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.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.
#

from PIL 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.

[docs]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.
[docs]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.
[docs]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.
[docs]class Sharpness(_Enhance): "Adjust image sharpness" def __init__(self, image): self.image = image self.degenerate = image.filter(ImageFilter.SMOOTH)