add tsx_file and parent_dir properties to TileSet

pytiled_parser/objects.py

@@ -444,6 +444,10 @@ class TileSet:
             Ordered according to the terrain element's appearance in the TSX \
             file.
         tiles (Optional[Dict[int, Tile]]): Dict of Tile objects by Tile.id.
+        tsx_file (Path): Path of the file containing the tileset, \
+            None if loaded internally from a map
+        parent_dir (Path): Path of the parent directory of the file \
+            containing the tileset, None if loaded internally from a map
     """
 
     name: str
@@ -459,6 +463,8 @@ class TileSet:
     image: Optional[Image] = None
     terrain_types: Optional[List[Terrain]] = None
     tiles: Optional[Dict[int, "Tile"]] = None
+    tsx_file: Path = None
+    parent_dir: Path = None
 
 
 TileSetDict = Dict[int, TileSet]

pytiled_parser/xml_parser.py

@@ -465,9 +465,15 @@ def _parse_external_tile_set(
         objects.Tileset: The tileset being parsed.
     """
     source = Path(tile_set_element.attrib["source"])
+    resolved_path = parent_dir / source
     tile_set_tree = etree.parse(str(parent_dir / Path(source))).getroot()
 
-    return _parse_tile_set(tile_set_tree)
+    parsed_tile_set = _parse_tile_set(tile_set_tree)
+
+    parsed_tile_set.tsx_file = resolved_path
+    parsed_tile_set.parent_dir = resolved_path.parent
+
+    return parsed_tile_set
 
 
 def _parse_points(point_string: str) -> List[objects.OrderedPair]: