Pillow/Tests/test_image_resize.py

329 lines
11 KiB
Python

"""
Tests for resize functionality.
"""
from __future__ import annotations
from collections.abc import Generator
from itertools import permutations
from pathlib import Path
import pytest
from PIL import Image
from .helper import (
assert_image_equal,
assert_image_equal_tofile,
assert_image_similar,
hopper,
skip_unless_feature,
)
class TestImagingCoreResize:
def resize(
self, im: Image.Image, size: tuple[int, int], f: Image.Resampling
) -> Image.Image:
# Image class independent version of resize.
im.load()
return im._new(im.im.resize(size, f))
@pytest.mark.parametrize(
"mode", ("1", "P", "L", "I", "F", "RGB", "RGBA", "CMYK", "YCbCr", "I;16")
)
def test_nearest_mode(self, mode: str) -> None:
im = hopper(mode)
r = self.resize(im, (15, 12), Image.Resampling.NEAREST)
assert r.mode == mode
assert r.size == (15, 12)
assert r.im.bands == im.im.bands
def test_convolution_modes(self) -> None:
with pytest.raises(ValueError):
self.resize(hopper("1"), (15, 12), Image.Resampling.BILINEAR)
with pytest.raises(ValueError):
self.resize(hopper("P"), (15, 12), Image.Resampling.BILINEAR)
for mode in [
"L",
"I",
"I;16",
"I;16L",
"I;16B",
"I;16N",
"F",
"RGB",
"RGBA",
"CMYK",
"YCbCr",
]:
im = hopper(mode)
r = self.resize(im, (15, 12), Image.Resampling.BILINEAR)
assert r.mode == mode
assert r.size == (15, 12)
assert r.im.bands == im.im.bands
@pytest.mark.parametrize(
"resample",
(
Image.Resampling.NEAREST,
Image.Resampling.BOX,
Image.Resampling.BILINEAR,
Image.Resampling.HAMMING,
Image.Resampling.BICUBIC,
Image.Resampling.LANCZOS,
),
)
def test_reduce_filters(self, resample: Image.Resampling) -> None:
r = self.resize(hopper("RGB"), (15, 12), resample)
assert r.mode == "RGB"
assert r.size == (15, 12)
@pytest.mark.parametrize(
"resample",
(
Image.Resampling.NEAREST,
Image.Resampling.BOX,
Image.Resampling.BILINEAR,
Image.Resampling.HAMMING,
Image.Resampling.BICUBIC,
Image.Resampling.LANCZOS,
),
)
def test_enlarge_filters(self, resample: Image.Resampling) -> None:
r = self.resize(hopper("RGB"), (212, 195), resample)
assert r.mode == "RGB"
assert r.size == (212, 195)
@pytest.mark.parametrize(
"resample",
(
Image.Resampling.NEAREST,
Image.Resampling.BOX,
Image.Resampling.BILINEAR,
Image.Resampling.HAMMING,
Image.Resampling.BICUBIC,
Image.Resampling.LANCZOS,
),
)
@pytest.mark.parametrize(
"mode, channels_set",
(
("RGB", ("blank", "filled", "dirty")),
("RGBA", ("blank", "blank", "filled", "dirty")),
("LA", ("filled", "dirty")),
),
)
def test_endianness(
self, resample: Image.Resampling, mode: str, channels_set: tuple[str, ...]
) -> None:
# Make an image with one colored pixel, in one channel.
# When resized, that channel should be the same as a GS image.
# Other channels should be unaffected.
# The R and A channels should not swap, which is indicative of
# an endianness issues.
samples = {
"blank": Image.new("L", (2, 2), 0),
"filled": Image.new("L", (2, 2), 255),
"dirty": Image.new("L", (2, 2), 0),
}
samples["dirty"].putpixel((1, 1), 128)
# samples resized with current filter
references = {
name: self.resize(ch, (4, 4), resample) for name, ch in samples.items()
}
for channels in set(permutations(channels_set)):
# compile image from different channels permutations
im = Image.merge(mode, [samples[ch] for ch in channels])
resized = self.resize(im, (4, 4), resample)
for i, ch in enumerate(resized.split()):
# check what resized channel in image is the same
# as separately resized channel
assert_image_equal(ch, references[channels[i]])
@pytest.mark.parametrize(
"resample",
(
Image.Resampling.NEAREST,
Image.Resampling.BOX,
Image.Resampling.BILINEAR,
Image.Resampling.HAMMING,
Image.Resampling.BICUBIC,
Image.Resampling.LANCZOS,
),
)
def test_enlarge_zero(self, resample: Image.Resampling) -> None:
r = self.resize(Image.new("RGB", (0, 0), "white"), (212, 195), resample)
assert r.mode == "RGB"
assert r.size == (212, 195)
assert r.getdata()[0] == (0, 0, 0)
def test_unknown_filter(self) -> None:
with pytest.raises(ValueError):
self.resize(hopper(), (10, 10), 9) # type: ignore[arg-type]
def test_cross_platform(self, tmp_path: Path) -> None:
