JPH0634208B2 - Graphic display - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a graphic display device that clearly indicates to a user when the end points of two drawn straight lines are separated.

[Prior art and its problems]

With the development of personal CAD, it has become possible to easily process and draw graphics on a CRT. There are the following two methods for drawing a straight line in conventional personal CAD.

(I) Line segment end points are automatically corrected and set to mesh intersections that are always displayed. That is, for example, FIG. 9 (a)
First, assume that a line segment having the same end point as the line segment A is drawn at the position a. Next, when the end point of the line segment is determined at position b as shown in Fig. 2 (b), the point is automatically corrected to the closest point on the mesh, and the end point moves to position a. Then, set the other end point of the line segment to be drawn at the position of C as shown in Figure (c). As a result, a line segment B having the same end point at the position a can be obtained as shown in FIG.

(Ii) Those having an end point detection function. That is, for example, as shown in FIG. 10 (a), a line segment B having an end point that coincides with the line segment A at the position of the end point a is drawn. Therefore, the figure (b)
The end point coordinates of the line segment B are set to the position of B as shown in. When the end point detection function is executed, the end point coordinate position of the line segment B is automatically corrected and moved to the position of the end point a closest to the position of (b) in FIG. Finally, the line segment B can be drawn by setting the other end of the line segment B at the position of C as shown in FIG.

As described above, in personal CAD, all the line segments drawn on the CRT have a certain unit length, and in some cases, the end points must also be exactly matched. However, in the simple graphic processing, strictness is not required so much, and if the upper end points of the appearances coincide with each other, it may often be sufficient. Given that,
On the contrary, the conventional example takes time, and the (i)
In the case where the end point coordinates of the line segment can be set only at the intersection points of the mesh, there is a problem that the line segment cannot be drawn in the middle of the mesh as shown in FIG.

On the other hand, among graphic processes, those having a hatching function and an enlarging / reducing function are becoming common. Therefore, the following inconveniences will occur if there is no end point between the line segments. That is, as shown in FIG. 12 (a), it is assumed that there is a triangle whose end points coincide with each other in appearance at a certain magnification. Now, suppose that hatching is performed inside this. However, this triangle is at the position of A in FIG. 7A, and the end points of the line segments A and B do not match. Therefore, the same figure
As in (b), there is a problem in that the end points that did not match become clear when enlarged, and if hatching is performed on this, the hatching will leak from this part and cover the entire screen. It was

[Object of the Invention] In order to solve the above problems, an object of the present invention is to provide a graphic display device capable of clearly indicating to a user a portion where the end points of line segments do not match.

[Summary of the Invention] In order to achieve the above object, the present invention comprises storage means for storing coordinates of two end points of each straight line in graphic element data,
A discriminating means for discriminating whether or not the coordinates have a discrepancy of a predetermined value or less, and when the discriminant discriminates that the discrepancy is the predetermined value or less, it is determined that the corresponding two end points do not coincide. It is characterized in that it is provided with a clarification means for clarification.

〔Example〕

 Hereinafter, embodiments of the present invention will be described in detail.

FIG. 1 is a block diagram of an embodiment of the present invention. In this embodiment, a graphic element data storage device 1, a target / target coordinate number calculation circuit 14 for calculating the number of target and target coordinates in the graphic element data storage device,
The target coordinate number count register 12 that stores and counts down the result, the target coordinate number count register 13,
The linear coordinate data transfer control circuit 2 for reading the target / target coordinates from the graphic element data storage device 2, the target coordinate latch register 3 for storing these values, the target coordinate latch register 4, and the registers 3, 4 have the same value. The same coordinate value determination circuit 5 for determining whether or not the end point mismatch determination circuit 6 for determining whether or not the end points based on those values do not match, according to the result, the explicit portion (circle)
Explicit part central coordinate discriminating circuit 7 for calculating the center of the explicit part, explicit part central coordinate duplicating check circuit 8 for indicating whether or not the central coordinates already exist, explicit part central coordinate storage device 9 for storing the central coordinates, retrieval Display control circuit 11, CRT for displaying contents of end point mismatch search width storage devices 10, 9 and 10 for storing width data via AND circuits 17, 18.
It is composed of 15.

Next, the operation of the above embodiment will be described with reference to the operation flowchart of FIG. 2 and the explanatory views of FIGS.

