Python PIL.Image.BOX Examples

def test_subsample(self):
        # This test shows advantages of the subpixel resizing
        # after supersampling (e.g. during JPEG decoding).
        im = Image.open("Tests/images/flower.jpg")
        self.assertEqual(im.size, (480, 360))
        dst_size = (48, 36)
        # Reference is cropped image resized to destination
        reference = im.crop((0, 0, 473, 353)).resize(dst_size, Image.BICUBIC)
        # Image.BOX emulates supersampling (480 / 8 = 60, 360 / 8 = 45)
        supersampled = im.resize((60, 45), Image.BOX)

        with_box = supersampled.resize(dst_size, Image.BICUBIC,
                                       (0, 0, 59.125, 44.125))
        without_box = supersampled.resize(dst_size, Image.BICUBIC)

        # error with box should be much smaller than without
        self.assert_image_similar(reference, with_box, 6)
        with self.assertRaisesRegex(AssertionError, r"difference 29\."):
            self.assert_image_similar(reference, without_box, 5) 

def __init__(self, size, maintain_aspect_ratio=False, resample='bicubic'):
        self.size = size
        self.maintain_aspect_ratio = maintain_aspect_ratio
        resampling_mapping = {
            'nearest': Image.NEAREST,
            'bilinear': Image.BILINEAR,
            'bicubic': Image.BICUBIC,
            'lanczos': Image.LANCZOS,
            'box': Image.BOX,
            'hamming': Image.HAMMING,
        }
        if resample.lower() not in resampling_mapping.keys():
            raise ValueError(
                "Unknown resampling method '{}'. Allowed values are '{}'"
                .format(resample, "', '".join(resampling_mapping.keys())))
        self.resample = resampling_mapping[resample]
        super().__init__() 

def __init__(self, interpolation):
        if Image is None:
            raise ImportError(
                'pillow backend for resize operation requires TensorFlow. Please install it before usage.'
            )
        self._supported_interpolations = {
            'NEAREST': Image.NEAREST,
            'NONE': Image.NONE,
            'BILINEAR': Image.BILINEAR,
            'LINEAR': Image.LINEAR,
            'BICUBIC': Image.BICUBIC,
            'CUBIC': Image.CUBIC,
            'ANTIALIAS': Image.ANTIALIAS,
        }
        try:
            optional_interpolations = {
                'BOX': Image.BOX,
                'LANCZOS': Image.LANCZOS,
                'HAMMING': Image.HAMMING,
            }
            self._supported_interpolations.update(optional_interpolations)
        except AttributeError:
            pass
        super().__init__(interpolation) 

def supported_interpolations(cls):
        if Image is None:
            return {}
        intrp = {
            'NEAREST': Image.NEAREST,
            'NONE': Image.NONE,
            'BILINEAR': Image.BILINEAR,
            'LINEAR': Image.LINEAR,
            'BICUBIC': Image.BICUBIC,
            'CUBIC': Image.CUBIC,
            'ANTIALIAS': Image.ANTIALIAS
        }
        try:
            optional_interpolations = {
                'BOX': Image.BOX,
                'LANCZOS': Image.LANCZOS,
                'HAMMING': Image.HAMMING,
            }
            intrp.update(optional_interpolations)
        except AttributeError:
            pass
        return intrp 

def pixelate(x, severity=1):
    c = [0.6, 0.5, 0.4, 0.3, 0.25][severity - 1]

    x = x.resize((int(224 * c), int(224 * c)), PILImage.BOX)
    x = x.resize((224, 224), PILImage.BOX)

    return x


# mod of https://gist.github.com/erniejunior/601cdf56d2b424757de5 

def pixelate(x, severity=1):
    c = [0.6, 0.5, 0.4, 0.3, 0.25][severity - 1]

    x = x.resize((int(224 * c), int(224 * c)), PILImage.BOX)
    x = x.resize((224, 224), PILImage.BOX)

    return x


# mod of https://gist.github.com/erniejunior/601cdf56d2b424757de5 

def pixelate(x, severity=1):
    c = [0.95, 0.9, 0.85, 0.75, 0.65][severity - 1]

    x = x.resize((int(32 * c), int(32 * c)), PILImage.BOX)
    x = x.resize((32, 32), PILImage.BOX)

    return x


# mod of https://gist.github.com/erniejunior/601cdf56d2b424757de5 

def pixelate(x, severity=1):
    c = [0.9, 0.8, 0.7, 0.6, 0.5][severity - 1]

    x = x.resize((int(64 * c), int(64 * c)), PILImage.BOX)
    x = x.resize((64, 64), PILImage.BOX)

