Remove WebP support without anim, mux/demux, and with buggy alpha

Tests/test_features.py

@@ -10,11 +10,6 @@
 
 from .helper import skip_unless_feature
 
-try:
-    from PIL import _webp
-except ImportError:
-    pass
-
 
 def test_check() -> None:
     # Check the correctness of the convenience function
@@ -23,7 +18,11 @@ def test_check() -> None:
     for codec in features.codecs:
         assert features.check_codec(codec) == features.check(codec)
     for feature in features.features:
-        assert features.check_feature(feature) == features.check(feature)
+        if "webp" in feature:
+            with pytest.warns(DeprecationWarning):
+                assert features.check_feature(feature) == features.check(feature)
+        else:
+            assert features.check_feature(feature) == features.check(feature)
 
 
 def test_version() -> None:
@@ -48,23 +47,26 @@ def test(name: str, function: Callable[[str], str | None]) -> None:
     for codec in features.codecs:
         test(codec, features.version_codec)
     for feature in features.features:
-        test(feature, features.version_feature)
+        if "webp" in feature:
+            with pytest.warns(DeprecationWarning):
+                test(feature, features.version_feature)
+        else:
+            test(feature, features.version_feature)
 
 
-@skip_unless_feature("webp")
 def test_webp_transparency() -> None:
-    assert features.check("transp_webp") != _webp.WebPDecoderBuggyAlpha()
-    assert features.check("transp_webp") == _webp.HAVE_TRANSPARENCY
+    with pytest.warns(DeprecationWarning):
+        assert features.check("transp_webp") == features.check_module("webp")
 
 
-@skip_unless_feature("webp")
 def test_webp_mux() -> None:
-    assert features.check("webp_mux") == _webp.HAVE_WEBPMUX
+    with pytest.warns(DeprecationWarning):
+        assert features.check("webp_mux") == features.check_module("webp")
 
 
-@skip_unless_feature("webp")
 def test_webp_anim() -> None:
-    assert features.check("webp_anim") == _webp.HAVE_WEBPANIM
+    with pytest.warns(DeprecationWarning):
+        assert features.check("webp_anim") == features.check_module("webp")
 
 
 @skip_unless_feature("libjpeg_turbo")

Tests/test_file_gif.py

@@ -978,7 +978,7 @@ def test_webp_background(tmp_path: Path) -> None:
     out = str(tmp_path / "temp.gif")
 
     # Test opaque WebP background
-    if features.check("webp") and features.check("webp_anim"):
+    if features.check("webp"):
         with Image.open("Tests/images/hopper.webp") as im:
             assert im.info["background"] == (255, 255, 255, 255)
             im.save(out)

Tests/test_file_webp.py

@@ -48,8 +48,6 @@ def setup_method(self) -> None:
         self.rgb_mode = "RGB"
 
     def test_version(self) -> None:
-        _webp.WebPDecoderVersion()
-        _webp.WebPDecoderBuggyAlpha()
         version = features.version_module("webp")
         assert version is not None
         assert re.search(r"\d+\.\d+\.\d+$", version)
@@ -117,7 +115,6 @@ def test_write_method(self, tmp_path: Path) -> None:
         hopper().save(buffer_method, format="WEBP", method=6)
         assert buffer_no_args.getbuffer() != buffer_method.getbuffer()
 
-    @skip_unless_feature("webp_anim")
     def test_save_all(self, tmp_path: Path) -> None:
         temp_file = str(tmp_path / "temp.webp")
         im = Image.new("RGB", (1, 1))
@@ -132,10 +129,9 @@ def test_save_all(self, tmp_path: Path) -> None:
 
     def test_icc_profile(self, tmp_path: Path) -> None:
         self._roundtrip(tmp_path, self.rgb_mode, 12.5, {"icc_profile": None})
-        if _webp.HAVE_WEBPANIM:
-            self._roundtrip(
-                tmp_path, self.rgb_mode, 12.5, {"icc_profile": None, "save_all": True}
-            )
+        self._roundtrip(
+            tmp_path, self.rgb_mode, 12.5, {"icc_profile": None, "save_all": True}
+        )
 
     def test_write_unsupported_mode_L(self, tmp_path: Path) -> None:
         """
@@ -165,23 +161,17 @@ def test_WebPEncode_with_invalid_args(self) -> None:
         """
         Calling encoder functions with no arguments should result in an error.
         """
-
-        if _webp.HAVE_WEBPANIM:
-            with pytest.raises(TypeError):
-                _webp.WebPAnimEncoder()
+        with pytest.raises(TypeError):
+            _webp.WebPAnimEncoder()
         with pytest.raises(TypeError):
             _webp.WebPEncode()
 
