JPH04205281A - Graph display system - Google Patents

Abstract

PURPOSE:To decrease the memory capacity necessary for replotting of a graph and to decrease the processing burden at the time of replotting the graph by copying the dot data on a display memory to another region. CONSTITUTION:The dot data of the graph existing in the rectangular region assigned by a region assigning means 3 is copied into another region of an image memory means 1 when the point of the successively displayed graphs arrives at the end of the display region. Then, the graph within the assigned region is redisplayed in another position within the display region. Further, the writing position of the dot data of the next graph following the copied graph on the image memory means 1 is calculated and the dot data of the subsequent graphs is written successively from this writing position. The need for previously storing the coordinate data, etc., of the graphs to be replotted into a memory is eliminated in this way and the quantity of the memories to be used is decreased. The processing for replotting is simple as well.

Description

[Detailed Description of the Invention] [Summary] Regarding the graph display method of computers, etc., the memory capacity required to redraw the graph is reduced,
Furthermore, for the purpose of reducing the processing load when redrawing a graph, the present invention includes an image storage means for storing dot data of a graph to be displayed, and a display means for displaying a graph based on the dot data of the image storage means. an area specifying means for specifying an arbitrary rectangular area including the edge of the graph display area; a detection means for detecting that the displayed graph has reached the edge of the display area; Copying means for copying dot data of a graph within a designated rectangular area to another area of an image storage means when it is detected that the end of a display area has been reached; and a graph copied by the copying means. and write position calculation means for calculating the write position of the dot data of the next graph on the image storage means.

(Industrial application field) The present invention relates to a graph display method for computers and the like.

[Conventional technology]

For example, when time series data collected at predetermined sampling time intervals are plotted sequentially on the display screen, if the vertical axis is the data displacement and the horizontal axis is the data sampling time, the displayed graph will be as shown in Figure 6. As shown in , it extends from the left to the right of the screen as time passes. Such a graph is called a real-time trend graph.

When displaying such time-series data, when the display data of each sampling point plotted in sequence on the screen reaches the right edge of the screen, the next sampling data is displayed sequentially from the left side of the screen. There are the following two display methods at this time.

(1) As shown in FIG. 7(a), a display method in which the entire graph is erased once and subsequent data is plotted sequentially from the left end of the screen.

(2) As shown in FIG. 7(b), a display method in which a portion of the data at the right end of the screen is redrawn at the left end of the screen, and subsequent data is sequentially plotted following the drawn graph.

In the display method (2), when the display of the graph for one screen is finished and the next data is displayed, a part of the graph from the previous screen continues to be displayed, so the display method in (1) It has the advantage that changes in the graph are easier to understand than the conventional method.

However, for example, in a system in which a computer on the host side stores sampled data and sends a drawing command corresponding to the stored data to a display device to display the data, the conventional graph display method described in (2) above cannot be used. In order to continuously display a graph using this method, it was necessary to save the data to be redrawn on the host side.

FIG. 8 is an explanatory diagram of the conventional graph display method of (2) above. This figure shows the case where the graph in the right half of the display area is redrawn on the left side as shown in FIG.

In this case, sampling data is plotted sequentially from the left edge of the display screen, and from the point at which the sampling point crosses the center of the display area, the X and Y coordinates of each point are stored in the storage area on the host side in order (see Figure 8). ■〜■).

Thereafter, when the plotted points reach the right end of the display area, the graph displayed by the display device is erased.

At this time, on the host side, the X coordinate of the data stored in the storage area is converted to coordinates based on the origin of the display area, and a drawing command is created based on the converted coordinates (Fig. ).

On the display device side, "1" or "0" is written to the bit address of the display memory corresponding to the X and Y coordinates based on the analysis result of the drawing command.

As a result, the graph that was displayed on the right side of the display area is redisplayed on the left side of the display area (FIG. 8).

[Problem to be solved by the invention]

In the conventional display method described above, all the coordinate data of the graph to be redrawn must be stored in a storage area on the host side, so there is a problem in that the storage capacity available on the host side is reduced accordingly.

Furthermore, each time a part of the graph is redrawn, the host needs to issue a drawing command, which increases the processing load on the host.

An object of the present invention is to reduce the memory capacity required to redraw a graph and further reduce the processing load when redrawing a graph.

[Means to solve the problem] FIG. 1 is a diagram explaining the principle of the present invention.

In the figure, image storage means 1 is means for storing tod data of a graph to be displayed. The means is, for example, a display memory having a memory area corresponding to the display screen.

The display means 2 displays a graph based on the dot data stored in the image storage means 1.

The area specifying means 3 specifies an arbitrary rectangular area including the edge of the graph display area.

The detection means 4 detects that the graph has reached the end of the display area.

When the graph reaches the end of the display area, the copying means 5
The dot data of the graph within the designated rectangular area is copied to another area of the image storage means 1.

The writing position calculation means 6 calculates the writing position on the image storage means 1 of the tod data of the next graph following the graph copied by the copying means 5.

[For production]

In the graph display method of the present invention, dot data of a graph to be displayed is written into the image storage means 1, and the display means 2 displays the graph. Then, when the points of the graph that are sequentially displayed reach the end of the display area, the tod data of the graph within the rectangular area specified by the area specifying means 3 is copied to another area of the image storage means 1. . This causes the graph within the specified area to be redisplayed at a different position within the display area.

Furthermore, the writing position on the image storage means 1 of the dot data of the next graph following the copied graph is calculated, and the dot data of subsequent graphs are written in order from that writing position.

