[cairo] Porting GTK+ to use Cairo

Carl Worth cworth at east.isi.edu
Fri Jun 4 08:14:08 PDT 2004


On Wed, 12 May 2004 19:16:31 +0200, Jost Boekemeier wrote:
> For example cairo rendering of 1000 layers sitting on top of each other
> seems to be quite slow; cairo sends everything, even the non-visible
> parts, to the server. Does cairo expect that we use layers only when
> stricly necessary (layer is not opaque) or can we assume that a future
> version of cairo can optimize the picture before it is sent to the
> server?

You can assume that a future version cairo will provide support for
efficient clipping to pixel-aligned regions.

> Not really. In this environment a VNC picture would be 640x480*8=300K,
> compressed ca 3K..30K which can be send in 3..30 seconds.  
> I don't know where cairo pictures fit in there, I hope they are usually
> 10 times smaller than VNC images.

It's not obvious that geometry is necessarily more compact than the
rendered image. An interesting lesson from the land of 3D graphics is
that the most compact representation is the rendered image. The amount
of geometry and texture information needed to make the image is many
times larger. 2D is a a different beast, but still.

One thing that is nice about the cairo architecture is that we have the
flexibility to experiment with interesting combinations of client- and
server-side rendering.

-Carl




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