code: def size_allocate(self, widget, allocation):
      dpival = self.figure.dpi
      winch = allocation.width * self.device_pixel_ratio / dpival
      hinch = allocation.height * self.device_pixel_ratio / dpival
      self.figure.set_size_inches(winch, hinch, forward=False)
      ResizeEvent("resize_event", self)._process()
      self.draw_idle()
  
imports: import functools
  import logging
  import os
  from pathlib import Path
  import matplotlib
  from matplotlib import _api, backend_tools, cbook
  from matplotlib.backend_bases import ToolContainerBase, CloseEvent, KeyEvent, LocationEvent, MouseEvent, ResizeEvent
  from gi.repository import Gio, GLib, GObject, Gtk, Gdk
  from .None import _backend_gtk
  from ._backend_gtk import _BackendGTK, _FigureCanvasGTK, _FigureManagerGTK, _NavigationToolbar2GTK, TimerGTK
label_desc: Use image node_id 13 for calling the FigureCanvasGTK3 obj's underlying member method code with example usage: obj.size_allocate(widget, allocation) without return types