class_docstr: Pyglet backend for Canvas abstract class.
class_docstr_tok: ["Pyglet","backend","for","Canvas","abstract","class","."]
code: def on_show(self):
      if self._vispy_canvas is None:
          return
      if not self._initialize_sent:
          self._initialize_sent = True
          self._vispy_canvas.set_current()
          self._vispy_canvas.events.initialize()
      # Set location now if we must. For some reason we get weird
      # offsets in viewport if set_location is called before the
      # widget is shown.
      if self._pending_position:
          x, y = self._pending_position
          self._pending_position = None
          self.set_location(x, y)
      # Redraw
      self._vispy_update()
  
imports: from __future__ import division
  from packaging.version import Version
  from time import sleep
  from ..base import BaseApplicationBackend, BaseCanvasBackend, BaseTimerBackend
  from ...util import keys
  from ...util.ptime import time
  from ...None import config
label_desc: Use image node_id 19 for calling the CanvasBackend obj's underlying member method code with example usage: obj.on_show() without return types