ブレ全ハムってこれか

plot(x0,y0, x1,y1)
 dx=x1-x0
 dy=y1-y0

 D = 2*dy - dx
 plot(x0,y0)
 y=y0

 for x from x0+1 to x1
  if D > 0
   y = y+1
   plot(x,y)
   D = D + (2*dy-2*dx)
  else
   plot(x,y)
   D = D + (2*dy)