[cairo] Patches for speeding up _cairo_fixed_from_double

[Daniel Amelang]

On 11/6/06, Carl Worth <cworth at cworth.org> wrote:
> On Wed, 1 Nov 2006 22:53:33 -0800, "Daniel Amelang" wrote:
> > Attached are patches resulting from the discussion here:
> >
> > http://lists.freedesktop.org/archives/cairo/2006-October/008285.html
>
> Thank you so much for such an excellent patch submission!

My pleasure. My recent Summer of Code attempt to contribute to
cairo/mozilla failed miserably (all my fault, long story), so this is
some sorely-needed encouragement.

> ...I'm going to be putting together a development snapshot
> with all the performance work that's been happening since the
> 1.2 branch...

You might want to hold off on that development snapshot for a just
little longer. I have two more performance-related patches in the oven
that could potentially make a number of people happy.

First, I'm fixing up this (orphaned?) patch:

http://lists.freedesktop.org/archives/cairo/2006-September/007861.html

to incorporate the feedback you gave. I addition, I have a little
tweak for it that produces an even greater speedup. This patch is very
important for the embedded guys, as it significantly reduces a common
and clearly-identified bottleneck. They won't be nearly as excited
about the upcoming development snapshot without it.

Second, I have an optimization that's similar to this
_cairo_fixed_from_double one that addresses some of the slowness in
rendering glyphs, especially in the case that was profiled here:

http://www.o-hand.com/~jorn/pango-benchmarks/210-softfloat/

This optimization, plus a small patch for pango (also in the works),
should improve text rendering on both ARM and x86.

Unfortunately, I've got midterms this week, but I should be able to
finish the patches over the weekend.

Dan