JPH04313171A - System for recording and selecting line segment data - Google Patents

Abstract

PURPOSE:To reduce the calculation amount for processing discriminating a display line segment and a non-display line segment and to shorten screen display processing time when the screen is shifted. CONSTITUTION:A line segment data recording means 4 obtains data indicating the screen specific range when the line segment is the display line segment if the data concerning the coordinate of the line segment for processing is notified from a data input device 3, and the line segment data equipped with the data indicating the line segment and the data indicating the screen specific range are recorded on a line segment data management table 6. A line segment data selection means 5 selects the display line segment by referring to the line segment data management table 6 when the data indicating the change of the location of the screen is inputted by the data input device 3, and the display line segment data is notified to a screen control means 2.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention displays a screen having line segments (including figures made up of line segments) on a display device, and displays part of the line segment/figure area (area larger than the screen) on the screen. Regarding information processing systems that appear to be displayed (screen display processing systems), especially line segments that are displayed on the screen (hereinafter referred to as "displayed line segments") and line segments that are not displayed on the screen (hereinafter referred to as "hidden line segments") This invention relates to a line segment data recording/selection method for determining line segment data based on screen position, line segment coordinates, etc.

0002

2. Description of the Related Art Conventionally, in the information processing system as described above, the following processing has been performed in order to distinguish between display line segments and non-display line segments and select display line segments.

First, if at least one of the end points of a line segment to be processed is within the range of the screen, that line segment is determined to be a display line segment.

[0004] If both end points of the line segment are outside the range of the screen, it is determined whether the line segment crosses the screen.

[0005] If the line segment crosses the screen, the line segment is determined to be a display line segment. If the line segment does not cross the screen, the line segment is determined to be a non-display line segment.

Note that "determining whether a line segment crosses the screen" means "determining whether a line segment intersects with lines around the screen" or "determining whether a line segment intersects with a diagonal line of the screen". (This method is used when the screen is a rectangle).

[0007]

[Problem to be Solved by the Invention] In the conventional display line segment selection method described above, for all line segments whose both end points are outside the range of the screen, it is necessary to "determine whether the line segment crosses the screen or not."
Therefore, as the number of line segments to be processed increases, the amount of calculation increases, and the processing time (screen This has the disadvantage that the display processing time (display processing time) becomes long (the operator cannot perform other operations during the processing time).

[0008] Recently, it has become common for various design work to be carried out by drawing a large number of line segments or figures made up of line segments on the screen, so the delay in screen display processing described above is due to the delay in such design work, etc. It was also a cause of.

In view of the above-mentioned points, it is an object of the present invention to reduce the amount of calculation required for the process of discriminating between display line segments and non-display line segments, and to improve the screen display process when moving the screen, etc. An object of the present invention is to provide a line segment data recording/selection method that can reduce time.

0010

[Means for Solving the Problems] The line segment data recording/selection method of the present invention displays a screen having line segments on a display device, and displays part of the line segment/figure area on the screen. In an information processing system that is displayed on a screen, a screen control means for controlling display of a screen on a display device;
a data input device for inputting data regarding screen display; a line segment data management table for storing line segment data based on the data input by the data input device; and a line segment data management table for storing line segment data based on the data input by the data input device; When the data is notified, the data indicating the screen specific range when the line segment is to be displayed is obtained, and the line segment data having the data indicating the line segment and the data indicating the screen specific range is obtained from the line segment. a line segment data recording means for recording in a data management table; and the line segment in which line segment data is recorded by the line segment data recording means when data indicating a change in screen position is inputted by the data input device. and line segment data selection means for selecting a display line segment related to the screen after the position change by referring to a data management table and notifying data indicating the display line segment to the screen control means.

[0011]

[Operation] In the line segment data recording/selection method of the present invention, the screen control means controls the screen display on the display device, the data input device inputs data related to the screen display, and the line segment data management table inputs data. When storing line segment data based on data input by the device and using the line segment as a display line segment when the line segment data recording means is notified of data regarding the coordinates of the line segment to be processed by the data input device. The line segment data having the data indicating the screen specific range and the data indicating the screen specific range is recorded in the line segment data management table, and the line segment data selection means selects the data indicating the screen specific range using the data input device. When data indicating a change in position is input, the line segment data recording means refers to the line segment data management table in which line segment data is recorded and selects the display line segment related to the screen after the position change. Data indicating display line segments is notified to the screen control means.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the line segment data recording/selection method of the present invention. The line segment data recording/selection method of this embodiment includes a display device 1, a screen control means 2, a data input device 3 (keyboard, mouse, etc.), a line segment data recording means 4, and a line segment data selection means 5. and a line segment data management table 6.

