Method test_mesh

Tests/test_image_transform.py:112–149

(self)

        assert transformed.getpixel((w - 1, h - 1)) == expected_pixel

    def test_mesh(self) -> None:
        # this should be a checkerboard of halfsized hoppers in ul, lr
        im = hopper("RGBA")
        w, h = im.size
        transformed = im.transform(
            im.size,
            Image.Transform.MESH,
            (
                (
                    (0, 0, w // 2, h // 2),  # box
                    (0, 0, 0, h, w, h, w, 0),  # ul -> ccw around quad
                ),
                (
                    (w // 2, h // 2, w, h),  # box
                    (0, 0, 0, h, w, h, w, 0),  # ul -> ccw around quad
                ),
            ),
            Image.Resampling.BILINEAR,
        )

        scaled = im.transform(
            (w // 2, h // 2),
            Image.Transform.AFFINE,
            (2, 0, 0, 0, 2, 0),
            Image.Resampling.BILINEAR,
        )

        checker = Image.new("RGBA", im.size)
        checker.paste(scaled, (0, 0))
        checker.paste(scaled, (w // 2, h // 2))

        assert_image_equal(transformed, checker)

        # now, check to see that the extra area is (0, 0, 0, 0)
        blank = Image.new("RGBA", (w // 2, h // 2), (0, 0, 0, 0))

        assert_image_equal(blank, transformed.crop((w // 2, 0, w, h // 2)))
        assert_image_equal(blank, transformed.crop((0, h // 2, w // 2, h)))

    def _test_alpha_premult(
        self, op: Callable[[Image.Image, tuple[int, int]], Image.Image]