[vtkusers] Crashes in Java wrapped vtk on linux because of xcb problems

[Luke Dodd]

Hi Sebastian,

>
> I don't think your are doing something silly there with vtkPanel.
> And if you come up with some solution, I'll be glad to integrate it into VTK.
>

Unfortunately the current solution adds lwjgl as a dependency which I
was unhappy to do in the context of my small project, so I'm not sure
it would fit well in VTK itself. Perhaps I'll dig though enough lwjgl
code to figure out how to make a more stable OpneGL panel myself.

The least amount of work would be to include a add tweaked
vtkGenericOpenGLRenderWindow to vtk which allows for for easier use
from wrapped languages - this could be useful for integrating with
many GUI toolkits. Then we could use my LWJGLVTKPanel java class
without any changes to vtk. (If I recall correctly the problem is that
the vtkGenericOpenGLRenderWindow delegates out operations to the
client code though observers, sometimes outputs are required for these
operations so pointers are passed as "arguments" to the observer. I
don't think it's possible to use those arguments in java - so I had to
tweak things a little.)

Best Regards,
Luke Dodd