code: def on_viewbox_change(event):
      # workaround for vispy/#2501
      markers.update_gl_state(blend=not picking_filter.enabled)
  
file_path: vispy/examples/scene/marker_picking.py
imports: import random
  import time
  import numpy
  from scipy.constants import golden
  from vispy import app, scene
  from vispy.scene.visuals import Markers
  from vispy.visuals.filters import MarkerPickingFilter
label_desc: Use image node_id 1 for calling a global function with example usage: on_viewbox_change(event) without return types