JPS6254377A - Selecting method for vector - Google Patents

Abstract

PURPOSE:To reduce calculation for selecting an objective vector by using area comparison of vectors and linear equations to discriminate whether a given point exists on a vector or not. CONSTITUTION:Whether the coordinates of a given point are included in a rectangle formed by defining the coordinates of the start point and end point of a vector group as two vertexes on a diagonal or not is discriminated in an area discriminating step 4. As to the vector discriminated by the step 4 that the coordinates of the given point are included within the area, a linearity discriminating step 5 for discriminating whether the coordinates of the given point are set up on the vector or not is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vector selection method, and particularly to a method for selecting one vector containing one specified point from a plurality of vectors. .

[Conventional technology]

Conventionally, in order to select one vector containing one designated point from multiple vectors in a graphic display, etc., all of the multiple vectors are decomposed into digital line segments, that is, the coordinate values 1t of all the points constituting the vector are calculated. This was done by calculating and determining whether or not any of all the calculated coordinate positions matched a specified point. Each vector in a given vector group is expressed as V-(1=1xn), where n is the total number of vectors), and the coordinates of the starting point and ending point of each vector are expressed as the starting point (x-y-) and the ending point ( xei, yei)st
, 5t (i=1 to n).

FIG. 2 is a flowchart showing the conventional method. In the figure, (1) is an initial setting step for initializing the count variable i, (2) is an increment step for incrementing the variable i, and (3) is an increment step for incrementing the variable i. n determination step (6) for determining whether or not it has been performed.

is decomposed into digital line segments, each time (P.

This is a digital line segment generation comparison step to determine whether or not they match Py). By the way, in a graphic display of digital signals, the increment of both X and y has a minimum unit (hereinafter, it will be represented by the number 1), and it is not possible to take a fractional value less than that minimum unit. Cx-y・) and (xsi,
ysi) 81, 111 61
, el\, G! f)l[! &ij! Mat:
&< 11-: &&IOt! ml to form a broken line approximated to a straight line. For example, X81〉xsi, ye
i >3'si dechakatsu(xei-xsi)>
In the case of (yei-3'si), (Xsi e YBi
), X increases by 1 each time, and when X increases by 1, y should remain at the previous value of y, or should it be increased by 1 from the previous value of y? , which is closer to the value of y on the exact straight line and sequentially (
The coordinate position (x, y) must be determined. Generation of digital line segments and 2 mentioned above refer to such operations.

Next, the operation of the method shown in FIG. 2 will be explained.

In step f1+, the variable i is set on the IK, and in step (6), the vector V is decomposed into digital line segments, and each decomposed point is compared with CP, P)y. If this matches (Px, Py)
It can be determined that the vector to which belongs is V, and the picking is successful (
found).

If all the decomposed points do not match (PX, Py), it is determined that %(Px, Py) is not above V, and the process moves to step (3) K. In step (3), it is determined whether or not i has reached n, and if it has reached n (Px).

Py)'s! It is determined that the vector 14-r does not exist, and picking is unsuccessful (not found). If j has not reached n, go to step (2)! 1
Increment lli by 1 and repeat the process from step (6) on the next vector.

[Problem that the invention seeks to solve]

In the conventional method described above, a given group of vectors is once decomposed into digital line segments, which requires a very large amount of calculation and therefore consumes a large amount of time.

This invention was made to solve this problem, and aims to provide a determination method that reduces the amount of calculation required to select a target vector.

In the invention of [Means for solving c-interval kneeling points], instead of decomposing a vector into digital line segments and determining whether or not a given point is included,
It is determined whether a given point exists on a vector using vector area comparison and a straight line equation.

[Effect]

In this invention, since a simple allelevolism is used to select the target vector, the amount of calculation involved is significantly reduced compared to the conventional method.

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

As before, for a given vector group, let the number be n, and let the coordinates of the starting point and ending point of the vector group be the starting point (xat, 3'si) and the ending point (xei, yei) (
1=lxn), and the coordinates of the given point are (PK, Py
).

FIG. 1 is a flowchart showing an embodiment of the present invention. In FIG. 1, (1), (21, and (3) indicate the same steps as in the conventional method shown in FIG. ,Py
) is within a rectangle with ("si, YBi,) and (xei, Xei as two vertices of diagonal binding).
Xei or xat≦Py≦ysi, and ysi≦P
This can be easily determined by determining y≦yei or yei≦Pa≦7si.

Next, in step (4), (Px, Py) becomes the vector V
For a vector determined to be within the region of l, it is determined whether (PK, Py) is placed on the vector V. If it is within the area, the process moves to the next step, straight line determination step (5). In step (5), (Px, Py) is the vector vI
Determine whether it is above. The equation of the straight line including (X3i * 73i) and (X6i + 76i), that is, (P
If x, Py) are satisfied, then V is on top of (yei −)'si )・Px” ysi−Xei
-X5i-yei =Py・(Xei-Xsi)...
The determination can be made based on whether (2) holds. X・, y・ , X・, y・, PP81 81 of formula (2)
el el Since ll'N is not included, the problem of fractions does not occur in the operation of equation (2).

〔Effect of the invention〕

As described above, according to the present invention, by significantly reducing the amount of calculation required to determine whether CF, py) is on v1, a vector containing one specified point is selected from multiple vectors at an extremely high speed. It has the effect of being able to

[Brief explanation of drawings]

FIG. 1 is a flow chart diagram showing an embodiment of the present invention;
FIG. 2 is a flow chart diagram illustrating a conventional method. (1) initial setting step, (2) increment step, (31n determination step, (4) area determination step,
(5) Straight line determination step. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] In a vector selection method of selecting a vector containing one specified point from n vectors, where n is an arbitrary plural number, the coordinates of the starting point and ending point of the n vectors are respectively ( x_s_i, y_s_i) and (x_e_iy
_e_i) (i=1 to n), and the coordinates (P_x, P_y) of the point specified above for each vector are x_s_i
≦P_x≦x_e_i or x_e_i≦P_x≦x_s
_i, and y_s_i≦P_y≦y_e_i or y_
By determining whether e_i≦P_y≦y_s_i, P_x, P_y are (x_s_i, y_s_i)
and an area determination step in which it is determined whether or not the vector is within a rectangle with (x_e_i, y_e_i) as its diagonal vertices; About (P_xP
_y) is (x_s_i, y_s_i) and (x_e_i,
The straight line equation y=ysi+[(y_e_i−y_s_i)/(x_e
_i−x_s_i)]x, P_y(x_e_i
−x_s_i)=y_s_i, x_e_i−y_s_i
- A vector selection method characterized by comprising a straight line determination step of determining whether or not x_s_i+P_x(y_e_i−y_s_i) holds.