    return x


# mod of https://gist.github.com/erniejunior/601cdf56d2b424757de5 

def pixelate(x, severity=1):
    c = [0.5, 0.4, 0.3, 0.25, 0.2][severity - 1]

    x = x.resize((int(299 * c), int(299 * c)), PILImage.BOX)
    x = x.resize((299, 299), PILImage.BOX)

    return x


# mod of https://gist.github.com/erniejunior/601cdf56d2b424757de5 

def test_reduce_box(self):
        for mode in ['RGBX', 'RGB', 'La', 'L']:
            case = self.make_case(mode, (8, 8), 0xe1)
            case = case.resize((4, 4), Image.BOX)
            data = ('e1 e1'
                    'e1 e1')
            for channel in case.split():
                self.check_case(channel, self.make_sample(data, (4, 4))) 

def test_enlarge_box(self):
        for mode in ['RGBX', 'RGB', 'La', 'L']:
            case = self.make_case(mode, (2, 2), 0xe1)
            case = case.resize((4, 4), Image.BOX)
            data = ('e1 e1'
                    'e1 e1')
            for channel in case.split():
                self.check_case(channel, self.make_sample(data, (4, 4))) 

def test_levels_rgba(self):
        case = self.make_levels_case('RGBA')
        self.run_levels_case(case.resize((512, 32), Image.BOX))
        self.run_levels_case(case.resize((512, 32), Image.BILINEAR))
        self.run_levels_case(case.resize((512, 32), Image.HAMMING))
        self.run_levels_case(case.resize((512, 32), Image.BICUBIC))
        self.run_levels_case(case.resize((512, 32), Image.LANCZOS)) 

def test_levels_la(self):
        case = self.make_levels_case('LA')
        self.run_levels_case(case.resize((512, 32), Image.BOX))
        self.run_levels_case(case.resize((512, 32), Image.BILINEAR))
        self.run_levels_case(case.resize((512, 32), Image.HAMMING))
        self.run_levels_case(case.resize((512, 32), Image.BICUBIC))
        self.run_levels_case(case.resize((512, 32), Image.LANCZOS)) 

def test_dirty_pixels_rgba(self):
        case = self.make_dirty_case('RGBA', (255, 255, 0, 128), (0, 0, 255, 0))
        self.run_dirty_case(case.resize((20, 20), Image.BOX), (255, 255, 0))
        self.run_dirty_case(case.resize((20, 20), Image.BILINEAR),
                            (255, 255, 0))
        self.run_dirty_case(case.resize((20, 20), Image.HAMMING),
                            (255, 255, 0))
        self.run_dirty_case(case.resize((20, 20), Image.BICUBIC),
                            (255, 255, 0))
        self.run_dirty_case(case.resize((20, 20), Image.LANCZOS),
                            (255, 255, 0)) 

def test_wrong_arguments(self):
        im = hopper()
        for resample in (Image.NEAREST, Image.BOX, Image.BILINEAR,
                         Image.HAMMING, Image.BICUBIC, Image.LANCZOS):
            im.resize((32, 32), resample, (0, 0, im.width, im.height))
            im.resize((32, 32), resample, (20, 20, im.width, im.height))
            im.resize((32, 32), resample, (20, 20, 20, 100))
            im.resize((32, 32), resample, (20, 20, 100, 20))

            with self.assertRaisesRegex(TypeError,
                                        "must be sequence of length 4"):
                im.resize((32, 32), resample, (im.width, im.height))

            with self.assertRaisesRegex(ValueError, "can't be negative"):
                im.resize((32, 32), resample, (-20, 20, 100, 100))
            with self.assertRaisesRegex(ValueError, "can't be negative"):
                im.resize((32, 32), resample, (20, -20, 100, 100))

            with self.assertRaisesRegex(ValueError, "can't be empty"):
                im.resize((32, 32), resample, (20.1, 20, 20, 100))
            with self.assertRaisesRegex(ValueError, "can't be empty"):
                im.resize((32, 32), resample, (20, 20.1, 100, 20))
            with self.assertRaisesRegex(ValueError, "can't be empty"):
                im.resize((32, 32), resample, (20.1, 20.1, 20, 20))

            with self.assertRaisesRegex(ValueError, "can't exceed"):
                im.resize((32, 32), resample, (0, 0, im.width + 1, im.height))
            with self.assertRaisesRegex(ValueError, "can't exceed"):
                im.resize((32, 32), resample, (0, 0, im.width, im.height + 1)) 

def test_reduce_filters(self):
        for f in [Image.NEAREST, Image.BOX, Image.BILINEAR,
                  Image.HAMMING, Image.BICUBIC, Image.LANCZOS]:
            r = self.resize(hopper("RGB"), (15, 12), f)
            self.assertEqual(r.mode, "RGB")
            self.assertEqual(r.size, (15, 12)) 

def test_enlarge_filters(self):
        for f in [Image.NEAREST, Image.BOX, Image.BILINEAR,
                  Image.HAMMING, Image.BICUBIC, Image.LANCZOS]:
            r = self.resize(hopper("RGB"), (212, 195), f)
            self.assertEqual(r.mode, "RGB")
            self.assertEqual(r.size, (212, 195)) 

def test_endianness(self):
        # Make an image with one colored pixel, in one channel.
        # When resized, that channel should be the same as a GS image.
        # Other channels should be unaffected.
        # The R and A channels should not swap, which is indicative of
        # an endianness issues.

