XInput func param questions

Peter Hutterer peter.hutterer at
Thu Sep 4 02:21:40 PDT 2008

On Tue, Sep 02, 2008 at 09:31:08PM -0400, Chuck Robey wrote:
> First, for the valuators, my 3rd one is the z axis.  It's in fact my stylus tip
> pressure, but I haven't seen any way to explicitly tell the server that it IS
> tip pressure.  Is there any way to do that, or do I just trust that things
> understand that the 3rd and last valuator (for z axis) must be the Tip Pressure?

you can't, you have to rely on the client to interpret it correctly.

> 2nd, function InitValuatorAxisStruct, the 5th, 6th and 7th (last 3) parameters
> are "resolution", "min_res", and "max_res".  The two previous parameters (3rd
> and 4th) are the min_x and max x.  My X and Y are 15 bit unsigned, my Z is 10
> bit unsigned, so I set all of the min/max_x's to (0-32767),(0-32767), and
> (0-1023) for X, Y, and Z...  BUT I can't figure out what the heck are those 6th
> and 7th params (the min_res and max_res).  The min/max_x seem to do the range
> setting, so I can't guess what those min/max_res things could be good for.  I
> looked at other drivers, but can't get a clear enough example to do me any good.
>  Anyone got any idea what this might be?

probably to set min_resolution and max_resolution, for devices that don't have
a fixed resolution. Look at the XI protocol spec, there may be something in

> I found a "focus" initialization function in another driver
> (InitFocusClassDeviceStruct) so I put one  in this driver, but I don't really
> know why, and I've set up no focus-type events.  Do I need to send any focus
> events for a tablet, and why would I do this (what would happen to the tablet,
> that would trigger me to send the event?)  Or can I ignore this?

if you send key events, you need a focus class. otherwise ignore it.

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