Re: GdkPixbuf and Xrender scales

[Federico Mena Quintero <federico ximian com>]

On Wed, 2006-10-18 at 15:48 -0200, Carlos Eduardo Rodrigues Di�es
wrote:

> GdkPixbuf will start to use cairo/xrender or other library to do it's
> scale operations? If the answear is no, what are the reasons, since use
> cairo will enable hardware accelarating when glitz be finished.

The answer is "wrong question" :)

GdkPixbuf is a representation for images in your process's memory.  When
you scale a pixbuf, you get another pixbuf in your process's memory.
So, it is like this:

  pixbuf-in-process -> scale operation -> pixbuf-in-process

When you use acceleration in a video card to do scaling, you do this:

  image-in-process -> scale operation -> display memory

I.e. the scaled image goes to a completely different place.  You don't
get that image back in your process.

Every application paints things differently.  Some create temporary
images in memory, draw stuff to them (including scaled images), and
finally paint the final image to the screen.  Others create temporary
pixmaps in the video card, draw everything there, and then paint the
pixmap to the screen.  It is this second kind of applications that would
benefit from hardware acceleration in video cards.

  Federico