On 07/04/2012 03:37 AM, Martin von Gagern wrote: > With that patch by Chase, I also wonder what would happen if two touch > devices were used simultaneously. > > When I both touch my screen and click my conventional mouse button, I > get two button events, but the state is the bitwise or of both, so the > second click will be "pressed button 1 while button 1 was pressed". > Makes sense, in a certain way, although it might well confuse some > applications. > > But what if I had two touch devices controlling the core pointer? I > believe it is likely with the current setup that in this case, the > second device would generate a ButtonPress with state 0x000. Or is it > impossible for more than one touch device to control the core pointer at > a given time? I don't have more than one device, so I can't test this. > > I'll agree that given current technology, this seems a rather rare > corner case, and probably not worth the effort to deal with properly. > But any shortcomings in that respect should perhaps at least be > documented somewhere.
Great point here :). I had to look at the code to determine the correct answer. I worried that, like you said, it would be buggy if you had two touchscreens. However, this should not be a problem. Input devices have a two-layer hierarchy. There are slave devices and master devices. Slave devices represent a physical device, like a touchscreen. Master devices represent a group of slave devices. Most people only have one master device configured, and all the slave devices are attached to it. If you have two mice, you can create a second master and attach one slave mouse to each. Then you'll have two independent pointers on screen :). A client can listen to events from master and/or slave devices. The events look and behave almost exactly the same. When you press your mouse button, a button press event is generated for the slave device and the attached master device. If you have two touchscreens with one master, then each slave device can emulate a button press event. However, there can be only one emulated touch per device (no matter whether it's a slave or a master), so the first touch is emulated for the master, and the second touch is not. Thanks! -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg-server in Ubuntu. https://bugs.launchpad.net/bugs/1015183 Title: Inconsistent mouse events for Acer T231H multitouch monitor To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1015183/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
