WM suport for grab key scrolling

[Marco Pesenti Gritti]

Hi Matthew,

we have a grab key on the OLPC keyboard. When it's pressed we should
grab the pointer and mouse movements should cause the main view on the
currently active window to scroll (the web page for a browser, the
document for a word processor etc).

Zephaniah was suggesting the WM should manage this which sounds like a
sensible approach to me. Basically when pressing the grab key the WM
would:

1 Grab the pointer, hide it and ensure it's always at the center of the
screen (otherwise when you get on the edges you would not be able to
scroll in that direction anymore)
2 Ask the active window to scroll of a certain amount of pixels on x,y
axis.

What do you think? Is there a clean way for the WM to communicate 2 to
the active window?

Thanks,
Marco