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#
# 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:
def enhance(self, factor):
"""
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):
self.image = image
self.intermediate_mode = "L"
if "A" in image.getbands():
self.intermediate_mode = "LA"
self.degenerate = image.convert(self.intermediate_mode).convert(image.mode)
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):
self.image = image
mean = int(ImageStat.Stat(image.convert("L")).mean[0] + 0.5)
self.degenerate = Image.new("L", image.size, mean).convert(image.mode)
if "A" in image.getbands():
self.degenerate.putalpha(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):
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):
self.image = image
self.degenerate = image.filter(ImageFilter.SMOOTH)
if "A" in image.getbands():
self.degenerate.putalpha(image.getchannel("A"))
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