Qt-contributors-summit-2014-QtCS14TouchAndGestures

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Touch and Gestures

mouse and touch

• Qt Quick: handle actual touch events instead of synthetic mouse events when possible (work in progress)
• propagating events without consuming them
• hover events: if one MouseArea contains another, they both should see hover when it happens
• macOS: enabling gestures means we eat hover events in PinchArea
• dragging stuff with touch is not as smooth as flicking is
  • synthesize interpolated touch events per-frame?
  • then we need a means to turn it on/off
• should every event contain velocity?
• use platform timestamps when possible/available

the transfer-of-touch problem

• touch a control like a ComboBox, a window pops up, then drag to select an item
• drag in one Flickable and continue dragging in another (in the same window)
• reemit(event, targetItem);
• similar to keys forwardTo
• idea: MouseArea { priority: 2 }

system gestures

• no more gesture framework
  • could recognize only one gesture at a time
  • too many bugs
• OSX and Windows 8.x can give us native flick/scroll and pinch
  • qtquick needs to support them
  • Note though that on Windows, gestures will suppress touch events
• still have to solve the issue of choosing, or being able to get both gestures and touch somehow
• could receive one type of event first, accept/reject, then the other type will come
• TouchCancel is intended as notification that touch started but the effects should be un-done
  • sometimes difficult….