How to make clock ticks stuck to the clock border?

I try to make a clock, in swift, but now i want to make something strange. I want make border radius settable. This is the easy part (is easy because I already did that). I drew 60 ticks around the clock. The problem is that 60 ticks are a perfect circle. If I change the border radius I obtain this clock:

All ticks are made with NSBezierPath, and code for calculate position for every tick is :

tickPath.moveToPoint(CGPoint(
            x: center.x + cos(angle) *  point1 ,
            y: center.y + sin(angle) * point1
            ))

        tickPath.lineToPoint(CGPoint(
            x: center.x + cos(angle) * point2,
            y: center.y + sin(angle) * point2
            ))

point1 and point2 are points for 12 clock tick.

My clock background is made with bezier path:

 let bezierPath = NSBezierPath(roundedRect:self.bounds, xRadius:currentRadius, yRadius:currentRadius) 

currentRadius - is a settable var , so my background cam be, from a perfect circle (when corner radius = height / 2) to a square (when corner radius = 0 ).

Is any formula to calculate position for every tick so, for any border radius , in the end all ticks to be at same distance to border ?