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