First, in the present embodiment, when an execution request is made, the figure element data storage device 1 causes the target / target coordinate number calculation circuit 14
At, the number of straight line data is searched, and the number of target coordinates and the number of target coordinates are stored in the counter registers 13 and 12 ((1) and (3) in FIG. 2).

The number of target coordinates is the number of linear elements × 2, and the number of target coordinates is the number of linear elements × 2-2. For example, if a graphic element data table as shown in FIG. 3 is stored in the graphic element data storage device 1, the number of target coordinates is 14, and the number of target coordinates is 12. Next, the starting point coordinate data of the first line data searched from the graphic element data storage device 1 is put into the target coordinate latch register 3, and the starting point coordinate data of the line data found next is searched for. Put it in the latch register 4 ((2) and (4) in Fig. 2).
Next, in the same coordinate value discriminating circuit 5, the coordinates in these two registers are compared, and if they match, the target coordinate number counter register 12 is downed and the next data, in this case the same target coordinate, is detected. The coordinate value of the end point of the data is brought (Fig. 2, (5), (5), (7)). If this coordinate value is also the same as the target coordinate, 12 is counted down and the starting point coordinate of the next target straight line data is brought to 4. In this way, the linear coordinate data transfer control circuit 2 performs the task of bringing the required coordinate data based on the count register 12 or 13 from the graphic element data storage device 1 to the latch register 4 or 3. (Figures (4), (5), and (6) are repeated). If you compare the target and target coordinate data,
If they do not match, the end point mismatch determination circuit 6 determines whether the interval is within the mismatch search width or outside. At this time, the mismatch search width is a value stored in advance in the end point mismatch search width storage device (Fig. 2, (8), (9)). If it is within the search width, the center point coordinates of the target coordinates and the target coordinates are calculated by the explicit part center coordinate discriminating circuit 7, and it is determined whether or not there is the same center coordinate value previously, the explicit part central coordinate duplicate check circuit. Check in 8 (Fig. 2 (10), (1
1)). If the same center coordinate value does not exist in the explicit part center coordinate storage device 9, this coordinate value is newly stored in 9 and the target coordinate number counter register 12 is downed (see FIG.
1), (12), (6), (7)). If the same center coordinate value is 9, this center coordinate value is not stored and only the target coordinate number counter register 12 goes down (Fig. 2 (11),
(6), (7)). The above signals bring down the target coordinate number counter register 13 when the end point mismatch determination circuit 6, the target coordinate number counter register 12 becomes 0, and bring the next target coordinate value (FIGS. 2 (6), (13), (14), (2)). Further, when the target coordinate number counter becomes 0, the central coordinate value stored in 9 is taken out, and an explicit circle centered on this point and having a search width as a radius is drawn. These operations are performed by the AND circuit 16,
This is done by turning on 17 (Fig. 2 (14), (1
Five)).

The result of the above operation is shown in FIG. In the same figure (a), if the straight line end points of a, b, and c do not match, the part is clearly indicated by a circle as shown in the same figure (b).

Next, more specific operations will be listed in order using the example of FIG.

1. Number of target coordinates = number of linear elements x 2 = 3 x 2 = 6 Number of target coordinates = number of linear elements x 2-2 = 3 x 2-2 = 4 is calculated and stored in each counter register 13, 12.

2. The target linear element is searched from the graphic element data table above 1. In this case, it is set as the starting point of the straight line A (FIG. 3).

3. Search the target element from the same table. Bring the start point of straight line B (Fig. 1, Fig. 4).

4. Compare with. They do not match (Fig. 1, Fig. 5).

5. Since the interval between and is within the mismatch search width of 3 dots, it is regarded as a mismatch end point (FIG. 1).

6. The center point on the line segment connecting and is calculated (FIG. 1 and FIG. 7).

7. It is checked whether there is the same center point before (Fig. 1, Fig. 8). In this case, it is not necessary because it is the coordinate data of the first center point.

The center point coordinates are stored in the staff within 8.9.

9. Target coordinate number counter register 12 down. Set from 4 to 3.

10. Since the target coordinate number counter register 12 is not 0, the next target coordinate is brought. In this case, the end point of the straight line B (FIG. 1).

