如何为视图或图像沿弯曲路径的运动设置动画？

Answers:

153

为了扩展Nikolai所说的话，处理此问题的最佳方法是使用Core Animation来使图像运动或沿Bezier路径的视图动画化。这是使用CAKeyframeAnimation完成的。例如，我使用以下代码将视图图像动画化为图标以指示保存（如在此应用程序的视频中所示）：

首先导入QuartzCore头文件 #import <QuartzCore/QuartzCore.h>

UIImageView *imageViewForAnimation = [[UIImageView alloc] initWithImage:imageToAnimate];
imageViewForAnimation.alpha = 1.0f;
CGRect imageFrame = imageViewForAnimation.frame;
//Your image frame.origin from where the animation need to get start
CGPoint viewOrigin = imageViewForAnimation.frame.origin;
viewOrigin.y = viewOrigin.y + imageFrame.size.height / 2.0f;
viewOrigin.x = viewOrigin.x + imageFrame.size.width / 2.0f;

imageViewForAnimation.frame = imageFrame;
imageViewForAnimation.layer.position = viewOrigin;
[self.view addSubview:imageViewForAnimation];

// Set up fade out effect
CABasicAnimation *fadeOutAnimation = [CABasicAnimation animationWithKeyPath:@"opacity"];
[fadeOutAnimation setToValue:[NSNumber numberWithFloat:0.3]];
fadeOutAnimation.fillMode = kCAFillModeForwards;
fadeOutAnimation.removedOnCompletion = NO;

// Set up scaling
CABasicAnimation *resizeAnimation = [CABasicAnimation animationWithKeyPath:@"bounds.size"];
[resizeAnimation setToValue:[NSValue valueWithCGSize:CGSizeMake(40.0f, imageFrame.size.height * (40.0f / imageFrame.size.width))]];
resizeAnimation.fillMode = kCAFillModeForwards;
resizeAnimation.removedOnCompletion = NO;

// Set up path movement
CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
pathAnimation.calculationMode = kCAAnimationPaced;
pathAnimation.fillMode = kCAFillModeForwards;
pathAnimation.removedOnCompletion = NO;
//Setting Endpoint of the animation
CGPoint endPoint = CGPointMake(480.0f - 30.0f, 40.0f);
//to end animation in last tab use 
//CGPoint endPoint = CGPointMake( 320-40.0f, 480.0f);
CGMutablePathRef curvedPath = CGPathCreateMutable();
CGPathMoveToPoint(curvedPath, NULL, viewOrigin.x, viewOrigin.y);
CGPathAddCurveToPoint(curvedPath, NULL, endPoint.x, viewOrigin.y, endPoint.x, viewOrigin.y, endPoint.x, endPoint.y);
pathAnimation.path = curvedPath;
CGPathRelease(curvedPath);

CAAnimationGroup *group = [CAAnimationGroup animation]; 
group.fillMode = kCAFillModeForwards;
group.removedOnCompletion = NO;
[group setAnimations:[NSArray arrayWithObjects:fadeOutAnimation, pathAnimation, resizeAnimation, nil]];
group.duration = 0.7f;
group.delegate = self;
[group setValue:imageViewForAnimation forKey:@"imageViewBeingAnimated"];

[imageViewForAnimation.layer addAnimation:group forKey:@"savingAnimation"];

[imageViewForAnimation release];
— 布拉德·拉森
source
我知道了，但是我想创建动画效果，就像我拥有大图像一样，应该将图像调整大小到大图像的中心，然后添加动画路径。
我不确定您要问的是什么，但是上面的动画做了三件事：沿着弯曲的路径移动图像，在移动时缩小图像，使其在到达终点时变得很小，然后逐渐淡出它移动。您可以根据需要通过更改from或to值来调整大小。
— 布拉德·拉尔森
我必须包括什么才能使Xcode识别所有CAKey ...东西？它说找不到符号。
— 感谢
2
您需要包括对Core Animation，QuartzCore / QuartzCore.h始终执行的操作，并链接到QuartzCore框架。
— 布拉德·拉尔森
那就是解决方案。完善！
— 感谢
4

