each pixel on the screen of the CRT in an l to l ratio at least to the extent corresponding to the number of pixels on the screen. In color display, a plurality of memory planes are provided, and column data in which a set of bits corresponding to the same pixel are arranged in each plane is used as the color code of the pixel corresponding to the bit. Furthermore, in recent years, look-up tables (LT) that store color codes in advance have been introduced.
).

The mainstream is a graphic display device which has a color map, uses the bit column data as an address, reads out the contents of the address in the LT, and uses it as the color code of the corresponding pixel. In such a graphic display device, overlapping priority display is possible. That is, first, a priority order is determined for each plane of the FB, and similarly, a priority order indicating which of the figures to be displayed is prioritized and displayed when they are superimposed is determined. Next, for each LT address, the display color code of the figure to be expanded to the plane with the highest priority among the combinations of planes corresponding to the bits whose bit contents are turned on is stored in the LT part of the address. put. Then, the graphics in the display range are cut out from the SB, and each graphic is bit-developed into the FB plane corresponding to its priority order. On the other hand, when several figures in each plane overlap, the LT is referred to using the bit string corresponding to the pixels in the overlapped part as an address.
Since the address field stores in advance the color code of the highest priority display figure when the set of figures of the plane corresponding to the address "on" pin overlap, superimposition priority display is realized. This will be explained with reference to FIG. There are display figures ・, mu, and ■, and the order of priority for superimposition priority display is from highest to highest. The display colors are red, green,
Make it blue.

The priority order of the FB planes is P2. P.L.
.

The order shall be PO. Display figures・,mu,■ are each P2
．． It is assumed that Pi and PO are expanded. FB
The set of bits corresponding to one pixel read out from each plane of P2. It is assumed that they are arranged in the order of PI and PO and become the reference address of LT.

The combinations of overlapping figures in each pixel, the corresponding LT reference addresses, and the LT contents of the addresses are shown below. (Where the bit content of the address is ×, O/1
Indicates that either is acceptable. )〈Graphic type or combination〉 Converter T reference address〉〈LT contents〉1,・
,mu, ■ 1××red 2,...mu same''2
Same as above 3,・ Same” 2
Same as above 4, Mu, Kaku 01×
Green 5, Mu same”2
Same as above 6 ■ 001 Blue 7, no overlap 000 Background color The figure types and combinations are also shown in the figures. The numbers written on the surface surrounded by line segments are the numbers assigned to the above graphic types or combinations. The screen displayed on the screen is as shown in the figure.

LT is a table that stores the luminance of the three basic primary colors R, G, and B. R stored at each address,
A unique color is expressed by combining the G and H luminance colors.

The video interface (VIF) reads the contents of F'H, uses the bit string corresponding to each pixel as an address, reads out the color code of LT, and sends a video signal (R, G, B, high rate) to the CRT.

It also generates synchronizing signals (vertical synchronizing signal VD, horizontal synchronizing signal 2WD) to the CRT. These operations are independent of CPU control and are always executed at high speed and cyclically. The mechanism up to video signal generation will be explained using FIG. 11. VIP generates a bit address (FBAD) corresponding to a certain pixel for each plane of the FB. The bit contents thus read out are arranged in respective predetermined positions to create an LT reference address. Using this LT reference address, the contents of the corresponding LT are read out in R, G, and B units. The read contents I)
- Send to A converter. Here, D-A conversion is performed, and each R, ,
Generates G and B video signals. The following two processes are performed one after another in the order in which the pixels are arranged.

Since these processes are executed extremely quickly and simulcastly, to the human eye, the image appears as a single screen, aided by the after-image phenomenon.

