圆形到矩形变换动画

Question

我是 iOS 的新手，我需要制作以下动画：

圆形到矩形的转换应该是平滑的，但在上面的动画中它不是很平滑。

我所做的是使用以下代码创建一个圆形和一个矩形 in this tutorial:

  Circle : 
        class OvalLayer: CAShapeLayer {

        let animationDuration: CFTimeInterval = 0.3

        override init() {
            super.init()
            fillColor = Colors.red.CGColor
            path = ovalPathSmall.CGPath
        }

        required init?(coder aDecoder: NSCoder) {
            fatalError("init(coder:) has not been implemented")
        }

        var ovalPathSmall: UIBezierPath {
            return UIBezierPath(ovalInRect: CGRect(x: 50.0, y: 50.0, width: 0.0, height: 0.0))
        }

        var ovalPathLarge: UIBezierPath {
            return UIBezierPath(ovalInRect: CGRect(x: 2.5, y: 17.5, width: 95.0, height: 95.0))
        }

        var ovalPathSquishVertical: UIBezierPath {
            return UIBezierPath(ovalInRect: CGRect(x: 2.5, y: 20.0, width: 95.0, height: 90.0))
        }

        var ovalPathSquishHorizontal: UIBezierPath {
            return UIBezierPath(ovalInRect: CGRect(x: 5.0, y: 20.0, width: 90.0, height: 90.0))
        }

        func expand() {
            let expandAnimation: CABasicAnimation = CABasicAnimation(keyPath: "path")
            expandAnimation.fromValue = ovalPathLarge.CGPath// change ovalPathLarge to ovalPathSmail for animation
            expandAnimation.toValue = ovalPathLarge.CGPath
            expandAnimation.duration = animationDuration
            expandAnimation.fillMode = kCAFillModeForwards
            expandAnimation.removedOnCompletion = false
            addAnimation(expandAnimation, forKey: nil)
        }

    }

Rectangle : 

    class RectangleLayer: CAShapeLayer {


    override init() {
        super.init()
        fillColor = Colors.clear.CGColor
        lineWidth = 5.0
        path = rectanglePathFull.CGPath
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    var rectanglePathFull: UIBezierPath {
        let rectanglePath = UIBezierPath()
        rectanglePath.moveToPoint(CGPoint(x: 0.0, y: 100.0))
        rectanglePath.addLineToPoint(CGPoint(x: 0.0, y: -lineWidth))
        rectanglePath.addLineToPoint(CGPoint(x: 100.0, y: -lineWidth))
        rectanglePath.addLineToPoint(CGPoint(x: 100.0, y: 100.0))
        rectanglePath.addLineToPoint(CGPoint(x: -lineWidth / 2, y: 100.0))
        rectanglePath.closePath()

//        fillColor = Colors.red.CGColor
        return rectanglePath
    }

//    var topLeft: UIBezierPath {}

    func animateStrokeWithColor(color: UIColor, view : UIView) {
        strokeColor = color.CGColor

//        CATransaction.setDisableActions(true)
//        view.layer.bounds.size.height = view.layer.bounds.width + 50

        let strokeAnimation: CABasicAnimation = CABasicAnimation(keyPath: "bounds.size.width") //bounds.size.width
        strokeAnimation.fromValue = view.layer.bounds.width
        strokeAnimation.toValue = view.layer.bounds.size.width - 50
        strokeAnimation.duration = 0.4
        addAnimation(strokeAnimation, forKey: nil)
    }
}

my view : 

    protocol HolderViewDelegate:class {
    func animateLabel()
}

class HolderView: UIView {

    let ovalLayer = OvalLayer()
    let redRectangleLayer = RectangleLayer()

    var parentFrame :CGRect = CGRectZero
    weak var delegate:HolderViewDelegate?

    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = Colors.clear
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }

    func addOval() {
        layer.addSublayer(ovalLayer)
        ovalLayer.expand()
//        NSTimer.scheduledTimerWithTimeInterval(0.3, target: self, selector: "wobbleOval",
//            userInfo: nil, repeats: false)
    }

    func expandRectangle(){
        NSTimer.scheduledTimerWithTimeInterval(0.45, target: self,
            selector: "drawRedAnimatedRectangle",
            userInfo: nil, repeats: false)
    }

    func drawRedAnimatedRectangle() {
        layer.addSublayer(redRectangleLayer)
        redRectangleLayer.animateStrokeWithColor(Colors.red,view: self)
    }

但是我不知道怎么做我的动画，请问谁能帮帮我吗？

Answer 1

为了获得流畅的动画效果，您想查看 cornerRadius 属性的动画，而不是乱用贝塞尔曲线路径。

所以动画将是这样的：

将角半径从当前值设置为零
动画宽度达到屏幕宽度
反转宽度动画
反转角半径动画

那么，让我们开始定义一些我们将要使用的属性：

class ViewController: UIViewController {

    let animLayer = CALayer() // the layer that is going to be animated
    let cornerRadiusAnim = CABasicAnimation(keyPath: "cornerRadius") // the corner radius reducing animation
    let cornerRadiusUndoAnim = CABasicAnimation(keyPath: "cornerRadius") // the corner radius increasing animation
    let widthAnim = CABasicAnimation(keyPath: "bounds.size.width") // the width animation
    let animDuration = NSTimeInterval(1.0) // the duration of one 'segment' of the animation
    let layerSize = CGFloat(100) // the width & height of the layer (when it's a square)

    ...

在这里我们定义了我们将要使用的图层、动画、其中一个动画的持续时间 'segments' 和 CALayer 的大小。

接下来，让我们在 viewDidLoad

中设置我们的动画

override func viewDidLoad() {
    super.viewDidLoad()

    let rect = view.frame

    animLayer.backgroundColor = UIColor.blueColor().CGColor // color of the layer, feel free to change
    animLayer.frame = CGRect(x: rect.width-layerSize*0.5, y: rect.height-layerSize*0.5, width: layerSize, height: layerSize)
    animLayer.cornerRadius = layerSize*0.5;
    animLayer.anchorPoint = CGPoint(x: 1, y: 1) // sets so that when the width is changed, it goes to the left
    view.layer.addSublayer(animLayer)

    // decreases the corner radius
    cornerRadiusAnim.duration = animDuration
    cornerRadiusAnim.fromValue = animLayer.cornerRadius
    cornerRadiusAnim.toValue = 0;
    cornerRadiusAnim.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseIn) // timing function to make it look nice


    // inverse of the cornerRadiusAnim
    cornerRadiusUndoAnim.duration = animDuration
    cornerRadiusUndoAnim.fromValue = 0;
    cornerRadiusUndoAnim.toValue = animLayer.cornerRadius
    cornerRadiusUndoAnim.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut) // timing function to make it look nice

    // increases the width, and autoreverses on completion
    widthAnim.duration = animDuration
    widthAnim.fromValue = animLayer.frame.size.width
    widthAnim.toValue = rect.size.width
    widthAnim.autoreverses = true
    widthAnim.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut) // timing function to make it look nice
    widthAnim.delegate = self // so that we get notified when the width animation finishes

}

这里没什么难的，我们只需定义图层和动画属性。我还添加了一些计时功能，以使动画看起来漂亮流畅，而不是线性的。

接下来，让我们开始我们的动画吧。我将在 touchesBegan 函数中执行此操作，但您可以将其放在任何地方。

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    widthAnim.beginTime = CACurrentMediaTime()+animDuration // starts after the corner radius anim has finished

    animLayer.addAnimation(widthAnim, forKey: "widthAnim")
    animLayer.addAnimation(cornerRadiusAnim, forKey: "cornerRadius")

    CATransaction.begin()
    CATransaction.setDisableActions(true) // disables implicit animations
    animLayer.cornerRadius = 0
    CATransaction.commit()
}