FIG. 2 shows a line segment/figure area (an area larger than the screen displayed on the display device 1) having line segments.
3 is a diagram illustrating an example of the relationship between the image data and the screen actually displayed on the display device 1. FIG. Here, it is assumed that line segments 21 to 25 exist on the line segment/graphic area.

The screen can be moved to any position in the line/graphic area based on instructions from the data input device 3. Line segments existing within the screen range of the position specified by the data input device 3 are displayed on the display device 1. For example, line segment 21 in FIG. 2 has both end points within the range of the screen, so it is displayed on the screen (line segment 21 in this case becomes a display line segment). Line segment 22 has both end points outside the range of the screen, but part of it is within the range of the screen, so it is displayed on the screen (line segment 21 in this case becomes a display line segment). Line segments 23 to 25 are completely outside the screen range, so they are not displayed on the screen (in this case, line segments 23 to 2
5 is a hidden line segment).

FIGS. 3A to 3D are diagrams showing the range of positions on the screen in which a line segment AB having end points A and B is displayed as a display line segment. Each of the dashed rectangles in FIGS. 3(a) to (d) indicates one screen, and each rectangle (
The screen) has a horizontal (X direction) length Wx and a vertical (Y direction) length Wy.

FIG. 3(a) is a diagram showing the case where the line segment AB is upward to the right, FIG. 3(b) is a diagram showing the case where the line segment AB is upward to the left, and FIG. 3(c) is a diagram showing the case where the line segment AB is upward to the left. 3(d) is a diagram showing a case where line segment AB is horizontal, and FIG. 3(d) is a diagram showing a case where line segment AB is vertical.

In the case of FIG. 3(a), a specific position on the screen (in this embodiment, the upper left corner of the screen is the specific position on the screen) is surrounded by points C, D, A, B, E, and F. If the line segment AB is within the range shown by the solid line in the figure, the line segment AB becomes the displayed line segment on that screen, and in the case of FIG. 3(b), the specific position on the screen is the point C, D, E, B, If it is within the range surrounded by F and G, line segment AB becomes the displayed line segment on that screen, and in the case of Fig. 3(c), the specific position on the screen is point C, D.
, B, and E, line segment AB becomes the displayed line segment on that screen, and in the case of FIG. 3(d), the specific position on the screen is within the range surrounded by points C, D, B, and E. If it is within the range, line segment AB becomes the displayed line segment on that screen. Note that the range of a specific position on the screen where line segment AB is a display line segment will be hereinafter referred to as the "screen specific range" of line segment AB.

FIG. 4 is a diagram showing the contents of the line segment data management table 6. The line segment data management table 6 manages line segment data having coordinates of the line segment to be processed (data indicating the line segment) and data indicating the screen specific range of the line segment. This line segment data management table 6 records line segment data regarding one line segment in one entry, and the maximum number of entries is N (positive integer). In addition, the number of entries currently recorded in the line segment data management table 6 is n (a positive integer less than or equal to N), and this n
are also recorded in the line segment data management table 6. The line segment data of each entry (segment data of line segment AB shown in Figure 3) consists of the coordinates of end point A (XA, YA), the coordinates of end point B (XB, YB), and the X The minimum coordinate value Xmin, the maximum X coordinate value Xmax in the screen specific range, and the minimum Y coordinate value Ym in the screen specific range
in and the maximum value Ymax of the Y coordinate in the screen specific range
and a flag for identifying whether line segment AB is horizontal or vertical (in the case of FIG. 3(c) or (d), "1"
” is set, and in the case of FIG. 3(a) or (b), “0
" is set), the slope a of the line segment AB in the case of FIG. 3(a) or (b), and the Y-axis intercept of the line segment CF in the case of FIG. 3(a). In the case of b), b1 is the Y-axis intercept of the line segment GF, and in the case of FIG. 3(a), it is the Y-axis intercept of the line segment AB, and in the case of FIG. 3(b), the line segment DE
b2, which is the Y-axis intercept of .

FIG. 5 is a flow chart showing the processing of the line segment data recording means 4. This process includes both end point setting step 51
, X coordinate determination step 52, and Y coordinate determination step 5.
3, "XA≠XB" and "YA<YB" processing step 54, "XA≠XB" and "YA>YB" processing step 55, and "XA=XB" or "YA=YB" processing step 56. , line segment data recording step 57.

FIG. 6 is a flowchart showing the processing of the line segment data selection means 5. This process includes an initial setting step 61, a counter determination step 62, a line segment data acquisition step 63, a first X coordinate range determination step 64, and a first X coordinate range determination step 64.
Next Y coordinate range determination step 65, flag determination step 66, second X coordinate determination step 67, second Y coordinate determination step 68, display line segment coordinate notification step 69
and a counter increment step 70.

Next, the operation of the line segment data recording/selection method of this embodiment configured as described above will be explained.

