Complicated QwtPlotZoomer crash, possible bug? Help request.

[Uwe]

I will have a look at the problem the next time I will check Qwt on Windows ( what might take some time ).

Uwe

[jomarin]

Hi everyone,

I have a similar problem on Windows. My QwtPlot window crashes after a number of zoom in and out, that seems to depend on the machine used.

I did not experience the same problem on Solaris.

Any news on this subject ?

Thanks in advance,

Joel.

[philwinder]

Ah, I am glad it is not just me. I still have the problem, and I do think it is restricted to windows. They must handle their graphics memory management differently. Having you on board with the same problem may inspire Uwe to take a look at the problem.

[gambr]

Same problem on windows XP, VS 2003 7.1 SP1, Qt 4.4.0, Qwt 5.0.2 & 5.1.0 & 5.1.1.

Gianni

[gambr]

Qt support confirms there is a GDI leak on their part. It should be already fixed in Qt 4.5.0 coming but I didn't try that.

Gianni

[Azraiyl]

Same bug here. You can open the Windows task manager and watch the GDI objects. If a Zoomer (and on my computer a Picker as well) is enabled you are able to create about 1000 GDI objects per second. After about 10'000 GDI objects Windows isn't happy anymore.

(About 50% of the Qwt demos crash on my computer when I recompile everything with Qt 4.5.0 rc1 (when I move the cursor over a plot), but this is maybe my problem).

[Uwe]

(About 50% of the Qwt demos crash on my computer when I recompile everything with Qt 4.5.0 rc1 (when I move the cursor over a plot), but this is maybe my problem).

No, it's because of an changed API of Qt 4.5.0 that let's Qwt run into a NULL pointer.

I adopted the Qwt code yesterday, but didn't check the Windows platform yet. So with the code from SVN ( 5.1 branch ) there are chances to have a working combination.

Uwe

[Azraiyl]

Thanks. Examples now build fine and the Picker/Zoomer does not create tons of GDI objects anymore (at least with Windows XP).

[gambr]

I confirm the leak was on Qt side. Qt 4.5.0 release candidate are fixed but you need to download Qwt 5.1 from svn to play with that Qt version.

Gianni

[philwinder]

Great to hear you got it all sorted. Thanks Uwe, and everyone else!

[dbrmik]

Hi

I've read through this thread, and unless I'm missed something my setup should be OK. I am running qt4.4.3 and qwt5.1.1 on windows xp. However my setup is suffering from the same problem

warning: ASSERT: "m_hdc" in file painting\qpaintengine_raster.cpp, line 4286

Anyone any ideas why this is

Best regards

[Uwe]

I've read through this thread, and unless I'm missed something my setup should be OK. I am running qt4.4.3 and qwt5.1.1 on windows xp. However my setup is suffering from the same problem

Everything is wrong with your setup: it's a Qt 4.4 bug fixed in Qt 4.5 and you need Qwt 5.2 from SVN (will be released the next days) because 5.1.1 is incompatible with Qt 4.5.

Uwe