JPH0414188A - Graphic painting-out method - Google Patents

Abstract

PURPOSE:To accurately paint out graphics by making the intersected points as the element point of a line segment only when the other end of a side is in one area divided by a scanning line when the scanning line is coincident with the endpoint of the one side of a polygon. CONSTITUTION:The objective polygon for painting out is provided with summits A-F, calculating the intersected point with a scanning line (1') to perform the required printing-out based on the scanning line area in the polygon. Namely, when the scanning line (1') is intersected with one intersected point, there is no painting out after an intersected point F if the state is inverted and the line (1') is painted out. For example, the scanning line (1') is not painted out from leftward to the summit F, but painted out from the summit F to an intersected point P2 of a side DE. The distance between the intersected point P2 and an intersected point P3 with a side DC is not painted out by an appointment, the distance between the intersected point P3 and an intersected point P4 with a side BC is painted out, and the painting-out is not performed afterwards. Thus, the accurate painting-out processing can be performed to the graphics.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for filling in figures, and in particular, to a method for filling in figures that can accurately perform fill-in processing using a simple method.

[Prior Art] FIG. 4 is a flowchart for explaining a conventional figure filling method. FIG. 5 is a diagram illustrating a figure to be filled out in the conventional example. FIG. 6 is an explanatory diagram when the filling process is performed in the conventional example. The conventional figure filling method described above will be described below with reference to FIGS. 4, 5, and 6 as appropriate.

Here, it is assumed that the figure to be filled in is a hexagon having vertices 1 B, C, D, E, and F, as shown in FIG. Further, in FIG. 5, one scanning line l is drawn and intersects the target figure at the following intersection points.

P, intersection with two sides FA, P2: Intersection with side EF, P, intersection with two sides DE, P4: Intersection with side CD, P: Intersection with side BC.

Assuming that a predetermined filling operation using scanning lines has started, first, in step (S40), the intersections between the scanning lines and the N-gons are found for the entire area of the target N-gons (hexagons in this example). Filling work by (
A determination is made as to whether or not this work (hereinafter referred to as scanning) has been completed. The result of the judgment here is YES
If it is S, there is no need to continue the filling operation, so the final step (END) is entered and the entire operation is completed. On the other hand, if the result of the above determination is NO, the process moves to the next step (S41), and the number i of the side of the N-gon whose intersection with the scanning line is to be checked is set to 1. Note that the figures shown in FIG. 5 can be numbered as follows, for example.

Side AB → 1, side BC → 2, side CD - 3° Side DE → 4, side EF → 5, side FA → 6° In the next step (S42), check the magnitude relationship between i and N. (Is i≦N?), thereby determining whether all sides of the target N-gon figure have been examined. When the result of the determination here is i=N, the process moves to Step (343), and the scanning line within the target N-gon is determined based on the obtained intersection point group (this will be described later). Fills the area corresponding to . On the other hand, when the result of the above determination is i<N,
The process moves to step (S44>) to find the intersection of the i-th side and the scanning line.Then, the following step (S44)
In step 45), it is determined whether or not there is an intersection as described above. If the result of this determination is YES, the information related to the corresponding intersection is stored in an appropriate memory means (S46), and the process proceeds to the next step (S47), where the side number is set to 1. (i=i+1).

On the other hand, if the result of the above-mentioned determination is No in the case of 1-, since there is no corresponding intersection, the above-mentioned step (S46) is skipped and the process goes directly to step (S47). Following execution of this step (S47), the process returns to step (S42), and steps from step (S44) to step (S47) are performed until a predetermined relationship is established between i and N.
The processes up to this point are repeated. Here, the results of the execution in step (S45) and step (S46) are shown in Table 1 below.

TABLE 1 Referring now to FIG. 6, one scan line e extends horizontally through vertex F. Here, when the scanning line l crosses one intersection, the state is reversed. That is, when the scanning line l is filled, the filling is no longer performed after crossing the intersection, whereas when the scanning line l is filled, the filling is no longer performed after the intersection with the intersection. Filling will be performed after the intersection. In the example of FIG. 6, the scanning line l is not filled in from the left side to the vertex F in the drawing, and the side F A (P
, ) and the end of the side E F (P ,). That is, at this vertex F, since it intersects at two intersections, the scanning line l does not change its state and is still not filled. This state continues until the intersection P, which intersects the side DE, and filling starts from this intersection P, and this state of filling continues until the intersection P4, which intersects the side CD.

