QPixmap::handle(): Pixmap is not an X11 class pixmap

[Christoph Feck]

On Monday 02 May 2011 16:15:42 Wolfgang Rohdewald wrote:
> since updating to kubuntu 11.04 I am getting this message
> while KApplication is created, but only if I use raster or opengl
> as graphics system:
> 
> kpat --graphicssystem raster
> QPixmap::handle(): Pixmap is not an X11 class pixmap
> 
> this seems to happen with all KDE programs.
> 
> Any idea?
> 
> kdelibs 4.6.2
> qt 4.7.2

I remember a recent discussion in #qt-labs about this, and I think it has 
already been fixed in Qt 4.8 branch.

The issue, if I understood the discussion correctly, is that even while you 
are setting a non X11 backend, it is still possible for applications to create 
an X11 native QPixmap via the fromX11Pixmap() function, but the checks in Qt 
"forgot" that case.

Those checks were added to make sure applications don't try to access the 
underlying X11 pixmap so that changing the default backend to raster (or 
opengl) is possible for a future version of Qt.

In other words, you likely don't need to worry about that warning, unless your 
application breaks because of it.

On the other hand, I am highly interested why kpat tries to use X11 pixmaps at 
all. Adding kde-games-devel.

Christoph Feck (kdepepo)