[vtkusers] Saving image with transparent background from Qt

[Ben Boeckel]

On Tue, Mar 06, 2018 at 18:48:43 +0000, Andras Lasso wrote:
> Thank you, this is very useful.
> 
> Is this a temporary workaround only or this is going to be the
> permanent solution? For augmented reality applications, where we need
> to generate transparent overlays at high refresh rate, this method
> would be quite expensive.

When I implemented the functionality, we couldn't think of anything else
without tracking things at the shader level or using some "never seen
anywhere" color as a baseline which is harder than this technique for
ParaView.

There may be some way to get OpenGL to do what you want though. There's
certainly support for rendering into a buffer with transparency
information, but I don't know how to get Qt to do so. Terminal
applications (e.g., Konsole) are most likely to have code to do so.

--Ben