Pillow/Tests/test_image_resize.py

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"""
Tests for resize functionality.
"""
from itertools import permutations
from helper import unittest, PillowTestCase, hopper
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from PIL import Image
class TestImagingCoreResize(PillowTestCase):
def resize(self, im, size, f):
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# 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",
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"I;16"]: # exotic mode
im = hopper(mode)
r = self.resize(im, (15, 12), Image.NEAREST)
self.assertEqual(r.mode, mode)
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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)
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self.assertEqual(r.size, (15, 12))
self.assertEqual(r.im.bands, im.im.bands)
def test_reduce_filters(self):
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for f in [Image.NEAREST, Image.BOX, Image.BILINEAR, Image.HAMMING,
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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):
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for f in [Image.NEAREST, Image.BOX, Image.BILINEAR, Image.HAMMING,
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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.
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# 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)
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for f in [Image.NEAREST, Image.BOX, Image.BILINEAR, Image.HAMMING,
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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]])
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class TestImageResize(PillowTestCase):
def test_resize(self):
def resize(mode, size):
out = hopper(mode).resize(size)
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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))
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if __name__ == '__main__':
unittest.main()