JP3633011B2 - Figure extraction method - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a graphic extraction method for extracting a closed region of a graphic.
[0002]
[Prior art]
A graphic processor such as a word processor or DTP having a conventional graphic processing function can draw a graphic such as a circle, a rectangle, or a polygon. However, as shown in FIG. 1, a closed region formed by a complex intersection of a plurality of graphic components and a closed region closed by a single graphic component as shown in FIG. 2 are recognized. Most of the techniques for drawing are not disclosed. In this respect, descriptions related to Japanese Patent Application Laid-Open Nos. 59-60560 and 2-294323 are recognized, but the former is limited to processing only simple figures such as rectangles, and the latter is also limited to polygons and circles. Only basic figure combinations such as are handled.
[0003]
[Problems to be solved by the invention]
As described above, the conventional technology cannot extract a closed region formed by graphic components such as an ellipse other than a circle, rectangle, or polygon, an arc, a Bezier curve, or a spline curve. Also. It is also impossible to extract a closed region formed by self-intersection of a single figure component. As described above, the conventional technique has a problem that the degree of freedom in extracting the closed region is low.
[0004]
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 components.
[0005]
[Means for Solving the Problems]
The figure extraction method of the present invention includes a step of acquiring selection information of a figure constituent element that displays a figure to form a closed region, a step of making each selected constituent element a polygonal line, and each constituent element having a polygonal line A step of calculating an intersection point between each other, and a step of calculating a section from the calculated intersection point and constructing a closed region extracted using a broken line in the section.
[0006]
[Action]
In the above configuration, by approximating the components of the figure with a polygonal line and calculating the intersection of the polygonal lines, it is formed by a quadratic curve such as an ellipse or arc, a curve such as a Bezier curve or a spline curve, and other various curve components. The closed region can be extracted by a unified method.
[0007]
【Example】
Next, embodiments of the present invention will be described with reference to the drawings.
[0008]
First, the outline of the graphic extraction method of the embodiment of the present invention will be briefly described. As shown in FIG. 1, when three circles and ellipses overlap on the display screen, seven closed regions (A, B, C, AB, BC, CA, ABC) are formed due to the overlapping of the components of the figure. Is formed. For example, in order to fill only the portion of the closed region AB among these closed regions, consider that the closed region AB is recognized as a figure. This closed region AB is a boundary portion L2 (P1 to P4), L8 (P1 to P2), and L11 (P2) of the figure whose end points are the points P1, P2, and P4, which are the intersections of the components of the three figures. ~ P4). The graphic extraction method of this embodiment recognizes one graphic and extracts a new graphic by connecting the boundary portions (referred to as sections in this specification) having these intersections P1, P2, and P4 as end points. It is.
[0009]
FIG. 3 is a block diagram of a graphic processing apparatus to which the graphic extraction method in one embodiment of the present invention is applied. In FIG. 3, 1 is a CPU (central processing unit) for controlling the whole, 2 is a display device such as a CRT for displaying a target figure and processing status, and 3 is for a user to input coordinates necessary for selection. An input device such as a mouse, 4 is a ROM (Read Only Memory) storing a control program executed by the CPU 1 in accordance with the flowchart of FIG. 12, and 5 is provided with a storage area for each list to be described later. This is a main storage unit comprising a RAM (Random Access Memory).
[0010]
FIG. 4 is a functional block diagram of a graphic processing apparatus to which the graphic extraction method in one embodiment of the present invention is applied. In FIG. 4, the main memory 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 polygonal data, and an intersection list for storing intersection coordinates. 10 includes a section list 11 for storing calculated section information and an extracted data list 12.
[0011]
Among these, the graphic list 7 includes a graphic number, a graphic type, 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. The polygonal line data list 9 includes a figure number, the number of vertices, and vertex coordinates as shown in FIG. As shown in FIG. 8, the intersection list 10 includes a figure number, the number of intersections, and intersection coordinates. The section list 11 includes a selection list number, a section end point coordinate 1, and a section end point coordinate 2, as shown in FIG. As shown in FIG. 10, the extracted data list 12 includes the number of vertices and vertex coordinates.
