Problem with saving image from clipboard

Hello,

I have Windows 8 x64 system and installed Pillow version 2.8.2
I'm trying to grab image from clipboard. I press "Alt+PrtSc" and then call grabclipboard function, and get such error:

ImageGrab.grabclipboard()
---------------------------------------------------------------------------
IOError                                   Traceback (most recent call last)
<ipython-input-2-c8274e888e6c> in <module>()
      1 from PIL import ImageGrab
      2 
----> 3 ImageGrab.grabclipboard()

C:\Anaconda\lib\site-packages\PIL\ImageGrab.pyc in grabclipboard()
     49         from PIL import BmpImagePlugin
     50         import io
---> 51         return BmpImagePlugin.DibImageFile(io.BytesIO(data))
     52     return data

C:\Anaconda\lib\site-packages\PIL\ImageFile.pyc in __init__(self, fp, filename)
     95 
     96         try:
---> 97             self._open()
     98         except IndexError as v:  # end of data
     99             if Image.DEBUG > 1:

C:\Anaconda\lib\site-packages\PIL\BmpImagePlugin.pyc in _open(self)
    204 
    205     def _open(self):
--> 206         self._bitmap()
    207 
    208 #

C:\Anaconda\lib\site-packages\PIL\BmpImagePlugin.pyc in _bitmap(self, header, offset)
    145                     raw_mode = MASK_MODES[(file_info['bits'], file_info['rgb_mask'])]
    146                 else:
--> 147                     raise IOError("Unsupported BMP bitfields layout")
    148             else:
    149                 raise IOError("Unsupported BMP bitfields layout")

IOError: Unsupported BMP bitfields layout

But if I call ImageGrab.grab function, screenshot(of whole screen) is saved properly.

UPD It's version problem, when I installed Pillow version 2.6.0 everything worked ok

Reproducible with Pilllow 2.8.0, 2.8.1, 2.8.2.
Not reproducible with Pillow 2.6.0, 2.7.0.

E:\stufftodelete>cat test.py
from PIL import ImageGrab
ImageGrab.grabclipboard()

E:\stufftodelete>pip freeze | grep illow
Pillow==2.8.2

E:\stufftodelete>python test.py
Traceback (most recent call last):
  File "test.py", line 2, in <module>
    ImageGrab.grabclipboard()
  File "C:\Python27\lib\site-packages\PIL\ImageGrab.py", line 51, in grabclipboard
    return BmpImagePlugin.DibImageFile(io.BytesIO(data))
  File "C:\Python27\lib\site-packages\PIL\ImageFile.py", line 97, in __init__
    self._open()
  File "C:\Python27\lib\site-packages\PIL\BmpImagePlugin.py", line 206, in _open
    self._bitmap()
  File "C:\Python27\lib\site-packages\PIL\BmpImagePlugin.py", line 147, in _bitmap
    raise IOError("Unsupported BMP bitfields layout")
IOError: Unsupported BMP bitfields layout

E:\stufftodelete>pip install pillow==2.8.1
Collecting pillow==2.8.1
  Using cached Pillow-2.8.1-cp27-none-win_amd64.whl
Installing collected packages: pillow
  Found existing installation: Pillow 2.8.2
    Uninstalling Pillow-2.8.2:
      Successfully uninstalled Pillow-2.8.2
Successfully installed pillow-2.8.1

E:\stufftodelete>python test.py
Traceback (most recent call last):
  File "test.py", line 2, in <module>
    ImageGrab.grabclipboard()
  File "C:\Python27\lib\site-packages\PIL\ImageGrab.py", line 51, in grabclipboard
    return BmpImagePlugin.DibImageFile(io.BytesIO(data))
  File "C:\Python27\lib\site-packages\PIL\ImageFile.py", line 97, in __init__
    self._open()
  File "C:\Python27\lib\site-packages\PIL\BmpImagePlugin.py", line 206, in _open
    self._bitmap()
  File "C:\Python27\lib\site-packages\PIL\BmpImagePlugin.py", line 147, in _bitmap
    raise IOError("Unsupported BMP bitfields layout")
IOError: Unsupported BMP bitfields layout

E:\stufftodelete>pip install pillow==2.8.0
Collecting pillow==2.8.0
  Downloading Pillow-2.8.0-cp27-none-win_amd64.whl (1.3MB)
    100% |################################| 1.3MB 386kB/s
Installing collected packages: pillow
  Found existing installation: Pillow 2.8.1
    Uninstalling Pillow-2.8.1:
      Successfully uninstalled Pillow-2.8.1
Successfully installed pillow-2.8.0

E:\stufftodelete>python test.py
Traceback (most recent call last):
  File "test.py", line 2, in <module>
    ImageGrab.grabclipboard()
  File "C:\Python27\lib\site-packages\PIL\ImageGrab.py", line 51, in grabclipboard
    return BmpImagePlugin.DibImageFile(io.BytesIO(data))
  File "C:\Python27\lib\site-packages\PIL\ImageFile.py", line 97, in __init__
    self._open()
  File "C:\Python27\lib\site-packages\PIL\BmpImagePlugin.py", line 206, in _open
    self._bitmap()
  File "C:\Python27\lib\site-packages\PIL\BmpImagePlugin.py", line 147, in _bitmap
    raise IOError("Unsupported BMP bitfields layout")
IOError: Unsupported BMP bitfields layout

