class_docstr: The renderer handles all the drawing primitives using a graphics
  context instance that controls the colors/styles
docstr: Start filtering. It simply creates a new canvas (the old one is saved).
docstr_tok: ["Start","filtering",".","It","simply","creates","a","new","canvas","(","the","old","one","is","saved",")","."]
code: def start_filter(self):
      """
      Start filtering. It simply creates a new canvas (the old one is saved).
      """
      self._filter_renderers.append(self._renderer)
      self._renderer = _RendererAgg(
          int(self.width), int(self.height), self.dpi
      )
      self._update_methods()
  
imports: from contextlib import nullcontext
  from math import radians, cos, sin
  import numpy
  import matplotlib
  from matplotlib import _api, cbook
  from matplotlib.backend_bases import _Backend, FigureCanvasBase, FigureManagerBase, RendererBase
  from matplotlib.font_manager import fontManager, get_font
  from matplotlib.ft2font import LOAD_FORCE_AUTOHINT, LOAD_NO_HINTING, LOAD_DEFAULT, LOAD_NO_AUTOHINT
  from matplotlib.mathtext import MathTextParser
  from matplotlib.path import Path
  from matplotlib.transforms import Bbox, BboxBase
  from matplotlib.backends._backend_agg import RendererAgg
label_desc: Use image node_id 20 for calling the RendererAgg obj's underlying member method code with example usage: obj.start_filter() without return types