Pillow/Tests/test_image_resize.py
Jon Dufresne 7da17ad41e Improve pytest configuration to allow specific tests as CLI args
The previous test configuration made it difficult to run a single test
with the pytest CLI. There were two major issues:

- The Tests directory was not a package. It now includes a __init__.py
  file and imports from other tests modules are done with relative
  imports.

- setup.cfg always specified the Tests directory. So even if a specific
  test were specified as a CLI arg, this configuration would also always
  include all tests. This configuration has been removed to allow
  specifying a single test on the command line.

Contributors can now run specific tests with a single command such as:

  $ tox -e py37 -- Tests/test_file_pdf.py::TestFilePdf.test_rgb

This makes it easy and faster to iterate on a single test failure and is
very familiar to those that have previously used tox and pytest.

When running tox or pytest with no arguments, they still discover and
runs all tests in the Tests directory.
2019-01-13 09:00:12 -08:00

122 lines
4.6 KiB
Python

"""
Tests for resize functionality.
"""
from itertools import permutations
from .helper import unittest, 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")
if __name__ == '__main__':
unittest.main()