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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")) | |