> > How can a pointer grab stop a touch? A touch origins at a slave > > device, and I can imagine grabbing the pointer of a master device fed > > from that slave device. However, I cannot imagine that grab stopping > > the slave device touches from being delivered to someone listening to > > that device. > > What you've described is correct for pointer devices, but not for touch > devices. A device grab is intended to yield exclusive access to the > stream of events from that device. Continuing to send touch events when > the stream of events has been pointer grabbed breaks this exclusivity. I > will think more about this though.
I can see exlusivity working for the master device, but I am questioning whether this really needs to propagate back to the slave device. If the master is detached from the slave, and the master is grabbed, it makes a lot of sense that events are still available. Similarly, it makes no sense to pointer-grab a slave device, which does not event have to be a pointer in the first place. I wonder if one cannot continue to loosely couple master and slave devices, by not propagating pointer grabs across the master/slave boundary. > >> Another way would be to take the pointer events and translate them to > >> touch events internally if they are pointer emulated. To determine > >> whether they are pointer emulated would require converting them to XI > >> 2.1 grabs again, though. But if you don't mind people trying to use a > >> mouse, you could just translate all the mouse events. > > > > Really, this sounds more complicated than it needs to be. > > No one would disagree :). Again, we're caught having to work within a > window system that forces us to integrate pointers and touches when that > should never be the case. And SDL is actively pointer grabbing all the > time, and whenever you do that things invariably get more complicated. The touch interface is brand new, so we are not forced to couple things tighter than absolutely necessary - what ever that means. Thanks, Henrik _______________________________________________ Mailing list: https://launchpad.net/~multi-touch-dev Post to : multi-touch-dev@lists.launchpad.net Unsubscribe : https://launchpad.net/~multi-touch-dev More help : https://help.launchpad.net/ListHelp
