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BGR;[15,16,34,32] modes are documented but not part of ImageMode #5933
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On that note, is there any chance to add
"1;8"as an official mode and not just a rawmode?I might be going about this the wrong way, but I can't seem to figure out how to save a boolean array while setting the mode explicitly:
image = np.arange(256 * 256).reshape((256, 256)) % 2 == 0 Image.fromarray(expected).save("fancy.png") # works Image.fromarray(expected, mode="1").save("fancy.png") # saves corrupted image Image.fromarray(expected, mode="1;8").save("fancy.png") # invalid mode
I think when I documented BGR;* in #4047, I was just working from
Pillow/src/libImaging/Storage.c
Lines 131 to 155 in 3f77466
The support for those modes is not great -
BGR;32isn't even mentioned anywhere else insrc.That said, I don't see any problem with a PR adding those modes to ImageMode.
Image.fromarray(expected).save("fancy.png")goes through
Lines 2806 to 2816 in 3f77466
to come out with amodeof 1 and arawmodeof1;8- so yes, I'm not surprised that you can't get the same result when explicitly setting the mode, which would lead to identical values formodeandrawmode.But I'm also not clear on why you need to set the mode explicitly?
The support for those modes is not great - BGR;32 isn't even mentioned anywhere else in src.
I agree, I never saw this mode in real code neither.
My motivation for doing this is a refactor in our codebase that makes it lean on
ImageModeinstead of maintaining our own list of channels for each mode, which could go out of sync as pillow improves. I noticed that those modes are missing, so I think it makes sense to make that list complete.
But I'm also not clear on why you need to set the mode [
1;8] explicitly?Because I was writing a unit-test and it caught me off guard that the following round trip fails:
# a boolean ndarray saved as b/w expected = np.arange(256 * 256).reshape((256, 256)) % 2 == 0 Image.fromarray(expected, mode="1").save("fancy.png") actual = np.asarray(Image.open("fancy.png")) assert np.allclose(actual, expected)
In my case, the solution was to drop
mode=1completely, but it is unexpected that the above does not work. From here, I did some searching on what the correctmode=XXvalue should be, but it seems that it is impossible to set the mode explicitly for this scenario. Instead, it has to be resolved implicitly by pillow using the shape and dtype of the array.@radarhere I added a PR to add the
BGR;XXImageModes. Do I just wait for a review from here, or is there anything else I should do?Yes, it's now just a matter of waiting for reviews/comments on your PR.
I found a few image modes that are listed as partially supported in the docs (here), but that are not listed in
ImageMode:Is there any reason why these have not been added? If not, would a PR adding those be welcome?