0005153: gm convert: No decode delegate for postscript

(0010733)
laurent (manager)
2014-02-26 14:07

I see the issue, but I believe it's a GM issue.
I've checked that it picks up the correct ghostcript during build time.
A bump to the latest revision has the same issue.

truss shows it opens the ma
10142: open64("/opt/csw/lib/GraphicsMagick-1.3.19/config/delegates.mgk", O_RDONLY) = 3
/opt/csw/bin/pentium_pro/gm convert: No decode delegate for this image format (./Documents/Onera/Documents_2009/interSites.ps).

The content of the mgk file refers to gs, so no clue what's wrong there. Maybe you can try to use the old version to replace this one.
As a workaround, ImageMagick's convert does work.

(0010734)
wcohrs (reporter)
2014-02-26 14:14

i now ImageMagick's convert but the the result looks bad

(0010735)
laurent (manager)
2014-02-26 15:16

Really? But the backend is the same GS, so it really should look the same.

(0010736)
wcohrs (reporter)
2014-02-26 15:27

i have attached 3 files
the gs.jpg is convertet with
gs -dBATCH -dNOPAUSE -sDEVICE=jpeg -sOutputFile=test.jpg cd_ems.ps

(0010737)
laurent (manager)
2014-02-26 22:21

I see. Can you provide the .ps original too?

(0010738)
wcohrs (reporter)
2014-02-27 07:31

yes
Thank you for your help.

(0010739)
laurent (manager)
2014-02-27 10:09

Please note that since that's what I use, I'll focus on fixing ImageMagick for now.

I've determined that the issue happens when IM converts the PNG output of gs to JPEG. I think it has a problem handling the transparency of the background.
Keeping it as PNG, the output looks good, but with a transparent background.

Keeping it as PNG is probably the best solution for now, the file is even smaller than the JPEG. It should be possible to set a proper white background too.

(0010740)
wcohrs (reporter)
2014-02-27 10:58

many thanks again for the support
you can close the case

(0010746)
laurent (manager)
2014-03-04 10:07

After some testing, it seems it's an expected behaviour, though it's not apparent.
The conversion of the transparent PNG rasterized from the PS to a JPG needs parameters. Since the background in your PS is transparent, what you see is the antialias of black letters over nothingness, ie, black. You need to force a white background.

Like this, the output looks good:

convert -background white -flatten input.ps input.jpg

So you'd better force a white background to make it explicit, but of course, I'd still advise to stick with PNG output.

So in summary:
  - there's definitely an issue with GraphicksMagic, and it appears to be upstram
  - at this point, I don't have time to investigate it further
  - ImageMagick works and is an acceptable workaround.

(0010747)
laurent (manager)
2014-03-04 10:09

Workaround provided.
If anybody wants to work with upstream on the GM issue, feel free to reopen.

Notes
(0010733) laurent (manager) 2014-02-26 14:07	I see the issue, but I believe it's a GM issue. I've checked that it picks up the correct ghostcript during build time. A bump to the latest revision has the same issue. truss shows it opens the ma 10142: open64("/opt/csw/lib/GraphicsMagick-1.3.19/config/delegates.mgk", O_RDONLY) = 3 /opt/csw/bin/pentium_pro/gm convert: No decode delegate for this image format (./Documents/Onera/Documents_2009/interSites.ps). The content of the mgk file refers to gs, so no clue what's wrong there. Maybe you can try to use the old version to replace this one. As a workaround, ImageMagick's convert does work.

(0010734) wcohrs (reporter) 2014-02-26 14:14	i now ImageMagick's convert but the the result looks bad

(0010735) laurent (manager) 2014-02-26 15:16	Really? But the backend is the same GS, so it really should look the same.

(0010736) wcohrs (reporter) 2014-02-26 15:27	i have attached 3 files the gs.jpg is convertet with gs -dBATCH -dNOPAUSE -sDEVICE=jpeg -sOutputFile=test.jpg cd_ems.ps

(0010737) laurent (manager) 2014-02-26 22:21	I see. Can you provide the .ps original too?

(0010738) wcohrs (reporter) 2014-02-27 07:31	yes Thank you for your help.

(0010739) laurent (manager) 2014-02-27 10:09	Please note that since that's what I use, I'll focus on fixing ImageMagick for now. I've determined that the issue happens when IM converts the PNG output of gs to JPEG. I think it has a problem handling the transparency of the background. Keeping it as PNG, the output looks good, but with a transparent background. Keeping it as PNG is probably the best solution for now, the file is even smaller than the JPEG. It should be possible to set a proper white background too.

(0010740) wcohrs (reporter) 2014-02-27 10:58	many thanks again for the support you can close the case

(0010746) laurent (manager) 2014-03-04 10:07	After some testing, it seems it's an expected behaviour, though it's not apparent. The conversion of the transparent PNG rasterized from the PS to a JPG needs parameters. Since the background in your PS is transparent, what you see is the antialias of black letters over nothingness, ie, black. You need to force a white background. Like this, the output looks good: convert -background white -flatten input.ps input.jpg So you'd better force a white background to make it explicit, but of course, I'd still advise to stick with PNG output. So in summary: - there's definitely an issue with GraphicksMagic, and it appears to be upstram - at this point, I don't have time to investigate it further - ImageMagick works and is an acceptable workaround.

(0010747) laurent (manager) 2014-03-04 10:09	Workaround provided. If anybody wants to work with upstream on the GM issue, feel free to reopen.

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