Register 'avif' format when available in Pillow (matplotlib#30363)

* FIX: .avif files not registered

* Tests for avif format

* Update lib/matplotlib/backends/backend_agg.py

Co-authored-by: Tim Hoffmann <2836374+timhoffm@users.noreply.github.com>

* Update lib/matplotlib/backends/backend_agg.py

Co-authored-by: Tim Hoffmann <2836374+timhoffm@users.noreply.github.com>

* FIX: missing import for PIL

* FIX: missing import for PIL

* Update lib/matplotlib/backend_bases.py

Co-authored-by: Elliott Sales de Andrade <quantum.analyst@gmail.com>

* changing order of dependencies for better readability

---------

Co-authored-by: Tim Hoffmann <2836374+timhoffm@users.noreply.github.com>
Co-authored-by: Elliott Sales de Andrade <quantum.analyst@gmail.com>

Author: 3 people

lib/matplotlib/backend_bases.py

@@ -76,6 +76,7 @@
     'tif': 'Tagged Image File Format',
     'tiff': 'Tagged Image File Format',
     'webp': 'WebP Image Format',
+    'avif': 'AV1 Image File Format',
 }
 _default_backends = {
     'eps': 'matplotlib.backends.backend_ps',
@@ -93,6 +94,7 @@
     'tif': 'matplotlib.backends.backend_agg',
     'tiff': 'matplotlib.backends.backend_agg',
     'webp': 'matplotlib.backends.backend_agg',
+    'avif': 'matplotlib.backends.backend_agg',
 }
 
 

lib/matplotlib/backends/backend_agg.py

@@ -25,6 +25,7 @@
 from math import radians, cos, sin
 
 import numpy as np
+from PIL import features
 
 import matplotlib as mpl
 from matplotlib import _api, cbook
@@ -510,18 +511,33 @@ def print_tif(self, filename_or_obj, *, metadata=None, pil_kwargs=None):
     def print_webp(self, filename_or_obj, *, metadata=None, pil_kwargs=None):
         self._print_pil(filename_or_obj, "webp", pil_kwargs, metadata)
 
-    print_gif.__doc__, print_jpg.__doc__, print_tif.__doc__, print_webp.__doc__ = map(
+    def print_avif(self, filename_or_obj, *, metadata=None, pil_kwargs=None):
+        if not features.check("avif"):
+            raise RuntimeError(
+                "The installed pillow version does not support avif. Full "
+                "avif support has been added in pillow 11.3."
+            )
+        self._print_pil(filename_or_obj, "avif", pil_kwargs, metadata)
+
+    (print_gif.__doc__,
+     print_jpg.__doc__,
+     print_tif.__doc__,
+     print_webp.__doc__,
+     print_avif.__doc__) = map(
         """
         Write the figure to a {} file.
 
         Parameters
         ----------
         filename_or_obj : str or path-like or file-like
             The file to write to.
+        metadata : None
+            Unused for pillow-based writers. All supported options
+            can be passed via *pil_kwargs*.
         pil_kwargs : dict, optional
             Additional keyword arguments that are passed to
             `PIL.Image.Image.save` when saving the figure.
-        """.format, ["GIF", "JPEG", "TIFF", "WebP"])
+        """.format, ["GIF", "JPEG", "TIFF", "WebP", "AVIF"])
 
 
 @_Backend.export

lib/matplotlib/tests/test_agg.py

@@ -263,6 +263,20 @@ def test_pil_kwargs_webp():
     assert buf_large.getbuffer().nbytes > buf_small.getbuffer().nbytes
 
 
+@pytest.mark.skipif(not features.check("avif"), reason="AVIF support not available")
+def test_pil_kwargs_avif():
+    plt.plot([0, 1, 2], [0, 1, 0])
+    buf_small = io.BytesIO()
+    pil_kwargs_low = {"quality": 1}
+    plt.savefig(buf_small, format="avif", pil_kwargs=pil_kwargs_low)
+    assert len(pil_kwargs_low) == 1
+    buf_large = io.BytesIO()
+    pil_kwargs_high = {"quality": 100}
+    plt.savefig(buf_large, format="avif", pil_kwargs=pil_kwargs_high)
+    assert len(pil_kwargs_high) == 1
+    assert buf_large.getbuffer().nbytes > buf_small.getbuffer().nbytes
+
+
 def test_gif_no_alpha():
     plt.plot([0, 1, 2], [0, 1, 0])
     buf = io.BytesIO()
@@ -290,6 +304,15 @@ def test_webp_alpha():
     assert im.mode == "RGBA"
 
 
+@pytest.mark.skipif(not features.check("avif"), reason="AVIF support not available")
+def test_avif_alpha():
+    plt.plot([0, 1, 2], [0, 1, 0])
+    buf = io.BytesIO()
+    plt.savefig(buf, format="avif", transparent=True)
+    im = Image.open(buf)
+    assert im.mode == "RGBA"
+
+
 def test_draw_path_collection_error_handling():
     fig, ax = plt.subplots()
     ax.scatter([1], [1]).set_paths(Path([(0, 1), (2, 3)]))