touchscreens in multiscreen setups

Keith Packard keithp at
Thu Apr 8 09:22:21 PDT 2010

On Thu, 08 Apr 2010 17:22:56 +0200, Peter Korsgaard <jacmet at> wrote:

> - Add an XInput property to evdev to assign a screen number / randr
>   output name to a device

Use a window ID to identify the screen; the protocol never uses screen

> - Add an API to forward this info to the server (xf86XInputSetOutput?)

I don't know how this should work; feel free to try whatever strikes
you, including adding fields to the input device structure
itself. That might be easiest. Just a rectangle that identifies the
region of the screen that the touchscreen is aligned to may suffice,
along with a matrix to do the transforms.

> - Translate the raw coordinates in GetPointerEvents() if that flag is
>   set (POINTER_OUTPUT?), and optionally ignore event if output is
>   disabled.

Sounds reasonable.

keith.packard at
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