import pytest from PIL import Image from .helper import ( assert_image_equal, assert_image_similar, fromstring, hopper, tostring, ) def test_sanity(): im = hopper() assert im.thumbnail((100, 100)) is None assert im.size == (100, 100) def test_aspect(): im = Image.new("L", (128, 128)) im.thumbnail((100, 100)) assert im.size == (100, 100) im = Image.new("L", (128, 256)) im.thumbnail((100, 100)) assert im.size == (50, 100) im = Image.new("L", (128, 256)) im.thumbnail((50, 100)) assert im.size == (50, 100) im = Image.new("L", (256, 128)) im.thumbnail((100, 100)) assert im.size == (100, 50) im = Image.new("L", (256, 128)) im.thumbnail((100, 50)) assert im.size == (100, 50) im = Image.new("L", (128, 128)) im.thumbnail((100, 100)) assert im.size == (100, 100) im = Image.new("L", (256, 162)) # ratio is 1.5802469136 im.thumbnail((33, 33)) assert im.size == (33, 21) # ratio is 1.5714285714 im = Image.new("L", (162, 256)) # ratio is 0.6328125 im.thumbnail((33, 33)) assert im.size == (21, 33) # ratio is 0.6363636364 def test_float(): im = Image.new("L", (128, 128)) im.thumbnail((99.9, 99.9)) assert im.size == (100, 100) def test_no_resize(): # Check that draft() can resize the image to the destination size with Image.open("Tests/images/hopper.jpg") as im: im.draft(None, (64, 64)) assert im.size == (64, 64) # Test thumbnail(), where only draft() is necessary to resize the image with Image.open("Tests/images/hopper.jpg") as im: im.thumbnail((64, 64)) assert im.size == (64, 64) def test_DCT_scaling_edges(): # Make an image with red borders and size (N * 8) + 1 to cross DCT grid im = Image.new("RGB", (257, 257), "red") im.paste(Image.new("RGB", (235, 235)), (11, 11)) thumb = fromstring(tostring(im, "JPEG", quality=99, subsampling=0)) # small reducing_gap to amplify the effect thumb.thumbnail((32, 32), Image.BICUBIC, reducing_gap=1.0) ref = im.resize((32, 32), Image.BICUBIC) # This is still JPEG, some error is present. Without the fix it is 11.5 assert_image_similar(thumb, ref, 1.5) def test_reducing_gap_values(): im = hopper() im.thumbnail((18, 18), Image.BICUBIC) ref = hopper() ref.thumbnail((18, 18), Image.BICUBIC, reducing_gap=2.0) # reducing_gap=2.0 should be the default assert_image_equal(ref, im) ref = hopper() ref.thumbnail((18, 18), Image.BICUBIC, reducing_gap=None) with pytest.raises(AssertionError): assert_image_equal(ref, im) assert_image_similar(ref, im, 3.5) def test_reducing_gap_for_DCT_scaling(): with Image.open("Tests/images/hopper.jpg") as ref: # thumbnail should call draft with reducing_gap scale ref.draft(None, (18 * 3, 18 * 3)) ref = ref.resize((18, 18), Image.BICUBIC) with Image.open("Tests/images/hopper.jpg") as im: im.thumbnail((18, 18), Image.BICUBIC, reducing_gap=3.0) assert_image_equal(ref, im)