JPS59195761A - Diagram processing method - Google Patents

Abstract

PURPOSE:To decrease the processing time by sorting preliminarily X and Y coordinates of a line segment so as to require the discrimination not necessarily to all line segments even if a point is designated. CONSTITUTION:An operation is applied to a content of a storage section 44 by a comparator 45 as the processing to be conducted prior to the input of points, and the result is stored in a storage section 46. Further, the stored content is divided into four, they are sorted by a sorting processing section 48 and the result is stored in a storage section 49. When a point is inputted, the point is compared with a content of the storage section 49 by the comparator 45 and the result is stored in a storage section 47.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a graphic processing method in which a line segment to be processed on a displayed graphic is determined from an input point (a set of x+7 coordinates). In graphic processing systems, it is often necessary to modify a line segment already displayed on a display or to search for information on that line segment.

In this case, it is common for the user to specify a specific line segment by hitting a point on a tablet or the like, and then selecting the line segment passing through that point as the specified line segment. Conventionally, in order to recognize which line segment an input point is on the system side, a rectangle with each line segment as a diagonal is considered for all line segments, and whether the input point exists within that rectangle? The method was to determine whether or not it existed, and if it did not exist, it was excluded, and if it existed, it was investigated in more detail. That is, assuming that there are N line segments on the figure, the line segment data in the storage unit is L(i, 1)...Line segment ID L(i, 2)...X coordinate of the starting point L( i, 3)...X coordinate of the starting point L(i, 4)...X coordinate of the ending point L(i, 5)...X coordinate of the ending point (i=1...,
N) (There are other line types, 9 colors, etc. as data for line segments, but they are not needed here and will be omitted.

) Area d - ((x, y) 1 min (L(t, 2), L
(i, 4))≦X≦max(L(i, 2)l L(i
l 4)) 1 min (L(i, 3) + L(il 5)
))≦y≦max(L(i, 3), L(i, 5)
Month m1n(A, B)=A A>B max(A, B
) = AA≦B B A (B, B A > B), and it is determined whether or not there is an input point in this area d. A schematic flowchart of this method is shown in Figure 1 (a). This method shows that for all line segments,
Calculating whether a point is on a line segment takes processing time, so the simple judgment described above is performed on all line segments to limit the candidates, and the remaining line segments are It was an attempt to reduce processing time by calculating whether a point is on a line segment. FIG. 2 shows the relationship between the storage section and the arithmetic unit when implementing this method.

When the X and X coordinates of a point are input, comparators 45 perform calculations on the contents of the storage section 44, and the results are stored in the storage section 47.

However, the above method has the disadvantage that whenever a point is designated, the above comparison must be performed for all line segments, which takes time.

The object of the present invention is to overcome these drawbacks and provide a graphic processing method that requires less processing time. To achieve this objective, the method of the present invention calculates each coordinate value of a group of line segments displayed on the screen by
Of the X coordinates of the starting point and end point of the line segment, the non-smaller one is sorted in ascending order, the smaller one is sorted in descending order, and the non-smaller X coordinate is similarly sorted in ascending order. The operation of sorting the smaller one in descending order to create new line segment information, and when a point is input, based on this newly created line segment information, the input point is sorted in ascending order for the X coordinate Set 1 is the line segment whose X coordinate is smaller than the X coordinate of the input point, and set 2 is the line segment whose X coordinate is larger than the X coordinate of the input point for the X coordinate sorted in descending order. , for X coordinates sorted in ascending order, line segments with X coordinates not smaller than the X coordinate of the input point are set as set 3, and for X coordinates sorted in descending order, line segments with The line segments with X coordinates that are not large are set as set 4, the union of set 1, set 2, set 3, and set 4 is set as set 5, and set 5 is input as the set of line segments near the input point. This consists of an operation to limit in advance the line segments that pass through the points. That is, the present invention, as shown in the schematic flowchart in FIG. 1(b), sorts the X coordinates of line segments in advance, so that when a point is specified, the determination does not necessarily apply to all line segments. Since there is no need to perform the process on the other hand, the processing time can be shortened.

Hereinafter, the method of the present invention will be explained in detail based on specific procedure examples.

First, the operation of creating new line segment information by sorting will be explained.

The line segment data in the first storage section is stored as L(N, 5
). Furthermore, LλfAXX(N, 3)
, LMINX(N, 3), LMAXY(N.

3) Consider an array LMINY (N, 3), and use this as data in the second storage section.

■,...,N), LMAXX (s, 2), LuAxv (i, 2) are in ascending order, LMINX (t, 2), T, MINY (i, 2) are in descending order, LMINY is OI, DJ, MAXX,
OI, DLMINX.

OLDLMAXY, Or, DT, MINY and after sorting LMAXX, LMINX, T, MAXY, LM
INY as NEWLMAXX and NEWLMINX respectively
, NEWLMAXY.

LMAXX (i, 1), L so that NEWLMTNY holds true
MINX (i.

1), LMAXY(i, 1), I, MINY(i, 2)
Establish.

Furthermore, LMAXY and LMINY are held in the second storage unit. New line segment information can be obtained by the above operations.

Next, an operation for recognizing line segments from new line segment information will be described.

