import pytest from PIL import Image from .helper import ( assert_image_equal, assert_image_similar, assert_image_similar_tofile, hopper, ) _webp = pytest.importorskip("PIL._webp", reason="WebP support not installed") def setup_module(): if _webp.WebPDecoderBuggyAlpha(): pytest.skip("Buggy early version of WebP installed, not testing transparency") def test_read_rgba(): """ Can we read an RGBA mode file without error? Does it have the bits we expect? """ # Generated with `cwebp transparent.png -o transparent.webp` file_path = "Tests/images/transparent.webp" with Image.open(file_path) as image: assert image.mode == "RGBA" assert image.size == (200, 150) assert image.format == "WEBP" image.load() image.getdata() image.tobytes() assert_image_similar_tofile(image, "Tests/images/transparent.png", 20.0) def test_write_lossless_rgb(tmp_path): """ Can we write an RGBA mode file with lossless compression without error? Does it have the bits we expect? """ temp_file = str(tmp_path / "temp.webp") # temp_file = "temp.webp" pil_image = hopper("RGBA") mask = Image.new("RGBA", (64, 64), (128, 128, 128, 128)) # Add some partially transparent bits: pil_image.paste(mask, (0, 0), mask) pil_image.save(temp_file, lossless=True) with Image.open(temp_file) as image: image.load() assert image.mode == "RGBA" assert image.size == pil_image.size assert image.format == "WEBP" image.load() image.getdata() assert_image_equal(image, pil_image) def test_write_rgba(tmp_path): """ Can we write a RGBA mode file to WebP without error. Does it have the bits we expect? """ temp_file = str(tmp_path / "temp.webp") 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() assert image.mode == "RGBA" assert image.size == (10, 10) assert image.format == "WEBP" 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) def test_write_unsupported_mode_PA(tmp_path): """ Saving a palette-based file with transparency to WebP format should work, and be similar to the original file. """ temp_file = str(tmp_path / "temp.webp") file_path = "Tests/images/transparent.gif" with Image.open(file_path) as im: im.save(temp_file) with Image.open(temp_file) as image: assert image.mode == "RGBA" assert image.size == (200, 150) assert image.format == "WEBP" image.load() image.getdata() with Image.open(file_path) as im: target = im.convert("RGBA") assert_image_similar(image, target, 25.0)