intended direct touch behavior

[Peter Hutterer]

On Tue, Oct 09, 2012 at 08:31:12AM -0700, Chase Douglas wrote:
> On Mon, Oct 8, 2012 at 4:30 PM, Thomas Jaeger <thjaeger at gmail.com> wrote:
> > Hi,
> >
> > I'm trying to debug a few issues that I suspect are ultimately the
> > result of wacom touch screens having a resolution different from the
> > screen resolution [1], and I realized I don't even know what is supposed
> > to happen when a relative device is used after a touch.  The two
> > possible behaviors are
> > (1) jump back to the last (pre-touch) position of the master pointer
> > (2) stay at the position of the last TouchEnd
> > The server exhibits behaviors approximating both (1) and (2) depending
> > on the circumstances: For example, on an empty session (with just the
> > root window it will do (1) (but the cursor is shown at the point of the
> > touch until the relative device is actually moved). In an xterm or xev
> > window, it will do (2) (but jump to the device coordinates of the last
> > touch, interpreted as screen coordinates, once the relative device is used).
> >
> > Which of the two behaviors is intended?  I don't personally care either
> > way, but it'd be nice to be consistent.
> 
> I think you're hitting an issue that just never was resolved properly.
> I think that, ideally, when you perform a direct touch interaction and
> the cursor moves to that location, any future relative device motion
> should be performed relative to the new location.

correct, that's the expected behaviour (and the behaviour for non-touch
devices). Fix would be in dix/getevents.c:updateSlaveDeviceCoords() and
figuring out why master->last.valuators apparently have the wrong values.

Cheers,
   Peter

> What is currently happening is the relative device is remembering its
> last location and performing future motion relative to its remembered
> location.
> 
> Basically, I think it would just take someone who is annoyed enough to
> spend a half hour to fix it :).
> 
> -- Chase
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