-    def test_WebPDecode_with_invalid_args(self) -> None:
+    def test_WebPAnimDecoder_with_invalid_args(self) -> None:
         """
         Calling decoder functions with no arguments should result in an error.
         """
-
-        if _webp.HAVE_WEBPANIM:
-            with pytest.raises(TypeError):
-                _webp.WebPAnimDecoder()
         with pytest.raises(TypeError):
-            _webp.WebPDecode()
+            _webp.WebPAnimDecoder()
 
     def test_no_resource_warning(self, tmp_path: Path) -> None:
         file_path = "Tests/images/hopper.webp"
@@ -200,7 +190,6 @@ def test_file_pointer_could_be_reused(self) -> None:
         "background",
         (0, (0,), (-1, 0, 1, 2), (253, 254, 255, 256)),
     )
-    @skip_unless_feature("webp_anim")
     def test_invalid_background(
         self, background: int | tuple[int, ...], tmp_path: Path
     ) -> None:
@@ -209,7 +198,6 @@ def test_invalid_background(
         with pytest.raises(OSError):
             im.save(temp_file, save_all=True, append_images=[im], background=background)
 
-    @skip_unless_feature("webp_anim")
     def test_background_from_gif(self, tmp_path: Path) -> None:
         # Save L mode GIF with background
         with Image.open("Tests/images/no_palette_with_background.gif") as im:
@@ -234,7 +222,6 @@ def test_background_from_gif(self, tmp_path: Path) -> None:
         difference = sum(abs(original_value[i] - reread_value[i]) for i in range(0, 3))
         assert difference < 5
 
-    @skip_unless_feature("webp_anim")
     def test_duration(self, tmp_path: Path) -> None:
         with Image.open("Tests/images/dispose_bgnd.gif") as im:
             assert im.info["duration"] == 1000

Tests/test_file_webp_alpha.py

@@ -13,12 +13,7 @@
     hopper,
 )
 
-_webp = pytest.importorskip("PIL._webp", reason="WebP support not installed")
-
-
-def setup_module() -> None:
-    if _webp.WebPDecoderBuggyAlpha():
-        pytest.skip("Buggy early version of WebP installed, not testing transparency")
+pytest.importorskip("PIL._webp", reason="WebP support not installed")
 
 
 def test_read_rgba() -> None:
@@ -81,9 +76,6 @@ def test_write_rgba(tmp_path: Path) -> None:
     pil_image = Image.new("RGBA", (10, 10), (255, 0, 0, 20))
     pil_image.save(temp_file)
 
-    if _webp.WebPDecoderBuggyAlpha():
-        return
-
     with Image.open(temp_file) as image:
         image.load()
 
@@ -93,12 +85,7 @@ def test_write_rgba(tmp_path: Path) -> None:
         image.load()
         image.getdata()
 
-        # Early versions of WebP are known to produce higher deviations:
-        # deal with it
-        if _webp.WebPDecoderVersion() <= 0x201:
-            assert_image_similar(image, pil_image, 3.0)
-        else:
-            assert_image_similar(image, pil_image, 1.0)
+        assert_image_similar(image, pil_image, 1.0)
 
 
 def test_keep_rgb_values_when_transparent(tmp_path: Path) -> None:

Tests/test_file_webp_animated.py

@@ -15,10 +15,7 @@
     skip_unless_feature,
 )
 
-pytestmark = [
-    skip_unless_feature("webp"),
-    skip_unless_feature("webp_anim"),
-]
+pytestmark = skip_unless_feature("webp")
 
 
 def test_n_frames() -> None:

