动画的动态 UIBezierPath

Question

我想创建一个动画，其中对象沿 path 对其位置进行动画处理。我遇到的问题是使这个 path 动态意味着它适用于所有屏幕尺寸。

上面 gif 中的宇宙飞船最初遵循 "U" 形状 path。

我使用这个 "U" 形状 path 并且有效，这是代码：

func animateAlongPath() {
    // Create and add image to view
    let myImage = UIImage(named: "myImage")!
    let myImageView = UIImageView(image: myImage)

    myImageView.frame = CGRect(x: 100, y: 100, width: myImage.size.width, height: myImage.size.height)
    holderView.addSubview(myImageView)

    // Create "U" shape path for animation (path code created in PaintCode)
    let path = UIBezierPath()
    path.moveToPoint(CGPointMake(59.5, 81.5))
    path.addCurveToPoint(CGPointMake(66.5, 91.5), controlPoint1: CGPointMake(63.64, 84.13), controlPoint2: CGPointMake(62.62, 85.9))
    path.addCurveToPoint(CGPointMake(81.5, 110.5), controlPoint1: CGPointMake(72.31, 99.88), controlPoint2: CGPointMake(75.91, 103.08))
    path.addCurveToPoint(CGPointMake(109.5, 142.5), controlPoint1: CGPointMake(88.44, 119.71), controlPoint2: CGPointMake(102.39, 135.23))
    path.addCurveToPoint(CGPointMake(145.5, 156.5), controlPoint1: CGPointMake(122.47, 155.76), controlPoint2: CGPointMake(129.15, 157.54))
    path.addCurveToPoint(CGPointMake(237.5, 81.5), controlPoint1: CGPointMake(185.04, 153.99), controlPoint2: CGPointMake(237.5, 81.5))

    let pathAnimation = CAKeyframeAnimation(keyPath: "position")
    pathAnimation.path = path.CGPath // Use "U" shape path for animation
    pathAnimation.calculationMode = kCAAnimationPaced
    pathAnimation.timingFunctions = [CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)]
    pathAnimation.duration = 1
    pathAnimation.removedOnCompletion = false
    pathAnimation.fillMode = kCAFillModeForwards

    myImageView.layer.addAnimation(pathAnimation, forKey: nil)
    myImageView.layer.position = path.currentPoint
}

问题是 UIBezierPath 不是动态的。它在 iPhone 6 设备屏幕尺寸上运行良好，但在任何其他设备尺寸上效果不佳，因为它是静态的。我尝试使用 PaintCode 创建带有变量的动态路径，但就是无法正常工作。

有什么想法吗？

Answer 1

PaintCode 可以使用 Frames.

生成可调整大小的代码 UIBezierPaths

将 Bezier 放入 Frame 对象中，然后设置所需的自动调整弹簧（全部灵活）。生成的代码将使用 CGRect/NSRect 进行参数化，并将使用相对系数来计算贝塞尔点。

如果您想更深入地了解，还有一个视频教程about Dynamic Shapes。

动画的动态 UIBezierPath

Dynamic UIBezierPath for Animations

animation

core-animation

ios

paintcode

swift