As a result, subsequent graphs will be displayed following the redisplayed graph.

That is, in the graph display method of the present invention, a part of the graph can be redisplayed by copying the dot data stored in the image storage means 1 to another area. Therefore, there is no need to store coordinate data of the graph to be redrawn in memory, and the amount of memory used can be reduced.

Furthermore, processing for redrawing becomes easier.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram of a display system based on the graph display method of the present invention.

In FIG. 2, a host (computer) 11 stores data sampled at predetermined time intervals in a memory (not shown) and creates a drawing command based on the X and Y coordinates of the sample data. The display device 12 analyzes the drawing command issued by the host 11, and writes "1" or "0" to the bit address of the display memory 13 corresponding to the display position on the display screen 14. As a result, dot data corresponding to each dot on the display screen 14 on a one-to-one basis is written into the display memory 13.

Next, specify an arbitrary rectangular area including the right end of the real-time trend graph as shown in Figure 3 (a), and copy the graph of the specified area to the position shown in Figure 3 (b). The processing operation will be explained with reference to the flowchart in FIG.

In this case, the host 11 first sets the origin coordinate of the graph display area as the X coordinate, and initializes the X coordinate (
Figure 4, Sl). Next, it is checked whether the time calculated by counting clock signals, for example, matches the sampling period, and it is determined whether the data sampling timing has arrived (S2). If it is not the sampling timing, the determination in step S2 is repeated and the process waits for the next sampling timing.

On the other hand, if the counted time matches the sampling period, data sampling is performed (S3). and,
Convert sample data (data displacement) to Y coordinate data based on the standard unit of the Y axis when displaying a graph (S
4).

Furthermore, a drawing command is created based on this X, Y coordinate data (S5). The display device 12 writes dot data of "1" or "0" to the address of the display memory 13 corresponding to the X and Y coordinates based on the drawing command, and further writes the dot data of "1" or "0" to the display screen 1 from the dot data of the display memory 13.
4. Plot each point of the graph in turn.

Next, the host 11 determines whether the X coordinate of the sample data matches the X coordinate of the right end of the display area (S6).
. If the X coordinate of the point to be plotted this time does not match the X coordinate of the right end of the display area, the X coordinate is incremented by "1" (S7), and then the process returns to step S2.

If the X coordinate of the point to be plotted this time matches the X coordinate of the right end of the display area, for example, a rectangular area on the display memory 13 corresponding to the rectangular area specified on the screen by the user is set as the copy source area. (S8). Furthermore, a copy command is issued to copy the dot data of the rectangular area to another area of the display memory 13 (S9).

For example, when copying a graph to the left end of the display area, this copy command will copy the dot data in the specified rectangular area on the display memory 13 shown in FIG.
As shown in FIG. 5, the origin (X
-0, Y-0). This results in
The graph within the rectangular area shown in Figure 3(a) is
) is displayed at the left end of the display area.

Also, by copying the graph of the rectangular area, it is necessary to shift the X coordinate of the sample data to be used next time by the length XN of the copied rectangular area in the X-axis direction.
Set XN as the initial value of coordinates (SIO). Thereafter, by returning to step S2 and repeating the above-described process, subsequent sample data can be plotted in sequence following the copied graph.

As described above, according to the above embodiment, when a part of the displayed graph is redisplayed at a different display position, the host 11
There is no need to remember the coordinate data of the graph to be redisplayed. Therefore, the storage capacity used for redisplaying the graph is reduced, and the storage capacity of the host 11 can be utilized more effectively.

In addition, since it is sufficient to simply copy the dot data on the display memory 13 directly to another area, the host 11 does not need to create a drawing command each time.
Alternatively, there is no need to recognize whether there is more than one, and the burden on the host 11 is reduced.

In the above embodiments, the case where the X coordinate is a time variable has been described, but the present invention can also be applied to cases where the X coordinate is a variable other than time.

〔Effect of the invention〕

According to the present invention, for example, by copying the tod data on the display memory to another area, the graph can be redisplayed at another position in the display area. Therefore, it is not necessary to store the X and Y coordinate data of the graph as in the past, and the storage capacity of the system can be used more effectively. Furthermore, since it is sufficient to simply copy the stored tod data to another area, the processing for redisplaying the graph becomes simple.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention, FIG. 2 is a configuration diagram of a display system according to an embodiment, and FIG.
FIG. 4 is a flowchart showing the operation of the embodiment; FIG. 5 is an explanatory diagram of the graph display method of the present invention; FIG. 6 is an example of a real-time trend graph. 7 and 8 are explanatory diagrams of conventional graph display methods, and FIG. 9 is a diagram showing an example of a redrawn graph. 1... Image storage means, 2... Display means, 3... Area specification means, 4... Detection means, 5... Copying means, 6... Writing position calculation means.

Claims (1)

[Scope of Claims] Image storage means (1) for storing dot data of a graph to be displayed; display means (2) for displaying a graph based on the dot data of the image storage means (1); and a graph. area specifying means (3) for specifying an arbitrary rectangular area including the edge of the display area; detection means (4) for detecting that the displayed graph has reached the edge of the display area; and the detection means When it is detected in (4) that the graph has reached the end of the display area, a copying means ( 5), and writing position calculation means (6) for calculating the writing position on the image storage means (1) of the dot data data of the next graph following the graph copied by the copying means (5). A graph display method featuring: