SnapGestureRecognizer

SnapGestureRecognizer provides dynamic pan and snap interaction for UIVIew objects.

Installation

Carthage

github "matsune/SnapGestureRecognizer

Usage

SnapGestureRecognizer is a subclass of UIPanGestureRecognizer. You can use by addGestureRecognizer for any UIView instance.

let snapGesture = SnapGestureRecognizer()

let view = UIView()
view.addGestureRecognizer(snapGesture)

Properties

Snap Properties

SnapGestureRecognizer has these configurable snap properties.

var panDirection: PanDirection
var snapTo:       SnapTo
var snapPoints:   [SnapPoint]
var anchorPoint:  SnapAnchor

PanDirection

enum PanDirection {
    case diagonal
    case horizontal
    case vertical
}

This property allows object direction to move by user's pan gesture. If set .horizontal, object moves along horizontal direction.

SnapTo

enum SnapTo {
  case .direction
  case .nearest
}

This property is used to determine snap point at the moment that user released object.

.direction	.nearest
find the nearest snap point towards swiped direction	find the nearest snap point from current object position

SnapPoint & SnapAnchor

enum SnapAnchor {
    case origin
    case center
}

let snapPoints = [
  SnapPoint(x: view.center.x, y: 100),
  SnapPoint(x: view.center.x, y: 300, snapKey: "pointA") // you can set key to point
]
snapGesture.anchorPoint = .center
snapGesture.snapPoints  = snapPoints

Animation Properties

You can configure snap animation properties.

var duration:       TimeInterval
var delay:          TimeInterval
var dampingRatio:   CGFloat
var springVelocity: CGFloat
var options:        UIViewAnimationOptions

Programatically Methods

There are some methods to snap object programatically.

func snap(to point: SnapPoint)
func snap(to point: CGPoint)
func snap(to snapKey: String)

If you have set snapKey for snap point, you can specify the point by the key name.

let snapPoints = [
  SnapPoint(x: 100, y: 100, snapKey: "pointA")
]
snapGesture.snapPoints  = snapPoints
snapGesture.snap(to: "pointA")

Delegate

protocol SnapGestureRecognizerDelegate: class {
  func snapRecognizer(_ snapRecognizer: SnapGestureRecognizer, decayAt point: CGPoint) -> CGFloat
  func snapRecognizer(_ snapRecognizer: SnapGestureRecognizer, towardSnapPointAt point: CGPoint) -> CGPoint
  func snapRecognizerWillBeginPan(_ snapRecognizer: SnapGestureRecognizer)
  func snapRecognizerDidPan(_ snapRecognizer: SnapGestureRecognizer)
  func snapRecognizerDidEndPan(_ snapRecognizer: SnapGestureRecognizer)
  func snapRecognizerWillBeginSnap(_ snapRecognizer: SnapGestureRecognizer, began: SnapPoint, toward: SnapPoint)
  func snapRecognizerDidEndSnap(_ snapRecognizer: SnapGestureRecognizer, began: SnapPoint, toward: SnapPoint)
  func withSnapAnimation(_ snapRecognizer: SnapGestureRecognizer, began: SnapPoint, toward: SnapPoint)
}

You can make more customized gesture by using delegate.

SnapMenu

I made a snappable tableView menu UI by using SnapGestureRecognizer, like Facebook app. Please see Example projects for details.

License

SnapGestureRecognizer is released under an MIT license. See LICENSE.md for more information.