[Sugar-devel] Browse.xo performance & resolution - Hulahop 200dpi vs Browse 134dpi

[Mihai Sucan]

Le Fri, 15 May 2009 15:26:42 +0300, Lucian Branescu  
<lucian.branescu at gmail.com> a écrit:

> This is very interesting, similar to the problem Qt used to have on  
> Maemo.
>
> I was always surprised by report of <canvas> being slow on the XO,
> it's probably the fastest and the lowest overhead drawing technology
> available to JavaScript.

It's true it's the fastest and the lowest overhead drawing technology  
available to JavaScript - which is really the reason I picked it for the  
development of the paint tool.

I wouldn't agree with the idea of Canvas being actually (too) slow on the  
XO, nor on desktops. Once I changed the DPI to 96 on the XO, I was rather  
amazed / very pleased by the performance of the drawing tool. It's almost  
as fast as on the desktop.

Surely, the Canvas drawing performance should be something we all desire  
to improve, constantly. ;) Yet, it looks like the main performance hit on  
the XO comes from the DPI setting. The bilinear rescaling of the Canvas  
element being performed by Gecko slows things very much. We need to work  
around this issue somehow.

Would the experience of making Qt faster on Maemo provide us with anything  
of use in this case? (it seems to me it's unlikely, but ... it never hurts  
to ask)


-- 
Mihai Sucan
http://www.robodesign.ro