Support I;16 modes in BoxBlur and GaussianBlur

Tests/test_box_blur.py

@@ -61,6 +61,10 @@ def test_color_modes() -> None:
     box_blur(sample.convert("L"))
     box_blur(sample.convert("LA"))
     box_blur(sample.convert("LA").convert("La"))
+    box_blur(sample.convert("I;16"))
+    box_blur(sample.convert("I;16L"))
+    box_blur(sample.convert("I;16B"))
+    box_blur(sample.convert("I;16N"))
     with pytest.raises(ValueError):
         box_blur(sample.convert("I"))
     with pytest.raises(ValueError):
@@ -73,6 +77,15 @@ def test_color_modes() -> None:
         box_blur(sample.convert("YCbCr"))
 
 
+@pytest.mark.parametrize("mode", ("I;16", "I;16L", "I;16B", "I;16N"))
+def test_i16_max_value(mode: str) -> None:
+    im = Image.new(mode, sample.size, 65535)
+    assert (
+        box_blur(im, 600, 3).get_flattened_data()
+        == (65535,) * sample.width * sample.height
+    )
+
+
 @pytest.mark.parametrize("size", ((0, 1), (1, 0)))
 def test_zero_dimension(size: tuple[int, int]) -> None:
     assert box_blur(Image.new("L", size)).size == size

Tests/test_image_filter.py

@@ -265,6 +265,35 @@ def test_consistency_i16_high_byte(mode: str) -> None:
         assert im.getpixel((4, 4)) == 1000
 
 
+@pytest.mark.parametrize(
+    "filter_to_apply",
+    (
+        ImageFilter.GaussianBlur,
+        ImageFilter.GaussianBlur(0),
+        ImageFilter.GaussianBlur(5),
+        ImageFilter.GaussianBlur((2, 5)),
+        ImageFilter.BoxBlur(0),
+        ImageFilter.BoxBlur(5),
+        ImageFilter.BoxBlur((2, 5)),
+    ),
+)
+@pytest.mark.parametrize("mode", ("I;16", "I;16L", "I;16B", "I;16N"))
+def test_blur_i16(
+    filter_to_apply: ImageFilter.Filter | type[ImageFilter.Filter], mode: str
+) -> None:
+    im = hopper("L")
+    reference = im.filter(filter_to_apply)
+    result = im.convert(mode).filter(filter_to_apply)
+    assert result.mode == mode
+    assert_image_equal(result.convert("L"), reference)
+
+
+@pytest.mark.parametrize("mode", ("I;16", "I;16L", "I;16B", "I;16N"))
+def test_unsharp_mask_i16(mode: str) -> None:
+    with pytest.raises(ValueError, match="image has wrong mode"):
+        hopper(mode).filter(ImageFilter.UnsharpMask)
+
+
 @pytest.mark.parametrize("size", (-1, math.nan, math.inf, 2**31))
 def test_invalid_box_blur_filter(size: int) -> None:
     for radius in (size, (size, size), (size, 1), (1, size)):

docs/releasenotes/13.1.0.rst

@@ -0,0 +1,56 @@
+13.1.0
+------
+
+Security
+========
+
+TODO
+^^^^
+
+TODO
+
+:cve:`YYYY-XXXXX`: TODO
+^^^^^^^^^^^^^^^^^^^^^^^
+
+TODO
+
+Backwards incompatible changes
+==============================
+
+TODO
+^^^^
+
+TODO
+
+Deprecations
+============
+
+TODO
+^^^^
+
+TODO
+
+API changes
+===========
+
+TODO
+^^^^
+
+TODO
+
+API additions
+=============
+
+TODO
+^^^^
+
+TODO
+
+Other changes
+=============
+
+Blurring I;16 images
+^^^^^^^^^^^^^^^^^^^^
+
+:py:class:`~PIL.ImageFilter.GaussianBlur` and :py:class:`~PIL.ImageFilter.BoxBlur`
+now support I;16, I;16L, I;16B and I;16N images.

docs/releasenotes/index.rst

@@ -15,6 +15,7 @@ expected to be backported to earlier versions.
   :maxdepth: 2
 
   versioning
+  13.1.0
   13.0.0
   12.3.0
   12.2.0