The CRT performs refresh drawing using a rask scan display method. In other words, upon receiving the R, G, and B video signals for each pixel, an electron beam of the corresponding intensity is emitted to the pixel position of the phosphor screen, and the color of the R, G, and B fluorescent points that emit light at each brightness is determined. Various colors are displayed by compositing. Furthermore, the designation of pixels, that is, the radiation position of the beam, is controlled by a horizontal synchronization signal and a vertical synchronization signal. Zunaji, the electron beam is scanned horizontally from the 2nd left corner of the screen, and the required number of scanning lines are 30 to 6 times per second to the bottom right.
Make it 0 times. The value of 30 to 60 times is called a vertical scanning frequency (refresh rate 1-), and is generally set to a value close to the lower limit within a range that does not cause flickering.

The CPU analyzes and executes input information from the host computer and IM. However, most of the specific processing is performed by each dedicated processor (MTX, CLP, VIP, etc.).
In reality, they are often controlled.

The input device (IM) is used by an operator to input various information to the graphic display device. There are many different types available depending on the purpose. A keyboard is standard. Devices for inputting coordinate values include digitizers, tablets, and the like.

Furthermore, there are joysticks, trackballs, etc. for moving figures and cursors on the screen.

As described above, in the drawing display device composed of the host computer and the graphic display device, the drawing information is managed by the host computer. This can be thought of as having a virtual continuous large drawing inside the computer. In the conventional method, when there is a display request from an operator, the host computer cuts out drawing information of the requested location on the virtual large screen and transmits it to the graphic display device. The graphic display device that receives the information stores each graphical element of the drawing information in the form of a segment in the SH, expands it into bits in the FB, and displays it on the screen. In this method, it takes a considerable amount of time to transmit a large amount of information between the host computer and the graphic display device and to register segments within the graphic display device, and it takes a long time from the display request to the display on the screen. As mentioned above, the highest requirement for drawing display devices is good responsiveness, which has been a problem with this system.

Recently, a drawing display device is configured using a drawing display device that has a large amount of SB (about 4MB), and all drawing information corresponding to all the drawing information managed by the host computer is registered in the SB at the time of startup. During operation, when there is a display request, the host computer gives instructions only for the display range to the graphic display device, and the graphic display device cuts out the graphic information in the requested range from the graphic information corresponding to all drawings in the SB and sends the bits to the FB. A method of expanding and displaying has been developed. This is because only a small amount of information is required to be transmitted when a display request is made, and there is no need for segment registration processing, so any drawing location can be displayed at high speed. A drawing display device with extremely good responsiveness has been realized.

Now, in recent years, in drawing information processing systems, there has been a demand for a function for visually changing drawing information in a simulated manner. This is a function that allows you to change the drawing information while visually checking it on the drawing display device, and then restore it again. In other words, it is a drawing simulation that changes drawing information. For example, local governments construct new roads, water supplies, and public facilities.

In cases where plans for removal etc. are made on drawings. Similarly, when electric power companies, telephone companies, and gas companies use drawings to plan new installations, removals, etc. of power lines, telephone lines, and gas pipes. A drawing display device displays the actual construction or removal of roads, water supplies, public facilities, power lines, telephone lines, gas pipes, etc. When the simulation is stopped, the original drawing information is restored so that the current drawing can be displayed.

In the above function, good responsiveness is naturally required in the drawing change process, but responsiveness is also required in the function that can return to the previous drawing information and display it after stopping the simulation. This is because various operations that are performed based on current drawings are a more realistic problem, and it is necessary to be able to display current drawings if the need arises at any time during simulation. This is because it will not happen.

For example, when an accident occurs on a power line under the jurisdiction of an electric power company, it is necessary to display current drawings to understand the area of the accident and promptly carry out accident recovery operations. Similarly, when a fire breaks out in the area under its jurisdiction, a fire department must display the current drawings, grasp the area where the fire occurred, and quickly rush to the scene to extinguish the fire. Furthermore, even in cases where there is no urgency, priority is given to tasks that are executed based on current drawing information. Current drawings are also frequently used. Therefore, it is required to quickly return to the original state even while the simulation is in progress.

Hereinafter, restoring the simulated drawing information to its original state will be referred to as current restoration.

