class_docstr: A helper class to implement a renderer that switches between
  vector and raster drawing.  An example may be a PDF writer, where
  most things are drawn with PDF vector commands, but some very
  complex objects, such as quad meshes, are rasterised and then
  output as images.
docstr: Enter "raster" mode.  All subsequent drawing commands (until
  `stop_rasterizing` is called) will be drawn with the raster backend.
code: def start_rasterizing(self):
      """
      Enter "raster" mode.  All subsequent drawing commands (until
      `stop_rasterizing` is called) will be drawn with the raster backend.
      """
      # change the dpi of the figure temporarily.
      self.figure.dpi = self.dpi
      if self._bbox_inches_restore:  # when tight bbox is used
          r = process_figure_for_rasterizing(
              self.figure, self._bbox_inches_restore
          )
          self._bbox_inches_restore = r
  
      self._raster_renderer = self._raster_renderer_class(
          self._width * self.dpi, self._height * self.dpi, self.dpi
      )
      self._renderer = self._raster_renderer
  
file_path: matplotlib/lib/matplotlib/backends/backend_mixed.py
imports: import numpy
  from matplotlib import cbook
  from .backend_agg import RendererAgg
  from matplotlib._tight_bbox import process_figure_for_rasterizing
label_desc: Use image node_id 3 for calling the MixedModeRenderer obj's underlying member method code with example usage: obj.start_rasterizing() without return types