code: def _href_to_radian(opposite, f=15_000):
      """Convert HREF eyegaze samples to radians.
  
      Parameters
      ----------
      opposite : int
          The x or y coordinate in an HREF gaze sample.
      f : int (default 15_000)
          distance of plane from the eye. Defaults to 15,000 units, which was taken
          from the Eyelink 1000 plus user manual.
  
      Returns
      -------
      x or y coordinate in radians
  
      Notes
      -----
      See section 4.4.2.2 in the Eyelink 1000 Plus User Manual
      (version 1.0.19) for a detailed description of HREF data.
      """
      return np.arcsin(opposite / f)
  
imports: import re
  from datetime import datetime, timedelta, timezone
  import numpy
  from ..._fiff.constants import FIFF
  from ..._fiff.meas_info import create_info
  from ...annotations import Annotations
  from ...utils import _check_pandas_installed, logger, warn
label_desc: Use image node_id 19 for calling a global function with example usage: _href_to_radian(opposite, f) and returns: np