Grab key scrolling

Jim Gettys jg at
Mon Apr 16 18:07:08 EDT 2007

On Mon, 2007-04-16 at 16:42 +0200, Marco Pesenti Gritti wrote:
> Hello,
> we have the grab key on the keyboard which, when pressed, should
> activate the scrolling mode. It should work like this:
> 1 The user press the grab key on the keyboard.
> 2 The scrollbars of the current view are highlighted.
> 3 Movements on the trackpad (both resistive and not resistive) scrolls
> the view. The mouse pointer is "locked" and does not change position.
> We are having problems with the X side of this but I think Jim said to
> Eben it was possible. Can someone with more with more X knowledge than
> me suggest a good way of implementing it?

I don't believe I ever claimed this is possible.

I think we're going to have to extend X to get these semantics.

The closest one can come is to confine the cursor to a window; but that
is different than nailing it to one place and causing the window
coordinate system to move.
                                        - Jim

> What I tried is to detach the pointer device from the core pointer.
> (XChangePointerDevice). But then how do I get notified about trackpad
> movements?
> Thanks,
> Marco
Jim Gettys
One Laptop Per Child

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