Re: Optimized rendering for big files

Hi Ersin,

Thanks so much for rolling this together. I'll test this patch over
the next two days.

Cheers

Martin

On Wed, Apr 6, 2011 at 8:26 PM, Ersin Akinci <ersin.akinci@gmail.com> wrote:
> Hi all,
>
> Attached is a patch that integrates my work from last GSoC into the
> current trunk.  It implements a new algorithm for finding which pages
> are on screen and drawing them: instead of starting at the beginning
> of the doc and iterating through every single page, the new code
> selects an optimized starting page (currently hardwired to wherever
> the cursor is, which is still a much better guess than the beginning)
> and then goes up and down the doc from that point looking for which
> pages to render until it exits the viewport.
>
> Also, the rendering itself has been greatly simplified: the old
> approach was to split the screen into many different rectangles
> representing the pages and the spaces between them, but now we just
> redraw the background and lay the pages on top each time we need to
> redraw an entire page.  I don't think there's a big performance hit,
> maybe performance has even improved.  It shouldn't matter at all once
> we get double buffering.
>
> Finally, finding pages to render has been separated from the loop to
> actually draw them, which should make putting the rendering process
> into a background thread easier later on.
>
> Why you should care: very large files are now practical to edit, as
> long as breakSection is not called (i.e., no pressing enter or
> deleting lines).
>
> A note on having taken so long to integrate into trunk.  My original
> intention was to remove all assumptions about page sizes to allow for
> variable page size and eventually arbitrary page positions.  This
> broke many things and eventually I realized that the assumptions are
> just too deeply embedded.  So, I've abandoned trying to change them
> and instead have focused purely on performance.  Once my doctoral
> program started, time became scarce =).  I hope to build on this work
> for this summer's GSoC, ideally by moving breakSection into a
> background thread.
>
> -Ersin
>
> P.S.: This patch also fixes that annoying bug with the lower right
> corner of the page's drop shadow in page view.
>
> --
> Ersin Y. Akinci -- ersinakinci.com
>
> What Digital Revolution? -- www.whatdigitalrevolution.com
> Thinking critically about digital worlds.
>
Received on Fri Apr 8 08:32:30 2011