ios - 给定一个自定义形状，如何增加尺寸以适应 SwiftUI 中的框架？

Question

我有一系列自定义的Shape和一个具有设定框架的ZStack，有没有办法增加每个自定义Shape<的大小 可以有不同的尺寸来适应 Zstack 框架？

将绘制给定点的各种形状的代码。

struct DrawShape: Shape {

    var points: [CGPoint]
    
    func path(in rect: CGRect) -> Path {
        var path: Path = Path()

        guard let startingPoint = points.first else {
            return path
        }

        path.move(to: startingPoint)

        for pointLocation in points {
            
            path.addLine(to: pointLocation)
            
        }

        return path
    }
}

Answer 1

这是我想到的:

1. 像往常一样绘制路径
2. 获取 boundingRect 路径的
3. 确定路径所需的比例因子
   • rect是形状的可用面积
   • 如果 boundingRect比 rect 胖，使用它们的宽度
   • 如果 boundingRect比 rect 更瘦，使用他们的高度
4. 绘制一条新路径，这次使用缩放点和偏移量(如果需要)
   • 如果路径的起点不是 (0, 0) ，每个新点都需要减去原点
5. 返回新路径

struct DrawShape: Shape {
    var points: [CGPoint]
    
    func path(in rect: CGRect) -> Path {
        
        /// draw the path
        var path = Path()
        guard let startingPoint = points.first else { return path }
        path.move(to: startingPoint)
        for pointLocation in points {
            path.addLine(to: pointLocation)
        }
        
        /// aspect fit scale
        let scale: CGFloat
        if path.boundingRect.height / path.boundingRect.width < rect.height / rect.width {
            scale = rect.width / path.boundingRect.width /// boundingRect is fatter
        } else {
            scale = rect.height / path.boundingRect.height /// boundingRect is skinnier
        }

        /// draw the scaled path
        var scaledPath = Path()
        scaledPath.move(to: convertPoint(startingPoint, offset: path.boundingRect.origin, scale: scale))
        for pointLocation in points {
            scaledPath.addLine(to: convertPoint(pointLocation, offset: path.boundingRect.origin, scale: scale))
        }
        
        /// return the scaled path
        return scaledPath
    }
    
    /// point = original point
    /// offset = in case the origin of `boundingRect` isn't (0,0), make sure to offset each point
    /// scale = how much to scale the point by
    func convertPoint(_ point: CGPoint, offset: CGPoint, scale: CGFloat) -> CGPoint {
        return CGPoint(x: (point.x - offset.x) * scale, y: (point.y - offset.y) * scale)
    }
}

struct ContentView: View {
    var body: some View {
        ZStack {
            Color.blue
            
            DrawShape(points: [
                CGPoint(x: 0, y: 0),
                CGPoint(x: 200, y: 0),
                CGPoint(x: 100, y: 250),
                CGPoint(x: 0, y: 0)
            ])
        }
        .frame(width: 300, height: 500)
    }
}

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