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import pytest
from PIL import Image
from .helper import assert_image_equal, assert_image_similar, 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()
with Image.open("Tests/images/transparent.png") as target:
assert_image_similar(image, target, 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)
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