[0012]
The graphic selection means 13 determines whether or not a graphic displayed on the screen of the display device 2 is instructed by the input device 3, and stores the selected graphic number and designated coordinates in the selection list 8. The polygonal line forming 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 and the vertex data of the polygonal line data. The number is stored in the broken 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 stored after the coordinate conversion.
[0013]
The intersection calculation means 15 takes out two of the combinations that can be selected from the figures stored in the polygonal line data list 9, calculates the intersection between the extracted figures, and calculates the intersection coordinates and the number of intersections together with the figure number. Store in list 10. The section calculation means 16 takes out the designated coordinates of the figure stored in the selection list 8, and the designated coordinates are sandwiched between which intersection of the intersection list 10 having the same figure number as the figure number of the designated coordinate. Search for If the searched intersection coordinates are found, one intersection coordinate is set as the section end point coordinate 1 and the other intersection coordinate is stored as the section end point coordinate 2 in the section list 11 together with the selection list number.
[0014]
The section connection means 17 takes out the section data stored in the section list 11 and uses the section end point coordinates of the first section data as the starting point of the graphic data to be extracted, and thereafter the same from the start point to the other section end point coordinates. Interpolation is performed using the polygonal line data registered in the polygonal line data list 9 having the figure number, and the last point is set as the section end point coordinate. Next, a section end point coordinate having the same coordinates as the section end point coordinate which is the last point is taken out from the section list 11, and similarly, the section end point coordinate to the other section end point coordinate is interpolated using the broken line data list 9. To do. The polygonal line data obtained by connecting these sections is stored in the extracted data list 12.
[0015]
The control unit 6 controls other elements. The graphic selection unit 13, the polygonal line conversion unit 14, the intersection calculation unit 15, the section calculation unit 16, the section connection unit 17, and the control unit 6 are stored in the ROM 4 by the CPU 1. This is realized by executing the control program.
[0016]
Next, each process of the graphic extraction method of this embodiment will be described with reference to the flowchart of FIG. First, it is assumed that three graphics F1, F2, and F3 are displayed on the display device 2 as shown in FIG. The figure F2 is a rotated ellipse. Then, when the point Q1 is instructed by the input device 3, the graphic selection means 13 searches which graphic is selected, and the graphic F2 searched as a result is registered in the selection list 8. Similarly, when the points Q2 and Q3 are designated, the graphics F1 and F3 are registered in the selection list 8 (step 1).
[0017]
Thereafter, when a closed area extraction command (not shown) is input, first, the polygonal line forming means 14 performs the polygonal line conversion process on the graphic data of the graphic elements F1, F2, and F3 registered in the selection list 8 to obtain the polygonal line data. Is stored in the polygonal line data list 9 (step 2). At this time, the elliptical polygonal data is subjected to rotational 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 performs intersection calculation for combinations that can select two figures from the registered three figure data, and the result is calculated for each figure. Store in the list 10 (step 3). For example, as shown in FIG. 8, the intersections of the figure F1 are P1, P4, P5, P3, the intersections of the figure F2 are P1, P2, P5, P6, and the intersections of the figure F3 are P6, P4, P2, P3. Next, the section calculation means 16 takes out the selected coordinates Q1, Q2, and Q3 of the graphic stored in the selection list 8, and the selected coordinate Q1, Q2, Q3 and which intersection of the intersection list 10 having the same graphic number. It is searched which intersection is located, and the result is stored in the section list 11 (step 4). Finally, the section connection 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 takes out the section end point coordinate 1 (P1) stored at the head of the section list 11 and uses this coordinate as the starting point of the extracted figure, and this section is subjected to polygonal interpolation (segmentation of the section L8). ). At this time, for the data to be interpolated, the figure 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 line data list 9 of the figure number 2 is used. Next, a section end point coordinate having the same coordinates as the section end point coordinate 2 (P2), which is the end coordinate of the section, is searched. As a result, the section end point coordinate 2 (P2) of the third section is searched, and the first section The section end point coordinate 2 (P2) of this section and the section end point coordinate 2 (P2) of this section are connected. Similarly, this section is interpolated with polygonal lines (segmentation of the section L11), and the end point coordinates having the same coordinates as the end point coordinates 1 (P4) as the end coordinates of this section are searched. 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 is connected to the section end point coordinate 2 (P4) of this section. Similarly, this section is interpolated with a polygonal line (segmentation of the section L2), and a section end point coordinate having the same coordinates as the section end point coordinate 1 (P1), which is the end coordinate of this section, is searched. As a result, the first section The section end point coordinate 1 (P1) is searched, and the section end point coordinate 1 (P1) of the second section and the section end point coordinate 1 (P1) of the first section are connected. Since the section end point coordinate 1 of the first section is the starting point of the extracted figure, the processing is interrupted here. The broken line data is stored in the extracted data list 12 together with the number of vertices.
