Animation with control re-use

I need to animate controls by moving them along the x axis from x to x-1000.

My container view is 200 pixels across and each control is 100 pixels wide. There is a maximum of 4 controls (the controls are heavy and I need to re-use them)

So therefore, as I animate the controls from x to x-1000, I need to re-use them.

So as control 1 goes off to the left, it becomes invisible and needs to be re-positioned to the right hand side of the container view.

As I will be using an ease in function, the control needs to inherit the same speed and deceleration is it had before; so it literally just animates from right to left, once off screen, instantly re-positioned to the right of the container view, and carries on animating from right to left at the same deceleration rat开发者_StackOverflow中文版e.

Is there anyway to invoke a function for each frame of a CAPropertyAnimation? or something along those lines?

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As far as I know, you can't get velocity information from core animation.

You will have to roll your own animation for this. Setup a timer, and give each view an xVelocity. Every time the timer fires, have it adjust the xVelocity of all objects (you could apply a sine curve to it to give it an ease/out effect). Then change the center point of all the objects.