from __future__ import annotations from collections.abc import Generator from pathlib import Path import pytest from packaging.version import parse as parse_version from PIL import Image, features from .helper import ( assert_image_equal, assert_image_similar, is_big_endian, skip_unless_feature, ) pytestmark = skip_unless_feature("webp") def test_n_frames() -> None: """Ensure that WebP format sets n_frames and is_animated attributes correctly.""" with Image.open("Tests/images/hopper.webp") as im: assert im.n_frames == 1 assert not im.is_animated with Image.open("Tests/images/iss634.webp") as im: assert im.n_frames == 42 assert im.is_animated def test_write_animation_L(tmp_path: Path) -> None: """ Convert an animated GIF to animated WebP, then compare the frame count, and first and last frames to ensure they're visually similar. """ with Image.open("Tests/images/iss634.gif") as orig: assert orig.n_frames > 1 temp_file = str(tmp_path / "temp.webp") orig.save(temp_file, save_all=True) with Image.open(temp_file) as im: assert im.n_frames == orig.n_frames # Compare first and last frames to the original animated GIF orig.load() im.load() assert_image_similar(im, orig.convert("RGBA"), 32.9) if is_big_endian(): version = features.version_module("webp") assert version is not None if parse_version(version) < parse_version("1.2.2"): pytest.skip("Fails with libwebp earlier than 1.2.2") orig.seek(orig.n_frames - 1) im.seek(im.n_frames - 1) orig.load() im.load() assert_image_similar(im, orig.convert("RGBA"), 32.9) def test_write_animation_RGB(tmp_path: Path) -> None: """ Write an animated WebP from RGB frames, and ensure the frames are visually similar to the originals. """ def check(temp_file: str) -> None: with Image.open(temp_file) as im: assert im.n_frames == 2 # Compare first frame to original im.load() assert_image_equal(im, frame1.convert("RGBA")) # Compare second frame to original if is_big_endian(): version = features.version_module("webp") assert version is not None if parse_version(version) < parse_version("1.2.2"): pytest.skip("Fails with libwebp earlier than 1.2.2") im.seek(1) im.load() assert_image_equal(im, frame2.convert("RGBA")) with Image.open("Tests/images/anim_frame1.webp") as frame1: with Image.open("Tests/images/anim_frame2.webp") as frame2: temp_file1 = str(tmp_path / "temp.webp") frame1.copy().save( temp_file1, save_all=True, append_images=[frame2], lossless=True ) check(temp_file1) # Tests appending using a generator def im_generator( ims: list[Image.Image], ) -> Generator[Image.Image, None, None]: yield from ims temp_file2 = str(tmp_path / "temp_generator.webp") frame1.copy().save( temp_file2, save_all=True, append_images=im_generator([frame2]), lossless=True, ) check(temp_file2) def test_timestamp_and_duration(tmp_path: Path) -> None: """ Try passing a list of durations, and make sure the encoded timestamps and durations are correct. """ durations = [0, 10, 20, 30, 40] temp_file = str(tmp_path / "temp.webp") with Image.open("Tests/images/anim_frame1.webp") as frame1: with Image.open("Tests/images/anim_frame2.webp") as frame2: frame1.save( temp_file, save_all=True, append_images=[frame2, frame1, frame2, frame1], duration=durations, ) with Image.open(temp_file) as im: assert im.n_frames == 5 assert im.is_animated # Check that timestamps and durations match original values specified ts = 0 for frame in range(im.n_frames): im.seek(frame) im.load() assert im.info["duration"] == durations[frame] assert im.info["timestamp"] == ts ts += durations[frame] def test_float_duration(tmp_path: Path) -> None: temp_file = str(tmp_path / "temp.webp") with Image.open("Tests/images/iss634.apng") as im: assert im.info["duration"] == 70.0 im.save(temp_file, save_all=True) with Image.open(temp_file) as reloaded: reloaded.load() assert reloaded.info["duration"] == 70 def test_seeking(tmp_path: Path) -> None: """ Create an animated WebP file, and then try seeking through frames in reverse-order, verifying the timestamps and durations are correct. """ dur = 33 temp_file = str(tmp_path / "temp.webp") with Image.open("Tests/images/anim_frame1.webp") as frame1: with Image.open("Tests/images/anim_frame2.webp") as frame2: frame1.save( temp_file, save_all=True, append_images=[frame2, frame1, frame2, frame1], duration=dur, ) with Image.open(temp_file) as im: assert im.n_frames == 5 assert im.is_animated # Traverse frames in reverse, checking timestamps and durations ts = dur * (im.n_frames - 1) for frame in reversed(range(im.n_frames)): im.seek(frame) im.load() assert im.info["duration"] == dur assert im.info["timestamp"] == ts ts -= dur def test_seek_errors() -> None: with Image.open("Tests/images/iss634.webp") as im: with pytest.raises(EOFError): im.seek(-1) with pytest.raises(EOFError): im.seek(42) def test_alpha_quality(tmp_path: Path) -> None: with Image.open("Tests/images/transparent.png") as im: first_frame = Image.new("L", im.size) out = str(tmp_path / "temp.webp") first_frame.save(out, save_all=True, append_images=[im]) out_quality = str(tmp_path / "quality.webp") first_frame.save( out_quality, save_all=True, append_images=[im], alpha_quality=50 ) with Image.open(out) as reloaded: reloaded.seek(1) with Image.open(out_quality) as reloaded_quality: reloaded_quality.seek(1) assert reloaded.tobytes() != reloaded_quality.tobytes()