docstr: Return the approximate size of a screen pixel at the location pos
  Pos may be a Vector or an (N,3) array of locations
docstr_tok: ["Return","the","approximate","size","of","a","screen","pixel","at","the","location","pos","Pos","may","be","a","Vector","or","an","(","N,3",")","array","of","locations"]
code: def pixelSize(self, pos):
      """
      Return the approximate size of a screen pixel at the location pos
      Pos may be a Vector or an (N,3) array of locations
      """
      cam = self.cameraPosition()
      if isinstance(pos, np.ndarray):
          cam = np.array(cam).reshape((1,) * (pos.ndim - 1) + (3,))
          dist = ((pos - cam) ** 2).sum(axis=-1) ** 0.5
      else:
          dist = (pos - cam).length()
      xDist = dist * 2.0 * tan(0.5 * radians(self.opts["fov"]))
      return xDist / self.width()
  
imports: from OpenGL.GL import *
  import OpenGL.GL.framebufferobjects
  from math import cos, radians, sin, tan
  import numpy
  from ..None import Vector
  from ..None import functions
  from ..None import getConfigOption
  from ..Qt import QtCore, QtGui, QtWidgets
label_desc: Use image node_id 24 for calling the GLViewMixin obj's underlying member method code with example usage: obj.pixelSize(pos) and returns: unknown