使用UIView.animateKeyframes（Swift 4）沿CGPath设置动画的方式

private func animateNew() {

   let alphaFrom: CGFloat = 1
   let alphaTo: CGFloat = 0.3
   let sizeFrom = CGSize(width: 40, height: 20)
   let sizeTo = CGSize(width: 80, height: 60)
   let originFrom = CGPoint(x: 40, y: 40)
   let originTo = CGPoint(x: 240, y: 480)

   let deltaWidth = sizeTo.width - sizeFrom.width
   let deltaHeight = sizeTo.height - sizeFrom.height
   let deltaAlpha = alphaTo - alphaFrom

   // Setting default values
   imageViewNew.alpha = alphaFrom
   imageViewNew.frame = CGRect(origin: originFrom, size: sizeFrom)

   // CGPath setup for calculating points on curve.
   let curvedPath = CGMutablePath()
   curvedPath.move(to: originFrom)
   curvedPath.addQuadCurve(to: originTo, control: CGPoint(x: originFrom.x,  y: originTo.y))
   let path = Math.BezierPath(cgPath: curvedPath, approximationIterations: 10)

   // Calculating timing parameters
   let duration: TimeInterval = 0.7
   let numberOfKeyFrames = 16
   let curvePoints = Math.Easing.timing(numberOfSteps: numberOfKeyFrames, .easeOutQuad)

   UIView.animateKeyframes(withDuration: duration, delay: 0, options: [.calculationModeCubic], animations: {
      // Iterating curve points and adding key frames
      for point in curvePoints {
         let origin = path.point(atPercentOfLength: point.end)
         let size = CGSize(width: sizeFrom.width + deltaWidth * point.end,
                           height: sizeFrom.height + deltaHeight * point.end)
         let alpha = alphaFrom + deltaAlpha * point.end
         UIView.addKeyframe(withRelativeStartTime: TimeInterval(point.start), relativeDuration: TimeInterval(point.duration)) {
            self.imageViewNew.frame = CGRect(origin: origin, size: size)
            self.imageViewNew.alpha = alpha
         }
      }
   }, completion: nil)
}

文件： Math.Easing.swift

// Inspired by: RBBAnimation/RBBEasingFunction.m: https://github.com/robb/RBBAnimation/blob/master/RBBAnimation/RBBEasingFunction.m
extension Math { public struct Easing { } }

extension Math.Easing {

   public enum Algorithm: Int {
      case linear, easeInQuad, easeOutQuad, easeInOutQuad
   }

   @inline(__always)
   public static func linear(_ t: CGFloat) -> CGFloat {
      return t
   }

   @inline(__always)
   public static func easeInQuad(_ t: CGFloat) -> CGFloat  {
      return t * t
   }

   @inline(__always)
   public static func easeOutQuad(_ t: CGFloat) -> CGFloat  {
      return t * (2 - t)
   }

   @inline(__always)
   public static func easeInOutQuad(_ t: CGFloat) -> CGFloat  {
      if t < 0.5 {
         return 2 * t * t
      } else {
         return -1 + (4 - 2 * t) * t
      }
   }
}

extension Math.Easing {

   public struct Timing {

      public let start: CGFloat
      public let end: CGFloat
      public let duration: CGFloat

      init(start: CGFloat, end: CGFloat) {
         self.start = start
         self.end = end
         self.duration = end - start
      }

      public func multiplying(by: CGFloat) -> Timing {
         return Timing(start: start * by, end: end * by)
      }
   }

   public static func process(_ t: CGFloat, _ algorithm: Algorithm) -> CGFloat {
      switch algorithm {
      case .linear:
         return linear(t)
      case .easeInQuad:
         return easeInQuad(t)
      case .easeOutQuad:
         return easeOutQuad(t)
      case .easeInOutQuad:
         return easeInOutQuad(t)
      }
   }