# This test is intended for only check for consistent behaviour across
# platforms. So if a future Pillow change requires that the test file
# be updated, that is okay.
im = hopper().resize((64, 64))
temp_file = str(tmp_path / "temp.gif")
im.save(temp_file)
with Image.open(temp_file) as reloaded:
assert_image_equal_tofile(reloaded, "Tests/images/hopper_resized.gif")
@pytest.fixture
def gradients_image() -> Generator[Image.Image, None, None]:
with Image.open("Tests/images/radial_gradients.png") as im:
im.load()
try:
yield im
finally:
im.close()
class TestReducingGapResize:
def test_reducing_gap_values(self, gradients_image: Image.Image) -> None:
ref = gradients_image.resize(
(52, 34), Image.Resampling.BICUBIC, reducing_gap=None
)
im = gradients_image.resize((52, 34), Image.Resampling.BICUBIC)
assert_image_equal(ref, im)
with pytest.raises(ValueError):
gradients_image.resize((52, 34), Image.Resampling.BICUBIC, reducing_gap=0)
with pytest.raises(ValueError):
gradients_image.resize(
(52, 34), Image.Resampling.BICUBIC, reducing_gap=0.99
)
@pytest.mark.parametrize(
"box, epsilon",
((None, 4), ((1.1, 2.2, 510.8, 510.9), 4), ((3, 10, 410, 256), 10)),
)
def test_reducing_gap_1(
self,
gradients_image: Image.Image,
box: tuple[float, float, float, float],
epsilon: float,
) -> None:
ref = gradients_image.resize((52, 34), Image.Resampling.BICUBIC, box=box)
im = gradients_image.resize(
(52, 34), Image.Resampling.BICUBIC, box=box, reducing_gap=1.0
)
with pytest.raises(pytest.fail.Exception):
assert_image_equal(ref, im)
assert_image_similar(ref, im, epsilon)
@pytest.mark.parametrize(
"box, epsilon",
((None, 1.5), ((1.1, 2.2, 510.8, 510.9), 1.5), ((3, 10, 410, 256), 1)),
)
def test_reducing_gap_2(
self,
gradients_image: Image.Image,
box: tuple[float, float, float, float],
epsilon: float,
) -> None:
ref = gradients_image.resize((52, 34), Image.Resampling.BICUBIC, box=box)
im = gradients_image.resize(
(52, 34), Image.Resampling.BICUBIC, box=box, reducing_gap=2.0
)
with pytest.raises(pytest.fail.Exception):
assert_image_equal(ref, im)
assert_image_similar(ref, im, epsilon)
@pytest.mark.parametrize(
"box, epsilon",
((None, 1), ((1.1, 2.2, 510.8, 510.9), 1), ((3, 10, 410, 256), 0.5)),
)
def test_reducing_gap_3(
self,
gradients_image: Image.Image,
box: tuple[float, float, float, float],
epsilon: float,
) -> None:
ref = gradients_image.resize((52, 34), Image.Resampling.BICUBIC, box=box)
im = gradients_image.resize(
(52, 34), Image.Resampling.BICUBIC, box=box, reducing_gap=3.0
)
with pytest.raises(pytest.fail.Exception):
assert_image_equal(ref, im)
assert_image_similar(ref, im, epsilon)
@pytest.mark.parametrize("box", (None, (1.1, 2.2, 510.8, 510.9), (3, 10, 410, 256)))
def test_reducing_gap_8(
self, gradients_image: Image.Image, box: tuple[float, float, float, float]
) -> None:
ref = gradients_image.resize((52, 34), Image.Resampling.BICUBIC, box=box)
im = gradients_image.resize(
(52, 34), Image.Resampling.BICUBIC, box=box, reducing_gap=8.0
)
assert_image_equal(ref, im)
@pytest.mark.parametrize(
"box, epsilon",
(((0, 0, 512, 512), 5.5), ((0.9, 1.7, 128, 128), 9.5)),
)
def test_box_filter(
self,
gradients_image: Image.Image,
box: tuple[float, float, float, float],
epsilon: float,
) -> None:
ref = gradients_image.resize((52, 34), Image.Resampling.BOX, box=box)
im = gradients_image.resize(
(52, 34), Image.Resampling.BOX, box=box, reducing_gap=1.0
)
assert_image_similar(ref, im, epsilon)
class TestImageResize:
def test_resize(self) -> None:
def resize(mode: str, size: tuple[int, int] | list[int]) -> None:
out = hopper(mode).resize(size)
assert out.mode == mode
assert out.size == tuple(size)
for mode in "1", "P", "L", "RGB", "I", "F":
resize(mode, (112, 103))
resize(mode, [188, 214])
# Test unknown resampling filter
with hopper() as im:
with pytest.raises(ValueError):
im.resize((10, 10), "unknown")
@skip_unless_feature("libtiff")
def test_transposed(self) -> None:
with Image.open("Tests/images/g4_orientation_5.tif") as im:
im = im.resize((64, 64))
assert im.size == (64, 64)
@pytest.mark.parametrize("mode", ("L", "RGB", "I", "F"))
def test_default_filter_bicubic(self, mode: str) -> None:
im = hopper(mode)
assert im.resize((20, 20), Image.Resampling.BICUBIC) == im.resize((20, 20))
@pytest.mark.parametrize(
"mode", ("1", "P", "I;16", "I;16L", "I;16B", "BGR;15", "BGR;16")
)
def test_default_filter_nearest(self, mode: str) -> None:
im = hopper(mode)
assert im.resize((20, 20), Image.Resampling.NEAREST) == im.resize((20, 20))