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Merge pull request #2661 from uploadcare/get-channel

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New Image.getchannel method
This commit is contained in:
wiredfool 2017-08-16 15:33:54 +01:00 committed by GitHub
commit e2602452f4
12 changed files with 85 additions and 35 deletions
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25
PIL/Image.py
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@ -1948,6 +1948,9 @@ class Image(object):
containing a copy of one of the original bands (red, green,
blue).
If you need only one band, :py:meth:`~PIL.Image.Image.getchannel`
method can be more convenient and faster.
:returns: A tuple containing bands.
"""
@ -1960,6 +1963,28 @@ class Image(object):
ims.append(self._new(self.im.getband(i)))
return tuple(ims)
def getchannel(self, channel):
"""
Returns an image containing a single channel of the source image.
:param channel: What channel to return. Could be index
(0 for "R" channel of "RGB") or channel name
("A" for alpha channel of "RGBA").
:returns: An image in "L" mode.
.. versionadded:: 4.3.0
"""
self.load()
if isStringType(channel):
try:
channel = self.getbands().index(channel)
except ValueError:
raise ValueError(
'The image has no channel "{}"'.format(channel))
return self._new(self.im.getband(channel))
def tell(self):
"""
Returns the current frame number. See :py:meth:`~PIL.Image.Image.seek`.

6
PIL/ImageEnhance.py
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@ -67,7 +67,7 @@ class Contrast(_Enhance):
self.degenerate = Image.new("L", image.size, mean).convert(image.mode)
if 'A' in image.getbands():
self.degenerate.putalpha(image.split()[-1])
self.degenerate.putalpha(image.getchannel('A'))
class Brightness(_Enhance):
@ -82,7 +82,7 @@ class Brightness(_Enhance):
self.degenerate = Image.new(image.mode, image.size, 0)
if 'A' in image.getbands():
self.degenerate.putalpha(image.split()[-1])
self.degenerate.putalpha(image.getchannel('A'))
class Sharpness(_Enhance):
@ -97,4 +97,4 @@ class Sharpness(_Enhance):
self.degenerate = image.filter(ImageFilter.SMOOTH)
if 'A' in image.getbands():
self.degenerate.putalpha(image.split()[-1])
self.degenerate.putalpha(image.getchannel('A'))

10
Tests/test_file_png.py
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@ -200,7 +200,7 @@ class TestFilePng(PillowTestCase):
self.assert_image(im, "RGBA", (162, 150))
# image has 124 unique alpha values
self.assertEqual(len(im.split()[3].getcolors()), 124)
self.assertEqual(len(im.getchannel('A').getcolors()), 124)
def test_load_transparent_rgb(self):
test_file = "Tests/images/rgb_trns.png"
@ -212,7 +212,7 @@ class TestFilePng(PillowTestCase):
self.assert_image(im, "RGBA", (64, 64))
# image has 876 transparent pixels
self.assertEqual(im.split()[3].getcolors()[0][0], 876)
self.assertEqual(im.getchannel('A').getcolors()[0][0], 876)
def test_save_p_transparent_palette(self):
in_file = "Tests/images/pil123p.png"
@ -234,7 +234,7 @@ class TestFilePng(PillowTestCase):
self.assert_image(im, "RGBA", (162, 150))
# image has 124 unique alpha values
self.assertEqual(len(im.split()[3].getcolors()), 124)
self.assertEqual(len(im.getchannel('A').getcolors()), 124)
def test_save_p_single_transparency(self):
in_file = "Tests/images/p_trns_single.png"
@ -258,7 +258,7 @@ class TestFilePng(PillowTestCase):
self.assertEqual(im.getpixel((31, 31)), (0, 255, 52, 0))
# image has 876 transparent pixels
self.assertEqual(im.split()[3].getcolors()[0][0], 876)
self.assertEqual(im.getchannel('A').getcolors()[0][0], 876)
def test_save_p_transparent_black(self):
# check if solid black image with full transparency
@ -287,7 +287,7 @@ class TestFilePng(PillowTestCase):
# There are 559 transparent pixels.
im = im.convert('RGBA')
self.assertEqual(im.split()[3].getcolors()[0][0], 559)
self.assertEqual(im.getchannel('A').getcolors()[0][0], 559)
def test_save_rgb_single_transparency(self):
in_file = "Tests/images/caption_6_33_22.png"