In this simulated change process, it is problematic from the viewpoint of data protection to change real data in the current drawing information managed within the host computer. For example, there may be a case where the host computer goes down during the simulated change process and the current drawing information remains unchanged.

Therefore, when making a simulated change, a possible method is to first copy the real (current) drawing information to another area in the storage device, and then perform the simulated change process on the copied drawing information. During the simulated modification process, no operations are performed on the real drawing information, thus ensuring complete data protection. In addition, with this method, when returning to the current state, it is only necessary to discard the simulated drawing information as is, no data manipulation is required, and the return can be made instantly.

Therefore, the responsiveness of the host computer's processing is very good.

However, in a graphic display device that stores all drawing information (graphic information format), there is a problem in adopting the method described in item 1 above. That is, the storage area (SB) of the graphic display device for storing drawing information is not so large, and it is not possible to secure an area for storing both current drawing information and simulated drawing information.

The storage device of the graphic display device is an IC memory, and at present, it is technically difficult to implement an extremely large-capacity device, and it is also expensive. On the other hand, a host computer can have a practically infinite storage area by using an auxiliary storage device such as a disk or a virtual storage mechanism.

Therefore, while the host computer executes a simulated change process on the simulated drawing information, the only method available for the graphic display device is to directly change the current drawing information. In this case, when returning to the current state, even if the return process on the host computer side can be executed instantaneously, the current drawing information has actually been changed in the graphic display device, so it is not possible to easily return to the current state. In order to return the drawing information in the graphic display device to the current one, all the current drawing information managed by the host computer must be re-registered into segments in the same way as when the system is restarted. However, this requires a long time to transmit a large amount of information and to process segment registration, and the responsiveness of returning to the current state is extremely poor.

In order to solve these problems, the present inventor is considering the following method. That is, the host computer is provided with a simulation drawing information storage area separate from the current drawing information storage area, and is further provided with a recording section (hereinafter referred to as a log). During the current operation, the host computer performs various processes using the current drawing information, but when starting the simulation change process, the current drawing information is copied to the simulation drawing information storage area, and the simulation drawing information is to be processed. When a request for changing drawing information is made, the relevant changing process is performed on the simulation drawing and the drawing in the graphic display device, and history information regarding the changing operation of the drawing in the graphic display device is recorded in a log. At this time, various display operations are also performed with the simulated drawing as the object. When returning to the current state, the log and current
Referring to the drawing information of the simulation, the drawing information in the graphic display device is operated without returning from the simulation to the current one.

According to the above method, when returning to the current state, it is only necessary to perform a data operation on the graphic display device to return only the segments recorded in the log to the original state (current drawing). Therefore, compared to re-registering all the drawing information into segments, there is no needless transmission processing or segment registration processing, and the original state can be restored efficiently and in a very short time.

Now, in the simulation change process, specific drawing information may be changed many times. For example, in a drawing for managing artifacts installed in a region, a plan for constructing a new facility in the near future and repeating changes to the same facility may be visually confirmed using a drawing display device. In such a case, it is assumed that at the same time as the drawing information of the graphic display device is changed, the change history is recorded in a log according to the above method. The content of one change history is the change type.

The changed segment is the segment content immediately before the change. This change history is successively recorded in a log according to the change processing. When returning to the current drawing, the user can return to the current drawing by referring to the log contents and performing the exact opposite operation to the drawing information on the graphic display device in the reverse order.

An example is shown in FIG. This drawing is a residential map. Each house symbol is recorded as one segment on the graphical display. First, the current drawing is as shown in ■. There are only houses in Seg and J. In ■, Seg
.

■House was newly built, and the shape of houses Seg and J was changed. The log is as shown in the table in the figure. In ■, Seg
, the shape and location coordinates of I's house are changed, and SegJ
house has been deleted. The log contents are added to those recorded with ■ as shown in the figure. Kononi Seg.

