[poppler] about patterns

[Rafael Rodríguez]

El Domingo, 20 de Agosto de 2006 01:34, escribió:
>          AFAIK, it's still 100% the original Xpdf sources.
>
>          What don't you understand?  (and I
> assume you've read the relevant sections of the PDF Reference, yes).

I've read sections 2, 3 and relevant subsections in 4 of PDF Reference 1.6.

>          Tiling patterns are pretty simple - you
> simply "replay" the pattern each time with
> appropriate transformation handling.  

So it's all about looping in X and Y and modifying the needed transformation 
matrix (state->concatCTM() and out->updateCTM()) everytime I find a painting 
operator inside the pattern stream?

> That's 
> probably one reason for the performance problems
> - - Xpdf doesn't cache anything nor does it use a
> "display list architecture", while Acrobat does
> both.  So in the case of a tiled pattern, Xpdf
> must reparse and rerender each time.

What's a display list architecture? Any place where i can read about it?

>          Replacing Xpdf with a DL-based
> architecture would be a MAJOR piece of work - BUT
> you might be able to find a way to cache a one
> rendered instance of the pattern and simply blit
> that multiple times.  

"a rendered instance"? Didn't catch this...
>
>          Please do, as I have not seen a case
> where it renders incorrectly - and I've been
> working with Xpdf for almost 10 years now.

Maybe i'm wrong, but the attached one-page pdf file doesn't render right with 
poppler from CVS (using test-poppler-qt4).

Regards,
-- 
Rafael Rodríguez

http://unrincon.blogspot.com
http://cornerofcode.blogspot.com
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