Cannot save .TIF file with tag 297 (Page Number) having value of 0/0.

[jamesrusso]

Script:

from PIL import Image
im = Image.open('output14024671122-1021-094450-118_p001.tif')
im.save('test.tif')

Exception:

[root@app02 pil-page-test]# python tif-test.py 
Traceback (most recent call last):
  File "tif-test.py", line 4, in <module>
    im.save('test.tif')
  File "/usr/lib64/python2.7/site-packages/PIL/Image.py", line 1685, in save
    save_handler(self, fp, filename)
  File "/usr/lib64/python2.7/site-packages/PIL/TiffImagePlugin.py", line 1161, in _save
    atts[k] = float(v[0])/float(v[1])
ZeroDivisionError: float division by zero

TiffInfo on the input file:

TIFF Directory at offset 0x8 (8)
  Subfile Type: multi-page document (2 = 0x2)
  Image Width: 1728 Image Length: 2202
  Resolution: 204, 196 pixels/inch
  Bits/Sample: 1
  Compression Scheme: CCITT Group 3
  Photometric Interpretation: min-is-white
  FillOrder: msb-to-lsb
  Orientation: row 0 top, col 0 lhs
  Samples/Pixel: 1
  Rows/Strip: 4854
  Planar Configuration: single image plane
  Page Number: 0-0
  Software: GPL Ghostscript 9.07
  DateTime: 2014:10:25 11:08:31
  Group 3 Options: EOL padding (4 = 0x4)

According to the spec, the second value in the page number can be "0" indicating that the maximum number of pages is not available.

http://www.awaresystems.be/imaging/tiff/tifftags/pagenumber.html

Not sure what the actual fix is, but wanted to log this with my research thus far.

[jamesrusso]

A work around, is to simply remove this tag from the Image object.

This now works:

im = Image.open('output14024671122-1021-094450-118_p001.tif')
del im.tag[297]
im.save('test.tif', ImageFileDirectory='')

[hugovk]

Well, there's obviously a divide by zero error there: the spec says a Page Number of (0, 0) is valid, we shouldn't flatten it to a float 0/0.

The comment says:

                if type(v) == tuple and len(v) == 2:
                    # one rational tuple
                    # flatten to float,
                    # following tiffcp.c->cpTag->TIFF_RATIONAL
                    atts[k] = float(v[0])/float(v[1])
                    continue

Perhaps it'd be better to deal with this in the same way as the previous clause (or at least if the second value is zero):

                if type(v) == tuple and len(v) > 2:
                    # List of ints?
                    if type(v[0]) in (int, float):
                        atts[k] = list(v)
                    continue

Anyway, these bits of code were introduced fairly recently, in #388 and released in 2.3.0.

@jamesrusso, do you have a (distributable, not too large) test image you can share that reproduces this problem? Or can you give instructions how to create one with common tools?

[hugovk]

At least this sort of change doesn't cause any build failures with existing tests.

[jamesrusso]

All the example ones I have, I cannot share. I will create one and post it here.

[jamesrusso]

Cannot attach the TIF, but here is a link: https://dl.dropboxusercontent.com/u/638947/total-pages-zero.tif

To create this one, I printed this page in Chrome to PDF. Then ran gs on it with the following command line:

/usr/bin/gs -q -sDEVICE=tiffg3 -sOutputFile=total-pages-zero.tif -dNOPAUSE /tmp/test.pdf -c quit

Now, tiffinfo shows:

[root@app02 pdf-files]# tiffinfo total-pages-zero.tif  | grep Page\ Number
  Page Number: 0-0
  Page Number: 1-0
  Page Number: 2-0

Here is 3 liner which causes the div by zero exception..

from PIL import Image

im = Image.open("total-pages-zero.tif")
im.save("out.tif")

[hugovk]

Thanks, I've created a test case with that image which fails locally without the fix, and included the image in PR #976.

[hugovk]

PR #976 has been merged, thanks for the report.