Similarly, an intersection point P that intersects side BC from this intersection point P4
Filling is not performed until , and filling is performed after this intersection P5.

Thus, this conventional filling method has the disadvantage that desired areas are not filled in, but other areas are filled in.

For example, in Japanese Patent Application Laid-open No. 63-239568,
Examples of countermeasures to solve the above-mentioned difficulties are given, but according to this, the outline of the figure to be filled and the changing points of the outline are treated as separate binarized data. It is necessary to store the information in a memory means, and a memory means with a corresponding capacity must be prepared. In addition to this, as mentioned above, it is necessary to perform a separate process to convert the contour line into binarized data, which increases the processing time and complicates the process itself. There is a drawback. That is, this conventionally known method cannot be said to be a sufficient solution.

[Problems to be Solved by the Invention] This invention has been made in view of the actual situation as described in 1.The problem to be solved in the conventional figure filling method is that When performing this, if the scanning line passes over the apex of the target figure, the filled area may be reversed, making it impossible to perform the desired filling process accurately.

The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a figure filling method that can perform accurate filling processing in a simple manner. be.

[Means for Solving the Problems] In the figure filling method according to the present invention, in order to fill in the inside of the outline of a polygon to be filled using scanning lines, the edges of the polygon and the scanning lines are In a figure filling method that calculates the intersection point and performs the required filling process based on the scanning line area within the polygon: Only when the other end point of the side exists in a certain predetermined region of the two regions divided by the scanning line,
This method is characterized in that the intersection point is used as an element point of a line segment in a scanning line for filling processing.

[Operation] In this invention, when the intersection of a scanning line and a side of a polygon coincides with one endpoint of one side of the polygon, the other endpoint of the side is divided 2
Only if it exists in one of the areas,
The above-mentioned intersection points are used as element points of the line segments used for filling processing, so that no inversion occurs in the filling area, and accurate filling processing of the figure can be performed.

[Embodiment] FIG. 1 is a flowchart for explaining a figure filling method according to an embodiment of the present invention. Figure 2 shows
FIG. 6 is a diagram illustrating a figure to be filled in in the above embodiment. FIG. 3 is an explanatory diagram when the filling process is performed in the above embodiment. Wanishita, 1
The figure filling method according to the embodiment of the present invention will be described with reference to FIGS. 1, 2, and 3 as appropriate.

Here, it is assumed that the figure to be filled in is a hexagon having vertices A, B, C, D, E, and F, as shown in FIG. Furthermore, in FIG. 2, one scanning line l° is curved and intersects the target figure at the following intersection points.

P, °: Intersection with side FA (element point), Intersection with P2゛ and side DE (element point), P, ゛: Intersection with side CD (element point), P4゛: Element point that intersects with side BC).

Assuming that a predetermined filling operation using a scanning line is started, first, in step (SIO), the intersection of the scanning line and the N-gon is found for the entire area of the target N-gon (hexagon in this example). Filling work by (
A determination is made as to whether or not this work (hereinafter referred to as scanning) has been completed. The result of the judgment here is YES
If it is S, there is no need to continue the filling operation, so the final step (END) is entered and the entire operation is completed. On the other hand, if the result of the above determination is NO, the process moves to the next step (S11), and the number i of the side of the N-gon whose intersection with the scanning line is to be checked is set to 1. Note that the figures shown in FIG. 2 can be numbered as follows, for example.

Side AB→1, Side BC→2, Side CD → 3, Side DE → 4, Side EF → 5, Side FA→6. .

In the next step (S12), by checking the magnitude relationship between i and N (whether or not i≦N?), it is determined whether all sides of the target N-gon figure have been investigated. A judgment is made. If the result of the determination here is i=N, the process moves to step (313) and the obtained intersection point group (
(This will be described later), the area corresponding to the scanning line within the target N-gon is filled in. On the other hand, if the result of the above determination is i<N, the process moves to step (S14) to find the intersection between the i-th side and the scanning line. And the following step (315)
In this step, it is determined whether or not there is an intersection as described above. If the result of the determination here is NO, there is no corresponding intersection, so step (S1
Go straight to 9).

