clear all;close all;clc;

h=256;
w=256;
img=zeros(h,w);

for i=1:100
    x1=round(rand()*(w-1))+1;
    y1=round(rand()*(h-1))+1;
    x2=round(rand()*(w-1))+1;
    y2=round(rand()*(h-1))+1;

    img=BresenhamDraw(img,x1,y1,x2,y2);

    figure(1);
    imshow(img,[])

end

function img=BresenhamDraw(img,x1,y1,x2,y2)
     if x1~=x2
        k=(y2-y1)/(x2-x1);
        flag=0;         %斜率判断标记位
        if abs(k)>1     %如果斜率大于1,则把x和y方向置换
            flag=1;
            k=1/k;
            [y1 x1]=Swap(x1,y1);
            [y2 x2]=Swap(x2,y2);
        end
        
        %计算开始画线的像素            
        mi=min(x1,x2);      
        ma=max(x1,x2);
        if mi==x1
            s=y1; 
        else
            s=y2;
        end
        
        d=0;
        for i=mi:ma
            if flag==0
                img(s,i)=1;
            else
                img(i,s)=1; 
            end
            d=d+k; 
            %自变量i每加1，根据d是否超过一个像素来确定因变量s增加或减少
            if d>=1
                d=d-1;
                s=s+1;
            elseif d<=-1
                d=d+1;
                s=s-1;
            end     
        end
     end

end

function [y x]=Swap(x1,y1)
    x=y1;
    y=x1;
end