Author
Travis Kirton


Velocity

You might see the velocity parameter in a gesture. This parameter is a representation of the speed of movement of the gesture between the current event and previous event. It is also measured by the change in the center.

obj.addPanGestureRecognizer { locations, center, translation, velocity, state in
    print(velocity)
}

Velocity can vary greatly, depending on how fast the user moves their touches. For example, it can range from 0…3000+, so you’ll have to calibrate a bit like we do in the example below.

Example

let c = Circle(center: canvas.center, radius: 100)
canvas.add(c)

canvas.addPanGestureRecognizer { locations, center, translation, velocity, state in
    c.center = center
    c.lineWidth = velocity.magnitude / 10.0
}