Clarification of docs

[molecule]

The docs say:

Note that the sequence object returned by this method is an internal PIL data type, which only supports certain sequence operations. To convert it to an ordinary sequence (e.g. for printing), use list(im.getdata()).

src

Where can I learn more about the "certain sequence operations" that this internal PIL data type supports?

Here's what I've tried:

1. im.getdata().len which returns: AttributeError: 'ImagingCore' object has no attribute 'len' So now I know the data type is known as "ImagingCore".
2. Searching through the Docs shows no relevant results: https://www.dropbox.com/s/6tw5ybwd1gy2kqb/Screenshot%202018-08-19%2009.53.10.png?dl=0
3. Searching in the repo yields two results: https://www.dropbox.com/s/dn53eu78asii47n/Screenshot%202018-08-19%2009.53.54.png?dl=0
4. The top result shows a single use of img.getdata() to get the length of the sequence. No other uses are shown.
5. The second results also shows a single user of "ImagingCore". It looks like just a way to name the data type.

Where can I learn more about the "certain sequence operations" that this internal PIL data type supports?

[radarhere]

Investigating -

>>> dir(im.getdata())
['__class__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__len__', '__lt__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__',
'bands', 'box_blur', 'chop_add', 'chop_add_modulo', 'chop_and', 'chop_darker',
'chop_difference', 'chop_invert', 'chop_lighter', 'chop_multiply', 'chop_or',
'chop_screen', 'chop_subtract', 'chop_subtract_modulo', 'chop_xor',
'color_lut_3d', 'convert', 'convert2', 'convert_matrix', 'convert_transparent',
'copy', 'crop', 'effect_spread', 'expand', 'fillband', 'filter', 'gaussian_blur',
'getband', 'getbbox', 'getcolors', 'getextrema', 'getpalette', 'getpalettemode',
'getpixel', 'getprojection', 'histogram', 'id', 'isblock', 'mode', 'modefilter',
'new_block', 'offset', 'paste', 'pixel_access', 'point', 'point_transform', 'ptr',
'putband', 'putdata', 'putpalette', 'putpalettealpha', 'putpalettealphas',
'putpixel', 'quantize', 'rankfilter', 'resize', 'save_ppm', 'setmode', 'size',
'split', 'transform2', 'transpose', 'unsafe_ptrs', 'unsharp_mask']

Which would correspond to these methods, as set on the object

[molecule]

Thanks! I see the actual method definition now: https://github.com/python-pillow/Pillow/blob/90a94e7dae19f75363c769713b1b6d10eb16f613/src/_imaging.c#L466

Is there any example of "get_pixel" being used somewhere? Or more information about what "ImagingAccess access" is supposed to represent? Or int x and int y? I can read through the code and try to figure it out, but I'm hoping there is some information in the otherwise excellent docs that I've missed!

Alternatively: I'm trying to write a compression algorithm for some custom .xbm files. To do so, I need low-level access to the actual bits of the images. Am I going about this in the wrong way? Is there another function I've missed that lets me iterate through the image bits and perform tasks on them?

[radarhere]

Here is a C function that calls that - https://github.com/python-pillow/Pillow/blob/90a94e7dae19f75363c769713b1b6d10eb16f613/src/_imaging.c#L1139-L1162

This is in turn called from Python - https://github.com/python-pillow/Pillow/blob/90a94e7dae19f75363c769713b1b6d10eb16f613/src/PIL/Image.py#L1284-L1297

The prettier documentation for this is at https://pillow.readthedocs.io/en/5.2.x/reference/Image.html?#PIL.Image.Image.getpixel

So if all you are after is getting the value of a pixel, you don't need to go through getdata(), you can fetch the value directly. There is also putpixel - https://pillow.readthedocs.io/en/5.2.x/reference/Image.html?#PIL.Image.Image.putpixel.

If you are interested in going through and changing individual pixels, there is also PixelAccess - https://pillow.readthedocs.io/en/5.2.x/reference/PixelAccess.html

[radarhere]

@molecule do you have any further questions, or is this issue resolved?

[molecule]

Not resolved, but I have a major deadline in the next two weeks, so won't be able to look at this for a while. Thanks for the links.

On Thu, Aug 30, 2018 at 3:35 AM Andrew Murray notifications@github.com wrote:

@molecule https://github.com/molecule do you have any further questions, or is this issue resolved?

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-- UC Berkeley / CS PhD Student / New Media DE BCNM - Invention Lab - Liebe Wetzel's Lunatique Fantastique UC Berkeley CS/CogSci '14 https://molecule.github.io/ https://molecule.github.io/

[radarhere]

Hi. Any updates? I'd just like to close this issue if it is resolved.

[radarhere]

This can be re-opened if there is anything further.