[Qt-qml] on device performance

[Thomas Perl]

Hi!

2010/12/14 Juha Turunen <turunen at iki.fi>:
> On Tue, Dec 14, 2010 at 1:51 PM, Cornelius Hald <hald at icandy.de> wrote:
>> As far as I know Symbian automatically uses OpenGL or OpenVG if
>> available. You have to #ifdef this part of the code :( You might also
>> want to have a look at this blog:
>> http://thpmaemo.blogspot.com/2010/10/qt-write-once-ifdef-everywhere.html
>
> I don't think it's automatic. You need to tell the app which graphics
> backend to use (OpenVG for accelerated Symbian^3 devices of course).
> What is automatic is that if you define the graphics system, you don't
> need to manually use a specific viewport widget (QGlWidget) and it
> will automatically revert to raster if OpenVG isn't available.
>
> All you need to do is call QApplication::setGraphicsSystem("openvg")
> _before_ you construct your QApplication object.

If it automatically reverts to raster, why does it not choose the
fastest backend available on each platform? (i.e. OpenVG on Symbian^3)
If it does not do that by default (I don't know - that was just an
assumption based on the on-device speed of the app I wrote), shouldn't
it do that by default? In which component of Qt should I file a
feature request for that (QGraphicsView?).

How would a cross-platform "make it fast" code snippet look like that
gives the best result on both Maemo and Symbian^3 as well as on
Desktop platforms and future MeeGo devices?

Thanks,
Thomas