MATLAB—求直线或者线段之间的交点坐标

 function  CrossPoint(  )
 %% 求两条直线的交点坐标
 x1  = [7.8 8];
 y1  = [0.96 0.94];
 %line2
 x2 = [8.25 8.25];
 y2 = [0 0.99];
 %fit linear polynomial
 p1 = polyfit(x1,y1,1);
 p2 = polyfit(x2,y2,1);
 %calculate intersection
 x_intersect = fzero(@(x) polyval(p1-p2,x),3);
 y_intersect = polyval(p1,x_intersect);
 line(x1,y1);
 hold on;
 line(x2,y2);
 plot(x_intersect,y_intersect,'r*')
 axis([5,10,0,2]);

 %% 求线段的交点坐标
 n=20;
 p=rand(n,4);        %（x1,y1,x2,y2）线段两端点

 for i=1:n
     pbar=p(i,:);
     pbar=reshape(pbar,[2,2]);
     line(pbar(1,:),pbar(2,:));
 end

 hold on;
 for i=1:n-1
     p1=p(i,:);
     k1=(p1(2)-p1(4))/(p1(1)-p1(3));
     b1=p1(2)-k1*p1(1);
     for j=i+1:n
         p2=p(j,:);
         k2=(p2(2)-p2(4))/(p2(1)-p2(3));
         b2=p2(2)-k2*p2(1);

         x=-(b1-b2)/(k1-k2);             %求两直线交点
         y=-(-b2*k1+b1*k2)/(k1-k2);
                                         %判断交点是否在两线段上
         if min(p1(1),p1(3))<=x && x<=max(p1(1),p1(3)) && ...
            min(p1(2),p1(4))<=y && y<=max(p1(2),p1(4)) && ...
            min(p2(1),p2(3))<=x && x<=max(p2(1),p2(3)) && ...
            min(p2(2),p2(4))<=y && y<=max(p2(2),p2(4))
             plot(x,y,'r.');
         end
     end
 end
 end