Rotating a UIView to point at another UIView - swift

Question

I'm trying to get a UIView called object to rotate to point at the center of another UIView called orig. I can't seem to be able to calculate the angle correctly. My trig is a bit rusty so I can't figure out how my math is wrong.
let y0 = object.center.y
let y1 = orig?.center.y
let x0 = object.center.x
let x1 = orig?.center.x
let angle = atan2((y1! - y0), (x1! - x0)) * 180 / CGFloat.pi
rotateTo(object: object, degrees: angle, time: deplexed[1] as! CGFloat)

Answer 1

To make the top of rotator view point at the target point.
let direction = CGPoint(x: targetPoint.x - rotatorView.center.x, y: targetPoint.y - rotatorView.center.y)
var angle = atan2(direction.y, direction.x)
rotatorView.transform = CGAffineTransform(rotationAngle: angle + .pi/2)
atan2 returns zero if point is to the right.
If you want to convert the atan2 result to degrees:
if angle < 0 {
angle += .pi * 2
}
let degrees = angle * 180.0/.pi
You add a full circle if the angle is negative. 0 degrees points to the right.

Answer 2

Create a default object and suppose it's a button :
let button = UIButton()
if button.transform == CGAffineTransform.identity {
UIView.animate(withDuration: 0.5, animations: {
button.transform = CGAffineTransform(rotationAngle: self.radians(degrees: 180))
})
} else {
UIView.animate(withDuration: 0.5, animations: {
button.transform = CGAffineTransform.identity
})
}
func radians(degrees: CGFloat) -> CGFloat {
return CGFloat(degrees * CGFloat.pi / degrees)
}