fill a polygon with a hole

Question

Qingping 2014-2-26

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/119139-fill-a-polygon-with-a-hole

回答： Steven Lord 2019-9-19

data=[
5,  0.8;
0,  0.0;
0,  0.0;
5,  0.8;
5,  0.4;
1,  0.1;
7,  0.1;
5,  0.4;
];
h=fill(data(:,1),data(:,2),'r')

the image is:

there is a line between dot(0.5,0.8) and (0.5,0.4) how to delete this line in prefectly? such as

I used the code set(h,'EdgeColor','r') to disappear this line.

2 个评论
显示无隐藏无

Azzi Abdelmalek 2014-2-26

What is the problem?

Qingping 2014-2-28

I want to delete the line between two triangle in automatic!

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

lvn 2014-2-28

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/119139-fill-a-polygon-with-a-hole#answer_126532

在 MATLAB Online 中打开

Alternatively, you can remove all black lines (like that the figure looks good to me)

h=fill(data(:,1),data(:,2),'r','Linestyle','none')

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Image Analyst 2014-2-26

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/119139-fill-a-polygon-with-a-hole#answer_126212

在 MATLAB Online 中打开

Simply get rid of the last 5 rows of your data.

data=[
0.5,  0.8;
1.0,  0.0;
0.0,  0.0;
];
h=fill(data(:,1),data(:,2),'r')

That's so simple I guess I'm missing something, or you are.

4 个评论
显示 2更早的评论隐藏 2更早的评论

Qingping 2014-3-3

In this way, I want to confirm which one is outer object and which one is inner object.

Patrik Ek 2014-3-3

编辑：Patrik Ek 2014-3-3

@Image Analyst: That was not expected, that matlab would not handle the case of polygons with holes, when plotting. I will remove my answer. I also did some research since it felt a bit incredulous that matlab could not do this. However the solution proposed by you were the most commonly recommended. +1 for that

@Qingping: Answer one is is of course the simplest one. However, to keep direction of the polygons you can check the direction or windiness or what you prefer to call it. The dierction should be opposite if the polygons are properly defined. Depending on standard the direction of the outer polygon may vary, but mathematics it is most often defined counter clockwise. However, MATLAB does in a number of occations define it the other way around (eg in mapping toolbox since this is more or less standard when working with maps)

请先登录，再进行评论。

Answer 3

Steven Lord 2019-9-19

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/119139-fill-a-polygon-with-a-hole#answer_392666

在 MATLAB Online 中打开

Consider creating and plotting a polyshape. You will receive a warning but depending on how you've generated your data you may be able to avoid this.

data=[
0.5,  0.8;
1.0,  0.0;
0.0,  0.0;
0.5,  0.8;
0.5,  0.4;
0.1,  0.1;
0.7,  0.1;
0.5,  0.4;
];
p = polyshape(data);
plot(p)

Or, if you're building the outermost shape then subtracting away the inner holes:

outer=[
0.5,  0.8;
1.0,  0.0;
0.0,  0.0;
0.5,  0.8];
outerP = polyshape(outer);
hole = [
0.5,  0.4;
0.1,  0.1;
0.7,  0.1;
0.5,  0.4;
];
holeP = polyshape(hole);
totalP = subtract(outerP, holeP);
plot(totalP)