283 lines
6 KiB
Python
283 lines
6 KiB
Python
#
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# The Python Imaging Library.
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# $Id$
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#
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# standard channel operations
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#
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# History:
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# 1996-03-24 fl Created
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# 1996-08-13 fl Added logical operations (for "1" images)
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# 2000-10-12 fl Added offset method (from Image.py)
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#
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# Copyright (c) 1997-2000 by Secret Labs AB
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# Copyright (c) 1996-2000 by Fredrik Lundh
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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 PIL import Image
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def constant(image, value):
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"""Fill a channel with a given grey level.
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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return Image.new("L", image.size, value)
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def duplicate(image):
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"""Copy a channel. Alias for :py:meth:`PIL.Image.Image.copy`.
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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return image.copy()
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def invert(image):
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"""
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Invert an image (channel).
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.. code-block:: python
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out = MAX - image
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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image.load()
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return image._new(image.im.chop_invert())
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def lighter(image1, image2):
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"""
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Compares the two images, pixel by pixel, and returns a new image containing
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the lighter values.
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.. code-block:: python
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out = max(image1, image2)
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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image1.load()
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image2.load()
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return image1._new(image1.im.chop_lighter(image2.im))
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def darker(image1, image2):
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"""
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Compares the two images, pixel by pixel, and returns a new image
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containing the darker values.
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.. code-block:: python
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out = min(image1, image2)
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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image1.load()
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image2.load()
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return image1._new(image1.im.chop_darker(image2.im))
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def difference(image1, image2):
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"""
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Returns the absolute value of the pixel-by-pixel difference between the two
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images.
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.. code-block:: python
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out = abs(image1 - image2)
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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image1.load()
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image2.load()
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return image1._new(image1.im.chop_difference(image2.im))
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def multiply(image1, image2):
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"""
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Superimposes two images on top of each other.
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If you multiply an image with a solid black image, the result is black. If
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you multiply with a solid white image, the image is unaffected.
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.. code-block:: python
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out = image1 * image2 / MAX
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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image1.load()
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image2.load()
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return image1._new(image1.im.chop_multiply(image2.im))
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def screen(image1, image2):
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"""
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Superimposes two inverted images on top of each other.
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.. code-block:: python
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out = MAX - ((MAX - image1) * (MAX - image2) / MAX)
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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image1.load()
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image2.load()
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return image1._new(image1.im.chop_screen(image2.im))
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def add(image1, image2, scale=1.0, offset=0):
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"""
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Adds two images, dividing the result by scale and adding the
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offset. If omitted, scale defaults to 1.0, and offset to 0.0.
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.. code-block:: python
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out = ((image1 + image2) / scale + offset)
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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image1.load()
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image2.load()
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return image1._new(image1.im.chop_add(image2.im, scale, offset))
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def subtract(image1, image2, scale=1.0, offset=0):
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"""
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Subtracts two images, dividing the result by scale and adding the
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offset. If omitted, scale defaults to 1.0, and offset to 0.0.
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.. code-block:: python
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out = ((image1 - image2) / scale + offset)
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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image1.load()
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image2.load()
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return image1._new(image1.im.chop_subtract(image2.im, scale, offset))
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def add_modulo(image1, image2):
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"""Add two images, without clipping the result.
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.. code-block:: python
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out = ((image1 + image2) % MAX)
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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image1.load()
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image2.load()
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return image1._new(image1.im.chop_add_modulo(image2.im))
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def subtract_modulo(image1, image2):
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"""Subtract two images, without clipping the result.
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.. code-block:: python
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out = ((image1 - image2) % MAX)
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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image1.load()
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image2.load()
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return image1._new(image1.im.chop_subtract_modulo(image2.im))
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def logical_and(image1, image2):
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"""Logical AND between two images.
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.. code-block:: python
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out = ((image1 and image2) % MAX)
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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image1.load()
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image2.load()
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return image1._new(image1.im.chop_and(image2.im))
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def logical_or(image1, image2):
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"""Logical OR between two images.
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.. code-block:: python
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out = ((image1 or image2) % MAX)
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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image1.load()
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image2.load()
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return image1._new(image1.im.chop_or(image2.im))
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def logical_xor(image1, image2):
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"""Logical XOR between two images.
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.. code-block:: python
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out = ((bool(image1) != bool(image2)) % MAX)
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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image1.load()
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image2.load()
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return image1._new(image1.im.chop_xor(image2.im))
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def blend(image1, image2, alpha):
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"""Blend images using constant transparency weight. Alias for
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:py:meth:`PIL.Image.Image.blend`.
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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return Image.blend(image1, image2, alpha)
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def composite(image1, image2, mask):
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"""Create composite using transparency mask. Alias for
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:py:meth:`PIL.Image.Image.composite`.
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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return Image.composite(image1, image2, mask)
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def offset(image, xoffset, yoffset=None):
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"""Returns a copy of the image where data has been offset by the given
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distances. Data wraps around the edges. If **yoffset** is omitted, it
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is assumed to be equal to **xoffset**.
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:param xoffset: The horizontal distance.
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:param yoffset: The vertical distance. If omitted, both
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distances are set to the same value.
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:rtype: :py:class:`~PIL.Image.Image`
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"""
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if yoffset is None:
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yoffset = xoffset
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image.load()
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return image._new(image.im.offset(xoffset, yoffset))
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