KIO::PreviewJob pixmaps + Qt4.5 crashes

[Aleix Pol]

On Fri, Mar 13, 2009 at 2:23 PM, Maksim Orlovich <mo85 at cornell.edu> wrote:

> > Same happens on both systems tested, both using GNU/Linux environments.
> > This
> > crash happens also in dolphin (when used with the information panel,
> > because
> > there is a thumbnail drawn inside), same arguments workaround is
> > applicable
> > (--graphicssystem).
> >
> > Is there any additional information needed?
>
> #1) Well, for starters, you need to explain why in the world your
> application seems to be using the raster engine and not the X11 engine.
> There are absolutely no guarantees that KDE will work this way, at all, as
> changing it is not behaviorally compatible.

My Qt was installed using the configure command proposed by README.qt-copy.
I don't have any special interest on raster in this application.


>
>
> #2) valgrind output will say a lot more than the backtrace.

I checked that, I didn't see anything relevant. I'll recheck later and send
later on in case i think it is needed.


>
>
> #3) The other response is likely right. I bet the following accesses
> deleted memory with the Raster engine:
>
> const int w = 16, h = 16;
> QRgb* data = new QRgb[w*h*4];
> std::memset(data, 0, w*h*4);
> QImage* i = new QImage(data, w, h, QImage::Format_ARGB32_Premultiplied);
> QPixmap p = QPixmap::fromImage(*i);
> delete i;
> //Do stuff with p here
>
> There seems to be no deep copy going on here (and coincidentally,
> QImage::convertToFormat docs lie --- it doesn't always return a copy)
>
>
Yes it is possible, but I don't know where this copy happens at all.
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