214 lines
7.5 KiB
Python
214 lines
7.5 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, all_formats, have
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# Run a function expecting a complex image on a two-band image
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def run_cmplx(fn, image):
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if image.format == pyvips.BandFormat.FLOAT:
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new_format = pyvips.BandFormat.COMPLEX
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elif image.format == pyvips.BandFormat.DOUBLE:
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new_format = pyvips.BandFormat.DPCOMPLEX
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else:
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raise pyvips.Error("run_cmplx: not float or double")
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# tag as complex, run, revert tagging
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cmplx = image.copy(bands=1, format=new_format)
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cmplx_result = fn(cmplx)
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return cmplx_result.copy(bands=2, format=image.format)
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def to_polar(image):
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"""Transform image coordinates to polar.
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The image is transformed so that it is wrapped around a point in the
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centre. Vertical straight lines become circles or segments of circles,
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horizontal straight lines become radial spokes.
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"""
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# xy image, zero in the centre, scaled to fit image to a circle
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xy = pyvips.Image.xyz(image.width, image.height)
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xy -= [image.width / 2.0, image.height / 2.0]
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scale = min(image.width, image.height) / float(image.width)
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xy *= 2.0 / scale
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# to polar, scale vertical axis to 360 degrees
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index = run_cmplx(lambda x: x.polar(), xy)
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index *= [1, image.height / 360.0]
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return image.mapim(index)
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def to_rectangular(image):
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"""Transform image coordinates to rectangular.
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The image is transformed so that it is unwrapped from a point in the
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centre. Circles or segments of circles become vertical straight lines,
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radial lines become horizontal lines.
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"""
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# xy image, vertical scaled to 360 degrees
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xy = pyvips.Image.xyz(image.width, image.height)
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xy *= [1, 360.0 / image.height]
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# to rect, scale to image rect
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index = run_cmplx(lambda x: x.rect(), xy)
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scale = min(image.width, image.height) / float(image.width)
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index *= scale / 2.0
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index += [image.width / 2.0, image.height / 2.0]
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return image.mapim(index)
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class TestResample:
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def test_affine(self):
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im = pyvips.Image.new_from_file(JPEG_FILE)
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# vsqbs is non-interpolatory, don't test this way
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for name in ["nearest", "bicubic", "bilinear", "nohalo", "lbb"]:
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x = im
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interpolate = pyvips.Interpolate.new(name)
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for i in range(4):
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x = x.affine([0, 1, 1, 0], interpolate=interpolate)
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assert (x - im).abs().max() == 0
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def test_reduce(self):
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im = pyvips.Image.new_from_file(JPEG_FILE)
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# cast down to 0-127, the smallest range, so we aren't messed up by
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# clipping
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im = im.cast(pyvips.BandFormat.CHAR)
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for fac in [1, 1.1, 1.5, 1.999]:
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for fmt in all_formats:
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for kernel in ["nearest", "linear",
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"cubic", "lanczos2", "lanczos3"]:
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x = im.cast(fmt)
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r = x.reduce(fac, fac, kernel=kernel)
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d = abs(r.avg() - im.avg())
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assert d < 2
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# try constant images ... should not change the constant
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for const in [0, 1, 2, 254, 255]:
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im = (pyvips.Image.black(10, 10) + const).cast("uchar")
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for kernel in ["nearest", "linear",
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"cubic", "lanczos2", "lanczos3"]:
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# print "testing kernel =", kernel
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# print "testing const =", const
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shr = im.reduce(2, 2, kernel=kernel)
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d = abs(shr.avg() - im.avg())
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assert d == 0
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def test_resize(self):
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im = pyvips.Image.new_from_file(JPEG_FILE)
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im2 = im.resize(0.25)
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# in py3, round() does not round to nearest in the obvious way, so we
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# have to do it by hand
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assert im2.width == int(im.width / 4.0 + 0.5)
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assert im2.height == int(im.height / 4.0 + 0.5)
