JPH08161501A - Graphic extracting method - Google Patents

Abstract

PURPOSE: To provide the graphic extracting method which can extracts a closed area consisting of constituent elements of graphic in optional combination. CONSTITUTION: This method has a step 1 which displays the graphic and obtains selection information on the constituent element of the graphic which form the closed area, a step 2 which represents the respective selected constituent elements as a polygonal line, a step 3 which calculates the intersections of the constituent elements represented as the polygonal line, a step 4 which calculates sections from the calculated intersections, and a step 5 which structures the extracted closed area by using polygonal line in the sections.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a figure extracting method for extracting a closed area of a figure.

[0002]

2. Description of the Related Art In a conventional graphic processing device such as a word processor or DTP having a graphic processing function, circles, rectangles,
You can draw figures such as polygons. However, conventionally, as shown in FIG. 1, a closed region formed by complexly intersecting a plurality of graphic components, or as shown in FIG.
A technique for recognizing and drawing a closed region closed by a single graphic component is hardly disclosed. In this respect, JP-A-59-60560 and JP-A-2-294
Although the description related to Japanese Patent No. 323 is recognized, the former is limited to the processing of only simple figures such as rectangles, and the latter is only the combination of basic figures such as polygons and circles. Absent.

[0003]

As described above, in the prior art, ellipses other than circles, rectangles, and polygons, arcs, Bezier curves,
It is not possible to extract a closed region formed by graphic components such as spline curves. Also. Neither can the extraction of closed regions formed by the self-intersection of the components of a single figure. As described above, the conventional technique has a problem that the degree of freedom in extracting a closed region is low.

Therefore, an object of the present invention is to provide a graphic extraction method capable of extracting a closed region by an arbitrary combination of graphic constituent elements.

[0005]

According to the figure extracting method of the present invention, a step of displaying a figure to obtain selection information of a constituent element of the figure forming a closed region, and converting each selected constituent element into a polygonal line. The method includes a step, a step of calculating an intersection of each of the polygonalized components, and a step of calculating a section from the calculated intersection and constructing a closed region extracted by using the polygonal line in the section.

[0006]

In the above construction, the constituent elements of the figure are approximated to a polygonal line and the intersections of the polygonal lines are obtained to obtain quadratic curves such as ellipses and arcs, curves such as Bezier curves and spline curves, and various other constituent elements of curves. The closed region formed by can be extracted by a uniform method.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

First, the outline of the figure extracting method according to the embodiment of the present invention will be briefly described. As shown in Fig. 1, on the display screen,
When three circles and ellipses overlap, due to the overlapping of the constituent elements of the figure, seven closed areas (A, B, C, A
B, BC, CA, ABC) are formed. For example, let us consider recognizing the closed area AB as a figure in order to paint only the closed area AB of these closed areas. This closed area AB includes boundary portions L2 (P1 to P4), L8 (P1 to P2), and L1 of a figure whose ends are points P1, P2, and P4, which are the intersections of the components of the three figures.
1 (P2 to P4). The figure extracting method of the present embodiment recognizes one figure and extracts a new figure by connecting boundary portions (referred to as sections in this specification) having these intersections P1, P2 and P4 as end points. Is.

FIG. 3 is a block diagram of a graphic processing apparatus to which the graphic extraction method according to the embodiment of the present invention is applied. In FIG. 3, 1 is a CPU (central processing unit) that controls the whole, and 2 is a CRT that displays a target graphic and a processing status.
Such as a display device, 3 is an input device such as a mouse for the user to input coordinates necessary for selection, and 4 is a ROM (read-out memory) that stores a control program executed by the CPU 1 according to the flowchart of FIG. Only memory) 5 is a main storage unit including a RAM (random access memory) provided with a storage area for each list described later.

FIG. 4 is a functional block diagram of a graphic processing apparatus to which the graphic extraction method according to one embodiment of the present invention is applied. In FIG. 4, the main storage unit 5 includes a graphic list 7 for storing graphic data, a selection list 8 for storing graphic selection information, a polygonal line data list 9 for storing polygonalized data,
Intersection point list 10 for storing intersection point coordinates, section list 11 for storing information on calculated sections, extracted data list 12
Is included.

