Pillow/Tests/test_image_resize.py
Jon Dufresne 4de5477b61 Remove unnecessary unittest.main() boilerplate from test files
With the introduction and use of pytest, it is simple and easy to
execute specific tests in isolation through documented command line
arguments. Either by specifying the module path or through the `-k
EXPRESSION` argument. There is no longer any need to provide the
boilerplate:

    if __name__ == '__main__':
        unittest.main()

To every test file. It is simply noise.

The pattern remains in test files that aren't named with `test_*` as
those files are not discovered and executed by pytest by default.
2019-02-03 10:10:16 -08:00

118 lines
4.5 KiB
Python

"""
Tests for resize functionality.
"""
from itertools import permutations
from .helper import PillowTestCase, hopper
from PIL import Image
class TestImagingCoreResize(PillowTestCase):
def resize(self, im, size, f):
# Image class independent version of resize.
im.load()
return im._new(im.im.resize(size, f))
def test_nearest_mode(self):
for mode in ["1", "P", "L", "I", "F", "RGB", "RGBA", "CMYK", "YCbCr",
"I;16"]: # exotic mode
im = hopper(mode)
r = self.resize(im, (15, 12), Image.NEAREST)
self.assertEqual(r.mode, mode)
self.assertEqual(r.size, (15, 12))
self.assertEqual(r.im.bands, im.im.bands)
def test_convolution_modes(self):
self.assertRaises(ValueError, self.resize, hopper("1"),
(15, 12), Image.BILINEAR)
self.assertRaises(ValueError, self.resize, hopper("P"),
(15, 12), Image.BILINEAR)
self.assertRaises(ValueError, self.resize, hopper("I;16"),
(15, 12), Image.BILINEAR)
for mode in ["L", "I", "F", "RGB", "RGBA", "CMYK", "YCbCr"]:
im = hopper(mode)
r = self.resize(im, (15, 12), Image.BILINEAR)
self.assertEqual(r.mode, mode)
self.assertEqual(r.size, (15, 12))
self.assertEqual(r.im.bands, im.im.bands)
def test_reduce_filters(self):
for f in [Image.NEAREST, Image.BOX, Image.BILINEAR,
Image.HAMMING, Image.BICUBIC, Image.LANCZOS]:
r = self.resize(hopper("RGB"), (15, 12), f)
self.assertEqual(r.mode, "RGB")
self.assertEqual(r.size, (15, 12))
def test_enlarge_filters(self):
for f in [Image.NEAREST, Image.BOX, Image.BILINEAR,
Image.HAMMING, Image.BICUBIC, Image.LANCZOS]:
r = self.resize(hopper("RGB"), (212, 195), f)
self.assertEqual(r.mode, "RGB")
self.assertEqual(r.size, (212, 195))
def test_endianness(self):
# 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)
for f in [Image.NEAREST, Image.BOX, Image.BILINEAR,
Image.HAMMING, Image.BICUBIC, Image.LANCZOS]:
# samples resized with current filter
references = {
name: self.resize(ch, (4, 4), f)
for name, ch in samples.items()
}
for mode, channels_set in [
('RGB', ('blank', 'filled', 'dirty')),
('RGBA', ('blank', 'blank', 'filled', 'dirty')),
('LA', ('filled', 'dirty')),
]:
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), f)
for i, ch in enumerate(resized.split()):
# check what resized channel in image is the same
# as separately resized channel
self.assert_image_equal(ch, references[channels[i]])
def test_enlarge_zero(self):
for f in [Image.NEAREST, Image.BOX, Image.BILINEAR,
Image.HAMMING, Image.BICUBIC, Image.LANCZOS]:
r = self.resize(Image.new('RGB', (0, 0), "white"), (212, 195), f)
self.assertEqual(r.mode, "RGB")
self.assertEqual(r.size, (212, 195))
self.assertEqual(r.getdata()[0], (0, 0, 0))
def test_unknown_filter(self):
self.assertRaises(ValueError, self.resize, hopper(), (10, 10), 9)
class TestImageResize(PillowTestCase):
def test_resize(self):
def resize(mode, size):
out = hopper(mode).resize(size)
self.assertEqual(out.mode, mode)
self.assertEqual(out.size, size)
for mode in "1", "P", "L", "RGB", "I", "F":
resize(mode, (112, 103))
resize(mode, (188, 214))
# Test unknown resampling filter
im = hopper()
self.assertRaises(ValueError, im.resize, (10, 10), "unknown")