¿Cómo puedo animar el movimiento de una vista o imagen a lo largo de una trayectoria curva?

Estoy desarrollando una aplicación comercial. Cuando agrego un artículo al carrito de la compra, quiero crear un efecto donde una imagen del artículo sigue una ruta curva y termina en la pestaña del carrito.

¿Cómo puedo crear una animación de una imagen a lo largo de una curva como esta?

Para ampliar lo que dijo Nikolai, la mejor manera de manejar esto es utilizar Core Animation para animar el movimiento de la imagen o ver a lo largo de una ruta Bezier. Esto se logra usando una CAKeyframeAnimation. Por ejemplo, he utilizado el siguiente código para animar una imagen de una vista en un icono para indicar el guardado (como se puede ver en el video de esta aplicación ):

Primero que nada, importe el archivo de cabecera QuartzCore #import

 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]; 

Puede animar una propiedad del centro de UIView utilizando una CAKeyframeAnimation. Vea la guía de progtwigción de CoreAnimation .

Swift 4 versión similar al ejemplo ObjC de la respuesta original.

 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") } } 

La forma de animar a lo largo de CGPath usando UIView.animateKeyframes (Swift 4)

 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) } 

Archivo: 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 } } 

Archivo: Math.BezierPath.swift . Mire esta respuesta SO: https://stackoverflow.com/a/50782971/1418981

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