这里我们添加 width 和 cornerRadius 动画，为宽度动画指定延迟开始。

你问的 CATransation 是怎么回事？好吧，一旦 cornerRadius 动画结束，Core Animation 就会将该层捕捉回它的表示层。我们不希望这样，所以我们将直接设置该值，同时还要确保 Core Animation 在我们这样做时不会添加隐式动画。使用 CATransaction 可以避免这种情况，因为 使用 removedOnCompletion = false 和 fillMode = kCAFillModeForwards 被认为是不好的做法。

最后，一旦宽度动画反转，我们要撤消角半径动画。我们可以这样做，因为我们之前为宽度动画分配了 delegate，因此我们可以覆盖 animationDidStop 函数。

override func animationDidStop(anim: CAAnimation, finished flag: Bool) {

    animLayer.addAnimation(cornerRadiusUndoAnim, forKey: "cornerRadiusUndo")

    CATransaction.begin()
    CATransaction.setDisableActions(true)
    animLayer.cornerRadius = layerSize*0.5
    CATransaction.commit()
}

同样，我们使用 CATransaction 将 cornerRadius 设置回其原始值。就是这样！

最终结果

完整项目：https://github.com/hamishknight/Circle-to-Rect-Animation

Answer 2

如果您希望同时同时进行放大和缩小角半径，您可以显着简化.

您现在不再需要将动画 'chain' 放在一起，因此您可以将它们同时添加到一个 CAAnimationGroup 和运行中。

我们使用的属性将保持几乎相同，除了添加 groupAnim 属性和删除 cornerRadiusUndoAnim.

class ViewController2: UIViewController {

    let animLayer = CALayer() // the layer that is going to be animated
    let cornerRadiusAnim = CABasicAnimation(keyPath: "cornerRadius") // the corner radius reducing animation
    let widthAnim = CABasicAnimation(keyPath: "bounds.size.width") // the width animation
    let groupAnim = CAAnimationGroup() // the combination of the corner and width animation
    let animDuration = NSTimeInterval(1.0) // the duration of one 'segment' of the animation
    let layerSize = CGFloat(100) // the width & height of the layer (when it's a square)

    ...

我们现在可以只添加 CAAnimationGroup 的设置，同时添加角半径动画和缩放动画

override func viewDidLoad() {
    super.viewDidLoad()

    let rect = view.frame

    animLayer.backgroundColor = UIColor.blueColor().CGColor // color of the layer, feel free to change
    animLayer.frame = CGRect(x: rect.width-layerSize*0.5, y: rect.height-layerSize*0.5, width: layerSize, height: layerSize)
    animLayer.cornerRadius = layerSize*0.5;
    animLayer.anchorPoint = CGPoint(x: 1, y: 1) // sets so that when the width is changed, it goes to the left
    view.layer.addSublayer(animLayer)

    // decreases the corner radius
    cornerRadiusAnim.duration = animDuration
    cornerRadiusAnim.fromValue = animLayer.cornerRadius
    cornerRadiusAnim.toValue = 0;
    cornerRadiusAnim.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut) // timing function to make it look nice

    // increases the width
    widthAnim.duration = animDuration
    widthAnim.fromValue = animLayer.frame.size.width
    widthAnim.toValue = rect.size.width
    widthAnim.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut) // timing function to make it look nice

    // adds both animations to a group animation
    groupAnim.animations = [cornerRadiusAnim, widthAnim]
    groupAnim.duration = animDuration;
    groupAnim.autoreverses = true; // auto-reverses the animation once completed

}

最后，我们可以运行触摸视图时的组动画，两个动画将同时运行在一起（完成后 auto-reverse）。

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    animLayer.addAnimation(groupAnim, forKey: "anims") // runs both animations concurrently
}

结果

完整项目：https://github.com/hamishknight/Circle-to-Rect-Animation

圆形到矩形变换动画

Circle to rectangle transformation animation

core-animation

cabasicanimation

cashapelayer

ios

swift

最终结果

结果