The change history of 1, Seg, and J is recorded in multiple logs for the same segment as it was changed. Next, when returning to the current state, the return operation is performed on the graphic display device in the reverse order in which the logs were recorded. First, N
For 094, the previous contents of Seg, J are registered. (■
At the time of , Seg,, J have been deleted from the drawing and do not exist. ) Next, regarding No. 3, Seg,
Replace I with the previous content. Regarding No. 2, Seg, J
Replace with previous content. For No, I, replace Seg, I with the previous content. Seg.

−27= Delete ■. By performing operations that are completely opposite to such change processing over all steps, it is possible to return to the current drawing shown in (3).

In the above example, since there are two simulated changes for each of Seg, I, Seg, and J, the reverse operation is performed twice each in the reverse order when returning to the current state. In this way, if changes are made to the same segment many times, the change history increases accordingly. Therefore, the number of current return processes related to the segment increases in the same way. In other words, if changes are made many times even in the same segment, it will be slow to return to the current state.

The present invention was made under these circumstances,
The purpose is to quickly return to the current state after the simulated change process, regardless of the number of simulated changes.

Means and operation for solving problem D1 FIG. 1 is a diagram showing the configuration of the present invention. The host computer 1 is provided with a current drawing information storage area 3 that constantly stores current drawing information and is used for actual operation, and a simulation drawing information storage area 4 that is used when changing the simulation. The graphic display device 2 stores, in the SB5, graphic information equivalent to the drawing information that is being processed by the host computer 1 at that time in the form of graphic information, so-called segments. The SB5 stores current drawing information during operation, and stores simulation drawing information during simulation change processing. The host computer I also has a recording unit (log) 6 that records a history of changes made to the drawing information in the graphic display device 2 at the time of simulated changes.

Now, to describe the recorded contents of log 6, log 6
The contents of the code are the basic change types.

Segment name and current content.

The change type is the type of difference between the current mock drawing and the current drawing regarding different segments, such as replacement, new installation,
There are three types of deletion. Replacement means that the contents of the segment, such as shape, color, and position coordinates, are changed from the current one. Newly established indicates that the segment does not exist in the current drawing and is newly registered in the current mock drawing. Deletion indicates that the segment exists in the current drawing, but has been deleted from the current simulated drawing.

The segment name is the name of the segment that is subject to the above change. i.e. substitution.

This is the name of a newly created or deleted segment. Replacement.

Since the segment to be deleted exists in the current drawing, the segment name is an existing one. Since the segment to be newly established does not exist in the current drawing, the segment name is newly registered, but it must be unique so that it can be distinguished from those existing in the drawing or log 6.

The current content is the content of the segment to be changed in the current drawing. The purpose of recording a change history is to restore a simulated drawing to a current drawing, but in a simulated drawing, the current contents of the segments are lost due to changes. Therefore, record the current drawing contents. In the case of replacement or deletion, this is the content of the replaced or deleted segment in the current drawing. In the case of a new establishment,
Since the segment does not exist in the current drawing, the current content is "none".

Furthermore, the host computer 1 is provided with a recording processing section 7, and this recording processing section 7 has the following functions.

That is, first, when a change is made to a certain segment, a search is made to see if any change history regarding the segment has already been recorded in the log 6. Depending on the result, the following processing is performed.

a. If not recorded, record the history of the segment as it is in the log 6 according to the change.

b. If it has already been recorded, check the change type of the change history recorded for the segment, and the processing differs as follows depending on the combination of this and the change type.

A. If the recorded change type is "replacement" If the change is "replacement", do nothing. That is, since the recorded change type is "replacement", the segment exists in both the current drawing and the current simulated drawing. Even if the content of the segment is further changed, it still exists in the current mock drawing. The only difference is the content compared to the current drawing. Therefore, the change type is still "replacement" and is the same as the recorded change history. The current contents of the segment have also been recorded. Therefore, there is no need to do anything.

