Opening a PDF File - All that is visible is transparent checker board

[zoltron_rulez]

All,

My environment:
Windows 7-64 bit
Image Magic - 6.9.1-Q16 (64-bit)
Ghostscript - 9.16

I have a PDF file that I needed to convert to jpg file. Unfortunately, the conversion did not work,- all I got was a blank output.
Therefore, I used IMDisplay to open the PDF file and all I see is transparent checker board.

Interestingly, we have an older machine (Win 2003 server 64bit) that runs 6.7.3-6, Ghostscript 9.04. When I open the same PDF file, it opens it fine. Also, the conversion works fine.

Please help me resolve this problem.

Regards

[fmw42]

You should probably post your PDF file to some place such as Dropbox.com and put the URL here, so other Windows user can test. But it would seem to be a problem with your Ghostscript and not IM. Does your PDF have transparency. If so, check what your sDEVICE is in your delegates.xml file.


<delegate decode="ps:alpha" stealth="True" command=""gs" -q -dQUIET -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 "-sDEVICE=pngalpha" -dTextAlphaBits=%u -dGraphicsAlphaBits=%u "-r%s" %s "-sOutputFile=%s" "-f%s" "-f%s""/>

Is your PDF in CMYK or RGB?

[zoltron_rulez]

I figured it may have to do w/ Ghost script or the file format, but I need to know the cause and fix for this issue. I am not sure if the PDF uses transparency since I don't know how to check this. It is generated by one of our scanners.

Here"s the pdf:
https://drive.google.com/file/d/0Bxzqjx ... sp=sharing

Command I am using:
convert t5.pdf -thumbnail 500x500 -trim t5.jpg

I checked the sDevice in delegages for ps:alpha and it is correct, here it is copied from delegates.xml:

<delegate decode="ps:alpha" stealth="True" command=""@PSDelegate@" -q -dQUIET -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 "-sDEVICE=pngalpha" -dTextAlphaBits=%u -dGraphicsAlphaBits=%u "-r%s" %s "-sOutputFile=%s" "-f%s" "-f%s""/>

[fmw42]

Your file is grayalpha. You can see what your file meta data is by using

Code: Select all

identify -verbose t5.PDF

But the alpha channel is fully opaque. JPG does not support transparency, so there is no reason for your output to be fully transparent. Are you sure of your command and using JPG for output?

This works fine for me on IM 6.9.2.1 Q16 Mac OSX and Ghostscript 9.10

Code: Select all

convert t5.PDF t5.jpg

Try

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convert -alpha off t5.PDF t5.jpg

Also you would get better quality using supersampling.

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convert -alpha off -density 288 t5.PDF -resize 25% t5.jpg

Normal density is 72 by default, so 288 = 72*4 and thus we resize by 1/4 = 25%. Or don't resize at all and get a 4x larger resulting image.

If these do not work, try backing off your GS version. Or upgrading IM. Perhaps there were issues with your version of IM.

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convert -version

will tell you the exact version of IM 6.9.1.x

[zoltron_rulez]

I guess I should of stated, what exactly I was trying to achieve. Our software use IM to create thumb nails of our PDF drawings (100x100, 500x500 thumbnails to be exact). These thumbnails are jpg but could be just as well png.

Regardless, I tried your suggestions, same issue, blank output. I will now try downgrading GS, and try latest IM. I'll post my findings, thank you for your prompt help.

[fmw42]

Before changing GS, try just upgrading IM. If you still get the same issue, then downgrade your GS.

I still don't see why you get fully transparent results if you are using JPG for the output. That might be the case, though very strange, if you are using PNG.

[zoltron_rulez]

"I still don't see why you get fully transparent results if you are using JPG for the output. That might be the case, though very strange, if you are using PNG."

That's what happened when I had trouble w/ the convert command and decided to use IMDisplay to open the actual PDF file I was converting.
I probably was not clear about this.

[fmw42]

As far as I can tell, the PDF has a fully opaque alpha channel. So it should not be showing as fully transparent. Try upgrading IM or use another viewer.

[zoltron_rulez]

Well, success. Apparently, latest, greatest of IM doesn't work that well with gs 9.16. I have downgraded my gs to 9.10 (what you have) and it works now. It would be interesting to know why ... since it is quite difficult to figure these things on your own,- w/out your help I would be stuck for a while.
Thanks for great and quick support.

[fmw42]

Magick -- please let us know if this is an IM issue with GS 9.16 or a GS bug.

[magick]

Likely a GS bug. Let's eliminate ImageMagick. Try this:

• gs -sDEVICE=pnmraw -sOutputFile=t5.pnm t5.pdf

gs 9.16 returns a completely white image. Other viewer display the image properly. GS likely bails on this image for security reasons. It detects and reports a problem with the content stream.

[fmw42]

On my IM 6.9.2.1 Q16 and GS 9.10, I get an error and no pnm image. Perhaps I am not running it correctly for my version of GS?


gs -sDEVICE=pnmraw -sOutputFile t5.pnm t5.pdf

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GPL Ghostscript 9.10 (2013-08-30)
Copyright (C) 2013 Artifex Software, Inc.  All rights reserved.
This software comes with NO WARRANTY: see the file PUBLIC for details.
Error: /undefinedfilename in (t5.pnm)
Operand stack:

Execution stack:
   %interp_exit   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push
Dictionary stack:
   --dict:1173/1684(ro)(G)--   --dict:0/20(G)--   --dict:77/200(L)--
Current allocation mode is local
Last OS error: Invalid argument
GPL Ghostscript 9.10: Unrecoverable error, exit code 1

However,

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convert t5.PDF t5.jpg

works fine.

[magick]

Use -sOutputFile=t5.pnm, no space.

[fmw42]

Use -sOutputFile=t5.pnm, no space.

Worked fine with IM 6.9.2.1 Q16 Mac OSX and GS 9.10

gs -sDEVICE=pnmraw -sOutputFile=t5.pnm t5.pdf

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GPL Ghostscript 9.10 (2013-08-30)
Copyright (C) 2013 Artifex Software, Inc.  All rights reserved.
This software comes with NO WARRANTY: see the file PUBLIC for details.
Processing pages 1 through 1.
Page 1
>>showpage, press <return> to continue<<

GS>quit

[246246]

Well, success. Apparently, latest, greatest of IM doesn't work that well with gs 9.16. I have downgraded my gs to 9.10 (what you have) and it works now.

FYI, it seems to work with gs 9.15.

[EDIT]
It is a known bug of Ghostscript.
http://bugs.ghostscript.com/show_bug.cgi?id=696005

Replace pdf_draw.ps with current repository one, it works.
So this issue will be expected to be solved when GhostScript 9.18 will be released in next few weeks (announced on 14-Sep-2015 at http://bugs.ghostscript.com/show_bug.cgi?id=696197 )