Implement img_source() for LoadedSpatialImage and make img_source() an abstract method

Author: keviny2

src/spatialexperiment/SpatialImage.py

@@ -109,6 +109,18 @@ def dimensions(self) -> Tuple[int, int]:
     ######>> img utils <<#######
     ############################
 
+    @abstractmethod
+    def img_source(self, as_path: bool = False) -> Union[str, None]:
+        """Get the source of the image.
+
+        Args:
+            as_path: If True, returns path as string. Defaults to False.
+
+        Returns:
+            Source path/URL of the image, or None if loaded in memory.
+        """
+        pass
+
     @abstractmethod
     def img_raster(self) -> Image.Image:
         """Get the image as a PIL Image object."""
@@ -290,6 +302,14 @@ def image(self, image: Union[Image.Image, np.ndarray]):
         )
         return self.set_image(image=image, in_place=True)
 
+    def img_source(self, as_path: bool = False) -> None:
+        """Get the source of the loaded image.
+        
+        Returns:
+            Always returns None.
+        """
+        return None
+
     ############################
     ######>> img utils <<#######
     ############################
@@ -450,7 +470,14 @@ def path(self, path: Union[str, Path]):
         return self.set_path(path=path, in_place=True)
 
     def img_source(self, as_path: bool = False) -> str:
-        """Get the source path of the image."""
+        """Get the source path of the image.
+
+        Args:
+            as_path: If True, returns string path. Defaults to False.
+
+        Returns:
+            Path to the image.
+        """
         return str(self._path) if as_path is True else self._path
 
     ############################
@@ -645,7 +672,14 @@ def img_raster(self) -> Image.Image:
         return Image.open(cache_path)
 
     def img_source(self, as_path: bool = False) -> str:
-        """Get the source URL or cached path of the image."""
+        """Get the source URL or cached path of the image.
+
+        Args:
+            as_path: If True, returns downloaded path. Defaults to False.
+
+        Returns:
+            URL or cached path of the image. 
+        """
         if as_path:
             return str(self._download_image())
         return self._url