[poppler] Proper Transparency Support in pdftops

[Albert Astals Cid]

El Dijous, 22 de març de 2012, a les 22:58:13, Jason A. Donenfeld va escriure:
> Dear Poppler Maintainers,

Hi

> Pdftops is a great utility. So great, in fact, that recent versions of CUPS
> ship with optional compile-time support for using pdftops instead of
> ghostscript. Gaining the confidence of print software is no small
> accomplishment, and poppler has proved itself to be a very complete and
> correct pdf parser.
> 
> There is one area, however, where poppler unfortunately makes a significant
> error:
> 
>     rasterize = scan->usesTransparency() || scan->usesPatternImageMask();
> 
> 
> The PSOutputDev uses Splash to rasterize PDFs if they're found to use
> transparency or patterned image masks. While this works well for some use
> cases, for many other use cases, especially in printing, rasterization is
> the worst of all options and is often insufficient
> 
> So I'm wondering -- is including proper support for transparency and
> patterned image masks on the schedule for the immediate future? If so,
> wonderful.

As far as my limited PS knowledge goes, PS does not support transparency, so 
if your PDF has transparency you need to rasterize it otherwise it can never 
end up in a PS file correctly.

Albert

> 
> If not, would you consider adding a "--dont-rasterize" flag to pdftops, so
> that if PSOutputDev is unable to convert without rasterization, it exits
> with a known error code? This way, pdftops could be preferred, and
> ghostscript might function as a fallback, for the case of a scripted
> conversion utility.
> 
> Thank you,
> Jason Donenfeld