Of these, the graphic list 7 includes graphic numbers, graphic types, graphic coordinate information, and coordinate conversion information, as shown in FIG. As shown in FIG. 6, the selection list 8 includes a selection list number, a selected figure number, and designated coordinates. As shown in FIG. 7, the polygonal line data list 9 includes a figure number, the number of vertices, and vertex coordinates. As shown in FIG. 8, the intersection list 10 includes the figure number, the number of intersections, and the coordinates of the intersections. As shown in FIG. 9, the section list 11 includes a selection list number, section end point coordinates 1 and section end point coordinates 2. The extracted data list 12 is shown in FIG.
As shown in 0, the number of vertices and vertex coordinates are included.

The figure selection means 13 determines whether or not a figure displayed on the screen of the display device 2 is designated by the input device 3, and stores the selected figure number and designated coordinates in the selection list 8. . The polygonalization means 14 reads the graphic data registered in the selection list 8 in order to subdivide the selected graphic, approximates each component of the graphic with a polygonal line, and calculates the number of vertices of the polygonal data and the vertex data. It is stored in the polygonal line data list 9 together with the number. At this time, if the figure has coordinate conversion such as rotation, the polygonal line data is subjected to coordinate conversion and stored.

The intersection calculation means 15 takes out two intersections of all the combinations of which the shapes stored in the polygonal line data list 9 can be selected, calculates the intersections of the extracted shapes, and calculates the obtained intersection coordinates and the number of intersections as the figure numbers. It is also stored in the intersection list 10. The section calculation means 16 takes out the designated coordinates of the graphic stored in the selection list 8, and the designated coordinates are sandwiched between which intersection in the intersection list 10 having the same graphic number as the designated coordinate. Search for If the searched intersection coordinates are found, one of the intersection coordinates is set as the section end point coordinate 1 and the other intersection point coordinate is set as the section end point coordinate 2 and stored in the section list 11 together with the selection list number.

The section connecting means 17 takes out the section data stored in the section list 11 and uses it as the starting point of the figure data for extracting the section end point coordinates of the first section data, and thereafter, from this starting point to the other section end point coordinates. Up to are interpolated using the polygonal line data registered in the polygonal line data list 9 having the same figure number, and the last point is set as the segment end point coordinate. Next, the section end point coordinates having the same coordinates as the section end point coordinates, which is the last point, are extracted from the section list 11, and similarly, the section end point coordinates to the other section end point coordinates are interpolated using the polygonal line data list 9. To do. The polygonal line data obtained by connecting these sections is stored in the extracted data list 12.

The control section 6 controls other elements, and includes the graphic selection means 13 and the polygonalization means 1.
4, the intersection calculation unit 15, the section calculation unit 16, the section connection unit 17, and the control unit 6 are realized by the CPU 1 executing the control program in the ROM 4.

Next, each process of the figure extracting method of this embodiment will be described with reference to the flowchart of FIG. First,
It is assumed that three figures F1, F2, and F3 are displayed on the display device 2 so as to overlap each other, as shown in FIG. The figure F2 is a rotated ellipse. Then, when the point Q1 is designated by the input device 3, the figure selecting means 13 searches which figure is selected, and the figure F2 searched as a result is registered in the selection list 8. Similarly point Q
Even when 2 and Q3 are instructed, figures F1 and F3, respectively
Is registered in the selection list 8 (step 1).

