[poppler] Implement overprint in qt interface?

[Thomas Freitag]

Am 15.10.2012 07:26, schrieb Adam Reichold:
> Hello,
>
> On 14.10.2012 19:50, Thomas Freitag wrote:
>> On 14.10.2012 17:23, Adam Reichold wrote:
>> 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.
> I am not sure I understand how this explanation conflicts with "sensible
> feature" as in "it makes sense to have this feature". May be a
> misunderstanding? Or do you refer to that it does not simulate the
> interaction of physical layers of colour?
Sorry, it was my poor English and a typical misunderstanding for a 
German: "sensible" sounds like "sensibel" which translation is 
"sensitive" in English, But I still think that "simulate" is the wrong 
explanation, because the use of overprint influences or change the 
interaction of physical layers of colour.

No harm meant,
Thomas
>
> Best regards, Adam.
>
>>> Cheers,
>>> Thomas
>> 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
>>>>>
>>>>>
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