Qtopia coming for Neo1973

Dr. H. Nikolaus Schaller hns at computer.org
Tue Sep 25 17:51:15 CEST 2007

Am 25.09.2007 um 17:20 schrieb Dani Anon:

> But hey I like how you conveniently left unanswered my comment about
> how the FBUI and DirectFB projects exist solely to remove the X server
> overhead. Can you explain to me and them why they are wrong and how
> they have wasted all those months of development to solve a problem
> that just doesn't exist?

It exists theoretically but the practical relevance depends on  
several factors.

I have done some experiments on the OpenMoko and I believe that the
framebuffer itself is the slowest part (don't know why). But X11 *is*  
quite fast.

I could achieve a lot of speed up in my GUI Framework (yes it is  
another choice!)
by double buffering X11 (i.e. drawing offscreen first and then  
copying the
modified block in a single bitmap copy command).

In my GUI toolkit the main speed killer is the missing FPU in ARM  
which has to rely on FPU emulation.

So, why optimize something that already works sufficiently? It is  
like washing whiter
than white. But if there is someone who wants to optimize it further  
- why not?

So - IMHO - the X11-Overhead is a neglectable problem. And the  
benefits of X11
overweight any drawbacks.

Summary: I am happy with X11 on OpenMoko (and other handhelds).

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