code: def crop_to_fit(self, image_size, view_size):
          
          self.blipFill.crop(self._fill_cropping(image_size, view_size))
docs: Set cropping values in `p:blipFill/a:srcRect` such that an image of
          *image_size* will stretch to exactly fit *view_size* when its aspect
          ratio is preserved.