Allow 1 mode images in apply() and match()

Author: radarhere

Tests/test_imagemorph.py

@@ -236,9 +236,9 @@ def test_incorrect_mode() -> None:
     im = hopper("RGB")
     mop = ImageMorph.MorphOp(op_name="erosion8")
 
-    with pytest.raises(ValueError, match="Image mode must be L"):
+    with pytest.raises(ValueError, match="Image mode must be 1 or L"):
         mop.apply(im)
-    with pytest.raises(ValueError, match="Image mode must be L"):
+    with pytest.raises(ValueError, match="Image mode must be 1 or L"):
         mop.match(im)
     with pytest.raises(ValueError, match="Image mode must be 1 or L"):
         mop.get_on_pixels(im)

src/PIL/ImageMorph.py

@@ -209,8 +209,10 @@ def apply(self, image: Image.Image) -> tuple[int, Image.Image]:
             msg = "No operator loaded"
             raise Exception(msg)
 
-        if image.mode != "L":
-            msg = "Image mode must be L"
+        if image.mode == "1":
+            image = image.convert("L")
+        elif image.mode != "L":
+            msg = "Image mode must be 1 or L"
             raise ValueError(msg)
         outimage = Image.new(image.mode, image.size, None)
         count = _imagingmorph.apply(bytes(self.lut), image.getim(), outimage.getim())
@@ -226,8 +228,10 @@ def match(self, image: Image.Image) -> list[tuple[int, int]]:
             msg = "No operator loaded"
             raise Exception(msg)
 
-        if image.mode != "L":
-            msg = "Image mode must be L"
+        if image.mode == "1":
+            image = image.convert("L")
+        elif image.mode != "L":
+            msg = "Image mode must be 1 or L"
             raise ValueError(msg)
         return _imagingmorph.match(bytes(self.lut), image.getim())