关于ios：CAShapeLayer和SpriteKit

CAShapeLayer and SpriteKit

我正在尝试使用SpriteKit中不可用的CAShapeLayer中的路径动画功能，因此必须将使用CAShapeLayer绘制的对象与SpriteKit对象合并在同一视图中。

坐标系似乎是相反的：CAShapeLayer的y轴指向下方，而SKScene的y轴指向上方。

下面是一个简单的XCODE运动场，它试图在0,0到200,100之间绘制一条黄线，并用较粗的红线对其进行阴影。

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import SpriteKit
import PlaygroundSupport

let bounds = CGRect(x: 0, y: 0, width: 400, height: 200)
let view = SKView(frame: bounds)
view.backgroundColor = UIColor.lightGray

PlaygroundPage.current.liveView = view

// Create SK Scene
let scene = SKScene(size: CGSize(width: 400, height: 200))
scene.scaleMode = SKSceneScaleMode.aspectFit
view.presentScene(scene);

// Define the path
let path: CGMutablePath = CGMutablePath();
path.move(to: CGPoint(x:0, y:0))
path.addLine(to: CGPoint(x:200, y:100))

// Use CAShapeLayer to draw the red line
var pathLayer: CAShapeLayer = CAShapeLayer()
pathLayer.path = path
pathLayer.strokeColor = UIColor.red.cgColor
pathLayer.fillColor = nil
pathLayer.lineWidth = 4.0
pathLayer.lineJoin = kCALineJoinBevel
pathLayer.zPosition = 1;
view.layer.addSublayer(pathLayer);

//Use SKShapeNode to draw the yellow line
let pathShape: SKShapeNode = SKShapeNode(path: path);
pathShape.strokeColor = .yellow;
pathShape.lineWidth = 1.0;
pathShape.zPosition = 10;
scene.addChild(pathShape);

我希望黄线与红线重合。而黄线和红线显示为镜像。

是否有重新定义CAShapeLayer坐标系以将ve Y轴指向上方的原因？