181 lines
6.7 KiB
Python
181 lines
6.7 KiB
Python
# vim: set fileencoding=utf-8 :
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import pytest
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import pyvips
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from helpers import JPEG_FILE, SRGB_FILE, colour_colourspaces, \
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mono_colourspaces, assert_almost_equal_objects, skip_if_no
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class TestColour:
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def test_colourspace(self):
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# mid-grey in Lab ... put 42 in the extra band, it should be copied
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# unmodified
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test = pyvips.Image.black(100, 100) + [50, 0, 0, 42]
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test = test.copy(interpretation=pyvips.Interpretation.LAB)
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# a long series should come in a circle
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im = test
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for col in colour_colourspaces + [pyvips.Interpretation.LAB]:
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im = im.colourspace(col)
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assert im.interpretation == col
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for i in range(0, 4):
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min_l = im.extract_band(i).min()
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max_h = im.extract_band(i).max()
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assert pytest.approx(min_l) == max_h
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pixel = im(10, 10)
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assert pytest.approx(pixel[3], 0.01) == 42
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# alpha won't be equal for RGB16, but it should be preserved if we go
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# there and back
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im = im.colourspace(pyvips.Interpretation.RGB16)
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im = im.colourspace(pyvips.Interpretation.LAB)
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before = test(10, 10)
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after = im(10, 10)
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assert_almost_equal_objects(before, after, threshold=0.1)
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# go between every pair of colour spaces
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for start in colour_colourspaces:
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for end in colour_colourspaces:
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im = test.colourspace(start)
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im2 = im.colourspace(end)
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im3 = im2.colourspace(pyvips.Interpretation.LAB)
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before = test(10, 10)
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after = im3(10, 10)
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assert_almost_equal_objects(before, after, threshold=0.1)
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# test Lab->XYZ on mid-grey
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# checked against http://www.brucelindbloom.com
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im = test.colourspace(pyvips.Interpretation.XYZ)
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after = im(10, 10)
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assert_almost_equal_objects(after, [17.5064, 18.4187, 20.0547, 42])
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# grey->colour->grey should be equal
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for mono_fmt in mono_colourspaces:
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test_grey = test.colourspace(mono_fmt)
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im = test_grey
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for col in colour_colourspaces + [mono_fmt]:
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im = im.colourspace(col)
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assert im.interpretation == col
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[before, alpha_before] = test_grey(10, 10)
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[after, alpha_after] = im(10, 10)
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assert abs(alpha_after - alpha_before) < 1
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if mono_fmt == pyvips.Interpretation.GREY16:
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# GREY16 can wind up rather different due to rounding
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assert abs(after - before) < 30
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else:
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# but 8-bit we should hit exactly
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assert abs(after - before) < 1
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# we should be able to go from cmyk to any 3-band space and back again,
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# approximately
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cmyk = test.colourspace(pyvips.Interpretation.CMYK)
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for end in colour_colourspaces:
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im = cmyk.colourspace(end)
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im2 = im.colourspace(pyvips.Interpretation.CMYK)
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before = cmyk(10, 10)
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after = im2(10, 10)
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assert_almost_equal_objects(before, after, threshold=10)
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# test results from Bruce Lindbloom's calculator:
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# http://www.brucelindbloom.com
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def test_dE00(self):
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# put 42 in the extra band, it should be copied unmodified
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reference = pyvips.Image.black(100, 100) + [50, 10, 20, 42]
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reference = reference.copy(interpretation=pyvips.Interpretation.LAB)
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sample = pyvips.Image.black(100, 100) + [40, -20, 10]
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sample = sample.copy(interpretation=pyvips.Interpretation.LAB)
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difference = reference.dE00(sample)
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result, alpha = difference(10, 10)
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assert pytest.approx(result, 0.001) == 30.238
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assert pytest.approx(alpha, 0.001) == 42.0
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def test_dE76(self):
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# put 42 in the extra band, it should be copied unmodified
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reference = pyvips.Image.black(100, 100) + [50, 10, 20, 42]
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reference = reference.copy(interpretation=pyvips.Interpretation.LAB)
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sample = pyvips.Image.black(100, 100) + [40, -20, 10]
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sample = sample.copy(interpretation=pyvips.Interpretation.LAB)
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difference = reference.dE76(sample)
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result, alpha = difference(10, 10)
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assert pytest.approx(result, 0.001) == 33.166
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assert pytest.approx(alpha, 0.001) == 42.0
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# the vips CMC calculation is based on distance in a colorspace
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# derived from the CMC formula, so it won't match exactly ...
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# see vips_LCh2CMC() for details
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def test_dECMC(self):
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reference = pyvips.Image.black(100, 100) + [50, 10, 20, 42]
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reference = reference.copy(interpretation=pyvips.Interpretation.LAB)
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sample = pyvips.Image.black(100, 100) + [55, 11, 23]
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sample = sample.copy(interpretation=pyvips.Interpretation.LAB)
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difference = reference.dECMC(sample)
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result, alpha = difference(10, 10)
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assert abs(result - 4.97) < 0.5
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assert pytest.approx(alpha, 0.001) == 42.0
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@skip_if_no("icc_import")
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def test_icc(self):
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test = pyvips.Image.new_from_file(JPEG_FILE)
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im = test.icc_import().icc_export()
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assert im.dE76(test).max() < 6
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im = test.icc_import()
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im2 = im.icc_export(depth=16)
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assert im2.format == pyvips.BandFormat.USHORT
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im3 = im2.icc_import()
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assert (im - im3).abs().max() < 3
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im = test.icc_import(intent=pyvips.Intent.ABSOLUTE)
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im2 = im.icc_export(intent=pyvips.Intent.ABSOLUTE)
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assert im2.dE76(test).max() < 6
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im = test.icc_import()
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im2 = im.icc_export(output_profile=SRGB_FILE)
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im3 = im.colourspace(pyvips.Interpretation.SRGB)
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assert im2.dE76(im3).max() < 6
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before_profile = test.get("icc-profile-data")
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im = test.icc_transform(SRGB_FILE)
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after_profile = im.get("icc-profile-data")
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im2 = test.icc_import()
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im3 = im2.colourspace(pyvips.Interpretation.SRGB)
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assert im.dE76(im3).max() < 6
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assert len(before_profile) != len(after_profile)
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im = test.icc_import(input_profile=SRGB_FILE)
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im2 = test.icc_import()
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assert 6 < im.dE76(im2).max()
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im = test.icc_import(pcs=pyvips.PCS.XYZ)
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assert im.interpretation == pyvips.Interpretation.XYZ
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im = test.icc_import()
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assert im.interpretation == pyvips.Interpretation.LAB
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# even without lcms, we should have a working approximation
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def test_cmyk(self):
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test = pyvips.Image.new_from_file(JPEG_FILE)
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im = test.colourspace("cmyk").colourspace("srgb")
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before = test(582, 210)
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after = im(582, 210)
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assert_almost_equal_objects(before, after, threshold=10)
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if __name__ == '__main__':
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pytest.main()
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