Pillow/Tests/test_image_rotate.py

from PIL import Image

from .helper import PillowTestCase, hopper


class TestImageRotate(PillowTestCase):
    def rotate(self, im, mode, angle, center=None, translate=None):
        out = im.rotate(angle, center=center, translate=translate)
        self.assertEqual(out.mode, mode)
        self.assertEqual(out.size, im.size)  # default rotate clips output
        out = im.rotate(angle, center=center, translate=translate, expand=1)
        self.assertEqual(out.mode, mode)
        if angle % 180 == 0:
            self.assertEqual(out.size, im.size)
        elif im.size == (0, 0):
            self.assertEqual(out.size, im.size)
        else:
            self.assertNotEqual(out.size, im.size)

    def test_mode(self):
        for mode in ("1", "P", "L", "RGB", "I", "F"):
            im = hopper(mode)
            self.rotate(im, mode, 45)

    def test_angle(self):
        for angle in (0, 90, 180, 270):
            with Image.open("Tests/images/test-card.png") as im:
                self.rotate(im, im.mode, angle)

    def test_zero(self):
        for angle in (0, 45, 90, 180, 270):
            im = Image.new("RGB", (0, 0))
            self.rotate(im, im.mode, angle)

    def test_resample(self):
        # Target image creation, inspected by eye.
        # >>> im = Image.open('Tests/images/hopper.ppm')
        # >>> im = im.rotate(45, resample=Image.BICUBIC, expand=True)
        # >>> im.save('Tests/images/hopper_45.png')

        with Image.open("Tests/images/hopper_45.png") as target:
            for (resample, epsilon) in (
                (Image.NEAREST, 10),
                (Image.BILINEAR, 5),
                (Image.BICUBIC, 0),
            ):
                im = hopper()
                im = im.rotate(45, resample=resample, expand=True)
                self.assert_image_similar(im, target, epsilon)

    def test_center_0(self):
        im = hopper()
        im = im.rotate(45, center=(0, 0), resample=Image.BICUBIC)

        with Image.open("Tests/images/hopper_45.png") as target:
            target_origin = target.size[1] / 2
            target = target.crop((0, target_origin, 128, target_origin + 128))

        self.assert_image_similar(im, target, 15)

    def test_center_14(self):
        im = hopper()
        im = im.rotate(45, center=(14, 14), resample=Image.BICUBIC)

        with Image.open("Tests/images/hopper_45.png") as target:
            target_origin = target.size[1] / 2 - 14
            target = target.crop((6, target_origin, 128 + 6, target_origin + 128))

            self.assert_image_similar(im, target, 10)

    def test_translate(self):
        im = hopper()
        with Image.open("Tests/images/hopper_45.png") as target:
            target_origin = (target.size[1] / 2 - 64) - 5
            target = target.crop(
                (target_origin, target_origin, target_origin + 128, target_origin + 128)
            )

        im = im.rotate(45, translate=(5, 5), resample=Image.BICUBIC)

        self.assert_image_similar(im, target, 1)

    def test_fastpath_center(self):
        # if the center is -1,-1 and we rotate by 90<=x<=270 the
        # resulting image should be black
        for angle in (90, 180, 270):
            im = hopper().rotate(angle, center=(-1, -1))
            self.assert_image_equal(im, Image.new("RGB", im.size, "black"))

    def test_fastpath_translate(self):
        # if we post-translate by -128
        # resulting image should be black
        for angle in (0, 90, 180, 270):
            im = hopper().rotate(angle, translate=(-128, -128))
            self.assert_image_equal(im, Image.new("RGB", im.size, "black"))

    def test_center(self):
        im = hopper()
        self.rotate(im, im.mode, 45, center=(0, 0))
        self.rotate(im, im.mode, 45, translate=(im.size[0] / 2, 0))
        self.rotate(im, im.mode, 45, center=(0, 0), translate=(im.size[0] / 2, 0))

    def test_rotate_no_fill(self):
        im = Image.new("RGB", (100, 100), "green")
        im = im.rotate(45)
        with Image.open("Tests/images/rotate_45_no_fill.png") as target:
            self.assert_image_equal(im, target)

    def test_rotate_with_fill(self):
        im = Image.new("RGB", (100, 100), "green")
        im = im.rotate(45, fillcolor="white")
        with Image.open("Tests/images/rotate_45_with_fill.png") as target:
            self.assert_image_equal(im, target)

    def test_alpha_rotate_no_fill(self):
        # Alpha images are handled differently internally
        im = Image.new("RGBA", (10, 10), "green")
        im = im.rotate(45, expand=1)
        corner = im.getpixel((0, 0))
        self.assertEqual(corner, (0, 0, 0, 0))

    def test_alpha_rotate_with_fill(self):
        # Alpha images are handled differently internally
        im = Image.new("RGBA", (10, 10), "green")
        im = im.rotate(45, expand=1, fillcolor=(255, 0, 0, 255))
        corner = im.getpixel((0, 0))
        self.assertEqual(corner, (255, 0, 0, 255))