faster paint tree traversal

[Antti Koivisto]

Hi,

David Hyatt wrote:

> While we're talking about painting and rects, one very big change 
> we've been contemplating here is that we'd really like to switch the 
> engine over to using floats instead of ints for positioning/painting.  
> (Cocoa is all float-based so we're having to put all these rounding 
> hacks in when text rendering, we fail CSS tests that use subpixel 
> positioning, e.g., Hixie's tests, etc.)

You might not be overly interested, but that would kill performance on 
platforms without FPU (eg. ARM).

> My thought was to possibly introduce a typedef, e.g., Pixel, that 
> could be an int for you and a float for us, and then start switching 
> the engine over to this unit.  We might also need typedefs for rects 
> and points so that we could use a float-based rect/point where you 
> used QRect/QPoint.

Use of float/int would stil be a rather big divergence between the trees.


  antti