我如何在SwiftUI中显示整个CALayer内容？

Question

我的代码非常简单，如下所示：

import PocketSVG
import SwiftUI

struct SVGImage: UIViewRepresentable {
    var SVGName: String?
    var tintStrokeColor: CGColor?
    var tintFillColor: CGColor?

    func makeUIView(context: Context) -> UIView {
        return UIView()
    }

    func updateUIView(_ view: UIView, context: Context) {
        let svgURL = Bundle.main.url(forResource: "tiger", withExtension: "svg")!
        let paths = SVGBezierPath.pathsFromSVG(at: svgURL)
        let layer = CALayer()
        for path in paths {
            let shapeLayer = CAShapeLayer()
            shapeLayer.path = path.cgPath

            if let any = path.svgAttributes["stroke"] {
                shapeLayer.strokeColor = (any as! CGColor)
            }

            if let any = path.svgAttributes["fill"] {
                shapeLayer.fillColor = (any as! CGColor)
            }

            layer.addSublayer(shapeLayer)
        }

        layer.contentsGravity = CALayerContentsGravity.resizeAspectFill
        layer.contentsScale = UIScreen.main.scale
        view.layer.addSublayer(layer)
    }
}

struct SVGImage_Previews: PreviewProvider {
    static var previews: some View {
        SVGImage()
    }
}

但是，它不会在View中显示整个图像，而只显示一部分。

我也设置了CALayerContentsGravity.resizeAspectFill和UIScreen.main.scale，但没有生效。

Answer 1

这是一个相对容易的解决方法：

layer.position = svgView.center

并且还将图层添加到UIView中，如下所示：

import PocketSVG
import SwiftUI

struct SVGImage: UIViewRepresentable {
    var SVGName: String?
    var tintStrokeColor: CGColor?
    var tintFillColor: CGColor?

    func makeUIView(context: Context) -> UIView {
        let svgView = UIView(frame: UIScreen.main.bounds)
        svgView.contentMode = .scaleAspectFit

        let svgURL = Bundle.main.url(forResource: "tiger", withExtension: "svg")!
        let paths = SVGBezierPath.pathsFromSVG(at: svgURL)
        let layer = CALayer()

        for path in paths {
            let shapeLayer = CAShapeLayer()
            shapeLayer.path = path.cgPath

            if let any = path.svgAttributes["stroke"] {
                shapeLayer.strokeColor = (any as! CGColor)
            }

            if let any = path.svgAttributes["fill"] {
                shapeLayer.fillColor = (any as! CGColor)
            }

            layer.addSublayer(shapeLayer)
        }

        layer.position = svgView.center
        svgView.layer.addSublayer(layer)

        return svgView
    }

    func updateUIView(_ view: UIView, context: Context) {

    }
}

struct SVGImage_Previews: PreviewProvider {
    static var previews: some View {
        SVGImage()
    }
}