   public static func timing(numberOfSteps: Int, _ algorithm: Algorithm) -> [Timing] {
      var result: [Timing] = []
      let linearStepSize = 1 / CGFloat(numberOfSteps)
      for step in (0 ..< numberOfSteps).reversed() {
         let linearValue = CGFloat(step) * linearStepSize
         let processedValue = process(linearValue, algorithm) // Always in range 0 ... 1
         let lastValue = result.last?.start ?? 1
         result.append(Timing(start: processedValue, end: lastValue))
      }
      result = result.reversed()
      return result
   }
}

档案：Math.BezierPath.swift。看看这个SO答案：https : //stackoverflow.com/a/50782971/1418981

在此处输入图片说明

— 弗拉德
source
0

来自原始响应的类似于ObjC示例的Swift 4版本。

class KeyFrameAnimationsViewController: ViewController {

   let sampleImage = ImageFactory.image(size: CGSize(width: 160, height: 120), fillColor: .blue)

   private lazy var imageView = ImageView(image: sampleImage)
   private lazy var actionButton = Button(title: "Animate").autolayoutView()

   override func setupUI() {
      view.addSubviews(imageView, actionButton)
      view.backgroundColor = .gray
   }

   override func setupLayout() {
      LayoutConstraint.withFormat("|-[*]", actionButton).activate()
      LayoutConstraint.withFormat("V:|-[*]", actionButton).activate()
   }

   override func setupHandlers() {
      actionButton.setTouchUpInsideHandler { [weak self] in
         self?.animate()
      }
   }

   private func animate() {

      imageView.alpha = 1
      let isRemovedOnCompletion = false

      let sizeFrom = CGSize(width: 40, height: 20)
      let sizeTo = CGSize(width: 80, height: 60)
      let originFrom = CGPoint(x: 40, y: 40)
      let originTo = CGPoint(x: 240, y: 480)

      imageView.frame = CGRect(origin: originFrom, size: sizeFrom)
      imageView.layer.position = originFrom

      // Set up fade out effect
      let fadeOutAnimation = CABasicAnimation(keyPath: "opacity")
      fadeOutAnimation.toValue = 0.3
      fadeOutAnimation.fillMode = kCAFillModeForwards
      fadeOutAnimation.isRemovedOnCompletion = isRemovedOnCompletion

      // Set up scaling
      let resizeAnimation = CABasicAnimation(keyPath: "bounds.size")
      resizeAnimation.toValue = sizeTo
      resizeAnimation.fillMode = kCAFillModeForwards
      resizeAnimation.isRemovedOnCompletion = isRemovedOnCompletion

      // Set up path movement
      let pathAnimation = CAKeyframeAnimation(keyPath: "position")
      pathAnimation.calculationMode = kCAAnimationPaced;
      pathAnimation.fillMode = kCAFillModeForwards;
      pathAnimation.isRemovedOnCompletion = isRemovedOnCompletion

      // Setting Endpoint of the animation to end animation in last tab use
      let curvedPath = CGMutablePath()
      curvedPath.move(to: originFrom)
      // About curves: https://www.bignerdranch.com/blog/core-graphics-part-4-a-path-a-path/
      curvedPath.addQuadCurve(to: originTo, control: CGPoint(x: originFrom.x,  y: originTo.y))
      pathAnimation.path = curvedPath

      let group = CAAnimationGroup()
      group.fillMode = kCAFillModeForwards
      group.isRemovedOnCompletion = isRemovedOnCompletion
      group.animations = [fadeOutAnimation, pathAnimation, resizeAnimation]
      group.duration = 0.7
      group.setValue(imageView, forKey: "imageViewBeingAnimated")

      imageView.layer.add(group, forKey: "savingAnimation")
   }
}
— 弗拉德
source
By using our site, you acknowledge that you have read and understand our Cookie Policy and Privacy Policy.
Licensed under cc by-sa 3.0 with attribution required.