code: def get_affine_transform(
      center, input_size, rot, output_size, shift=(0.0, 0.0), inv=False
  ):
      """Get the affine transform matrix, given the center/scale/rot/output_size.
      Args:
          center (np.ndarray[2, ]): Center of the bounding box (x, y).
          scale (np.ndarray[2, ]): Scale of the bounding box
              wrt [width, height].
          rot (float): Rotation angle (degree).
          output_size (np.ndarray[2, ]): Size of the destination heatmaps.
          shift (0-100%): Shift translation ratio wrt the width/height.
              Default (0., 0.).
          inv (bool): Option to inverse the affine transform direction.
              (inv=False: src->dst or inv=True: dst->src)
      Returns:
          np.ndarray: The transform matrix.
      """
      assert len(center) == 2
      assert len(output_size) == 2
      assert len(shift) == 2
      if not isinstance(input_size, (np.ndarray, list)):
          input_size = np.array(
              [input_size, input_size], dtype=np.float32
          )
      scale_tmp = input_size
  
      shift = np.array(shift)
      src_w = scale_tmp[0]
      dst_w = output_size[0]
      dst_h = output_size[1]
  
      rot_rad = np.pi * rot / 180
      src_dir = rotate_point([0.0, src_w * -0.5], rot_rad)
      dst_dir = np.array([0.0, dst_w * -0.5])
  
      src = np.zeros((3, 2), dtype=np.float32)
      src[0, :] = center + scale_tmp * shift
      src[1, :] = center + src_dir + scale_tmp * shift
      src[2, :] = _get_3rd_point(src[0, :], src[1, :])
  
      dst = np.zeros((3, 2), dtype=np.float32)
      dst[0, :] = [dst_w * 0.5, dst_h * 0.5]
      dst[1, :] = np.array([dst_w * 0.5, dst_h * 0.5]) + dst_dir
      dst[2, :] = _get_3rd_point(dst[0, :], dst[1, :])
  
      if inv:
          trans = cv2.getAffineTransform(
              np.float32(dst), np.float32(src)
          )
      else:
          trans = cv2.getAffineTransform(
              np.float32(src), np.float32(dst)
          )
  
      return trans
  
imports: import numpy
  import cv2
  import copy
label_desc: Use image node_id 4 for calling a global function with example usage: get_affine_transform(center, input_size, rot, output_size, shift, inv) and returns: trans