        samples = {
            'blank': Image.new('L', (2, 2), 0),
            'filled': Image.new('L', (2, 2), 255),
            'dirty': Image.new('L', (2, 2), 0),
        }
        samples['dirty'].putpixel((1, 1), 128)

        for f in [Image.NEAREST, Image.BOX, Image.BILINEAR,
                  Image.HAMMING, Image.BICUBIC, Image.LANCZOS]:
            # samples resized with current filter
            references = {
                name: self.resize(ch, (4, 4), f)
                for name, ch in samples.items()
            }

            for mode, channels_set in [
                ('RGB', ('blank', 'filled', 'dirty')),
                ('RGBA', ('blank', 'blank', 'filled', 'dirty')),
                ('LA', ('filled', 'dirty')),
            ]:
                for channels in set(permutations(channels_set)):
                    # compile image from different channels permutations
                    im = Image.merge(mode, [samples[ch] for ch in channels])
                    resized = self.resize(im, (4, 4), f)

                    for i, ch in enumerate(resized.split()):
                        # check what resized channel in image is the same
                        # as separately resized channel
                        self.assert_image_equal(ch, references[channels[i]]) 

def pixelate(x, severity=1):
    c = [0.6, 0.5, 0.4, 0.3, 0.25][severity - 1]

    x_shape = np.array(x).shape

    x = x.resize((int(x_shape[1] * c), int(x_shape[0] * c)), Image.BOX)

    x = x.resize((x_shape[1], x_shape[0]), Image.NEAREST)

    return x


# mod of https://gist.github.com/erniejunior/601cdf56d2b424757de5 

def normalize_raw(im, imsize, scale=8):
    cropsize = imsize * scale * 2
    assert im.width >= cropsize, "image is too small"
    assert im.height >= cropsize, "image is too small"

    wpad = (im.width - cropsize) // 2
    hpad = (im.height - cropsize) // 2
    if scale == 8:
        im = im.crop((wpad-2, hpad-2, wpad+2 + cropsize, hpad+2 + cropsize))
        im = im.resize((im.width // 4, im.height // 4), Image.BOX)
        im = im.resize((imsize * 2, imsize * 2), Image.NEAREST)
    else:
        im = im.crop((wpad, hpad, wpad + cropsize, hpad + cropsize))
        im = im.resize((imsize * 2, imsize * 2), Image.BOX)
    return im 

def pixelate(x: np.ndarray, strength: float, xrange: tuple = None) -> np.ndarray:
    """
    Change coarseness of pixels for an image.

    Parameters
    ----------
    x
        Instance to be perturbed.
    strength
        Strength of pixelation (<1). Lower is actually more pixelated.
    xrange
        Tuple with min and max data range.

    Returns
    -------
    Perturbed instance.
    """
    rows, cols = x.shape[:2]

    if not isinstance(xrange, tuple):
        xrange = (x.min(), x.max())

    if xrange[0] != 0 or xrange[1] != 255:
        x = (x - xrange[0]) / (xrange[1] - xrange[0]) * 255

    im = Image.fromarray(x.astype('uint8'), mode='RGB')
    im = im.resize((int(rows * strength), int(cols * strength)), Image.BOX)
    im = im.resize((rows, cols), Image.BOX)
    x_pi = np.array(im, dtype=np.float32) / 255
    x_pi = x_pi * (xrange[1] - xrange[0]) + xrange[0]
    return x_pi 

def __init__(self):
        ImageUtilsBackend.__init__(self)
        if hasattr(Image, "HAMMING"):  # version >3.4.0
            self._interpolations_map["hamming"] = Image.HAMMING

        if hasattr(Image, "BOX"):  # version >3.4.0
            self._interpolations_map["box"] = Image.BOX

        if hasattr(Image, "LANCZOS"):  # version >1.1.3
            self._interpolations_map["lanczos"] = Image.LANCZOS 

def resize_image(
        self,
        width: int,
        height: int,
        extension: str = "png",
        resample: str = "nearest",
        quality: int = 100,
    ):
        """Resize an image. 
        