11. And (FIG. 1).

12. There is a disagreement (Fig. 1).

13. The distances between and are outside the search range.

14. Target coordinate number counter register 12 is down. Three
To 2

15. Since the counter is not 0, the next target coordinate is brought (FIG. 1, FIG. 4).

16. Similarly, and are compared (FIG. 1, FIG. 5).

17. Both do not match with the original, and since they are out of the search range, the target coordinate number counter register 12 is simply lowered. (Fig. 1 6).

18. Since the target coordinate number counter register 12 has become 0, the target coordinate number counter register 13 is decremented by 6 to 5 to bring the end point of the straight line A which is the next target coordinate (FIG. 3 in FIG. 1).

19. Similarly, and are compared (Fig. 1, Fig. 5).

20. In this case, the coordinates of the center point are stored as the non-coincident end points (FIGS. 6, 7, 8, 9).

21. Lower the target coordinate number counter register 13, 5 → 4
And

22. Since the target coordinate number counter register 13 is not 0, the start point of the next target coordinate line B is brought (FIG. 1, FIG. 3).

23. Compare, and ,, (Fig. 1).

24. In this case, only and become the disagreement end points, but since the center point between these coordinates has already been stored in the stack, it is regarded as the same by the duplicate check,
It is not stored again (Fig. 1, 6, 7, 8).

25. Similarly, the remaining coordinate points are used as the target coordinates and compared to find a mismatched end point. The state of the coordinate search is shown in FIG.

26. When the target coordinate number counter register 13 reaches 0, the center coordinate is taken out from the stack of 9, and a circle having the same radius as the search width is drawn around this point. In Figure 7,
The center coordinates of the disagreement points stored in the stack and the output result are shown in FIG.

〔The invention's effect〕

According to the present invention, it is possible to easily know a portion where end points of line segments are separated from each other. This makes it possible to confirm in advance, for example, the paint that will stick out the area due to the mismatch of the end points in hatching.

These things make visual drawing easier.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an operation float chart of FIG. 1, FIG. 3 is an explanatory view of contents of a graphic element data storage device, and FIG. FIG. 5 is an explanatory diagram of the explicit output, FIG. 5 is an explanatory diagram of another operation example, FIG. 6 is an explanatory diagram of coordinate comparison with respect to FIG. 5, and FIG. Stack), FIG. 8 is an explanatory diagram of the explicit output for FIG. 5, FIGS. 9 and 10 are explanatory diagrams of the conventional method, and FIGS. 11 and 12 are explanatory diagrams of conventional problems. It is a figure. 1 ... Graphic element data storage device (RAM), 2 ... Linear coordinate data transfer control circuit, 3 ... Target coordinate latch register, 4 ... Target coordinate latch register, 5 ... Same coordinate value determination circuit, 6 ... … End point mismatch discriminating circuit, 7 …… Explicit part (circle) center coordinate discriminating circuit, 8 …… Explicit part (circle) center coordinate duplicate check circuit, 9 …… Explicit part (circle) center coordinate storage device (stack), 10 ... End point mismatch search width storage device (RAM), 11 ... Display control circuit, 12 ... Target coordinate number counter register, 13 ... Target coordinate number counter register, 14 ... Target / target coordinate number calculation circuit , 15 ... Display device (CRT), 16 ... AND circuit, 17 ... AND circuit.

Claims (3)

[Claims] 1. A storage means for storing the coordinates of the two end points of each straight line in the graphic element data, a determination means for determining whether or not the coordinates have a predetermined value or less, and a determination means for determining the mismatch. A graphic display device comprising: a clarification unit that clearly indicates that the corresponding two end points do not match when it is determined to be equal to or less than a predetermined value. 2. The coordinates for judging whether or not the end point stored in said storage means and all the end points other than other end points on a straight line including the end point are the same or not. The same discriminating means and the end point discriminating means for discriminating whether or not the distance between the coordinates of the corresponding two end points is less than or equal to a predetermined value when the coordinates are discriminated by the same coordinate discriminating means. The graphic display device according to claim 1, wherein: 3. The display means superimposes, on the display of the graphic element data, a computing means for computing the midpoint of the coordinate values of the two end points which do not match, and a circle having a predetermined radius with the midpoint as the central coordinate. The graphic display device according to claim 1, further comprising display means for displaying.