%integere-coordinate line drawing algorithm
function [x,y]=intline(x1,x2,y1,y2)
dx=abs(x2-x1);
dy=abs(y2-y1);
if ((dx == 0) & (dy == 0))
   x=x1;
   y=y1;
   return;
end
flip=0;
if (dx >= dy)
   if (x1 > x2)
       t=x1; x1=x2; x2=t;
       t=y1; y1=y2; y2=t;  
       flip=1;
   end
   m=(y2-y1)/(x2-x1);
   x=(x1:x2).';
   y=round(y1+m*(x-x1));
else
   if (y1 > y2)
       t=x1; x1=x2; x2=t;
       t=y1; y1=y2; y2=t;  
       flip=1;
   end
   m=(x2-x1)/(y2-y1);
   y=(y1:y2).';
   x=round(x1+m*(y-y1));
end
if (flip)
   x=flipud(x);
   y=flipud(y);
end