CardAnimation Technical Point

Change Anchor Point of CALayer

like: (0.5, 0.5) ->(0.5, 1)

Frame:

There are many ways to do this:

subView.frame = frame
subView.layer.anchorPoint = CGPointMake(0.5, 1)
subView.frame = frame

AutoLayout:

Discussion on stackoverflow, but I find a simple way:

let subViewHeight = 
let oldConstraintConstant = centerYConstraint.constant
subView.layer.anchorPoint = CGPointMake(0.5, 1)
//Like what you do with frame, you need to compensate for additional translation.
centerYConstraint.constant = subView.bounds.size.height/2 + oldConstraintConstant

Transform and AutoLayout

From iOS 8, transform and autolayout play nice. There is a blog for this: Constraints & Transformations

Transform doesn't affect autolayout, only constraints can affect autolayout.

Transform affects view's frame, but do nothing to view's center and bounds.

Flip animation with non-transparent background

Use a subview, and change the container view's background color to what color you want.

When the container view is vertical to screen, make the subview hidden, and after the container view back, make subview visible.

Rotation Animation Bug in action method

let flipTransform = CATransform3DRotate(CATransform3DIdentity, CGFloat(-M_PI), 1, 0, 0)
UIView.animateWithDuration(0.3, {
  view.layer.transform = flipTransform
})

The animation will not execute and the view just change if you execute above code in an action method, like clip a button. UIView keyFrame animation works fine.