Re: GdkPixbuf vs. Cairo, new image library needed?

["BJörn Lindqvist" <bjourne gmail com>]

On 10/15/07, Carl Worth <cworth redhat com> wrote:
> On Sat, 13 Oct 2007 00:51:44 +0000, "=?ISO-8859-1?Q?BJ=F6rn_Lindqvist?=" wrote:
> > I have played around with Cairo some more and it seems to me that it
> > is not fully ready yet. :( Cairo blits and scales much slower than
> > gdk-pixbuf (software that is)
>
> Do you have some simple test cases to demonstrate this so we can
> identify and fix anything necessary in cairo?

The slowness really is pixman's fault and not Cairo's. This bug
(https://bugs.freedesktop.org/show_bug.cgi?id=12801) contains a
program for measuring scaling performance and this one
(https://bugs.freedesktop.org/show_bug.cgi?id=12803) for measuring
"gdk_color_composite" performance.

Also see this post
(http://mail.gnome.org/archives/gtk-devel-list/2007-October/msg00071.html)
about pure blitting performance. A program that is equivalent to the
GDK example, is on my computer twice as slow as GDK.

> The scaling code in cairo, (for downscaling by factors greater than
> 2), could definitely use some improvement, (the current result is
> embarrassingly ugly). But what GdkPixbuf does here is actively bad for
> performance. I'd like to see some middle-ground implementation.

Yes. I'd really love to see one filter that is "backwards compatible"
with GdkPixbuf though.

-- 
mvh Björn