JPH02291083A - Pick processing method - Google Patents

Abstract

PURPOSE:To quickly perform judgement for pick hit/pick mis-hit by detecting the number of intersections of a half-line setting an arbitrary one point as an endpoint and an operation targeted drawing, and judging the odd-even of the number of intersections. CONSTITUTION:A quadrangle 21 is comprised of four line segments 22, 23, 24, and 25. The number of intersections of the half-line 27 extending in a right horizontal direction setting a left point as the endpoint and the line segment of the quadrangle goes to only one point, the intersection 31, when a pick aperture 26 exists in the quadrangle. When the pick aperture 26 is extended outside the quadrangle 21, two intersections 31 and 32 are generated. When the pick hit is applied, the number of intersections goes to an odd number, and when the pick mis-hit is applied, it goes to an even number. In such a way, it is possible to remarkably shorten the judging time of the pick hit/pick mis-hit.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application in Industry) The present invention relates to a pick processing method in graphic processing, and in particular, to a pink processing method that makes it possible to determine pick hiso 1/pick miss 1 in a short time. It is about the method.

(Prior Art) In computer graphics, when selecting a displayed figure in order to change the color or pattern of a figure displayed on a display, the displayed figure must be moved with a cursor or line. - A pick process is performed in which a figure selection signal is generated by pointing with a pen, and the selected figure is notified to the host computer.

FIG. 8 is a diagram for explaining the pink processing method when three figures, a triangle 81, a circle 82, and a rectangle 83, are displayed with parts of them overlapping each other. Circle numbers '-T: ■ to ■ indicate the number of times the figures overlap.

In the pink processing in general graphic processing when multiple figures are displayed in Table 7J, the number of overlaps due to each display figure or the odd number of times such as 1, 3, etc. (hereinafter referred to as pick) is If you specify one location (previous possible area), all overlapped or odd numbered locations will be picked at the same time.

However, if you change the application program etc.
-1 It is also possible to specify the opposite of the above. In that case, if you specify the number of overlaps or an even number such as 2 times, 4 times, etc., the number of overlaps will be an even number. All the times are picked at the same time.

When specifying a pick processing area, the area specified by the cursor etc. (hereinafter referred to as pick aperture) is
It is required to specify the pick permission area, and if the pick permission area is specified, the specification is determined to be a pick hit, and if any other location is specified, the specification is determined to be a big miss hit.

If it is determined that there is a big miss hit 1, the operator specifies the location again, and after it is determined that the pick hit is 1, the operator performs the next process.

Prior art pick processing methods are discussed, for example, in Nikkei Electronics, May 9, 19'83, pages 84-87.

In this case, pick hit 1/pick miss is determined by 121T: . The target value A is stored in a register etc., and then this coordinate value A is
This is performed by sequentially comparing the coordinate values Bn of all pixels on the view boat, and determining whether the coordinate value A matches the coordinate value Bn within the pick permission area, and if they match, it is determined as a pick hit, If it doesn't match, big miss hit 1
・It is determined that

(Problem to be Solved by the Invention) In the above-mentioned conventional technology, the determination of pick hit 1/pick miss hit is made by converting the coordinate value A of the position specified by the pick aperture to the coordinate value of all pixels of view points 1 and 7. B n
Since this was done by comparing the results with the previous one, there was a problem in that it took a long time to determine whether there was a pick hit or a pick miss.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a pick processing method that quickly determines pick hit 1/pick miss hit.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a pick processing method in a computer graphics device, in which a figure to be operated is displayed on a screen, and a desired position on the screen is Set a pick aperture to The feature is that pick hit/pick miss hit is determined according to the evenness of .

(Operation) According to the above-described configuration, pick hit/pick miss hit determination is performed based on whether the number of intersections of line segments is even or odd.

Therefore, it is no longer necessary to compare the coordinate values of the position specified by the pick aperture with the coordinates of all pixels in the viewport as in the conventional technology, and pick hits/pick misses can be determined in a short time. Become.

(Example) The present invention will be explained in detail below with reference to the drawings.

2 and 3 are diagrams for explaining the basic concept of the present invention, and in particular, four line segments 22, 23, 24, 25
The case where a rectangle 21 surrounded by is picked (instructed) by the pick aperture 26 is shown.

In both figures, looking at the number of intersections between the four line segments and the half-line 27 extending in the left horizontal direction with the lower left point on the contour of the pick aperture 26 as the end point, it is found that the pick aperture 26 is within the rectangle 21, that is, the pick In the case of a hit as shown in FIG. 2, there is only one intersection 28 with the line segment 25, and the pick aperture 26 is outside the rectangle 21.
In other words, in the case of a pick miss hit as shown in FIG. 3, the intersection is the intersection 31 with the line segment 25 and the line segment 23.
There are two points of intersection 32 with .

That is, the number of intersections is an odd number when there is a pick hit, and an even number when there is a pick miss hit. It will be easily understood that the relationship between the evenness of the number of intersections and the pick hit/pick miss hit similarly applies to the case where a plurality of figures overlap.

