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标题: 基于Matlab绘制N角星 [打印本页]

作者: 建不了的模。 时间: 2014-12-9 13:28
标题: 基于Matlab绘制N角星

画N角星(N为大于5的奇数)：七角星、九角星等
function PlotStarN(x0,y0,r,theta0,n,color)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Author    : wacs5
%Email    : wacs5@126.com
%Date    : 20100405
%Function : 画n角星(n为大于5的奇数)
%Called    : cos,cosd,deg2rad,error,fill,linspace,mod,plot,sin,sind
%Version : 只要上述Reference函数可运行的Matlab版本都可以运行
%Usage    : PlotStarN(x0,y0,r,theta0,n,color)
%          :    x0,y0是中心点坐标,缺省为(0,0)
%          :    r为半径,缺省为1
%          :    theta0为其中一个尖角的朝向,缺省为pi/2
%          :    n为星的角数,缺省为5
%          :    color为填充的颜色,缺省为红色
%Example : PlotStarN(0,0,1,pi/2,5,'r')
%See also : http://www.matlabsky.com/thread-6155-1-1.html
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
if (nargin<1) x0=0;          end
if (nargin<2) y0=0;          end
if (nargin<3) r=1;          end
if (nargin<4) theta0=pi/2; end
if (nargin<5) n=5;          end
if (nargin<6) color='r';    end
if n<5 || mod(n,2)==0
error('n必须是大于5的奇数');
end

FlagPlotEdge=0;  %不画边

theta1=theta0+linspace(0,2*pi,n+1);    %n角星的顶点的角度值
%%%%%%%%%%%%%%%%%%%%%%%%
%%n个顶点坐标
x1=x0+r*cos(theta1);
y1=y0+r*sin(theta1);
%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%
%%n角星边的交点坐标
r2=r*sind(180*(n-4)/2/n)/cosd(360/2/n); %交点的外接圆的半径
theta2=theta1+deg2rad(360/2/n);       %交点的角度值
x2=x0+r2*cos(theta2);
y2=y0+r2*sin(theta2);
%%%%%%%%%%%%%%%%%%%%%%%%

%%将顶点的交点混合隔开
x=[x1;x2];
y=[y1;y2];
x=[x(

;x1(end)];
y=[y(

;y1(end)];
fill(x,y,color)

if FlagPlotEdge==1
xx=x1(mod(0:2:2*n,n)+1);
yy=y1(mod(0:2:2*n,n)+1);
plot(xx,yy,'k')
end
复制代码

PlotStarN.rar (1.62 KB, 下载次数: 0)
figure;hold on
PlotStarN(-1.5, 1.5,1,pi/2,5,'r')
PlotStarN( 1.5, 1.5,1,pi/2,7,'b')
PlotStarN(-1.5,-1.5,1,pi/2,9,'g')
PlotStarN( 1.5,-1.5,1,pi/2,99,'y')
axis([-3,3,-3,3]);
axis equal
axis off

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