[Qt-qml] on device performance

[Alexey Zaryanov]

I have some new troubles (ListView and my own C++ model):
Spent a lot of time cleaning the model (more than 100 ms on n900)
example:

void QObjectListModel::clear()
{
    beginRemoveRows(QModelIndex(), 0, m_objects.count());
   // bla bla
    endRemoveRows();
    emit countChanged();
}

And next problem. IU works well at first time, but if i change model data -
performance is going down. =(

2010/12/18 Cornelius Hald <hald at icandy.de>

> > If you aren't doing so already, I'd suggest also:
> > * running using the raster graphics system (i.e. raster + GL viewport).
> This has an impact because so many of the items cache their drawing to
> pixmaps.
> > * turning off sample buffers (below is what we do in qmlviewer), as long
> as the graphical results are acceptable to you
> >
> > QGLFormat format = QGLFormat::defaultFormat();
> > format.setSampleBuffers(false);
> > QGLWidget *glWidget = new QGLWidget(format);
> > //### potentially faster, but causes junk to appear if top-level is Item,
> not Rectangle
> > //glWidget->setAutoFillBackground(false);
> > view->setViewport(glWidget);
> >
> > * As mentioned in an earlier reply, running fullscreen rather than
> maximized if possible (compositing is quite expensive, and avoiding it gives
> a very nice performance bump)
>
> Thanks for the tips! Are there any similar optimizations that can be done
> for Symbian^1 and Symbian^3 devices?
>
> Cheers,
> Conny
>
>
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