        Args:
            width (int): Required. Width in pixels
            height (int): Required. Height in pixels
            extension (str, optional): File extension of loaded image. Defaults to png
            resample (str, optional): Resample rate. Defaults to "nearest".
            quality (int, optional): Quality of output. Defaults to 100.
        
        Returns:
            Chepy: The Chepy object. 

        Examples:
            >>> c = Chepy("image.png").load_file().resize_image(256, 256, "png")
            >>> c.write_to_file("/path/to/file.png", as_binary=True)
        """
        fh = io.BytesIO()
        if resample == "nearest":
            resample = Image.NEAREST
        elif resample == "antialias":
            resample = Image.ANTIALIAS
        elif resample == "bilinear":
            resample = Image.BILINEAR
        elif resample == "box":
            resample = Image.BOX
        elif resample == "hamming":
            resample = Image.HAMMING
        else:  # pragma: no cover
            raise TypeError(
                "Valid resampling options are: nearest, antialias, bilinear, box and hamming"
            )
        image = Image.open(self._load_as_file())
        resized = image.resize((width, height), resample=resample)
        resized.save(fh, extension, quality=quality)
        self.state = fh.getvalue()
        return self 

def resize(img, boxes, size, max_size=1000, random_interpolation=False):
    '''Resize the input PIL image to given size.

    If boxes is not None, resize boxes accordingly.

    Args:
      img: (PIL.Image) image to be resized.
      boxes: (tensor) object boxes, sized [#obj,4].
      size: (tuple or int)
        - if is tuple, resize image to the size.
        - if is int, resize the shorter side to the size while maintaining the aspect ratio.
      max_size: (int) when size is int, limit the image longer size to max_size.
                This is essential to limit the usage of GPU memory.
      random_interpolation: (bool) randomly choose a resize interpolation method.

    Returns:
      img: (PIL.Image) resized image.
      boxes: (tensor) resized boxes.

    Example:
    >> img, boxes = resize(img, boxes, 600)  # resize shorter side to 600
    >> img, boxes = resize(img, boxes, (500,600))  # resize image size to (500,600)
    >> img, _ = resize(img, None, (500,600))  # resize image only
    '''
    w, h = img.size
    if isinstance(size, int):
        size_min = min(w,h)
        size_max = max(w,h)
        sw = sh = float(size) / size_min
        if sw * size_max > max_size:
            sw = sh = float(max_size) / size_max
        ow = int(w * sw + 0.5)
        oh = int(h * sh + 0.5)
    else:
        ow, oh = size
        sw = float(ow) / w
        sh = float(oh) / h

    method = random.choice([
        Image.BOX,
        Image.NEAREST,
        Image.HAMMING,
        Image.BICUBIC,
        Image.LANCZOS,
        Image.BILINEAR]) if random_interpolation else Image.BILINEAR
    img = img.resize((ow,oh), method)
    if boxes is not None:
        boxes = boxes * torch.Tensor([sw,sh,sw,sh])
    return img, boxes 

def resize(img, boxes, size, max_size=1000, random_interpolation=False):
    '''Resize the input PIL image to given size.

    If boxes is not None, resize boxes accordingly.

    Args:
      img: (PIL.Image) image to be resized.
      boxes: (tensor) object boxes, sized [#obj,4].
      size: (tuple or int)
        - if is tuple, resize image to the size.
        - if is int, resize the shorter side to the size while maintaining the aspect ratio.
      max_size: (int) when size is int, limit the image longer size to max_size.
                This is essential to limit the usage of GPU memory.
      random_interpolation: (bool) randomly choose a resize interpolation method.

    Returns:
      img: (PIL.Image) resized image.
      boxes: (tensor) resized boxes.

    Example:
    >> img, boxes = resize(img, boxes, 600)  # resize shorter side to 600
    >> img, boxes = resize(img, boxes, (500,600))  # resize image size to (500,600)
    >> img, _ = resize(img, None, (500,600))  # resize image only
    '''
    w, h = img.size
    if isinstance(size, int):
        size_min = min(w,h)
        size_max = max(w,h)
        sw = sh = float(size) / size_min
        if sw * size_max > max_size:
            sw = sh = float(max_size) / size_max
        ow = int(w * sw + 0.5)
        oh = int(h * sh + 0.5)
    else:
        ow, oh = size
        sw = float(ow) / w
        sh = float(oh) / h

    method = random.choice([
        Image.BOX,
        Image.NEAREST,
        Image.HAMMING,
        Image.BICUBIC,
        Image.LANCZOS,
        Image.BILINEAR]) if random_interpolation else Image.BILINEAR
    img = img.resize((ow,oh), method)
    if boxes is not None:
        boxes = boxes * torch.tensor([sw,sh,sw,sh])
    return img, boxes