#
# 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.sgi.com/grafica/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.
#
import Image, ImageFilter, ImageStat
class _Enhance:
##
# Returns an enhanced image. The enhancement factor is a floating
# point value controlling the enhancement. Factor 1.0 always
# returns a copy of the original image, lower factors mean less
# colour (brightness, contrast, etc), and higher values more.
# There are no restrictions on this value.
#
# @param factor Enhancement factor.
# @return An enhanced image.
def enhance(self, factor):
return Image.blend(self.degenerate, self.image, factor)
##
# Color enhancement object.
# <p>
# 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.
class Color(_Enhance):
"Adjust image colour balance"
def __init__(self, image):
self.image = image
self.degenerate = image.convert("L").convert(image.mode)
##
# Contrast enhancement object.
# <p>
# 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 grey image, factor 1.0 gives the original image.
class Contrast(_Enhance):
"Adjust image contrast"
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)
##
# Brightness enhancement object.
# <p>
# This class can be used to control the brighntess of an image. An
# enhancement factor of 0.0 gives a black image, factor 1.0 gives the
# original image.
class Brightness(_Enhance):
"Adjust image brightness"
def __init__(self, image):
self.image = image
self.degenerate = Image.new(image.mode, image.size, 0)
##
# Sharpness enhancement object.
# <p>
# This class can be used to adjust the sharpness of an image. The
# enhancement factor 0.0 gives a blurred image, 1.0 gives the original
# image, and a factor of 2.0 gives a sharpened image.
class Sharpness(_Enhance):
"Adjust image sharpness"
def __init__(self, image):
self.image = image
self.degenerate = image.filter(ImageFilter.SMOOTH)
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