[0018]
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. Also, in order to extract all the figures into polygonal lines and extract the closed region, for example, a complicated shape formed by a combination of figures such as a quadratic curve such as an ellipse or an arc, a Bezier curve, or a spline curve or a figure that is rotated. Similarly, the closed region can be extracted. For example, a colored portion in FIG. 11 can be extracted.
[0019]
Furthermore, when extracting a closed region due to self-intersection of a single graphic as shown in FIG. 2, the closed region can be extracted in the same manner by performing intersection calculation on the polygonal line itself.
[0020]
【The invention's effect】
The figure extraction method of the present invention includes a step of acquiring selection information of a figure constituent element that displays a figure to form a closed region, a step of making each selected constituent element a polygonal line, and each constituent element having a polygonal line Since it has a step of calculating an intersection point between each other and a step of calculating a section from the calculated intersection point and constructing a closed region extracted using a polygonal line in the section, it is composed of components of a figure of an arbitrary shape. The closed region can be extracted flexibly and easily by a unified method.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a closed region according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of a closed region due to self-intersection according to an embodiment of the present invention. 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. FIG. 5 is an exemplary diagram of a graphic list according to one embodiment of the present invention. FIG. 6 is a diagram illustrating an example of a selection list according to an embodiment of the present invention. FIG. 7 is a diagram illustrating an example of a polygonal line data list according to an embodiment of the present invention. 9 is an exemplary diagram of a section list according to an embodiment of the present invention. FIG. 10 is an exemplary diagram of an extracted data list according to an embodiment of the present invention. FIG. 11 is an exemplary diagram of a closed region according to an embodiment of the present invention. 12 In one embodiment of the present invention Flow chart of figure extraction method [EXPLANATION OF SYMBOLS]
2 Display device 3 Input device 5 Main storage unit 6 Control unit 7 Graphic list 8 Selection list 9 Polygonal line data list 10 Intersection list 11 Section list 12 Extracted data list 13 Graphic selection means 14 Polygonal section 15 Intersection calculation means 16 Section calculation means 17 Section connection means

Claims (1)

In a graphic extraction method for extracting a shape composed of a plurality of closed regions adjacent to each other as a single figure in a state where a plurality of figures are overlapped so as to form a closed region surrounded by a plurality of line segments,
A first step of storing a line segment surrounding the plurality of adjacent closed areas instructed by the user;
A second step of making the figure including the indicated line segment a polygonal line;
A third step of calculating the position information of the intersection of the polygonal lines;
A fourth step of selecting the line segment indicated in the first step among the line segments sandwiched between the intersection points;
A fifth step of extracting a shape composed of a plurality of closed regions adjacent to each other by connecting each end of the selected line segment based on the position information of the intersection. Extraction method.

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