JPH07122904B2 - Closed area filling method - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a closed area filling method for filling an arbitrary closed area drawn on the graphic display in an information processing system including a graphic display. Regarding

SUMMARY OF THE INVENTION According to the present invention, at least one auxiliary line segment is drawn in a closed region, a filling process is performed from one point on the auxiliary line segment, and the closed region intersects with each of the auxiliary line segments. After deleting all the line segments in the inside, the inside of the closed area is filled so that the inside of the closed area can be completely filled without being affected by the already drawn line segments. .

[Prior Art] In an information processing system equipped with a graphic display, various graphic processes are performed. As one of such graphic processing, filling in an arbitrary closed area drawn on the graphic display is performed.

This filling is performed by specifying the boundary color, the drawing color, and the filling start point. For example, in order to fill the inside of the rectangle drawn by the line segment of "red" with "blue", the boundary color "red", the drawing color "blue", and one point within the above rectangle as the filling start point are respectively It is done by specifying.

[Problems to be Solved by the Invention] However, in such a closed region filling method,
If a line segment of the same color exists in the closed area, the line segment is regarded as a boundary and the filling ends there.

5 (a) to 5 (c) each schematically show the display screen 10 of the graphic display. Here, for example, as shown in FIG. 5A, it is assumed that the line segments 12 and 14 have already been drawn in the same color. A desired closed region, for example, a quadrangle 16 as shown in FIG. 7B, is drawn in the same color as the line segments 12 and 14 here. Then, the square 16 is dotted with that color
Start filling from SP. Then, at this time, the above line segment
12, 14 and the quadrangle 16 have the same color, so when the filling is performed by the boundary color judgment, the line segments 12, 14 become boundaries, and as a result, the area 18 shown by hatching in FIG. Only the target area is filled, and the target area is completely filled.

As described above, in general, when a certain closed area is drawn and the inside of the area is filled, the filling may be incompletely completed depending on the line segment already drawn with the same color.

As a method for removing such a defect, conventionally,
There is a method in which all the coordinates on the line segment forming the closed region are stored or calculated and then filled with a straight line to complete the filling. But,
Such a method requires a memory for storing or calculating, and has a drawback that the processing is delayed because the calculation is performed for each dot.

The present invention has been made in view of the above points, and when drawing an arbitrary closed area, and when filling the closed area, the inside of the closed area is not affected by the line segment already drawn. It is an object of the present invention to provide a closed area filling method that enables complete filling.

[Means for Solving Problems] FIG. 1 is a flowchart of the present invention. In the figure, step S1 draws a closed region in the same color as those line segments where at least one line segment already drawn is included in the region, and draws the closed region within the closed region. In the case of filling with a color, draw at least one auxiliary line segment connecting arbitrary two points on a plurality of line segments forming the closed region in the closed region, and step S2 is to perform each of the auxiliary line segments. Erasing all line segments in the closed region that intersect with, and step S3 is filling in the closed region.

[Operation] The operation of the present invention will be described. At least one auxiliary line segment is drawn in the closed area to be filled (step
S1) After deleting all the line segments in the closed area that intersect with each of these auxiliary line segments (step S2), the closed area is filled (step S3). Therefore, when an arbitrary closed area is drawn and the inside of the closed area is filled, the inside of the closed area can be completely filled without being influenced by the line segment already drawn.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. In order to simplify the explanation, here, the operation of the present invention is performed with 1 bit / pixel, an arbitrary closed figure being a quadrangle, and one auxiliary line segment drawn in the closed figure. This will be described with reference to the flowchart of FIG. 3 and the display examples of FIGS.

That is, as shown in FIG. 3A, the color A (shown by the solid line in the figure) is already displayed on the display screen 10 of the graphic display.
It is assumed that line segments 12 and 14 are drawn with. First, as shown in FIG. 3B, an auxiliary line segment 20 (for example, a diagonal line) is drawn in the color A in the quadrangle 16 to be drawn (step S21). Next, the square is set to a color B different from the above color A.
Drawing is performed (indicated by a dotted line in the figure) (step S22). And from one point on this drawn auxiliary line segment (diagonal line) 20,
A filling process is executed with the boundary color "B" and the drawing color "B" (step S23). Then, the filling process is executed along the auxiliary line segment (diagonal line) 20 and is also performed on the line segments 12 and 14 that intersect with the auxiliary line segment (diagonal line) 20. This filling process is performed by the rectangle 16 drawn in color B.
It is executed up to the intersection with. As a result, the line segment that intersects the auxiliary line segment (diagonal line) 20 drawn in the rectangle 16 is
As shown in FIG. 3 (c), all are drawn (erased) in color B.

Next, as shown in FIG. 3D, the quadrangle 16 is drawn in the color A (step S24). And this square 16
Filling with the boundary color "A" and the drawing color "A" is started from one of the points SP (step S25). As a result, as shown in FIG. 3 (e), the inside of the quadrangle 16 can be completely filled.

Up to this point, in order to simplify the description, the case where one diagonal line is used as the auxiliary line segment has been described. However, if there is only one diagonal line as an auxiliary line segment, there is a high possibility that a line segment that does not intersect with the auxiliary line segment exists. Therefore, depending on the shape of the closed region, it is preferable to draw a plurality of auxiliary line segments so that the probability of existence of line segments that do not intersect decreases. For example,
In the case of a quadrangle, two diagonal lines and two line segments connecting the midpoints of opposite sides may be drawn as auxiliary line segments.

An apparatus for carrying out the above method may have the structure shown in FIG. That is, in the figure, 1 is a line segment determination unit for determining the coordinates and number of auxiliary line segments to be drawn according to the closed region, 2 is a line segment,
A drawing processing unit for drawing a figure and the like, 3 is a filling processing unit for filling the drawn closed region, and 4 is a memory.

Further, in the above-mentioned embodiment, the application example in the case of performing the filling is explained, but the present invention can be applied to the simple erasure of the line segment in the closed area.

In this way, by intentionally drawing at least one auxiliary line segment in an arbitrary closed region, the line segment that intersects these auxiliary line segments can be erased. It can be done completely independent of the graphic being drawn.

[Effects of the Invention] As described in detail above, according to the present invention, when an arbitrary closed region is drawn and the closed region is filled, the closed region is not affected by the line segment already drawn. It is possible to provide a closed area filling method that allows the inside to be completely filled.

[Brief description of drawings]

FIG. 1 is a flow chart of the closed area filling method of the present invention, FIG. 2 is a flow chart of an embodiment of the closed area filling method of the present invention, and FIGS. 3 (a) to 3 (e) show the operation of the above embodiment. FIG. 4 is a diagram showing a display example for explanation, FIG. 4 is a diagram showing an example of a configuration for carrying out the closed region filling method of the present invention, and FIGS. 5 (a) to 5 (c) are conventional closed region filling It is a figure which shows the example of a display for demonstrating a method. 10 …… Display screen, 12,14 …… Line segment, 16 …… Rectangle, 20…
… Auxiliary line segment (diagonal line), S1 to S3 …… Flow chart.

Claims (1)

[Claims] 1. A closed area, at least one of which has already been drawn.
When the line segments of the book are included in the area and drawn in the same color as those line segments, and when the closed area is filled with the color, a plurality of closed areas are formed in the closed area. Draw at least one auxiliary line segment that connects any two points on the line segment, erase all line segments in the closed area that intersect with each of these auxiliary line segments, and then fill in the closed area. Characterized closed area filling method.