def start_rasterizing(self):
if self._rasterizing == <NUM_LIT:0>:<EOL><INDENT>self._raster_renderer = self._raster_renderer_class(<EOL>self._width*self.dpi, self._height*self.dpi, self.dpi)<EOL>self._set_current_renderer(self._raster_renderer)<EOL><DEDENT>self._rasterizing += <NUM_LIT:1><EOL>
Enter "raster" mode.  All subsequent drawing commands (until
stop_rasterizing is called) will be drawn with the raster
backend.

If start_rasterizing is called multiple times before
stop_rasterizing is called, this method has no effect.