The line segment data recording means 4 performs the following processing (see FIG. 5). When coordinate data of both end points of the line segment to be processed is notified from the data input device 3, execution is started.

Both end points are divided into point A and point B (step 51). That is, among both end points, the end point with the smaller X coordinate value is set as point A, and the end point with the larger X coordinate value is set as point B. If both X coordinate values are the same, the end point with the larger Y coordinate value is set as point A, and the end point with the smaller Y coordinate value is set as point B. Based on the above classification, the line segment to be processed is positioned as line segment AB in FIG. 3, and the coordinates of both end points A and B of line segment AB are set as (XA, YA) and (XB, YB).

Next, it is determined whether XA and XB are equal, that is, whether line segment AB is perpendicular (step 52).
. Also, if XA and XB are not equal, then YA and Y
B is compared (step 53).

If "XA≠XB" and "YA<YB" are found in the judgment at step 52 and the comparison at step 53 (the case of FIG. 3(a)), the following values are set (
Step 54). ■ Set the flag to "0". ■
Set "XA-Wx" (X coordinate of point C or point D) to Xmin. ■ Set XB (X coordinate of point B or point E) to Xmax. ■ YA to Ymin (point A
or the Y coordinate of point D). ■ “Ymax”
YB+Wy” (Y coordinate of point E or point F). (2) Set "(YB-YA)/(XB-XA)" (the slope of line segment AB or line segment CF) to a. (2) Set "YA+Wy-a (XA-Wx)" (Y-axis intercept of line segment CF) to b1. ■ Set "YA-aXA" (Y-axis intercept of line segment AB) to b2.

If "XA≠XB" and "YA>YB" are found in the judgment at step 52 and the comparison at step 53 (the case of FIG. 3(b)), the following values are set (
Step 55). ■ Set the flag to "0". ■
Set "XA-Wx" (X coordinate of point C or point D) to Xmin. ■ Set XB (X coordinate of point B or point F) to Xmax. ■ YB to Ymin (point B
or the Y coordinate of point E). ■ “Ymax”
YA+Wy” (Y coordinate of point C or point G). (2) Set "(YB-YA)/(XB-XA)" (the slope of line segment AB, line segment DE, or line segment GF) to a. ■
Set "YA+Wy-aXA" (Y-axis intercept of line segment GF) to b1. ■ “YA-a (XA-Wx
)” (Y-axis intercept of line segment DE).

If "XA=XB" or "YA=YB" is found in the judgment in step 52 and the comparison in step 53 (in the case of FIG. 3(d) or (c)), set the following values. (step 56). ■ Set "1" to the flag. ■ Set "XA-Wx" (X coordinate of point C or point D) to Xmin. ■ XB to Xmax (
Set the X coordinate of point B or point E). ■ Ymin
Set YB (Y coordinate of point B or point D) to . ■
"YA+Wy" for Ymax (Y coordinate of point C or point E)
Set.

When the processing of steps 54, 55 or 56 is completed, the number n of recorded line segment data in the line segment data management table 6 is increased by 1, and the nth entry in the line segment data management table 6 is filled with steps 51 and 56. Steps 54, 55
Or each data obtained in 56 (XA, YA, XB, YB
, Xmin, Xmax, Ymin, Ymax, flag,
a, b1, and b2) as line segment data (step 57), and the process ends.

The line segment data selection means 5 performs the following processing (see FIG. 6).

The data input device 3 inputs the screen position change data (data indicating a change in the screen position), that is, the coordinates (Xw,
When Yw) is notified, execution starts.

The display of the line segment currently displayed on the screen is deleted, and a counter i for controlling repetition is set to 1 (step 61).

It is determined whether the counter i has exceeded the number n of recorded line segment data in the line segment data management table 6 (step 62).

If it is determined in step 62 that the counter i exceeds the recording line segment data number n, the process is terminated.

If it is determined in step 62 that the counter i does not exceed the number n of recorded line segment data, the line segment data (XA, YA, XB, YB, Xmin, Xmax
, Ymin, Ymax, flags, a, b1 and b2)
(step 63).

Coordinates of the specific position on the screen after the position change (Xw
, Yw) is within the range of Xmin and Xmax and Ymi
It is determined whether it is within the range between n and Ymax (steps 64 and 65).

In the judgments of steps 64 and 65, the coordinate (X
w, Yw) is within the range of Xmin and Xmax and Ym
If it is not within the range of in and Ymax, the line segment A
Since it is confirmed that B is a hidden line segment on the screen after the position change, the value of the counter i is increased by 1 (step 70).
Execution returns to step 62 to perform processing regarding the line segment data of the next entry in the line segment data management table 6.