Tests/test_file_webp_lossless.py

@@ -8,14 +8,11 @@
 
 from .helper import assert_image_equal, hopper
 
-_webp = pytest.importorskip("PIL._webp", reason="WebP support not installed")
+pytest.importorskip("PIL._webp", reason="WebP support not installed")
 RGB_MODE = "RGB"
 
 
 def test_write_lossless_rgb(tmp_path: Path) -> None:
-    if _webp.WebPDecoderVersion() < 0x0200:
-        pytest.skip("lossless not included")
-
     temp_file = str(tmp_path / "temp.webp")
 
     hopper(RGB_MODE).save(temp_file, lossless=True)

Tests/test_file_webp_metadata.py

@@ -10,10 +10,7 @@
 
 from .helper import mark_if_feature_version, skip_unless_feature
 
-pytestmark = [
-    skip_unless_feature("webp"),
-    skip_unless_feature("webp_mux"),
-]
+pytestmark = skip_unless_feature("webp")
 
 ElementTree: ModuleType | None
 try:
@@ -136,7 +133,6 @@ def test_getxmp() -> None:
             )
 
 
-@skip_unless_feature("webp_anim")
 def test_write_animated_metadata(tmp_path: Path) -> None:
     iccp_data = b"<iccp_data>"
     exif_data = b"<exif_data>"

Tests/test_image.py

@@ -817,7 +817,6 @@ def test_exif_jpeg(self, tmp_path: Path) -> None:
             assert reloaded_exif[305] == "Pillow test"
 
     @skip_unless_feature("webp")
-    @skip_unless_feature("webp_anim")
     def test_exif_webp(self, tmp_path: Path) -> None:
         with Image.open("Tests/images/hopper.webp") as im:
             exif = im.getexif()

Tests/test_imagefile.py

@@ -94,7 +94,6 @@ def test_ico(self) -> None:
             assert (48, 48) == p.image.size
 
     @skip_unless_feature("webp")
-    @skip_unless_feature("webp_anim")
     def test_incremental_webp(self) -> None:
         with ImageFile.Parser() as p:
             with open("Tests/images/hopper.webp", "rb") as f:

Tests/test_imageops.py

@@ -390,7 +390,7 @@ def test_colorize_3color_offset() -> None:
 
 def test_exif_transpose() -> None:
     exts = [".jpg"]
-    if features.check("webp") and features.check("webp_anim"):
+    if features.check("webp"):
         exts.append(".webp")
     for ext in exts:
         with Image.open("Tests/images/hopper" + ext) as base_im:

docs/deprecations.rst

@@ -126,6 +126,16 @@ JpegImageFile.huffman_ac and JpegImageFile.huffman_dc
 The ``huffman_ac`` and ``huffman_dc`` dictionaries on JPEG images were unused. They
 have been deprecated, and will be removed in Pillow 12 (2025-10-15).
 
+Specific WebP Feature Checks
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. deprecated:: 11.0.0
+
+``features.check("transp_webp")``, ``features.check("webp_mux")`` and
+``features.check("webp_anim")`` are now deprecated. They will always return
+``True`` if the WebP module is installed, until they are removed in Pillow
+12.0.0 (2025-10-15).
+
 Removed features
 ----------------
 

docs/handbook/image-file-formats.rst

@@ -1220,8 +1220,7 @@ using the general tags available through tiffinfo.
 WebP
 ^^^^
 
-Pillow reads and writes WebP files. The specifics of Pillow's capabilities with
-this format are currently undocumented.
+Pillow reads and writes WebP files. Requires libwebp v0.5.0 or later.
 
 .. _webp-saving:
 
@@ -1249,29 +1248,19 @@ The :py:meth:`~PIL.Image.Image.save` method supports the following options:
 **exact**
     If true, preserve the transparent RGB values. Otherwise, discard
     invisible RGB values for better compression. Defaults to false.
-    Requires libwebp 0.5.0 or later.
 
 **icc_profile**
-    The ICC Profile to include in the saved file. Only supported if
-    the system WebP library was built with webpmux support.
+    The ICC Profile to include in the saved file.
 
 **exif**
-    The exif data to include in the saved file. Only supported if
-    the system WebP library was built with webpmux support.
+    The exif data to include in the saved file.
 
 **xmp**
-    The XMP data to include in the saved file. Only supported if
-    the system WebP library was built with webpmux support.
+    The XMP data to include in the saved file.
 
