[Interest] QWindow::setTransientParent()

[John Weeks]

> renderPixmap() can be replaced with a call to grabFramebuffer(). They both perform (potentially expensive) readbacks.

Thanks Laszlo.

The expense is probably OK, since this is for exporting graphics as a file or on the clipboard. But grabFramebuffer() gives you the same resolution as on screen, and we need hi-res export.

I ran across some code in a JIRA bug using QGLFramebufferObject; I see there is also QOpenGLFramebufferObject so I guess we can use the same technique.

-John Weeks