[Image-SIG] IOError: decoder group3 not available
David Thibault
dthibault@esperion.com
Mon, 21 Apr 2003 13:36:34 -0400
If I try to import the TIFF image directly to PDF I get the following error:
----------------------------------------------------------
Traceback (most recent call last):
File "./tiff2pdf.py", line 8, in ?
c.drawImage(im,0,0)
File "/usr/local/zope/lib/python2.1/reportlab/pdfgen/canvas.py", line 513,
in drawImage
rawdata = image.convert('RGB').tostring()
File "/usr/local/zope/lib/python2.1/PIL/Image.py", line 427, in convert
self.load()
File "/usr/local/zope/lib/python2.1/PIL/ImageFile.py", line 140, in load
d = Image._getdecoder(self.mode, d, a, self.decoderconfig)
File "/usr/local/zope/lib/python2.1/PIL/Image.py", line 243, in
_getdecoder
raise IOError, "decoder %s not available" % decoder_name
IOError: decoder tiff_ccitt not available
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Note that now it's complaining about a different decoder not being
available...
Here's the code that causes this problem:
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#!/usr/local/zope/bin/python
from reportlab.pdfgen import canvas
from PIL import Image
im = Image.open('multipage2.tif')
c = canvas.Canvas('test.pdf')
c.drawImage(im,0,0)
c.showPage()
c.save()
-----------------------------------------------------------
Regards,
Dave
-----Original Message-----
From: D. Alan Stewart [mailto:astewart@layton-graphics.com]
Sent: Monday, April 21, 2003 1:12 PM
To: David Thibault
Cc: image-sig@python.org
Subject: Re: [Image-SIG] IOError: decoder group3 not available
From what you've said it sounds like your TIFF has 1-bit per pixel
images compressed, Group 3/4 compressed. You would need to decompress
eash image, convert it to 8-bit per pixel grayscale (which will be 8
times the size of the original uncompressed image; RGB would be 24 times
the original size), and then JPG compress it. I doubt this will produce
a compressed image smaller than the Group 3 image you have now. The
PDF specification supports Group 3 image compression, why not just
transfer the compressed image as is to the PDF and not hassle with all
this? See section 3.3.5 of the 1.4 PDF Specification for a description
of the CCITTFaxDecode filter....
David Thibault wrote:
>Hello all,
>
>I've got multipage TIFF files that I need to convert to PDF using PIL and
>reportlab. I think I'd be all set except I seem to be hitting an old bug.
>I saw this:
>http://mail.python.org/pipermail/image-sig/2002-February/001736.html and it
>seems to be the exact problem I'm running into. Has anyone ever figured
>this out? These tiff's are mode 1 and I get the exact error in the subject
>line if I try to convert them to RGB or if I try to convert them to JPG. I
>was hoping to take each tiff, pull out each page, convert it to jpg, then
>add it to the PDF file so that it would minimize the size of the files.
>However, anything that will work programmatically will make me happy...
>
>Regards,
>Dave
>
>_______________________________________________
>Image-SIG maillist - Image-SIG@python.org
>http://mail.python.org/mailman/listinfo/image-sig
>
>
>
--
D. Alan Stewart
Senior Software Developer
Layton Graphics, Inc.
Marietta, GA U.S.A.
770/973-4312
http://www.layton-graphics.com