[Qt-interest] why does QGrahicsView framework uses floats for coordiantes ?

[Pritam Ghanghas]

faster: fps with same animation done in QWidget was more than twice as
fast as in QGV. My board supports on raster and has no FPU.

On Wed, 2010-06-30 at 23:04 +0530, Jason H wrote:
> FPU multiplication is fast. (Scale, transform, any matrix multiplication etc)
> FPU addition is slow (translate)
> 
> GPUs can (in theory) be 
> used for acceleration (CUDA?).
> 
> The "lighter" comment is because 
> GVIs are elemtary shapes. They don't have QObject overhead. But they 
> don't do a lot that widgets do. QWs derive from QObject and all that 
> jazz.
> 
> And you failed to define "faster"
> 
> 
> ----- Original Message ----
> From: Pritam Ghanghas <pritam_ghanghas at infosys.com>
> To: "qt-interest at trolltech.com" <qt-interest at trolltech.com>
> Sent: Wed, June 30, 2010 8:17:42 AM
> Subject: [Qt-interest] why does QGrahicsView framework uses floats for coordiantes ?
> 
> Hi
> 
> why does QGrahicsView framework uses floats for coordinates ?
> is it just to have larger maximum value possible or some other reason?
> and
> is there a performance penalty because of that if my hardware doesn't
> have a FPU? 
> I found my Qwidgets to be signifacntly faster than QGraphicsItems. which
> is unexpected considering docs say that QGaphicsitems are lighter than 
> Qwidgets.
> 
>