[poppler] pdftops : issue with colorspaces with some printers (gray vs rgb)

[Benjamin Lefevre]

Thank you very much William, I will try to compile poppler today with your
patch and see if it solves my issues.

Benjamin.

2015-02-04 19:42 GMT+01:00 William Bader <williambader at hotmail.com>:

> I posted patches to add -preservecolorspace at
> https://bugs.freedesktop.org/show_bug.cgi?id=88971
>
> >Thank you for your advices about git
>
> pdftops works better if SPLASH_CMYK is set. I build the git source with
>  ./autogen; CXXFLAGS="-DSPLASH_CMYK=1 -O9 -ffast-math -fomit-frame-pointer
> -Wall -pipe" ./configure; make -j 4
>
> William
>
> ------------------------------
> Subject: Re: [poppler] pdftops : issue with colorspaces with some printers
> (gray vs rgb)
> From: benjamin.lefevre at photobox.com
> Date: Wed, 4 Feb 2015 19:12:19 +0100
> CC: poppler at lists.freedesktop.org
> To: williambader at hotmail.com
>
>
> It would be very nice, William.
> I would owe you one in return :)
>
> Thank you for your advices about git.
>
> Envoyé de mon iPhone
>
> Le 4 févr. 2015 à 18:37, William Bader <williambader at hotmail.com> a
> écrit :
>
> I could make a patch to add a -preservecolorspace option tonight if no one
> has any objections.
>
> >I'm a java developer, not comfortable in C/C++... not sure I would be
> able to make a pull-request in git.
>
> The command to get the poppler source is "git clone git://
> git.freedesktop.org/git/poppler/poppler" or download a stable release
> from http://poppler.freedesktop.org/ (The stable releases need less
> infrastructure to build than the git source.)  Patches can be posted to
> https://bugs.freedesktop.org
>
> William
>
> ------------------------------
> Date: Wed, 4 Feb 2015 18:05:03 +0100
> Subject: Re: [poppler] pdftops : issue with colorspaces with some printers
> (gray vs rgb)
> From: benjamin.lefevre at photobox.com
> To: williambader at hotmail.com
> CC: poppler at lists.freedesktop.org
>
> Thank you William for your answer.
>
> Actually I saw in the release notes (
> http://poppler.freedesktop.org/releases.html ) what you mention. The
> 0.17.2 introduces the optimization you are talking about:
> poppler-0.17.2.tar.gz
> <http://poppler.freedesktop.org/poppler-0.17.2.tar.gz> (Mon Aug 15, 2011):
> PSOutputDev: Make level1sep, level2sep and level3sep write gray instead of
> rgb for gray images
>
> Yes it makes a problem for me, and it would be great to have this feature.
> How can I proceed to have it?  I'm a java developer, not comfortable in
> C/C++... not sure I would be able to make a pull-request in git.
>
>
> 2015-02-04 17:44 GMT+01:00 William Bader <williambader at hotmail.com>:
>
> I think that the cause is a patch that I submitted in May 2011 around the
> time of poppler 0.17.0.
>
> Search for isGray in poppler/PSOutputDev.cc
>
> I use pdftops to make postscript files that will be printed on a newpaper
> press.
>
> My application was being sent PDFs with embedded logos that looked gray
> but were actually in RGB color space, and they were not getting separated
> correctly on color pages.
>
> I added a check in PSOutputDev that if every pixel of a RGB bitmap was
> equal R, G, B, it will be written as a grayscale bitmap, which fixed my
> separation problems and made the files smaller.
>
> If that makes a problem for you, it should be possible to add a command
> line option to control the RGB to grayscale conversion, maybe similar to
> some of the distiller options in ghostscript
> http://ghostscript.com/doc/current/Ps2pdf.htm
>
> William
>
> ------------------------------
> Date: Wed, 4 Feb 2015 16:18:59 +0100
> From: benjamin.lefevre at photobox.com
> To: poppler at lists.freedesktop.org
> Subject: [poppler] pdftops : issue with colorspaces with some printers
> (gray vs rgb)
>
>
> Hi everyone,
>
>
> My name is Benjamin and I am french.
>
>
> I'm new on this mailing list :)
>
>
>  I come to you for a question or maybe for a feature request (at this
> stage, I'm not sure).
>
>
> Please look at this pdf (dropbox: https://www.dropbox.com/s/yoj6h3o4irnlgun/source.pdf?dl=0
> ) <https://www.dropbox.com/s/yoj6h3o4irnlgun/source.pdf?dl=0>
>
>
> There are two monochrome images (in DeviceRGB in the pdf).
>
>
> After executing 'pdftops', the images are cut in half, with the top part
> in DeviceRGB and the bottom in DeviceGray. This causes colorimetric issues
> on some of my printers (most of them in fact).
>
>
> Is it possible to preserve DeviceRGB by executing pdftops? I did not
> manage to achieve it with the few available options provided by pdftops.....
>
> Or would it be possible to have a new option in poppler (pdftops in my
> case) to preserve colorspaces, and to not optimize the monochrome images in
> DeviceGray?
>
>
> Thank you in advance,
>
>
> Benjamin.
>
>
>
>
>
>
>
> _______________________________________________ poppler mailing list
> poppler at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/poppler
>
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/poppler/attachments/20150205/472dc93e/attachment.html>