 Saving sequences
 ~~~~~~~~~~~~~~~~
 
-.. note::
-
-    Support for animated WebP files will only be enabled if the system WebP
-    library is v0.5.0 or later. You can check webp animation support at
-    runtime by calling ``features.check("webp_anim")``.
-
 When calling :py:meth:`~PIL.Image.Image.save` to write a WebP file, by default
 only the first frame of a multiframe image will be saved. If the ``save_all``
 argument is present and true, then all frames will be saved, and the following

docs/installation/building-from-source.rst

@@ -55,10 +55,6 @@ Many of Pillow's features require external libraries:
 
 * **libwebp** provides the WebP format.
 
-  * Pillow has been tested with version **0.1.3**, which does not read
-    transparent WebP files. Versions **0.3.0** and above support
-    transparency.
-
 * **openjpeg** provides JPEG 2000 functionality.
 
   * Pillow has been tested with openjpeg **2.0.0**, **2.1.0**, **2.3.1**,
@@ -275,18 +271,18 @@ Build Options
 
 * Config settings: ``-C zlib=disable``, ``-C jpeg=disable``,
   ``-C tiff=disable``, ``-C freetype=disable``, ``-C raqm=disable``,
-  ``-C lcms=disable``, ``-C webp=disable``, ``-C webpmux=disable``,
+  ``-C lcms=disable``, ``-C webp=disable``,
   ``-C jpeg2000=disable``, ``-C imagequant=disable``, ``-C xcb=disable``.
   Disable building the corresponding feature even if the development
   libraries are present on the building machine.
 
 * Config settings: ``-C zlib=enable``, ``-C jpeg=enable``,
   ``-C tiff=enable``, ``-C freetype=enable``, ``-C raqm=enable``,
-  ``-C lcms=enable``, ``-C webp=enable``, ``-C webpmux=enable``,
+  ``-C lcms=enable``, ``-C webp=enable``,
   ``-C jpeg2000=enable``, ``-C imagequant=enable``, ``-C xcb=enable``.
   Require that the corresponding feature is built. The build will raise
-  an exception if the libraries are not found. Webpmux (WebP metadata)
-  relies on WebP support. Tcl and Tk also must be used together.
+  an exception if the libraries are not found. Tcl and Tk must be used
+  together.
 
 * Config settings: ``-C raqm=vendor``, ``-C fribidi=vendor``.
   These flags are used to compile a modified version of libraqm and

docs/reference/features.rst

@@ -54,12 +54,12 @@ Feature version numbers are available only where stated.
 Support for the following features can be checked:
 
 * ``libjpeg_turbo``: (compile time) Whether Pillow was compiled against the libjpeg-turbo version of libjpeg. Compile-time version number is available.
-* ``transp_webp``: Support for transparency in WebP images.
-* ``webp_mux``: (compile time) Support for EXIF data in WebP images.
-* ``webp_anim``: (compile time) Support for animated WebP images.
 * ``raqm``: Raqm library, required for ``ImageFont.Layout.RAQM`` in :py:func:`PIL.ImageFont.truetype`. Run-time version number is available for Raqm 0.7.0 or newer.
 * ``libimagequant``: (compile time) ImageQuant quantization support in :py:func:`PIL.Image.Image.quantize`. Run-time version number is available.
 * ``xcb``: (compile time) Support for X11 in :py:func:`PIL.ImageGrab.grab` via the XCB library.
+* ``transp_webp``: Deprecated. Always ``True`` if WebP module is installed.
+* ``webp_mux``: Deprecated. Always ``True`` if WebP module is installed.
+* ``webp_anim``: Deprecated. Always ``True`` if WebP module is installed.
 
 .. autofunction:: PIL.features.check_feature
 .. autofunction:: PIL.features.version_feature

docs/releasenotes/11.0.0.rst

@@ -58,6 +58,14 @@ JpegImageFile.huffman_ac and JpegImageFile.huffman_dc
 The ``huffman_ac`` and ``huffman_dc`` dictionaries on JPEG images were unused. They
 have been deprecated, and will be removed in Pillow 12 (2025-10-15).
 
+Specific WebP Feature Checks
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+``features.check("transp_webp")``, ``features.check("webp_mux")`` and
+``features.check("webp_anim")`` are now deprecated. They will always return
+``True`` if the WebP module is installed, until they are removed in Pillow
+12.0.0 (2025-10-15).
+
 API Changes
 ===========