When a closed area extraction command (not shown) is input thereafter, first, the figure F registered in the selection list 8 is entered.
The polygonalization processing of each figure data of 1, F2, F3 is performed by the polygonalization means 14, and the polygonalized data is stored in the polygonal line data list 9 (step 2). At this time,
The elliptic polygonalized data is subjected to rotation coordinate conversion by a coordinate conversion device (not shown). Next, using the data registered in the polygonal line data list 9, the intersection calculation means 15
However, intersection calculation is performed only for combinations that can select two figures from the registered three figure data, and the result is stored in the intersection list 10 for each figure (step 3). For example, as shown in FIG. 8, the intersections of the figure F1 are P1, P4, P
5, P3, the intersection of the figure F2 is P1, P2, P5, P6,
The intersections of the figure F3 are P6, P4, P2 and P3. Next, the section calculating means 16 takes out the selection coordinates Q1, Q2, Q3 of the graphic stored in the selection list 8, and these selection coordinates Q1, Q2, Q3 correspond to which intersection of the intersection list 10 having the same graphic number. A search is made between which intersections, and the result is stored in the section list 11 (step 4). Finally, the section connecting means 17 connects the three sections registered in the section list 11, constructs a new closed area as an extracted closed area, and stores it in the extracted data list 12 (step 5). Here, first, the section connecting means 17 stores the section end point coordinates 1 (P
1) is taken out, this coordinate is used as the starting point of the extracted figure, and this section is subjected to polygonal line interpolation (segmentation of section L8). At this time, as the data for the polygonal line interpolation, the graphic number 2 is selected from the selection list number 1 and the selection list 8 at the head of the section list 11, and the polygonal line data list 9 of the graphic number 2 is used. Next, the section end point coordinates 2 (P
The section end point coordinates having the same coordinates as 2) are searched, and as a result, the section end point coordinates 2 (P2) of the third section are searched and 1
The section end point coordinate 2 (P2) of the second section and the section end point coordinate 2 (P2) of this section are connected. Similarly, this section is subjected to polygonal line interpolation (segment L11 is made into a polygonal line), and section end point coordinates having the same coordinates as the section end point coordinate 1 (P4) which is the end coordinate of this section are searched, and as a result, the second section The section end point coordinate 2 (P4) is searched, and the section end point coordinate 1 (P4) of the third section and the section end point coordinate 2 (P4) of this section.
And connect. Similarly, this section is subjected to polygonal line interpolation (segment L2 is made into a polygonal line), and the section end point coordinates having the same coordinates as the section end point coordinate 1 (P1), which is the end coordinate of this section, are searched, and as a result, the first section The section end point coordinate 1 (P1) is searched and the section end point coordinate 1 (P1) and 1 of the second section are searched.
The section end point coordinate 1 (P1) of the second section is connected. 1
Since the section end point coordinate 1 of the second section is the start point of the extracted figure, the processing is interrupted here. The polygonalized data is stored in the extracted data list 12 together with the number of vertices.

Of course, according to the above method, another closed region (for example, A, ABC, etc.) in FIG. 1 can be extracted by the same process. Further, since all the figures are broken lines and the closed region is extracted, for example, a complex shape formed by a combination of figures such as a quadratic curve such as an ellipse and an arc, a Bezier curve, and a spline curve, and rotation is applied. The closed region can be easily extracted as well. For example, a colored part in FIG. 11 can also be extracted.

Further, in the case of extracting a closed area by self-intersection of a single figure as shown in FIG. 2, the closed area can be similarly extracted by calculating the intersection point of the polygonalized figure itself. .

[0020]

According to the figure extracting method of the present invention, the step of displaying the figure and acquiring the selection information of the constituent elements of the figure forming the closed region, the step of converting each selected constituent element into a broken line, and the broken line Since it has a step of calculating an intersection of each of the converted constituent elements and a step of calculating a section from the calculated intersection and constructing a closed area extracted using a polygonal line in the section, It is possible to extract a closed region composed of components flexibly and easily by a unified method.

[Brief description of drawings]

FIG. 1 is an exemplary view of a closed region according to an embodiment of the present invention.

FIG. 2 is an exemplary view of a closed region due to self-intersection in an embodiment of the present invention.

FIG. 3 is a block diagram of a graphic processing apparatus to which a graphic extraction method according to an embodiment of the present invention is applied.

FIG. 4 is a functional block diagram of a graphic processing apparatus to which a graphic extraction method according to an embodiment of the present invention is applied.

FIG. 5 is an exemplary diagram of a graphic list according to an embodiment of the present invention.

FIG. 6 is an exemplary diagram of a selection list according to an embodiment of the present invention.

FIG. 7 is an exemplary diagram of a polygonal line data list in one embodiment of the present invention.

FIG. 8 is an exemplary diagram of an intersection list according to an embodiment of the present invention.

FIG. 9 is an exemplary diagram of a section list according to an embodiment of the present invention.

FIG. 10 is a view showing an example of an extracted data list according to an embodiment of the present invention.

FIG. 11 is a view showing an example of a closed area according to an embodiment of the present invention.

FIG. 12 is a flowchart of a figure extracting method according to an embodiment of the present invention.

[Explanation of symbols]

 2 display device 3 input device 5 main memory unit 6 control unit 7 figure list 8 selection list 9 polygonal line data list 10 intersection point list 11 section list 12 extraction data list 13 figure selecting means 14 polygonal line forming section 15 intersection point calculating section 16 section calculating section 17 Section connection means

Claims (1)

[Claims] 1. A step of displaying selection information of a constituent element of a graphic forming a closed area, a step of converting each selected constituent element into a polygonal line, and an intersection point of each of the polygonalized constituent elements. And a step of calculating a section from the calculated intersection and constructing a closed region extracted by using a polygonal line in the section.