code: def viewMatrix(self):
      tr = QtGui.QMatrix4x4()
      tr.translate(0.0, 0.0, -self.opts["distance"])
      if self.opts["rotationMethod"] == "quaternion":
          tr.rotate(self.opts["rotation"])
      else:
          # default rotation method
          tr.rotate(self.opts["elevation"] - 90, 1, 0, 0)
          tr.rotate(self.opts["azimuth"] + 90, 0, 0, -1)
      center = self.opts["center"]
      tr.translate(-center.x(), -center.y(), -center.z())
      return tr
  
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 14 for calling the GLViewMixin obj's underlying member method code with example usage: obj.viewMatrix() and returns: tr