Therefore, in the present invention, the number of intersections is determined to be even or odd, and if it is determined to be an odd number, it is determined that it is a pick hit,
If it is judged as an even number, it is judged as a big miss hit.

[First Embodiment] FIG. 1 is a flowchart showing the processing procedure for the pick hit/pick miss hit determination described above.

In step S1, the total number of intersections N is initialized to 0 as an initial setting.

In step S2, line segments (elements) constituting the given display screen are extracted one by one.

In step S3, it is determined whether each of the extracted elements crosses a big aperture.

Note that this determination processing is clip processing itself, and conventional techniques can be applied, so a description thereof will be omitted.

If it is determined in step S3 that a certain element crosses the pick aperture, the process moves to step S9, where it is determined that a pick hit has occurred.

In step S4, it is determined whether each element intersects with a half-line with one point on the contour of the pick aperture as an end point. If the element intersects, the process moves to step S5; if it does not intersect, the process moves to step S6. do. Note that this determination process will be explained in detail later using FIG. 4.

In step S5, the current number of intersections is added to the total number of intersections N.

In step S6, it is determined whether or not the presence or absence of an intersection point has been determined for all elements constituting the display screen. If the determination has not been completed, the process moves to step S2 and the same process as above is performed. Do this for other elements as well.

In step S7, the total number of intersections N is determined to be even or odd. If it is an even number, it is determined to be a big miss hit in step S8, and if it is odd, it is determined to be a pick hit in step S9.

FIG. 4 is a diagram for explaining the method for determining the presence or absence of an intersection point performed in step S4.

In this embodiment, it is determined whether the intersection of a line segment and a half straight line 27 extending in the left horizontal direction with the lower left point 49 of the outline -L of the pick aperture 26 as an end point is determined.

The view point 1 centering on the pick aperture 26 is divided into nine parts I7, each in the upper left area 5]. (0110λ) 2 area 52 (0010), upper right area 53 (1010), left area 54 (0100), center area (pick aperture) 55
(0000), right area 56 (1000), lower left area 5
7 (0101), lower area 58 (0001.), and lower right area 59 (1001.).

Note that the four-digit numbers shown in parentheses are area codes given to indicate each area, and are used when determining the presence or absence of an intersection, which will be described later.

If we pay attention to the area divided into nine areas in this way, we can see that the half line 27
A line segment that intersects with and does not cross the pick aperture is
There are eight types of line segments 41 to 48.

FIG. 5 is a flowchart 1 for determining the presence or absence of an intersection using the area code.

In step Sll, it is determined whether the area code of either end point of the target line segment is ``'0 1 0 1'', and if it is ``0101'', the process moves to step S14. .

In step S14, it is determined whether the other end point is either "x010"x100"x110"("x" is either "1" or "0" or ijJ); If it is, it is determined that there is an intersection, and if neither is true, it is determined that there is no intersection.

On the other hand, if it is determined in step Sll that the area code of one end point is not "0101", in step S i 2, the logical sum and logical product for each bit of the area code of both end points are calculated. .

In step S13, it is determined whether the logical product is “×××O” and the logical sum is “×1×1”, and if these conditions are satisfied, it is determined that there is an “intersection”, and the condition is satisfied. If not, it is determined that there is no intersection.

According to this embodiment, the presence or absence of a line segment that crosses a big aperture and the presence or absence of an intersection between a half-line and a line segment are both easily determined using area codes, so processing can be simplified. become.

[Second Embodiment] In the second embodiment described above, the method of determining pick hit/pick miss hit based on the even/odd determination of the number of intersections has been explained. This can also be done by using the figure filling process on a scan-type graphics display device, and setting the pick hit 1/stop when the pick aperture is in the filled area, and the pick miss hint when it is located at A beyond the filled area. .

A pick hit/pick miss hit determination method using fill-in processing will be described below.

In a computer graphics device equipped with a raster scan type graphics display device, the operation target figure displayed on the screen is filled in by detecting the intersection of the operation line and the line segments that make up the operation target figure. Then, the trace is from the intersection of the odd number 1 from the scanning start point to the even number I
The area up to the intersection of is filled in, and the area from the even-numbered intersection to the odd-numbered intersection is not filled out.

FIG. 6 shows a combination j. - FIG. 2 is a diagram illustrating a filling method in a graphics device.

Intersections between the scanning line 62 and each line segment constituting the operation target figure 61 are sequentially detected from one end (for example, the left end) of the view point 1, which is the scanning start point. In the example shown in the figure, the first
Intersection 63, second intersection 64, third intersection 65, fourth intersection 66
detected.

Then, the area from the odd-numbered intersection to the even-numbered intersection, that is, the area from intersection 63 to intersection 64 and from intersection 65 to intersection 66, is filled in, and this operation is applied to all This is done for scanning lines.

