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….