Pillow/Tests/test_file_webp_alpha.py

115 lines
3.6 KiB
Python

import pytest
from PIL import Image
from .helper import PillowTestCase, assert_image_equal, assert_image_similar, hopper
_webp = pytest.importorskip("PIL._webp", reason="WebP support not installed")
class TestFileWebpAlpha(PillowTestCase):
def setUp(self):
if _webp.WebPDecoderBuggyAlpha(self):
self.skipTest(
"Buggy early version of WebP installed, not testing transparency"
)
def test_read_rgba(self):
"""
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:
self.assertEqual(image.mode, "RGBA")
self.assertEqual(image.size, (200, 150))
self.assertEqual(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(self):
"""
Can we write an RGBA mode file with lossless compression without
error? Does it have the bits we expect?
"""
temp_file = self.tempfile("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()
self.assertEqual(image.mode, "RGBA")
self.assertEqual(image.size, pil_image.size)
self.assertEqual(image.format, "WEBP")
image.load()
image.getdata()
assert_image_equal(image, pil_image)
def test_write_rgba(self):
"""
Can we write a RGBA mode file to webp without error.
Does it have the bits we expect?
"""
temp_file = self.tempfile("temp.webp")
pil_image = Image.new("RGBA", (10, 10), (255, 0, 0, 20))
pil_image.save(temp_file)
if _webp.WebPDecoderBuggyAlpha(self):
return
with Image.open(temp_file) as image:
image.load()
self.assertEqual(image.mode, "RGBA")
self.assertEqual(image.size, (10, 10))
self.assertEqual(image.format, "WEBP")
image.load()
image.getdata()
# early versions of webp are known to produce higher deviations:
# deal with it
if _webp.WebPDecoderVersion(self) <= 0x201:
assert_image_similar(image, pil_image, 3.0)
else:
assert_image_similar(image, pil_image, 1.0)
def test_write_unsupported_mode_PA(self):
"""
Saving a palette-based file with transparency to WebP format
should work, and be similar to the original file.
"""
temp_file = self.tempfile("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:
self.assertEqual(image.mode, "RGBA")
self.assertEqual(image.size, (200, 150))
self.assertEqual(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)