code: def get_normal_points(cx, cy, cos_t, sin_t, length):
      """
      For a line passing through (*cx*, *cy*) and having a angle *t*, return
      locations of the two points located along its perpendicular line at the
      distance of *length*.
      """
  
      if length == 0.0:
          return cx, cy, cx, cy
  
      cos_t1, sin_t1 = sin_t, -cos_t
      cos_t2, sin_t2 = -sin_t, cos_t
  
      x1, y1 = length * cos_t1 + cx, length * sin_t1 + cy
      x2, y2 = length * cos_t2 + cx, length * sin_t2 + cy
  
      return x1, y1, x2, y2
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import six
  import numpy
  from matplotlib.path import Path
  from operator import xor
  import warnings
label_desc: Use image node_id 2 for calling a global function with example usage: get_normal_points(cx, cy, cos_t, sin_t, length) and returns: x1,  y1,  x2,  y2, cx,  cy,  cx,  cy