3 examples of 'crop image opencv' in Python

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@staticmethod
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def _opencv_image(source: Image, resize: int = 0) -> CVImage:
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    """Read image file to grayscale openCV int array.
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    The OpenCV algorithms works on a two dimensional
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    numpy array integers where 0 is black and 255 is
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    white. Color images will be converted to grayscale.
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    """
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    if isinstance(source, Path):
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        assert source.exists(), 'file {} not found'.format(source)
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        source = source.read_bytes()
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    if not isinstance(source, bytes):
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        raise TypeError('incorrect type')
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    data = numpy.frombuffer(source, numpy.uint8)
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    cv_image = cv2.imdecode(data, cv2.IMREAD_COLOR)
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    cv_image = cv2.cvtColor(cv_image, cv2.COLOR_BGR2GRAY)
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    if resize > 0:
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        w, h = cv_image.shape[1::-1]  # type: int, int
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        multiplier = (resize**2 / (w * h))**0.5
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        dimensions = tuple(int(round(d * multiplier)) for d in (w, h))
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        cv_image = cv2.resize(
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            cv_image, dimensions, interpolation=cv2.INTER_AREA
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        )
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    return cv_image

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@tests.test_if(not skip_slow_tests)
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def crop():
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    """Crops in-place."""
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    with Image(filename=asset('croptest.png')) as img:
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        with img.clone() as cropped:
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            assert cropped.size == img.size
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            cropped.crop(100, 100, 200, 200)
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            assert cropped.size == (100, 100)
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            with Color('#000') as black:
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                for row in cropped:
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                    for col in row:
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                        assert col == black
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        with img.clone() as cropped:
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            assert cropped.size == img.size
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            cropped.crop(100, 100, width=100, height=100)
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            assert cropped.size == (100, 100)
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        with img.clone() as cropped:
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            assert cropped.size == img.size
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            cropped.crop(left=150, bottom=150)
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            assert cropped.size == (150, 150)
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        with img.clone() as cropped:
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            assert cropped.size == img.size
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            cropped.crop(left=150, height=150)
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            assert cropped.size == (150, 150)
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        with img.clone() as cropped:
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            assert cropped.size == img.size
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            cropped.crop(-200, -200, -100, -100)
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            assert cropped.size == (100, 100)
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        with img.clone() as cropped:
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            assert cropped.size == img.size
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            cropped.crop(top=100, bottom=200)
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            assert cropped.size == (300, 100)
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        with raises(ValueError):
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            img.crop(0, 0, 500, 500)
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        with raises(ValueError):
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            img.crop(290, 290, 50, 50)
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        with raises(ValueError):
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            img.crop(290, 290, width=0, height=0)

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def crop_image(img, i0, j0, ni, nj):
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    boxm2_batch.init_process("vilCropImageProcess")
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    boxm2_batch.set_input_from_db(0, img)
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    boxm2_batch.set_input_unsigned(1, i0)
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    boxm2_batch.set_input_unsigned(2, j0)
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    boxm2_batch.set_input_unsigned(3, ni)
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    boxm2_batch.set_input_unsigned(4, nj)
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    boxm2_batch.run_process()
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    (id, type) = boxm2_batch.commit_output(0)
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    img_out = dbvalue(id, type)
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    return img_out