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Comments/Docs, fixes #440

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This commit is contained in:
wiredfool 2013-12-10 16:05:05 -08:00
parent d05b5d9060
commit 4791d156f1
2 changed files with 19 additions and 6 deletions
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16
PIL/Image.py
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@ -1134,14 +1134,16 @@ class Image:
"""
Maps this image through a lookup table or function.
:param lut: A lookup table, containing 256 values per band in the
image. A function can be used instead, it should take a single
argument. The function is called once for each possible pixel
value, and the resulting table is applied to all bands of the
image.
:param lut: A lookup table, containing 256 (or 65336 if
self.mode=="I" and mode == "L") values per band in the
image. A function can be used instead, it should take a
single argument. The function is called once for each
possible pixel value, and the resulting table is applied to
all bands of the image.
:param mode: Output mode (default is same as input). In the
current version, this can only be used if the source image
has mode "L" or "P", and the output has mode "1".
has mode "L" or "P", and the output has mode "1" or the
source image mode is "I" and the output mode is "L".
:returns: An :py:class:`~PIL.Image.Image` object.
"""
@ -1154,6 +1156,8 @@ class Image:
# if it isn't a list, it should be a function
if self.mode in ("I", "I;16", "F"):
# check if the function can be used with point_transform
# UNDONE wiredfool -- I think this prevents us from ever doing
# a gamma function point transform on > 8bit images.
scale, offset = _getscaleoffset(lut)
return self._new(self.im.point_transform(scale, offset))
# for other modes, convert the function to a table

9
Tests/test_image_point.py
View File

@ -17,3 +17,12 @@ def test_sanity():
assert_no_exception(lambda: im.point(lambda x: x*1+1))
assert_exception(TypeError, lambda: im.point(lambda x: x-1))
assert_exception(TypeError, lambda: im.point(lambda x: x/1))
def test_16bit_lut():
""" Tests for 16 bit -> 8 bit lut for converting I->L images
see https://github.com/python-imaging/Pillow/issues/440
"""
im = lena("I")
assert_no_exception(lambda: im.point(list(range(256))*256, 'L'))