code: def on_draw(self, event):
      prof = Profiler()
      self.context.clear()
      for visual in self.visuals:
          visual.draw()
          prof("draw visual")
  
imports: import numpy
  import math
  from vispy import gloo, app, scene
  from vispy.visuals import Visual
  from vispy.visuals.shaders import Function, Variable
  from vispy.visuals.transforms import TransformSystem, BaseTransform
  from vispy.util.profiler import Profiler
label_desc: Use image node_id 11 for calling the PanZoomCanvas obj's underlying member method code with example usage: obj.on_draw(event) without return types