On the other hand, if the result of the above determination is YES, it is determined whether the current intersection coincides with a certain predetermined end point. If the result of this determination is No, the process moves to step (S18) and information related to the corresponding intersection is stored in an appropriate memory means. On the other hand, if the result of the above determination is YES, the process moves to the next step (S17) and the following determination is made. That is, (a) When the direction of the scanning line is horizontal: "The endpoints of the sides do not coincide with the intersection points. 1) The endpoints are above (below) the scanning line.
side? j or (b) When the direction of the scanning line is vertical.

"Among the end points of the side, are the end points that do not coincide with the intersection point on the right (left) side of the scanning line? Here, the direction of the scanning line is horizontal, so
Judgment (b) will be made. Then, if the result of the determination here is No, the step (
Go directly to S19). On the other hand, if the result of the above determination is YES, the process proceeds to the next step (S18), where information related to the corresponding intersection is stored in an appropriate memory means, and then step (S19) is performed. will be moved to.

In this step (S19), the side number is increased by 1 (i=i+1). This Ste Nobu (S
19), the process returns to step (S12), and the process continues in step (S1) until a predetermined relationship is established between i and N.
The execution of the processes from step 4) to step (S19) is repeated. Here, the results of the execution from step (S15) to step (S18) are shown in Table 2 below.

Table 2 Referring now to FIG. 3, one scan line l' is at the vertex F
It extends horizontally through the Here, the scanning line l° is 1
When it intersects with two intersections, its state is reversed. That is, when the scanning line l' is filled, no filling is performed after crossing the intersection, whereas when the scanning line l'' is filled, the intersection Filling will be performed after the intersection with .In the example shown in FIG. The area from the intersection of sides DE to the intersection of sides CD is not filled, and the area from the intersection of sides CD to the intersection of sides BC is filled.Furthermore, from this intersection of sides BC, filling is not performed. Not done, thus;
This means that the desired filling operation has been performed accurately.

[Effects of the Invention] As explained in detail above, the figure filling method according to the present invention uses scanning lines to fill in the inside of the outline of a polygon to be filled, by using scanning lines to fill in the inside of the outline of the polygon. In the figure clearing method, the intersection point with the scanning line is determined and the required clearing process is performed based on the scanning line area within the polygon. when the intersection point of the polygon coincides with an end point of one of the sides of the polygon, the other end point of the side exists in a predetermined one of the two areas divided by the scanning line. Only when you are
The above-mentioned intersection point is used as an element point of a line segment in the scanning line for filling processing, and the intersection point between the scanning line and a side of the polygon is one side of the polygon. Only when the other end point of the side is in a predetermined one of the two areas divided by the scanning line, the intersection point is filled out. The points are set as element points of the line segments to be used, and there is no reversal of the filled area, and it is possible to accurately fill out the figure.

[Brief explanation of the drawing]

FIG. 1 is a flowchart for explaining a figure filling method according to an embodiment of the present invention, and FIG. 2 is an illustration of a figure to be subjected to the clearing process in the above embodiment.
FIG. 3 is an explanatory diagram when the filling process is performed in the example of the actual ship, FIG. 4 is a flowchart diagram for explaining a figure filling method as a conventional example, and FIG. 5 is an explanatory diagram in the above conventional example. FIG. 6, which is an illustrative diagram of a figure to be subjected to the filling process, is an explanatory diagram when the filling process is performed in the above-mentioned conventional example. A, B, C, D, E, F are sides, Pl, P2, Pco, P4, P5 are intersection points (element points), P,
,P7,P,'',P,° is the intersection (element point), e +
1' is the scanning line. In addition, the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) In order to fill in the inside of the outline of a polygon to be filled using a scanning line, find the intersection of the side of the polygon and the scanning line, and use the scanning line area within the polygon to In a figure filling method configured to perform required filling processing: When the intersection of a scanning line and a certain predetermined side of a polygon coincides with one end point of the side of the polygon, the scanning line Only when the other end point of the side exists in a certain predetermined region among the two divided regions, the element point of the line segment in the scanning line for filling out the intersection point. A figure filling method characterized by: