Designs from [Meng To](https://twitter.com/mengto)'s [Design+Code](https://designcode.io)
```swift
public protocol ModalTransitionAnimator {
var duration: TimeInterval { get }
var onDismissed: (() -> Void)? { get set }
var onPresented: (() -> Void)? { get set }
func layout(presenting: Bool,
modalView: UIView,
in container: UIView)
func animate(presenting: Bool,
modalView: UIView,
in container: UIView)
}
```
During a modal transition we should only manage the view that is being presented modaly (modalView). We can inject animations on the root controller anyway.
The `ModalTransitionAnimator` is a really straight forward protocol. Just layout the views ready to be animated on `layout` function and perform the animations on `animate`. You can check the [AppStoreAnimator](https://github.com/marcosgriselli/EasyTransitions/blob/master/EasyTransitions/Classes/Animators/AppStoreAnimator.swift) for a basic example.
#### UINavigationController transitions
`UINavigationController` have a slightly different approach. Both the _from_ and _to_ view are accessible using `view(forKey: UITransitionContextViewKey)` so we add them to the protocol functions.
```swift
public protocol NavigationTransitionAnimator {
var duration: TimeInterval { get }
var auxAnimations: (Bool) -> [AuxAnimation] { get set }
func layout(presenting: Bool, fromView: UIView,
toView: UIView, in container: UIView)
func animations(presenting: Bool,
fromView: UIView, toView: UIView,
in container: UIView)
}
```
I've added the auxiliary animations as part of the protocol but expect multiple changes in this area.
#### UIPresentationController transitions
`UIPresentationController` follows the same approach as Modal presentations. The only thing you need to call is `func set(presentationController: UIPresentationController?)` on your `ModalTransitionDelegate` object.
### Interaction
`TransitionInteractiveController` handles wiring a `UIPanGestureRecognizer` to the current `UIViewController`. This works for any action as we should set the `navigationAction: () -> Void` for the interaction to work. This let's us use the same `TransitionInteractiveController` class for Modal, `UINavigationController` or even `UITabBarController` transitions.
It's wiring takes a `UIViewController` and a `Pan` object. EasyTransitions handles the swiping automatically. It responds to velocity and completness percentage to finish the transition. I plan to support configuring this.
Right now the transition will complete if we stop swiping when it's over 50% or if we swipe fast or release. It will cancel it self if we swipe fast and release in the oposite direction.
#### Pan
The `Pan` enum is a simple way to unify `UIPanGestureRecognizer` and `UIScreenEdgePanGestureRecognizer`. Internally EasyTransitions uses `TransitionPanGestureRecognizer` and `TransitionEdgePanGestureRecognier` to support a `PanGesture` protocol which calculates velocity and translation for each gesture and the correct sign they should have.
```swift
public enum Pan {
case regular(PanDirection)
case edge(UIRectEdge)
}
```
### Example
There's an example on `TodayCollectionViewController` but there should't be many changes on other implementations. Here's a generic example:
```swift
class MainViewController: UIViewController {
var modalTransitionDelegate = ModalTransitionDelegate()
func showDetailViewController() {
let detailController = DetailViewController()
let animator = MyAnimator() // ModalTransitionAnimator
modalTransitionDelegate.set(animator: animator)
modalTransitionDelegate.wire(viewController: detailController,
with: .regular(.fromTop),
navigationAction: {
detailController.dismiss(animated: true, completion: nil)
})
detailController.transitioningDelegate = modalTransitionDelegate
detailController.modalPresentationStyle = .custom
present(detailController, animated: true, completion: nil)
}
```
## ❤️ Contributing
This is an open source project, so feel free to contribute. How?
- Open an [issue](https://github.com/marcosgriselli/EasyTransitions/issues/new).
- Send feedback via [twitter](https://twitter.com/marcosgriselli).
- Propose your own fixes, suggestions and open a pull request with the changes.
See [all contributors](https://github.com/marcosgriselli/EasyTransitions/graphs/contributors)
[](https://sourcerer.io/fame/marcosgriselli/marcosgriselli/EasyTransitions/links/0)[](https://sourcerer.io/fame/marcosgriselli/marcosgriselli/EasyTransitions/links/1)[](https://sourcerer.io/fame/marcosgriselli/marcosgriselli/EasyTransitions/links/2)[](https://sourcerer.io/fame/marcosgriselli/marcosgriselli/EasyTransitions/links/3)[](https://sourcerer.io/fame/marcosgriselli/marcosgriselli/EasyTransitions/links/4)[](https://sourcerer.io/fame/marcosgriselli/marcosgriselli/EasyTransitions/links/5)[](https://sourcerer.io/fame/marcosgriselli/marcosgriselli/EasyTransitions/links/6)[](https://sourcerer.io/fame/marcosgriselli/marcosgriselli/EasyTransitions/links/7)
## 👨💻 Author
Marcos Griselli | 
[@marcosgriselli](https://twitter.com/marcosgriselli)
[](https://twitter.com/marcosgriselli)
[](https://github.com/marcosgriselli)
## 🛡 License
```
MIT License
Copyright (c) 2018 Marcos Griselli
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
```