Bresenham line doesn't terminate

问题

I've implemented the Bresenham algorithm from Wikipedia in python but for some lines it doesn't work, like from 1,0 to 0,1 it doesn't stop and keeps going on to make a super long line

def line(x0, y0, x1, y1):
    dx = x1 - x0
    dy = y1 - y0
    sx = x0 < x1 and 1 or -1
    sy = y0 < y1 and 1 or -1
    err = dx - dy

    points = []
    x, y = x0, y0
    while True:
        points += [(x, y)]
        if x == x1 and y == y1:
            break
        e2 = err * 2
        if e2 > -dy:
            err -= dy
            x += sx
        if e2 < dx:
            err += dx
            y += sy
    return points

回答1:

You are missing the call to abs in the initialization of dx and dy:

dx = abs(x1 - x0)
dy = abs(y1 - y0)

回答2:

You have a type in "if e2 > -dy:". The minus sign is wrong.

来源：https://stackoverflow.com/questions/7159228/bresenham-line-doesnt-terminate