Posted by Wade Walker on Jan 09, 2011; 3:23pm
URL: https://forum.jogamp.org/Overlay-is-stretched-when-viewport-is-not-covering-the-full-windows-tp2221069p2221613.html

Have you tried this?

overlay.beginRendering();
overlay.draw(int screenx, int screeny, int overlayx, int overlayy, int width, int height );
overlay.endRendering();

Supposedly it allows you to draw the overlay starting at a given screen location, and to draw a sub-section of the overlay there.

What behavior do you want to happen? Perhaps you could just use the draw call above instead of setting gl.glViewport()?