27
Tests/test_format_hsv.py
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@ -103,11 +103,11 @@ class TestFormatHSV(PillowTestCase):
# im.split()[0].show()
# comparable.split()[0].show()
self.assert_image_similar(im.split()[0], comparable.split()[0],
self.assert_image_similar(im.getchannel(0), comparable.getchannel(0),
1, "Hue conversion is wrong")
self.assert_image_similar(im.split()[1], comparable.split()[1],
self.assert_image_similar(im.getchannel(1), comparable.getchannel(1),
1, "Saturation conversion is wrong")
self.assert_image_similar(im.split()[2], comparable.split()[2],
self.assert_image_similar(im.getchannel(2), comparable.getchannel(2),
1, "Value conversion is wrong")
# print(im.getpixel((192, 64)))
@ -120,11 +120,11 @@ class TestFormatHSV(PillowTestCase):
# print(im.getpixel((192, 64)))
# print(comparable.getpixel((192, 64)))
self.assert_image_similar(im.split()[0], comparable.split()[0],
self.assert_image_similar(im.getchannel(0), comparable.getchannel(0),
3, "R conversion is wrong")
self.assert_image_similar(im.split()[1], comparable.split()[1],
self.assert_image_similar(im.getchannel(1), comparable.getchannel(1),
3, "G conversion is wrong")
self.assert_image_similar(im.split()[2], comparable.split()[2],
self.assert_image_similar(im.getchannel(2), comparable.getchannel(2),
3, "B conversion is wrong")
def test_convert(self):
@ -137,11 +137,11 @@ class TestFormatHSV(PillowTestCase):
# print(im.split()[0].histogram())
# print(comparable.split()[0].histogram())
self.assert_image_similar(im.split()[0], comparable.split()[0],
self.assert_image_similar(im.getchannel(0), comparable.getchannel(0),
1, "Hue conversion is wrong")
self.assert_image_similar(im.split()[1], comparable.split()[1],
self.assert_image_similar(im.getchannel(1), comparable.getchannel(1),
1, "Saturation conversion is wrong")
self.assert_image_similar(im.split()[2], comparable.split()[2],
self.assert_image_similar(im.getchannel(2), comparable.getchannel(2),
1, "Value conversion is wrong")
def test_hsv_to_rgb(self):
@ -155,11 +155,14 @@ class TestFormatHSV(PillowTestCase):
# print([ord(x) for x in target.split()[1].tobytes()[:80]])
# print([ord(x) for x in converted.split()[1].tobytes()[:80]])
self.assert_image_similar(converted.split()[0], comparable.split()[0],
self.assert_image_similar(converted.getchannel(0),
comparable.getchannel(0),
3, "R conversion is wrong")
self.assert_image_similar(converted.split()[1], comparable.split()[1],
self.assert_image_similar(converted.getchannel(1),
comparable.getchannel(1),
3, "G conversion is wrong")
self.assert_image_similar(converted.split()[2], comparable.split()[2],
self.assert_image_similar(converted.getchannel(2),
comparable.getchannel(2),
3, "B conversion is wrong")

24
Tests/test_image.py
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@ -164,14 +164,28 @@ class TestImage(PillowTestCase):
self.assertEqual(im.size[1], orig_size[1] + 2*ymargin)
def test_getbands(self):
# Arrange
# Assert
self.assertEqual(hopper('RGB').getbands(), ('R', 'G', 'B'))
self.assertEqual(hopper('YCbCr').getbands(), ('Y', 'Cb', 'Cr'))
def test_getchannel_wrong_params(self):
im = hopper()
# Act
bands = im.getbands()
self.assertRaises(ValueError, im.getchannel, -1)
self.assertRaises(ValueError, im.getchannel, 3)
self.assertRaises(ValueError, im.getchannel, 'Z')
self.assertRaises(ValueError, im.getchannel, '1')
# Assert
self.assertEqual(bands, ('R', 'G', 'B'))
def test_getchannel(self):
im = hopper('YCbCr')
Y, Cb, Cr = im.split()
self.assert_image_equal(Y, im.getchannel(0))
self.assert_image_equal(Y, im.getchannel('Y'))
self.assert_image_equal(Cb, im.getchannel(1))
self.assert_image_equal(Cb, im.getchannel('Cb'))
self.assert_image_equal(Cr, im.getchannel(2))
self.assert_image_equal(Cr, im.getchannel('Cr'))
def test_getbbox(self):
# Arrange

