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lynkfs

gestures

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Every now and then I read something so refreshing, that it jolts the old braincells out of its rut.
10/GUI describes a new gui system concept which does away with keyboards and mice, relying on gestures instead
Fun, and somehow very convincing

Recently I needed a mechanism to cycle through an image carousel. There are different ways of doing this, but for touch enabled devices I opted for a one-finger swipe gesture.

W3Image.OnSwipeLeft := procedure(sender: TObject) begin ... end;


The implementation of OnSwipeLeft below is somewhat project specific, but includes the following

- it is made a property of all customcomponents descendants (helper construct)
- it extends TNotifyEvent, so it does not only return the sending object (sender: TObject), but also the event object (event: variant). That way OnSwipeLeft has access to properties of both (and handles all event-types)
- it checks if the device has touch capabilities and uses the touch-api if that is the case, otherwise it uses pointerevents

Demo project  (covering all swipe orientations. Verbose code, can be simplified)

The touch-api supports multi-touch events to a certain maximum. My phone can handle 5 fingers.
That makes it possible to implement for instance two-finger swipes to slide-in the next form.

Form.OnFormSwipeRight := lambda Application.GotoForm('Form2', feFromRight); end;

 

 

 

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