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# Source code for PIL.ImageEnhance

    #
    # The Python Imaging Library.
    # $Id$
    #
    # image enhancement classes
    #
    # For a background, see "Image Processing By Interpolation and
    # Extrapolation", Paul Haeberli and Douglas Voorhies.  Available
    # at http://www.graficaobscura.com/interp/index.html
    #
    # History:
    # 1996-03-23 fl  Created
    # 2009-06-16 fl  Fixed mean calculation
    #
    # Copyright (c) Secret Labs AB 1997.
    # Copyright (c) Fredrik Lundh 1996.
    #
    # See the README file for information on usage and redistribution.
    #
    from __future__ import annotations

    from . import Image, ImageFilter, ImageStat

    class _Enhance:
        image: Image.Image
        degenerate: Image.Image

        def enhance(self, factor: float) -> Image.Image:
            """
            Returns an enhanced image.

            :param factor: A floating point value controlling the enhancement.
                           Factor 1.0 always returns a copy of the original image,
                           lower factors mean less color (brightness, contrast,
                           etc), and higher values more. There are no restrictions
                           on this value.
            :rtype: :py:class:`~PIL.Image.Image`
            """
            return Image.blend(self.degenerate, self.image, factor)

    class Color(_Enhance):
        """Adjust image color balance.

        This class can be used to adjust the colour balance of an image, in
        a manner similar to the controls on a colour TV set. An enhancement
        factor of 0.0 gives a black and white image. A factor of 1.0 gives
        the original image.
        """

        def __init__(self, image: Image.Image) -> None:
            self.image = image
            self.intermediate_mode = "L"
            if "A" in image.getbands():
                self.intermediate_mode = "LA"

            if self.intermediate_mode != image.mode:
                image = image.convert(self.intermediate_mode).convert(image.mode)
            self.degenerate = image

    class Contrast(_Enhance):
        """Adjust image contrast.

        This class can be used to control the contrast of an image, similar
        to the contrast control on a TV set. An enhancement factor of 0.0
        gives a solid gray image. A factor of 1.0 gives the original image.
        """

        def __init__(self, image: Image.Image) -> None:
            self.image = image
            if image.mode != "L":
                image = image.convert("L")
            mean = int(ImageStat.Stat(image).mean[0] + 0.5)
            self.degenerate = Image.new("L", image.size, mean)
            if self.degenerate.mode != self.image.mode:
                self.degenerate = self.degenerate.convert(self.image.mode)

            if "A" in self.image.getbands():
                self.degenerate.putalpha(self.image.getchannel("A"))

    class Brightness(_Enhance):
        """Adjust image brightness.

        This class can be used to control the brightness of an image.  An
        enhancement factor of 0.0 gives a black image. A factor of 1.0 gives the
        original image.
        """

        def __init__(self, image: Image.Image) -> None:
            self.image = image
            self.degenerate = Image.new(image.mode, image.size, 0)

            if "A" in image.getbands():
                self.degenerate.putalpha(image.getchannel("A"))

    class Sharpness(_Enhance):
        """Adjust image sharpness.

        This class can be used to adjust the sharpness of an image. An
        enhancement factor of 0.0 gives a blurred image, a factor of 1.0 gives the
        original image, and a factor of 2.0 gives a sharpened image.
        """

        def __init__(self, image: Image.Image) -> None:
            self.image = image
            self.degenerate = image.filter(ImageFilter.SMOOTH)

            if "A" in image.getbands():
                self.degenerate.putalpha(image.getchannel("A"))