[throw_a_grenade]

How do I implement type-ahead in Qt or GTK application?

[GrinningFool]

Not specifically for those but I have to assume the pattern would work: you could intercept the keystrokes in a parent window or an overlay, then forward them to the correct child window once it's rendered.

[1718627440]

So you implement a rendering system and an input queue on top of a drawing region. Sounds like you are implementing a Terminal emulator.