Union 0.5.0

Union 0.5.0

LangLanguage SwiftSwift
License MIT
ReleasedLast Release Oct 2015
SPMSupports SPM

Maintained by hirohisa.

Union 0.5.0

  • By
  • Hirohisa Kawasaki


Context transitioning’s animation manager for iOS written in Swift. Create animation tasks for each layer’s animation and deliver tasks on Union.Delegate.


  • [x] Support CABasicAnimation.
  • [x] Support CAKeyframeAnimation.
  • [ ] Support UIView.animateWithDuration Block.
  • [x] Link to other tasks, use property dependencies.
  • [x] Support UIViewControllerTransitioningDelegate.
  • [ ] Support UITabBarControllerDelegate.


  • iOS 8.0+
  • Xcode 7.0+ Swift 2.0



If you prefer not to use either of the aforementioned dependency managers, you can integrate Union into your project manually.

Embedded Framework

  • Open up Terminal, cd into your top-level project directory, and run the following command “if” your project is not initialized as a git repository:

  • Add ImageLoader as a git submodule by running the following command:

$ git submodule add https://github.com/TransitionKit/Union.git


I create sample animation with Union, it is like “User-Profile-Interface-Animation” from dribbble.com.

see project.


  1. Create animation.
  2. Implement animation tasks in Union.Delegate.
  3. Call Union transition on UINavigationControllerDelegate.

Create animation

Unit of animation is Union.Task. There are two ways to create it:

  • Init with layer and animation

    Most cases is this pattern

let animation = Animation(layer:layer, animation:animation)
  • Init with delay time and completion block

    Use when there is a process not an animation

let animation = Animation(delay: 0.3) {
    self.view.insertSubview(self.imageView, aboveSubview: self.backgroundView)

Union.Animation class:

public class Animation {
    // public property
    public var delay: NSTimeInterval = 0.0 // animation start after delay time
    public var completion: () -> () = {} // block called when animation is finished

    public init(layer: CALayer, animation: CAPropertyAnimation) {
        self.layer = layer
        self.animation = animation

    public init (delay: NSTimeInterval, completion: () -> ()) {
        self.delay = delay
        self.completion = completion

Implement animation tasks in Union.Delegate

Call animation tasks from UIViewControllers with Union.Delegate protocol.

Union.Delegate protocol:

public protocol Delegate {
    func animationsBeforeTransitionTo(viewController: UIViewController) -> [Animation]
    func animationsDuringTransitionFrom(viewController: UIViewController) -> [Animation]
  • animationsBeforeTransitionTo(viewController: UIViewController) -> [Animation]

    Transition begin after these tasks are completed and this method is called by UIViewController displayed only.

  • animationsDuringTransitionFrom(viewController: UIViewController) -> [Animation]

    Tasks called by two UIViewControllers start during transition. context.completeTransition(true) is called after all tasks are completed.

Animation start on UINavigationControllerDelegate

extension ViewController: UINavigationControllerDelegate {
    func navigationController(navigationController: UINavigationController,
         animationControllerForOperation operation: UINavigationControllerOperation,
                         fromViewController fromVC: UIViewController,
                             toViewController toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        return Union.Navigator.animate()

Animation start on UIViewControllerTransitioningDelegate

extension ViewController: UIViewControllerTransitioningDelegate {

    func animationControllerForPresentedController(presented: UIViewController, presentingController presenting: UIViewController, sourceController source: UIViewController) -> UIViewControllerAnimatedTransitioning? {

        return Union.Presentor.animate()


Union is available under the MIT license.