line_supercover

def line_supercover(Py_ssize_t y0, Py_ssize_t x0, Py_ssize_t y1, Py_ssize_t x1):

    cdef int dx = abs(x1-x0)
    cdef int dy = abs(y1-y0)
    cdef int x = x0
    cdef int y = y0
    cdef int ii = 0
    cdef int n = dx + dy
    cdef int err = dx - dy
    cdef int x_inc = 1 
    cdef int y_inc = 1 

    cdef int max_length = (max(dx,dy)+1)*3

    cdef Py_ssize_t[::1] rr = np.zeros(max_length, dtype=np.intp)
    cdef Py_ssize_t[::1] cc = np.zeros(max_length, dtype=np.intp)

    if x1 > x0: x_inc = 1 
    else:       x_inc = -1
    if y1 > y0: y_inc = 1 
    else:       y_inc = -1

    dx = 2 * dx
    dy = 2 * dy

    while n > 0:
        rr[ii] = y
        cc[ii] = x
        ii = ii + 1
        if (err > 0):
            x += x_inc
            err -= dy
        elif (err < 0):
            y += y_inc
            err += dx
        else: # If err == 0 the algorithm is on a corner
            rr[ii] = y + y_inc
            cc[ii] = x
            rr[ii+1] = y
            cc[ii+1] = x + x_inc
            ii = ii + 2
            x += x_inc
            y += y_inc
            err = err + dx - dy
            n = n - 1
        n = n - 1 
    rr[ii] = y
    cc[ii] = x
        
    return np.asarray(rr[0:ii+1]), np.asarray(cc[0:ii+1])
     

Thanks. Works beautifully.

What exactly are Py_ssize_t here? Do we import something from Cython?