UIScrollView 缩放和影响 CAShapeLayer lineWidth

Question

我有一堆用 UIBezierPath 构建并存储在 UIScrollView 中的 CAShapeLayers。

我想知道当 UIScrollView 放大 100% 时，是否有任何方法可以使 CAShapeLayer 路径的 lineWidth 远离缩放。我的意思是将 UIScrollView 的转换规则应用于 CAShapeLayer，但保持路径的宽度与以前在 1.0 zoomScale 上的宽度相同。 （所以当1pt路径lineWidth的层被缩放到300%时，@2x设备上层的lineWidth不会变成6px的高度，而是保持2px的高度）

Answer 1

class ViewController : UIViewController, UIScrollViewDelegate {

    private lazy var scrollView = UIScrollView()
    private lazy var contentView = UIView()
    private lazy var shapeLayer = CAShapeLayer()
    private let lineWidth: CGFloat = 1

    override func loadView() {
        view = UIView()
        view.addSubview(scrollView)
        scrollView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        scrollView.addSubview(contentView)
        scrollView.minimumZoomScale = 1.0
        scrollView.maximumZoomScale = 2.0
        scrollView.delegate = self
        contentView.backgroundColor = .red
        let viewSize = CGSize(width: 400, height: 400)
        scrollView.contentSize = viewSize
        contentView.frame = CGRect(x: 0, y: 0, width: viewSize.width, height: viewSize.height)
        setUpShapeLayer(in: viewSize)
    }

    //MARK: - UIScrollViewDelegate

    func scrollViewDidZoom(_ scrollView: UIScrollView) {
        shapeLayer.lineWidth = lineWidth * 1 / scrollView.zoomScale
    }

    func viewForZooming(in scrollView: UIScrollView) -> UIView? {
        return contentView
    }

    //MARK: - Private

    private func setUpShapeLayer(in size: CGSize) {
        shapeLayer.fillColor = UIColor.white.cgColor
        shapeLayer.strokeColor = UIColor.black.cgColor
        shapeLayer.lineWidth = lineWidth
        contentView.layer.addSublayer(shapeLayer)
        let shapeSize = CGSize(width: 200, height: 200)
        let shapeBounds = CGRect(origin: .zero, size: shapeSize)
        shapeLayer.bounds.size = shapeSize
        shapeLayer.path = UIBezierPath(ovalIn: shapeBounds).cgPath
        shapeLayer.position = CGPoint(x: size.width / 2, y: size.height / 2)
    }
}

这是你想要的吗？