|
|
| Author |
Message |
kanalia
 Total Messages 17
|
| Subject: | CCITTFaxDecode and Windows 7 |
Hi guys
Some time ago I wrote a library (vb.net) to convert images into pdf/a docs and then extract images from it if necessary. The requirement was to write it without using third party components so I wrote it from scratch. Most of my images were bw tiffs so I used the CCITTFaxDecode filter. It worked fine on all os until windows 7. I compared files and it turned out the image stream is diffrent.
Any idea why same code would produce diffrent results on windows 7?, Regards, Mike
| Posted: 29 Nov 2010 10:57 PM |
|
|
| |
aandi
 Total Messages 17064
|
| Subject: | CCITTFaxDecode and Windows 7 |
Do I have this right - your own code is producing different data? It isn't some other program, or an encrypted PDF?
| Posted: 29 Nov 2010 11:03 PM |
|
|
| |
kanalia
Total Messages 17
|
| Subject: | CCITTFaxDecode and Windows 7 |
Yes, my app, same code.
I just stepped through the code on Windows 7 and 2008 Server and it looks that bitmap returned by 'Bitmap.SelectActiveFrame' brings diffrent results (The Flags property is different). It looks like a change or a bug in GDI.
| Posted: 30 Nov 2010 12:01 AM |
|
|
| |
kanalia
Total Messages 17
|
| Subject: | CCITTFaxDecode and Windows 7 |
I attach two files. 'Test7.pdf'-created on Windows 7 and 'Test.pdf' created on 2008 server. I wonder if somebody could have a look at them and tell me what's wrong. Thanks guys
| Posted: 30 Nov 2010 02:55 AM |
|
|
| |
aandi
Total Messages 17064
|
| Subject: | CCITTFaxDecode and Windows 7 |
Can see Acrobat says "Insufficient data for an image". It doesn't report errors in filters, it just stops reading and so this error is typical.
What does the actual compression for you (with CCITT fax methods)? Is it a GDI+ API?
| Posted: 30 Nov 2010 04:00 AM |
|
|
| |
aandi
Total Messages 17064
|
| Subject: | CCITTFaxDecode and Windows 7 |
There is more wrong with this file too. Extracting pages in Acrobat fails, so does PDF/A preflight. I find the xref addresses peculiar, pointing as they do to a second newline before the obj line. The object metadata dictionary is certainly malformed. And there seems something else too.
| Posted: 30 Nov 2010 07:21 AM |
|
|
| |
erling_b
 Total Messages 8
|
| Subject: | CCITTFaxDecode and Windows 7 |
>Hi guys
>Some time ago I wrote a library (vb.net)
>to convert images into pdf/a docs and
>then extract images from it if
>necessary. The requirement was to write
>it without using third party components
>so I wrote it from scratch. Most of my
>images were bw tiffs so I used the
>CCITTFaxDecode filter. It worked fine on
>all os until windows 7. I compared files
>and it turned out the image stream is
>diffrent.
>Any idea why same code would produce
>diffrent results on windows 7?, Regards,
>Mike
Hi Mike,
I have the same problem.... The code is using .net and works on XP, but not in Windows 7 or Win Srv 2008 R2.
Found this on the net:
"It seems that the behaviour of GDI+ is changed in Windows 7: The resulting CCITT bitmap data is no longer encoded in a single strip. Because of this I cannot use this bitmap data in my PDF file."
Have you find any solutions?
Regards from Norway,
Erling
| Posted: 19 Jan 2011 09:10 AM |
|
|
| |
|
|