When the current point is specified and its coordinates are (x, y), LMAXX(i, 2)≧x-4>LMAXX(i+1.
2) Search for +l at t+j+ where J (C is error). If at least one i+Lk,l that satisfies the above does not exist, no line segment will pass through the specified point. In addition, to 1+J+ that meets the above
There can never be more than one set of l. For 1+jyk+l obtained in this way, set L+ E7. E3+
Let E4 be E4, and let the set I be E=:E+ n E2 n Es n 'E4.

The set E of people is obtained using the new method, and is also the same set as the group of line segments selected as candidates using the conventional method.

It can be determined to which line segment the input point belongs using the procedure described above.

FIGS. 3 and 4 show the relationship among the storage unit, sorting processing unit, and comparator in an example of an apparatus that actually performs the method of the present invention. FIG. 3 shows the processing performed before a point is input. Storage part 4
The comparator 45 performs calculations on the contents of 4 and stores the results in the storage unit 46. Furthermore, the stored contents are divided into four parts as described above, each is sorted by the sorting processing unit 48, and the results are stored in the storage unit 49.
Store in. FIG. 4 shows the processing performed when a point is input. A comparator 45 compares the points given to the content persons stored in the storage section 49, and the result is stored in the storage section 47.

FIG. 5 shows a flowchart for carrying out the present invention. The input data is the number N of line segments and the line segment information stored in the storage unit 1 in advance, that is, the above-mentioned L(i, 5)(i
=1. ..., N) and the error C. In block 10, LMAXX (i, 1), LMA
XX(i, 2), LMINX(i.

1), 'LMINX(t, 2), LMAXY(i, 1)
, LMAXY 口, 2), LMINY(i, 1)
, LMINY(t, 2) (i=1...,N). Next, in block 11, sorting is performed. Quicksort (Quick 5ort) is a fast sorting algorithm.

Heap sort (Heap 5 ort) + Batcher's bite 27 sort (Batcher's bito)
nic 5 ort), but is not particularly limited here. Further, sorting is performed so as to satisfy equations (2) and (3). This is the result.

The data obtained by sorting is held in a storage unit in block 12. When the point data is read, that information is used to search the data in the storage section. That is, the formula (
We find *l at 1+j+ that satisfies 4), and in block 13 we find / at 1+j+. (Since sorting has already been performed, it is sufficient to compare sequentially from the beginning.) Block 14 calculates the minimum value of it L k + l. The reason for finding the minimum value is that there will never be more line segments that satisfy the condition than the minimum value, so it will require fewer processing times to perform the processing in block 15 from the sorted array with the minimum value. It is. In block 15, it is determined whether the minimum value of 1+j++l is 0. If it is 0, there is no line segment that satisfies the condition, so the process ends. Also, in block 15, the one that satisfies the conditions in LMAXX is LM
Determine whether the INX conditions are met.

If the condition is not satisfied, the same determination is made for the next line segment. If the condition is satisfied, it is determined whether the LMAXY condition is satisfied. If it is satisfied, the same judgment is made for the next line segment. If the condition is satisfied, it is determined whether the LMINY condition is satisfied. If the condition is not satisfied, the same determination is made for the next line segment. If it is satisfied, all conditions are satisfied and the line segment ID is stored in L. The above series of operations is performed for i line segments. As a result, IDs of line segments that satisfy all the conditions are stored in an array.

As explained above, according to the present invention, line segment data is sorted in advance, so when a point is specified, it is possible to quickly limit which line segments pass through the point, and processing time can be shortened. .

[Brief explanation of the drawing]

FIG. 1(a) is a schematic flowchart of the conventional method, (
b) is a schematic flowchart of the method of the present invention, FIG. 2 is a diagram showing the relationship between the storage unit and the arithmetic unit of a device that implements the conventional method, and FIGS. 3 and 4 are diagrams that implement the method of the present invention. FIG. 5 is a diagram illustrating the relationship between a storage section, a sorting processing section, and a comparator in an example of an apparatus used for carrying out the method, and FIG. 5 is a diagram illustrating an example of a flowchart (13) for carrying out the method of the present invention. In the figure, 44, 46, 47, 49 are storage units, 45 is a comparator,
48 is a sorting processing section. Figure 1 (Roro) N Mei No. q Figure Lid Figure 5 TART 0 (1) De (tj squared) 7 rc LMAXX, LMAXY, I; -Inside the tinging system ``Ignition power t, ri, A, 1,--1-/''1

Claims (1)

[Claims] The coordinate values of the group of line segments displayed on the screen are sorted in ascending order for the X coordinate of the starting point and end point of the line segment, whichever is not smaller, and in descending order for the smaller X coordinate, Similarly, for the X coordinate, create new line segment information by sorting the smaller ones in ascending order and the smaller ones in descending order, and when a point is input, based on this newly created line segment information, For X coordinates sorted in ascending order, set 1 is a line segment with an X coordinate that is not smaller than the X coordinate of the input point, and for X coordinates sorted in descending order, set 1 is a line segment with an For the X coordinates sorted in ascending order, line segments with X coordinates that are not smaller than the input point's X coordinates are set 3, and the X coordinates sorted in descending order. For , set 4 is a line segment with an X coordinate that is not larger than the input point's 1. A graphic processing method comprising the step of: prelimiting line segments passing through a point input as a set of line segments in the vicinity of the point.