E:\stufftodelete>pip install pillow==2.7.0
Collecting pillow==2.7.0
  Downloading Pillow-2.7.0-cp27-none-win_amd64.whl (1.3MB)
    100% |################################| 1.3MB 393kB/s
Installing collected packages: pillow
  Found existing installation: Pillow 2.8.0
    Uninstalling Pillow-2.8.0:
      Successfully uninstalled Pillow-2.8.0
Successfully installed pillow-2.7.0

E:\stufftodelete>python test.py

E:\stufftodelete>pip install pillow==2.6.0
Collecting pillow==2.6.0
  Downloading Pillow-2.6.0-cp27-none-win_amd64.whl (1.3MB)
    100% |################################| 1.3MB 405kB/s
Installing collected packages: pillow
  Found existing installation: Pillow 2.7.0
    Uninstalling Pillow-2.7.0:
      Successfully uninstalled Pillow-2.7.0
Successfully installed pillow-2.6.0

E:\stufftodelete>python test.py

@artscoop

Pillow 2.7.0 was released on 1st January this year, and 2.8.0 was released on 1st April.

PR #1125 may have caused it. Ping @artscoop.

It'd be great to get this fixed for 2.9.0, due out on 1st July.

The good news is we now have a Windows-based CI to run unit tests, so if it's possible to simulate Alt+PrtSc (or just PrtSc, which also triggers it) on AppVeyor then this should definitely be unit-tested.

Running OS X, I can reproduce the error using one of the files in the test suite - Tests/images/bmp/g/rgb32bf.bmp

Interestingly though, it's listed as unsupported.

Unfortunately, the ImageGrab functions don't work on the windows CI, likely because there's something screwy with the graphics context on a headless vm.

Notes:

This can be partially fixed by adding this elif near here:

                elif file_info['bits'] == 32 and file_info['rgb_mask'] == (0xff0000, 0xff00, 0xff):
                    pass
                else:
                    raise IOError("Unsupported BMP bitfields layout")
            else:
                raise IOError("Unsupported BMP bitfields layout")

That will return an image, but the resulting image is truncated. It can be shown or saved only if LOAD_TRUNCATED_IMAGES is true, but the image is one pixel shifted left and missing the top line.

This is because, for example, self.tile is:
[('raw', (0, 0, 3360, 1050), 56L, ('BGRX', 13440, -1))]
instead of:
[('raw', (0, 0, 3360, 1050), 52L, ('BGRX', 13440, -1))]

That third value in both cases is offset or self.fp.tell(), the problem with 2.8.0 is that an extra read had been made to load in a file_info['a_mask'], which doesn't make sense for this format, and putting the file pointer at the wrong place.

We should only be reading that alpha value when needed.

The regression appears with 3.0.0 too. 2.7.0 works ok.

So, any news on that?

@radarhere

Ok I understand what is going on.
I rewrote part of the BMP loading process.
And I made sure it worked on supported bitmap files, fixed bogus behaviour from previous versions, but it did not have to work with unsupported files.
However @radarhere , the cause of the error you've been experiencing with this file may be... let's say, different.

Now I remember: the file rgb32bf.bmp is unsupported because it has a bitmask not supported by Pillow. Supported masks for 32-bit true color images have classic boundaries, with RGB channels in RGB or BGR order.
Here we have an esoteric RGB/A mask (the image is read correctly by XNView though), which has no matching dialect in PIL definitions for unpacking pixels.
Therefore I have been able to load this image, but with wrong colors (for instance, we have a problem with B and G channels)

This bug can be closed. This works with 3.2.0:

>>> from PIL import ImageGrab
>>> ImageGrab.grabclipboard()
>>>

It can be renamed "ImageGrab.grabclipboard() problem on Windows", because there are other issues there.

This bug is still present: I can reproduce it as described in the original report with Pillow 3.2.0 (Python 2.7, Windows 7).

I need to dig a bit more about the actual definition of what a DIB file is, and what the data in the spot that would normally be an alpha channel actually corresponds to. I think that the fix is actually correct for the RGB channels, for what that's worth.

BMP does not depend on any external library. (This particular version is essentially a header + raw image bytes)

Glad to hear that there are no external dependencies for BMP. I noticed the above problem because it seems that DIB is the internal bitmap representation for graphic shapes in OpenOffice (see XBitmap here).

Microsoft has an overview of DIBs here and a more historical piece here, and the actual “Bitmap Reference” is here. I hope this helps.

I've seen most of those links. What none of them are saying is the interpretation of the extra field of an RGBQuad, other than 'reserved'. There's possibly something newer that's done something documented with it, or we need to simply ignore it and just use the 'RGB' section of the image.

@wiredfool

@wiredfool lets close this ticket and move the discussion to #1811. Because saved .bmp is fine. There might be a bug in conversion routines.

#1293 (comment)

@wiredfool

@wiredfool "IOError: Unsupported BMP bitfields layout" problem is fixed, and it becomes hard to follow this ticket.

Fixes DIB image format

Respinning this with #1847.

Fixes DIB image format

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sallyruthstruik commented on Jun 20, 2015

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