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# test geometry rounding corner case
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im = pyvips.Image.black(100, 1)
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x = im.resize(0.5)
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assert x.width == 50
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assert x.height == 1
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def test_shrink(self):
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im = pyvips.Image.new_from_file(JPEG_FILE)
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im2 = im.shrink(4, 4)
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# in py3, round() does not round to nearest in the obvious way, so we
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# have to do it by hand
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assert im2.width == int(im.width / 4.0 + 0.5)
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assert im2.height == int(im.height / 4.0 + 0.5)
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assert abs(im.avg() - im2.avg()) < 1
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im2 = im.shrink(2.5, 2.5)
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assert im2.width == int(im.width / 2.5 + 0.5)
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assert im2.height == int(im.height / 2.5 + 0.5)
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assert abs(im.avg() - im2.avg()) < 1
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@pytest.mark.skipif(not pyvips.at_least_libvips(8, 5),
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reason="requires libvips >= 8.5")
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def test_thumbnail(self):
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im = pyvips.Image.thumbnail(JPEG_FILE, 100)
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assert im.height == 100
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assert im.bands == 3
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assert im.bands == 3
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# the average shouldn't move too much
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im_orig = pyvips.Image.new_from_file(JPEG_FILE)
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assert abs(im_orig.avg() - im.avg()) < 1
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# make sure we always get the right width
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for height in range(440, 1, -13):
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im = pyvips.Image.thumbnail(JPEG_FILE, height)
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assert im.height == height
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# should fit one of width or height
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im = pyvips.Image.thumbnail(JPEG_FILE, 100, height=300)
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assert im.width == 100
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assert im.height != 300
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im = pyvips.Image.thumbnail(JPEG_FILE, 300, height=100)
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assert im.width != 300
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assert im.height == 100
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# with @crop, should fit both width and height
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im = pyvips.Image.thumbnail(JPEG_FILE, 100,
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height=300, crop=True)
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assert im.width == 100
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assert im.height == 300
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im1 = pyvips.Image.thumbnail(JPEG_FILE, 100)
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with open(JPEG_FILE, 'rb') as f:
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buf = f.read()
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im2 = pyvips.Image.thumbnail_buffer(buf, 100)
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assert abs(im1.avg() - im2.avg()) < 1
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def test_similarity(self):
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im = pyvips.Image.new_from_file(JPEG_FILE)
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im2 = im.similarity(angle=90)
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im3 = im.affine([0, -1, 1, 0])
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# rounding in calculating the affine transform from the angle stops
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# this being exactly true
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assert (im2 - im3).abs().max() < 50
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def test_similarity_scale(self):
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im = pyvips.Image.new_from_file(JPEG_FILE)
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im2 = im.similarity(scale=2)
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im3 = im.affine([2, 0, 0, 2])
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assert (im2 - im3).abs().max() == 0
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# added in 8.7
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def test_rotate(self):
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if have("rotate"):
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im = pyvips.Image.new_from_file(JPEG_FILE)
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im2 = im.rotate(90)
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im3 = im.affine([0, -1, 1, 0])
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# rounding in calculating the affine transform from the angle stops
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# this being exactly true
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assert (im2 - im3).abs().max() < 50
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def test_mapim(self):
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im = pyvips.Image.new_from_file(JPEG_FILE)
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p = to_polar(im)
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r = to_rectangular(p)
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# the left edge (which is squashed to the origin) will be badly
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# distorted, but the rest should not be too bad
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a = r.crop(50, 0, im.width - 50, im.height).gaussblur(2)
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b = im.crop(50, 0, im.width - 50, im.height).gaussblur(2)
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assert (a - b).abs().max() < 40
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# this was a bug at one point, strangely, if executed with debug
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# enabled
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mp = pyvips.Image.xyz(im.width, im.height)
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interp = pyvips.Interpolate.new('bicubic')
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assert im.mapim(mp, interpolate=interp).avg() == im.avg()
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if __name__ == '__main__':
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pytest.main()
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