# vim: set fileencoding=utf-8 : import pytest import pyvips from helpers import JPEG_FILE, all_formats, have # Run a function expecting a complex image on a two-band image def run_cmplx(fn, image): if image.format == pyvips.BandFormat.FLOAT: new_format = pyvips.BandFormat.COMPLEX elif image.format == pyvips.BandFormat.DOUBLE: new_format = pyvips.BandFormat.DPCOMPLEX else: raise pyvips.Error("run_cmplx: not float or double") # tag as complex, run, revert tagging cmplx = image.copy(bands=1, format=new_format) cmplx_result = fn(cmplx) return cmplx_result.copy(bands=2, format=image.format) def to_polar(image): """Transform image coordinates to polar. The image is transformed so that it is wrapped around a point in the centre. Vertical straight lines become circles or segments of circles, horizontal straight lines become radial spokes. """ # xy image, zero in the centre, scaled to fit image to a circle xy = pyvips.Image.xyz(image.width, image.height) xy -= [image.width / 2.0, image.height / 2.0] scale = min(image.width, image.height) / float(image.width) xy *= 2.0 / scale # to polar, scale vertical axis to 360 degrees index = run_cmplx(lambda x: x.polar(), xy) index *= [1, image.height / 360.0] return image.mapim(index) def to_rectangular(image): """Transform image coordinates to rectangular. The image is transformed so that it is unwrapped from a point in the centre. Circles or segments of circles become vertical straight lines, radial lines become horizontal lines. """ # xy image, vertical scaled to 360 degrees xy = pyvips.Image.xyz(image.width, image.height) xy *= [1, 360.0 / image.height] # to rect, scale to image rect index = run_cmplx(lambda x: x.rect(), xy) scale = min(image.width, image.height) / float(image.width) index *= scale / 2.0 index += [image.width / 2.0, image.height / 2.0] return image.mapim(index) class TestResample: def test_affine(self): im = pyvips.Image.new_from_file(JPEG_FILE) # vsqbs is non-interpolatory, don't test this way for name in ["nearest", "bicubic", "bilinear", "nohalo", "lbb"]: x = im interpolate = pyvips.Interpolate.new(name) for i in range(4): x = x.affine([0, 1, 1, 0], interpolate=interpolate) assert (x - im).abs().max() == 0 def test_reduce(self): im = pyvips.Image.new_from_file(JPEG_FILE) # cast down to 0-127, the smallest range, so we aren't messed up by # clipping im = im.cast(pyvips.BandFormat.CHAR) for fac in [1, 1.1, 1.5, 1.999]: for fmt in all_formats: for kernel in ["nearest", "linear", "cubic", "lanczos2", "lanczos3"]: x = im.cast(fmt) r = x.reduce(fac, fac, kernel=kernel) d = abs(r.avg() - im.avg()) assert d < 2 # try constant images ... should not change the constant for const in [0, 1, 2, 254, 255]: im = (pyvips.Image.black(10, 10) + const).cast("uchar") for kernel in ["nearest", "linear", "cubic", "lanczos2", "lanczos3"]: # print "testing kernel =", kernel # print "testing const =", const shr = im.reduce(2, 2, kernel=kernel) d = abs(shr.avg() - im.avg()) assert d == 0 def test_resize(self): im = pyvips.Image.new_from_file(JPEG_FILE) im2 = im.resize(0.25) assert im2.width == round(im.width / 4.0) assert im2.height == round(im.height / 4.0) # test geometry rounding corner case im = pyvips.Image.black(100, 1) x = im.resize(0.5) assert x.width == 50 assert x.height == 1 def test_shrink(self): im = pyvips.Image.new_from_file(JPEG_FILE) im2 = im.shrink(4, 4) assert im2.width == round(im.width / 4.0) assert im2.height == round(im.height / 4.0) assert abs(im.avg() - im2.avg()) < 1 im2 = im.shrink(2.5, 2.5) assert im2.width == round(im.width / 2.5) assert im2.height == round(im.height / 2.5) assert abs(im.avg() - im2.avg()) < 1 @pytest.mark.skipif(not pyvips.at_least_libvips(8, 5), reason="requires libvips >= 8.5") def test_thumbnail(self): im = pyvips.Image.thumbnail(JPEG_FILE, 100) assert im.width == 100 assert im.bands == 3 assert im.bands == 3 # the average shouldn't move too much im_orig = pyvips.Image.new_from_file(JPEG_FILE) assert abs(im_orig.avg() - im.avg()) < 1 # make sure we always get the right width for width in range(1000, 1, -13): im = pyvips.Image.thumbnail(JPEG_FILE, width) assert im.width == width # should fit one of width or height im = pyvips.Image.thumbnail(JPEG_FILE, 100, height=300) assert im.width == 100 assert im.height != 300 im = pyvips.Image.thumbnail(JPEG_FILE, 300, height=100) assert im.width != 300 assert im.height == 100 # with @crop, should fit both width and height im = pyvips.Image.thumbnail(JPEG_FILE, 100, height=300, crop=True) assert im.width == 100 assert im.height == 300 im1 = pyvips.Image.thumbnail(JPEG_FILE, 100) with open(JPEG_FILE, 'rb') as f: buf = f.read() im2 = pyvips.Image.thumbnail_buffer(buf, 100) assert abs(im1.avg() - im2.avg()) < 1 def test_similarity(self): im = pyvips.Image.new_from_file(JPEG_FILE) im2 = im.similarity(angle=90) im3 = im.affine([0, -1, 1, 0]) # rounding in calculating the affine transform from the angle stops # this being exactly true assert (im2 - im3).abs().max() < 50 def test_similarity_scale(self): im = pyvips.Image.new_from_file(JPEG_FILE) im2 = im.similarity(scale=2) im3 = im.affine([2, 0, 0, 2]) assert (im2 - im3).abs().max() == 0 # added in 8.7 def test_rotate(self): if have("rotate"): im = pyvips.Image.new_from_file(JPEG_FILE) im2 = im.rotate(90) im3 = im.affine([0, -1, 1, 0]) # rounding in calculating the affine transform from the angle stops # this being exactly true assert (im2 - im3).abs().max() < 50 def test_mapim(self): im = pyvips.Image.new_from_file(JPEG_FILE) p = to_polar(im) r = to_rectangular(p) # the left edge (which is squashed to the origin) will be badly # distorted, but the rest should not be too bad a = r.crop(50, 0, im.width - 50, im.height).gaussblur(2) b = im.crop(50, 0, im.width - 50, im.height).gaussblur(2) assert (a - b).abs().max() < 20 if __name__ == '__main__': pytest.main()