[poppler] Implement overprint in qt interface?

Thomas Freitag Thomas.Freitag at kabelmail.de
Sun Oct 14 10:50:56 PDT 2012

On 14.10.2012 17:23, Adam Reichold wrote:
> Hash: SHA1
> Hello Thomas,
> Thanks for the offer. As I understand it, this simulates how the
> actual physical layers of colour would mix in real printing? It does
> sound like a sensible feature to me.
No, that's not true. Overprint is a feature already introduced in 
PostScript and is also defined in the PDF spec, see i.e. chapter 8.6.7 
as an introduction. But there are only a very few free available viewer 
which implements it. Beside acrobat reader (and of course poppler :-) ) 
I only know ghostscript which implements it. And even in ghostscript it 
is not well known because overprint works only in subtractive 
colorspaces like CMYK, so You have to render in a CMYK-like colorspace 
and then convert the result to RGB to see it on the monitor. And this is 
what the just uploaded patch does.

> Why not post the patch to discuss the feature's merits based on that?
> Best regards, Adam.
> On 14.10.2012 13:47, Thomas Freitag wrote:
>> Hi folks!
>> Is there anybody in the community who wants the possibility to
>> simulate overprint in qt library? With the implementation of
>> DeviceN support in splash this is quite easy now, so I can upload a
>> patch. For everybody who doesn't know anything about overprint I
>> attach three screenshots which shows the implementation in okular.
>> (This is not fake, I made a small apprentice piece today morning
>> :-) )
>> Cheers, Thomas
>> _______________________________________________ poppler mailing
>> list poppler at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/poppler
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