docstr: Generate center line by poly clock-wise point. (4, 2)
docstr_tok: ["Generate","center","line","by","poly","clock-wise","point",".","(","4",",","2",")"]
code: def quad2tcl(self, poly, ratio):
      """
      Generate center line by poly clock-wise point. (4, 2)
      """
      ratio_pair = np.array(
          [[0.5 - ratio / 2], [0.5 + ratio / 2]], dtype=np.float32
      )
      p0_3 = poly[0] + (poly[3] - poly[0]) * ratio_pair
      p1_2 = poly[1] + (poly[2] - poly[1]) * ratio_pair
      return np.array([p0_3[0], p1_2[0], p1_2[1], p0_3[1]])
  
imports: import math
  import cv2
  import numpy
  from skimage.morphology._skeletonize import thin
  from ppocr.utils.e2e_utils.extract_textpoint_fast import sort_and_expand_with_direction_v2
label_desc: Use image node_id 22 for calling the PGProcessTrain obj's underlying member method code with example usage: obj.quad2tcl(poly, ratio) and returns: np