4
Tests/test_image_convert.py
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@ -133,7 +133,7 @@ class TestImageConvert(PillowTestCase):
alpha = hopper('L')
im.putalpha(alpha)
comparable = im.convert('P').convert('LA').split()[1]
comparable = im.convert('P').convert('LA').getchannel('A')
self.assert_image_similar(alpha, comparable, 5)
@ -185,7 +185,7 @@ class TestImageConvert(PillowTestCase):
if converted_im.mode == 'RGB':
self.assert_image_similar(converted_im, target, 3)
else:
self.assert_image_similar(converted_im, target.split()[0], 1)
self.assert_image_similar(converted_im, target.getchannel(0), 1)
matrix_convert('RGB')
matrix_convert('L')

5
Tests/test_imagecms.py
View File

@ -360,8 +360,7 @@ class TestImageCms(PillowTestCase):
return Image.merge(mode, chans)
source_image = create_test_image()
preserved_channel_ndx = source_image.getbands().index(preserved_channel)
source_image_aux = source_image.split()[preserved_channel_ndx]
source_image_aux = source_image.getchannel(preserved_channel)
# create some transform, it doesn't matter which one
source_profile = ImageCms.createProfile("sRGB")
@ -374,7 +373,7 @@ class TestImageCms(PillowTestCase):
result_image = source_image
else:
result_image = ImageCms.applyTransform(source_image, t, inPlace=False)
result_image_aux = result_image.split()[preserved_channel_ndx]
result_image_aux = result_image.getchannel(preserved_channel)
self.assert_image_equal(source_image_aux, result_image_aux)

2
Tests/test_imageenhance.py
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@ -34,7 +34,7 @@ class TestImageEnhance(PillowTestCase):
def _check_alpha(self, im, original, op, amount):
self.assertEqual(im.getbands(), original.getbands())
self.assert_image_equal(im.split()[-1], original.split()[-1],
self.assert_image_equal(im.getchannel('A'), original.getchannel('A'),
"Diff on %s: %s" % (op, amount))
def test_alpha(self):

2
Tests/test_numpy.py
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@ -52,7 +52,7 @@ class TestNumpy(PillowTestCase):
a = numpy.array([[x]*bands for x in data], dtype=dtype)
a.shape = TEST_IMAGE_SIZE[0], TEST_IMAGE_SIZE[1], bands
i = Image.fromarray(a)
if list(i.split()[0].getdata()) != list(range(100)):
if list(i.getchannel(0).getdata()) != list(range(100)):
print("data mismatch for", dtype)
# print(dtype, list(i.getdata()))
return i

1
docs/reference/Image.rst
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@ -146,6 +146,7 @@ ITU-R 709, using the D65 luminant) to the CIE XYZ color space:
.. automethod:: PIL.Image.Image.seek
.. automethod:: PIL.Image.Image.show
.. automethod:: PIL.Image.Image.split
.. automethod:: PIL.Image.Image.getchannel
.. automethod:: PIL.Image.Image.tell
.. automethod:: PIL.Image.Image.thumbnail
.. automethod:: PIL.Image.Image.tobitmap

9
docs/releasenotes/4.3.0.rst Normal file
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@ -0,0 +1,9 @@
4.3.0
-----
Get One Channel From Image
==========================
New method :py:meth:`PIL.Image.Image.getchannel` added.
It returns single channel by index or name. For example,
``image.getchannel("A")`` will return alpha channel as seperate image.

3
docs/releasenotes/index.rst
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@ -6,6 +6,7 @@ Release Notes
.. toctree::
:maxdepth: 2
4.3.0
4.2.1
4.2.0
4.1.1
@ -21,5 +22,3 @@ Release Notes
3.0.0
2.8.0
2.7.0