class_docstr: The post process for SAST.
docstr: compute area of a quad.
docstr_tok: ["compute","area","of","a","quad","."]
code: def quad_area(self, quad):
      """
      compute area of a quad.
      """
      edge = [
          (quad[1][0] - quad[0][0]) * (quad[1][1] + quad[0][1]),
          (quad[2][0] - quad[1][0]) * (quad[2][1] + quad[1][1]),
          (quad[3][0] - quad[2][0]) * (quad[3][1] + quad[2][1]),
          (quad[0][0] - quad[3][0]) * (quad[0][1] + quad[3][1]),
      ]
      return np.sum(edge) / 2.0
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import sys
  import numpy
  from .locality_aware_nms import nms_locality
  import paddle
  import cv2
  import time
label_desc: Use image node_id 6 for calling the SASTPostProcess obj's underlying member method code with example usage: obj.quad_area(quad) and returns: unknown