let g = Gradient(frame: canvas.frame)
canvas.add(g)

let a = ViewAnimation(duration: 1.0) {
    g.colors = [C4Purple, C4Grey]
    g.startPoint = Point(1, 0)
    g.endPoint = Point(0, 1)
    g.locations = [0.49, 0.51]
}

a.delay = 1.0
a.autoreverses = true
a.repeats = true
a.animate()