code: def draw_collection(self, ax, collection,
                          force_pathtrans=None,
                          force_offsettrans=None):
          
          (transform, transOffset,
           offsets, paths) = collection._prepare_points()
  
          offset_coords, offsets = self.process_transform(
              transOffset, ax, offsets, force_trans=force_offsettrans)
          path_coords = self.process_transform(
              transform, ax, force_trans=force_pathtrans)
  
          processed_paths = [utils.SVG_path(path) for path in paths]
          processed_paths = [(self.process_transform(
              transform, ax, path[0], force_trans=force_pathtrans)[1], path[1])
              for path in processed_paths]
  
          path_transforms = collection.get_transforms()
          try:
              # matplotlib 1.3: path_transforms are transform objects.
              # Convert them to numpy arrays.
              path_transforms = [t.get_matrix() for t in path_transforms]
          except AttributeError:
              # matplotlib 1.4: path transforms are already numpy arrays.
              pass
  
          styles = {'linewidth': collection.get_linewidths(),
                    'facecolor': collection.get_facecolors(),
                    'edgecolor': collection.get_edgecolors(),
                    'alpha': collection._alpha,
                    'zorder': collection.get_zorder()}
  
          offset_dict = {"data": "before",
                         "screen": "after"}
          offset_order = offset_dict[collection.get_offset_position()]
  
          self.renderer.draw_path_collection(paths=processed_paths,
                                             path_coordinates=path_coords,
                                             path_transforms=path_transforms,
                                             offsets=offsets,
                                             offset_coordinates=offset_coords,
                                             offset_order=offset_order,
                                             styles=styles,
                                             mplobj=collection)
docs: Process a matplotlib collection and call renderer.draw_collection