Therefore, in this embodiment, the pick processing program is simplified by using a part of the even-odd or odd-even determination processing in such filling processing.

FIG. 7 is a diagram for explaining the processing contents of an embodiment in which a part of the filling process is used to determine pick hit/pick miss hit.

In this embodiment, a half straight line 73 extends in the left horizontal direction with the lower left point 72 of the contour of the pick aperture 71 as an end point, and a half straight line 73 extends in the left horizontal direction with the lower left point 76 on the contour of the pick aperture 75 as an end point. The straight line 70 shall be regarded as the scanning line.

When there is an operation display figure 61 as shown in the same figure, it is necessary to determine that it is a pick hit if an instruction is made inside the figure with the pick aperture.

If the pick aperture 71 is within the area that will be a pick hit, the half straight line 73 intersects the constituent line segments of the operation target figure 61 only at the intersection 74, so the pick aperture 71 will actually move from the odd-numbered intersection to the even-numbered intersection. It will be in the area up to the intersection.

On the other hand, a pick aperture 75 is provided outside the operation display figure 61.
If there is, the half straight line 70 intersects with the constituent line segments of the operation target figure 61 at four points: intersection 77, intersection 78, intersection 79, and intersection 80, so the pick aperture 75 is actually set from the even-numbered intersection to the odd-numbered intersection. It is in the area up to the th intersection point.

Therefore, it is clear that a pick hit/pick miss hit can also be determined by using the even-odd or odd-even determination in the filling process.

According to this embodiment, the pick hit/pick miss hit determination process according to the present invention can be performed using a part of the existing filling process, so the capacity of the processing program can be reduced. .

In the above-described embodiments, the case where the elements constituting the operation target graphic are mainly line segments has been described, but if curves are viewed as fine line segments, they can be processed in the same way.

Furthermore, the starting point of the half-line does not necessarily have to be on the outline of the pick aperture, and can be at any position as long as it is within the area specified by the pick aperture.

(Effects of the Invention) As is clear from the above description, the following effects are achieved according to the present invention.

(1) Pick hit/pick miss is determined based on the number of intersections between a half line whose end point is a point on the pick aperture and a line segment that constitutes the target figure.
Judgment time can be drastically reduced.

(2) Since the number of intersections can be detected using part of the conventional filling process, the capacity of the processing program can be saved.

[Brief explanation of the drawing]

FIG. 1 is a flowchart 1 showing a processing procedure for pick hit/pick miss hit determination according to the present invention. 2 and 3 are diagrams for explaining the basic concept of the present invention. FIG. 4 is a diagram for explaining the method for determining the presence or absence of an intersection point according to the present invention. FIG. 5 is a flowchart for determining the presence or absence of an intersection using area codes. FIG. 6 is a diagram for explaining a method of filling in an operation target figure in the raster scan method. FIG. 7 is a diagram for explaining the processing contents when a part of the filling process is used for determining pick hit/pick miss hit. FIG. 8 is a diagram for explaining the pick processing method.

Claims (5)

[Claims] (1) A pick processing method in which a figure to be manipulated is selected from among the figures displayed on the display device of a computer graphics device and a figure selection signal is generated, the target figure being displayed on the screen. display, set the pick aperture at the desired position on the screen, set a half line with an arbitrary point within the pick aperture as the end point, and find the intersections of the half line and all the line segments that make up the operation target figure. A pick processing method characterized by: detecting the number of intersection points, and determining pick hit/pick miss hit according to whether the number of intersections is even or odd. (2) It is further determined whether or not the line segment crosses within the pick aperture, and if there is a line segment that crosses within the pick aperture, a pick hit is determined regardless of whether the number of intersections is even or odd, and 2. The pick processing method according to claim 1, wherein if there is no line segment that crosses the line segment, pick hit/pick miss hit is determined depending on whether the number of intersections is even or odd. (3) The pick processing method according to claim 1 or 2, wherein the display method of the display device is a raster scan method, and the half line is parallel to a scanning line. (4) The filling process of the operation target figure displayed on the raster scan type graphics display device is performed by detecting the intersections of the scanning line and all the line segments that make up the operation target figure, and using a predetermined method. Selecting a figure to be operated from among the figures displayed on the display device of a computer graphics device by filling in from one of the even or odd numbered intersections to the next intersection from the scanning start point. The pick processing method generates the figure selection signal, and includes: displaying the figure to be manipulated on the screen; setting a pick aperture at a desired position on the screen; and setting an arbitrary point within the pick aperture as an end point; Set a half-line parallel to the scanning line, detect the intersection of the half-line and the line segment that constitutes the operation target figure, and check whether the pick aperture position is in the filled area or not using the same method as the filling process described above. A pick processing method characterized by detecting through processing and determining pick hit/pick miss hit based on the detection. (5) The pick processing method according to any one of claims 1 to 4, wherein the arbitrary point within the pick aperture is an arbitrary point on the outline of the pick aperture.