Get all points of a straight line in python

Question

Very simply, given a point A(x,y) and another point B(m,n), I need a function that can return in any iterable object a list[k,z] of all points in between.

Am only interested in integer points, so no need for floats.

I need the best possible pythonic way because this 'little' function is going to be heavily run and is the key pillar of a larger system.

EDIT:

@roippi, thanks pointing out the gotcha concerning the integers. From my code below, you can see I try to step across the x axis and get corresponding y, then do the same for y. My set of points will not have any non-discrete co-ordinate point, so for the moment I can afford to overlook that small flaw

import itertools
#Vars
origin = {'x':0, 'y':0}

def slope(origin, target):
    if target['x'] == origin['x']:
        return 0
    else:
        m = (target['y'] - origin['y']) / (target['x'] - origin['x'])
        return m

def line_eqn(origin, target):
    x = origin['x']
    y = origin['y']
    c = -(slope(origin, target)*x - y)
    c = y - (slope(origin, target)*x)
    #return 'y = ' + str(slope(target)) + 'x + ' + str(c)
    m = slope(origin, target)
    return {'m':m, 'c':c}

def get_y(x, slope, c):
    # y = mx + c    
    y = (slope*x) + c
    return y

def get_x(y, slope, c):     
    #x = (y-c)/m
    if slope == 0:
        c = 0   #vertical lines never intersect with y-axis
    if slope == 0:
        slope = 1   #Do NOT divide by zero
    x = (y - c)/slope
    return x

def get_points(origin, target):
    coord_list = []
    #Step along x-axis
    for i in range(origin['x'], target['x']+1):     
        eqn = line_eqn(origin, target)
        y = get_y(i, eqn['m'], eqn['c'])        
        coord_list.append([i, y])

    #Step along y-axis
    for i in range(origin['y'], target['y']+1):
        eqn = line_eqn(origin, target)
        x = get_x(i, eqn['m'], eqn['c'])
        coord_list.append([x, i])

    #return unique list     
    return list(k for k,_ in itertools.groupby(sorted(coord_list)))

origin = {'x':1, 'y':3}
target = {'x':1, 'y':6}

print get_points(origin, target)

Answer 1

def get_line(x1, y1, x2, y2):
    points = []
    issteep = abs(y2-y1) > abs(x2-x1)
    if issteep:
        x1, y1 = y1, x1
        x2, y2 = y2, x2
    rev = False
    if x1 > x2:
        x1, x2 = x2, x1
        y1, y2 = y2, y1
        rev = True
    deltax = x2 - x1
    deltay = abs(y2-y1)
    error = int(deltax / 2)
    y = y1
    ystep = None
    if y1 < y2:
        ystep = 1
    else:
        ystep = -1
    for x in range(x1, x2 + 1):
        if issteep:
            points.append((y, x))
        else:
            points.append((x, y))
        error -= deltay
        if error < 0:
            y += ystep
            error += deltax
    # Reverse the list if the coordinates were reversed
    if rev:
        points.reverse()
    return points