Pillow/Tests/test_image_thumbnail.py
Alexander 8181aed77f Merge branch 'reduce' into reduce-in-resize
# Conflicts:
#	docs/releasenotes/7.0.0.rst
#	src/PIL/Image.py
2019-12-20 20:27:11 +03:00

101 lines
3.5 KiB
Python

from PIL import Image
from .helper import PillowTestCase, fromstring, hopper, tostring
class TestImageThumbnail(PillowTestCase):
def test_sanity(self):
im = hopper()
self.assertIsNone(im.thumbnail((100, 100)))
self.assertEqual(im.size, (100, 100))
def test_aspect(self):
im = Image.new("L", (128, 128))
im.thumbnail((100, 100))
self.assertEqual(im.size, (100, 100))
im = Image.new("L", (128, 256))
im.thumbnail((100, 100))
self.assertEqual(im.size, (50, 100))
im = Image.new("L", (128, 256))
im.thumbnail((50, 100))
self.assertEqual(im.size, (50, 100))
im = Image.new("L", (256, 128))
im.thumbnail((100, 100))
self.assertEqual(im.size, (100, 50))
im = Image.new("L", (256, 128))
im.thumbnail((100, 50))
self.assertEqual(im.size, (100, 50))
im = Image.new("L", (128, 128))
im.thumbnail((100, 100))
self.assertEqual(im.size, (100, 100))
im = Image.new("L", (256, 162)) # ratio is 1.5802469136
im.thumbnail((33, 33))
self.assertEqual(im.size, (33, 21)) # ratio is 1.5714285714
im = Image.new("L", (162, 256)) # ratio is 0.6328125
im.thumbnail((33, 33))
self.assertEqual(im.size, (21, 33)) # ratio is 0.6363636364
def test_float(self):
im = Image.new("L", (128, 128))
im.thumbnail((99.9, 99.9))
self.assertEqual(im.size, (100, 100))
def test_no_resize(self):
# 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))
self.assertEqual(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))
self.assertEqual(im.size, (64, 64))
def test_DCT_scaling_edges(self):
# 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
self.assert_image_similar(thumb, ref, 1.5)
def test_reducing_gap_values(self):
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
self.assert_image_equal(ref, im)
ref = hopper()
ref.thumbnail((18, 18), Image.BICUBIC, reducing_gap=None)
with self.assertRaises(AssertionError):
self.assert_image_equal(ref, im)
self.assert_image_similar(ref, im, 3.5)
def test_reducing_gap_for_DCT_scaling(self):
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)
self.assert_image_equal(ref, im)