[cairo] Patches for speeding up _cairo_fixed_from_double

[Behdad Esfahbod]

On Mon, 2006-11-06 at 16:51 -0500, Carl Worth wrote:
> On Mon, 6 Nov 2006 13:26:51 -0800, "Daniel Amelang" wrote:
> > > ...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.
> 
> As a rule, we're going to try to break our bad habit of delaying
> development snapshots to try to get the next great feature in. I think
> we'll be a lot better off if we can release a new snapshot every week
> and each one faster than the one from the week before.

Yeah, I also want to emphasize that this is a lot more important about
the first developmental release in a cycle, as the longer we delay 1.3.x
the harder it will be to track down regressions between 1.3.x and the
latest stable release, ie. 1.2.6 at the moment.  When we have the first
devel release out, it's all linear from there on.


> > 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.

So, what is the required change in pango?
Again, too bad PangoMatrix and cairo_matrix_t are not compatible.  We
could use the optimized cairo matrix operations if they were.


> Jorn will be very excited to hear about these, as will others at
> opened hand and elsewhere in the embedded field. I'll look forward to
> hearing more about your ideas here.
> 
> Over on performance-list at gnome.org some people have started to
> maintain a set of patches to de-cairo-ify pango, (making it use Xft
> instead). So if you can help make that kind of patch unnecessary that
> will be exceedingly useful.

Well, those are about making Gtk+ use pangoxft instead of pangocairo.
But yeah, it would be nice.


-- 
behdad
http://behdad.org/

"Commandment Three says Do Not Kill, Amendment Two says Blood Will Spill"
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