One step affine transform for rotation around a point?

Question

How can I make a Core Graphics affine transform for rotation around a point x,y of angle a, using only a single call to CGAffineTransformMake() plus math.h trig functions su

Answer 1

Use the view's layer and anchor point. e.g.

view.layer.anchorPoint = CGPoint(x:0,y:1.0)