[poppler] patch for a progress callback

[Albert Astals Cid]

El Divendres, 4 de gener de 2013, a les 09:16:25, Damian Stewart va escriure:
> Hey all,

Hi

> My wife makes makes generative images (http://liaworks.com) using
> openFrameworks and exports them to PDF documents for large-format printing
> (100cm width at 300dpi). She often ends up with 10MB pdf docs containing
> tens of thousands of lines that can take between 30 minutes and 2 hours to
> render at print resolution.
> 
> To make the experience less miserable I built a progress callback into
> poppler. It's integrated into Page::displaySlice. If a progress callback is
> passed, displaySlice() does a preprocessing step where it constructs a
> DummyOutputDev and asks Gfx to render to that dev, counting the number of
> operations performed. Then it performs the real render to the passed output
> dev, calling the progress callback for every operation with a progress
> percent (0..1), a page number and optional user data.

Some comments:
 * The cpp facing api seems quite "un-C++-ish", i think that a class with a 
pure virtual progressDone() function and a Page::setProgressHandler method 
would make it more C++ish
 * How useful is this? I.e. i predict that there are operations that are 
really fast and others really slow, does it really help?
 * The DummyOutputDev should take the real outputdev and return the values of 
the real outputdev for the "querying" functions, e.g. your dummy outpudev 
returns false for useTilingPatternFill, but SplashOutputDev returns true, this 
probably means that you never get to 100% on files that have patterns, no?
 * Have you measured the performance hit?

> 
> As far as the outwards-facing parts of Poppler are concerned, I have only
> added the progress callback to the poppler::page_renderer class in the C++
> API. I can supply a demo application built using the C++ API if that helps.
> 
> Please find the patch attached; apologies if this is not the correct way to
> do submit patches.

This is fine.

Cheers,
  Albert

> 
> Thanks (Poppler is awesome!)
> Damian