If the change is “1 deletion”, change the recorded change type to “1 deletion”.
"Delete". That is, since the recorded change type is "replacement", the segment exists in the current drawing. If the segment is now deleted from the mock drawing, the difference between the current mock drawing and the current drawing with respect to the segment is that the segment is present in the current drawing but not in the mock drawing. In other words, the change type is "deletion". Therefore, the recorded change type for the segment is
Update from ``Replace'' to ``Delete-1.'' Note that the current content has already been recorded.

There is no logical case where the change is a "new establishment." That is, as noted in ``1'', the segment exists in the current drawing. Regarding such things,
There is no such thing as "new establishment".

Conversely, such changes are not permitted.

B. If the recorded change type is "deletion", no changes can be made. In this case, the segment does not exist in the simulated drawing at this point.

Therefore, it is impossible to specify and change a segment that does not exist. Conversely, specifying a segment that does not exist is not allowed. Also, the said change is “new establishment”
Even if the new segment name is a segment name that exists in the drawing or log 6, it is not possible to use the new segment name as described above.

If the recorded change type is "new establishment" and the change is "replacement", nothing is done. This is because, in the current simulated drawing, the segment continues to exist, although the content is changed by the "replacement". However, since this segment was originally newly created, it does not exist in the current drawing. Therefore, the difference between the current mock drawing and the current drawing regarding the segment remains "new construction". Therefore, the recorded change history can be left as is.

If the change is "deletion", the change history is deleted from the log 6. This is because the segment is deleted and no longer exists in the current simulation drawing. but,
Since this segment was originally newly created, it does not exist in the current drawing. In other words, the segment does not exist in either the current mock drawing or the current drawing. Therefore, there is no difference between the current mock drawing and the current drawing. Therefore, since there is no need for the change history for this segment, it is deleted from log 6.

It is impossible for the change to be a "new establishment." This is because the segment was originally newly established.
On the other hand, it is logically incorrect to create more new ones. Therefore, such changes are not permitted.

The above log update method is summarized in the table below.

table Registration: Newly recording the relevant history in the log.

Update: Updating an already recorded change type to the corresponding one.

History deletion: Deleting the history itself from the log.

-...Do nothing.

------This kind of situation is impossible.

By managing the recorded contents as described above, even if a specific segment is changed multiple times, the change history will never exceed the number of codes. (Lux code or no change history.) Therefore, even if a segment has been changed many times, it can be returned to the current state with one or less return processing without affecting the number of changes.

Next, the operation of this drawing display device will be explained.

■During current operation, the host computer l performs various processes using the current drawing information. The drawing information in the graphic display device 2 is also current. Therefore, the display operation is also performed on the current drawing of the host computer 11 graphic display device 2 (second
(see figure).

■When starting the simulation change process, the host computer 1 copies the current drawing information to the simulation drawing information storage area 4 (
(See Figure 3).

(2) When performing the simulation change process, the host computer 1 processes drawing information for simulation. When a request to change drawing information is made, the change processing is performed on the simulation drawing and the drawing in the graphic display device 2. At this time, the history information regarding the drawing change operation in the graphic display device 2 is recorded in the log 6 by the recording processing unit 7 as described above (see FIG. 4).

(2) When the host computer I is processing simulated drawing information, the drawing information in the graphic display device 2 is also for the same simulation, so it naturally displays the simulated drawing. Various display operations are also performed on the simulated drawing (see FIG. 5).

■When returning to the current state, record the recorded contents of log 6 and the current state.

=39- Referring to the simulation drawing information, perform an operation to return the drawing information in the graphic display device 2 from the simulation to the current one (see FIG. 6).

■After returning to the current state, the simulated drawing information and the recorded contents of log 6 are unnecessary and are discarded (see Figure 7). Note that since the current drawing information is copied to the storage area of the simulation drawing information at the start of the simulation, no operation is necessary at the time of restoration.

In the above, the management of log 6 has been described using segment units as graphic information units, but instead of managing in segment units, it may be managed in IDB units, or it may be managed in graphic information units larger than segments. Good too.

E. Example An example is shown in FIG. This drawing is a residential map, and each house symbol is expressed in one segment.

