100 lines
3.1 KiB
Python
100 lines
3.1 KiB
Python
#
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# The Python Imaging Library.
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# $Id$
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#
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# image enhancement classes
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#
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# For a background, see "Image Processing By Interpolation and
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# Extrapolation", Paul Haeberli and Douglas Voorhies. Available
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# at http://www.graficaobscura.com/interp/index.html
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#
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# History:
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# 1996-03-23 fl Created
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# 2009-06-16 fl Fixed mean calculation
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#
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# Copyright (c) Secret Labs AB 1997.
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# Copyright (c) Fredrik Lundh 1996.
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#
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# See the README file for information on usage and redistribution.
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#
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from . import Image, ImageFilter, ImageStat
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class _Enhance(object):
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def enhance(self, factor):
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"""
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Returns an enhanced image.
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:param factor: A floating point value controlling the enhancement.
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Factor 1.0 always returns a copy of the original image,
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lower factors mean less color (brightness, contrast,
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etc), and higher values more. There are no restrictions
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on this value.
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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return Image.blend(self.degenerate, self.image, factor)
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class Color(_Enhance):
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"""Adjust image color balance.
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This class can be used to adjust the colour balance of an image, in
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a manner similar to the controls on a colour TV set. An enhancement
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factor of 0.0 gives a black and white image. A factor of 1.0 gives
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the original image.
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"""
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def __init__(self, image):
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self.image = image
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self.intermediate_mode = 'L'
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if 'A' in image.getbands():
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self.intermediate_mode = 'LA'
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self.degenerate = image.convert(self.intermediate_mode).convert(image.mode)
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class Contrast(_Enhance):
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"""Adjust image contrast.
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This class can be used to control the contrast of an image, similar
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to the contrast control on a TV set. An enhancement factor of 0.0
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gives a solid grey image. A factor of 1.0 gives the original image.
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"""
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def __init__(self, image):
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self.image = image
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mean = int(ImageStat.Stat(image.convert("L")).mean[0] + 0.5)
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self.degenerate = Image.new("L", image.size, mean).convert(image.mode)
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if 'A' in image.getbands():
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self.degenerate.putalpha(image.getchannel('A'))
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class Brightness(_Enhance):
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"""Adjust image brightness.
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This class can be used to control the brightness of an image. An
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enhancement factor of 0.0 gives a black image. A factor of 1.0 gives the
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original image.
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"""
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def __init__(self, image):
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self.image = image
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self.degenerate = Image.new(image.mode, image.size, 0)
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if 'A' in image.getbands():
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self.degenerate.putalpha(image.getchannel('A'))
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class Sharpness(_Enhance):
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"""Adjust image sharpness.
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This class can be used to adjust the sharpness of an image. An
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enhancement factor of 0.0 gives a blurred image, a factor of 1.0 gives the
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original image, and a factor of 2.0 gives a sharpened image.
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"""
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def __init__(self, image):
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self.image = image
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self.degenerate = image.filter(ImageFilter.SMOOTH)
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if 'A' in image.getbands():
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self.degenerate.putalpha(image.getchannel('A'))
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