Modifying Bresenham's line algorithm

I'm trying to use Bresenham's line algorithm to compute Field of View on a grid. The code I'm using calculates the lines without a problem but I'm having problems getting it to always return the line running from start point to endpoint. What do I need to do so that all lines returned run from (x0,y0) to (x1,y1)

def bresenham_line(self, x0, y0, x1, y1):
    steep = abs(y1 - y0) > abs(x1 - x0)
    if steep:
        x0, y0 = y0, x0  
        x1, y1 = y1, x1

    if x0 > x1:
        x0, x1 = x1, x0
        y0, y1 = y1, y0

    if y0 < y1: 
        ystep = 1
    else:
        ystep = -1
        
    deltax = x1 - x0
    deltay = abs(y1 - y0)
    error = -deltax / 2
    y = y0

    line = []    
    for x in range(x0, x1 + 1):
        if steep:
            l开发者_高级运维ine.append((y,x))
        else:
            line.append((x,y))
                
        error = error + deltay
        if error > 0:
            y = y + ystep
            error = error - deltax
    return line

Remember whether you switched x0 and x1 and then reverse the list if you did.

if x0 > x1:
    x0, x1 = x1, x0
    y0, y1 = y1, y0

becomes

switched = False
if x0 > x1:
    switched = True
    x0, x1 = x1, x0
    y0, y1 = y1, y0

and at the end, just add:

if switched:
    line.reverse()