[poppler] user-defined output device & private functions in libpoppler

[Albert Astals Cid]

El divendres, 2 de desembre de 2016, a les 9:37:48 CET, suzuki toshiya va 
escriure:
> Dear Poppler maintainers,
> 
> I would like to hear your comments about the possibility
> of the disclosure of functions used "in" libpoppler, like,
> Goo, Fofi and Splash (if there was some discussion in the
> past, please give me the pointer to there).
> 
> It could be useful for the developers who want to make
> their own new OutputDevice, out of libpoppler. Or, it is
> better for the developers to propose new OutputDevice to
> be included by future release of libpoppler, rather than
> making external library referring private functions?
> 
> --
> 
> Recently, CUPS developers discussed about the future of the
> filter "pdftoopvp". OPVP is an API set for the non-PostScript
> printers discussed by the engineers in OpenPrinting consortium
> under Linux Foundation (OPVP is not yet another PDL).
> 
> Also Ghostscript supports OPVP output, some engineers
> regarded Ghostscript is overkilling for pdf-to-opvp data flow,
> and using Poppler would be more compact & straightforward.
> 
> However, libpoppler has no officially-exposed APIs to make
> user-defined OutputDevice. Thus, pdftoopvp filter links to
> private functions in libpoppler, to make OPVPOutputDevice
> (basically it is a diversion of SplashOutputDevice).
> 
> Some people have concerns that linking private functions
> might be risky, because nobody guarantees the compatibility.
> 
> Thus, I want to ask the questions in the beginning. Is
> there any possibility for libpoppler to expose some internal
> functions for user-defined OutputDevice developers, or,
> they should propose their OutputDevice to libpoppler?

You should not use libpoppler core if you expect stability, that's by 
definition.

If you want stability you can propose new API for the "cpp" frontend that 
suits your needs.

Or you can try to convince us that it's very important and it should be part 
of poppler itself and not of cups.

Cheers,
  Albert

> 
> I hope to hear your opinions.
> 
> Regards,
> mpsuzuki
> 
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