The coordinates (X
w, Yw) is within the range of Xmin and Xmax and Ym
If it is within the range of in and Ymax, check whether the value of the flag is 1 or not, that is, the line segment AB is shown in FIG. 3(c).
It is determined whether it is a horizontal line as shown in FIG. 3(d) or a vertical line as shown in FIG. 3(d) (step 66).

If the value of the flag is 1 in the determination at step 66, it is determined that the line segment AB is the displayed line segment on the screen after the position change, so steps 67 and 68 are performed.
The screen control means 2 is given the coordinates (XA, YA) and (XB,
YB) to prompt display of the line segment AB (step 69).

If the value of the flag is not 1 in the determination at step 66, the coordinates (Xw
, Yw) is located below the line segment CF in FIG. 3(a) or the line segment GF in FIG. 3(b) ("Yw<aXw+
b1" (step 67). Also, in the determination at step 67, the coordinates (Xw, Yw) are
If the coordinates (Xw, Yw) are located below the line segment CF in (a) or the line segment GF in FIG. 3(b), the coordinates (Xw, Yw) are
) or the line segment DE in FIG. 3B (step 68).

As determined in steps 67 and 68, the coordinates (Xw, Yw) of the specific position on the screen after the position change are as shown in FIG. 3(a).
If it is located below the middle line segment CF or the line segment GF in FIG. 3(b) and above the line segment AB in FIG. 3(a) or the line segment DE in FIG. 3(b), , since it is determined that the line segment AB is the line segment displayed on the screen after the position change, the screen control means 2 is informed of the coordinates of both end points A and B of the line segment AB (
XA, YA) and (XB, YB) to prompt display of the line segment AB (step 69).

It is determined in step 67 that the coordinates (Xw, Yw) of the specific position on the screen after the position change are the line segment C in FIG. 3(a).
If the coordinates (Xw, Yw) are not located below line segment AB in FIG. 3(a) or line segment GF in FIG. 3(b), or if it is determined in step 68 that the coordinates (Xw, Yw) If the line segment AB is not located above the minute DE, it is confirmed that the line segment AB is a hidden line segment on the screen after the position change, so the value of the counter i is increased by 1 (step 70), and the line segment data is Execution returns to step 62 to perform processing regarding the line segment data of the next entry in the management table 6.

When the process of step 69 is completed, the value of the counter i is incremented by 1 (step 70), and the process is executed in step 62 in order to process the line segment data of the next entry in the line segment data management table 6. return.

The determinations in steps 64 to 68 above determine whether the line segment related to the line segment data of the i-th entry in the line segment data management table 6 is a display line segment or a non-display line segment. This is a judgment for.

According to the prior art, the screen control means 2 displays information on the display device 1 based on the coordinates (XA, YA) and (XB, YB) of both end points A and B notified from the line segment data selection means 5. The line segment AB selected as the display line segment is displayed on the screen after the position change.

[0046]

As explained above, the present invention provides a process for discriminating between displayed line segments and non-displayed line segments by providing a line segment data management table, line segment data recording means, and line segment data selection means. The present invention has the advantage that the amount of calculation required for this can be reduced compared to the conventional method, and the screen display processing time when moving the screen can be shortened. Based on this effect, it is possible to improve the man-machine interface in various types of design work, etc., where many line segments and figures consisting of line segments are drawn on the screen, and avoid delays in such design work. You will be able to do this.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram for explaining the relationship between a screen and a line segment/graphic area handled by the line segment data recording/selection method shown in FIG. 1;

FIG. 3 is a diagram for explaining the relationship between a line segment to be processed and a screen specific range of the line segment in the line segment data recording/selection method shown in FIG. 1;

FIG. 4 is a diagram showing the contents of a line segment data management table in FIG. 1;

FIG. 5 is a flowchart showing the processing of the line segment data recording means in FIG. 1;

FIG. 6 is a flowchart showing the processing of the line segment data selection means in FIG. 1;

[Explanation of symbols]

1 Display device 2 Screen control means 3 Data input device 4 Line segment data recording means 5 Line segment data selection means 6 Line segment data management table 21-25 Line segment

Claims (1)

[Claims] Claim 1: In an information processing system that displays a screen having line segments on a display device and makes it appear as if part of the line segment/figure area is displayed on the screen, the display of the screen on the display device is controlled. a screen control means; a data input device for inputting data related to screen display; a line segment data management table for storing line segment data based on data input by the data input device; When data regarding the coordinates of a line segment is notified, data indicating a screen specific range when the line segment is to be displayed is obtained, and a line segment having data indicating the line segment and data indicating the screen specific range is obtained. a line segment data recording means for recording data in the line segment data management table; and a line segment data recording means for recording line segment data when data indicating a change in screen position is inputted by the data input device. and line segment data selection means for selecting a display line segment related to the screen after the position change by referring to the line segment data management table, and notifying the screen control means of data indicating the display line segment. Characteristic line segment data recording/selection method.