Changes in the drawing information and log contents of the graphic display device as the simulated change process progresses are shown in (1) to (2). The explanation is below. The numbers inside the circle correspond to the figures.

■Current drawing information. Only the house of Seg,,J exists.

Of course nothing is recorded in the log.

01 house was newly built and newly registered in the drawing information as Seg, r. Since the log does not have a change history regarding the segment, the change history is newly recorded in the log. Since this segment is newly established, the current content is naturally "None".

Also, the shape of the house in Seg and J was changed. Since the log does not have a change history regarding the segment, the change history is newly recorded in the log. The log is shown in the figure. Records the current contents of the segment.

■The position coordinates and shape of Seg and T have been changed. The change type is "replacement". The log has already recorded the change history regarding the segment, and the change type is "new establishment". Therefore, no log operations are performed in accordance with the inscription log update method.

Also, Seg,,J were deleted. The change type is "deletion". The log has already recorded the change history regarding the segment, and the change type is "replacement". Therefore, according to the log update method, the change type of the recorded change history is updated to "delete".

The examples shown in FIGS. 8 and 12 are cases where the same change processing is performed in the same drawing. Comparing the amount of logs, you can clearly see the difference in the log management methods in the two cases. 8th
In the figure, the amount of logs for one segment is less than or equal to the code regardless of the number of changes. 1st for soi 1
In the method shown in FIG. 2, the amount of logs related to one segment increases in proportion to the number of modification processes.

F1 Effects of the invention In the present invention, only drawing information operations such as segment operations are performed to return only the changed drawing information on the display device to the original (current) state, so processing efficiency is high and it is possible to return to the current state in a short time. Become. Therefore, even if the simulation change process is in progress, the current drawing can be displayed immediately if priority work using the current drawing occurs.

Moreover, no matter how many times the simulated change process is performed on the same drawing information, the change history managed in the log may be less than the I record.

Therefore, when simulated change processing is concentrated on specific drawing information, compared to the method of recording the number of changes in the tJ log, the amount of change history in the log is much smaller and the current return can be performed much faster. .

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing the configuration of the present invention, Figs. 2 to 7 are state explanation diagrams showing the state of transition from current operation to simulated display and return to current state, and Fig. 8 is a drawing information and recording section. FIG. 9 is a block diagram showing the overall configuration of the graphic display device, FIG. 10 is an explanatory diagram showing how graphics are superimposed, and FIG. 11 shows the mechanism of video signal generation. The block diagram shown in FIG. 12 is a correspondence diagram showing the correspondence between the graphic information according to the comparative example and the recorded contents of the recording section. ■...Host computer, 2... Graphic display device, 3...
Current drawing information storage area, 4... Simulation drawing information storage area, 5... Segment buffer, 6... Recording unit, 7...
... Recording processing section. 8th figure for each of the 7' circles and the 1st side

Claims (1)

[Claims] Drawing information to be processed by a host computer is registered as a segment in a segment buffer of a graphics display device, and graphics information in a display range designated by the host computer is extracted from the drawing information in the segment buffer for management. In the drawing display device for displaying on a screen, the host computer is provided with a current drawing information storage area and a simulation drawing information storage area in which the current drawing information in this storage area is copied as simulation drawing information, A record section is provided to register the change history of the drawing information for use in the drawing, and to record the change type, the name of the figure information unit to be changed, and the current contents of the figure information unit, and when there is a simulated change, the figure information unit is Searching whether the change history for has been previously recorded in the recording section,
A recording processing unit is provided that records the change in the recording unit if the change has not been recorded, and records the difference between the current drawing and the current simulation drawing in the recording unit if the change has already been recorded, and stores the simulation drawing information. The drawing information in the area is changed according to the simulated change request, and is also processed by the host computer during the simulated change process, and when returning to the current state, the recorded content of the recording section is referred to to display the simulated changed figure. A drawing display device characterized in that only the drawing information in the device is returned to the current drawing information.