TopCornersMaskShape.swift

struct TopCornersMaskShape: Shape {
  let radius: CGFloat
  
  func path(in rect: CGRect) -> Path {
    var path = Path()
    
    let topLeftCorner = CGPoint(x: rect.minX + radius, y: rect.minY + radius)
    let topRightCorner = CGPoint(x: rect.maxX - radius, y: rect.minY + radius)
    let topLeftCornerStart = CGPoint(x: rect.minX, y: rect.minY + radius)
    let topRightCornerStart = CGPoint(x: rect.maxX - radius, y: rect.minY)
    let bottomRight = CGPoint(x: rect.maxX, y: rect.maxY)
    let bottomLeft = CGPoint(x: rect.minX, y: rect.maxY)
    path.move(to: topLeftCornerStart)
    path.addRelativeArc(center: topLeftCorner, radius: radius, startAngle: .degrees(180), delta: .degrees(90))
    path.addLine(to: topRightCornerStart)
    path.addRelativeArc(center: topRightCorner, radius: radius, startAngle: .degrees(270), delta: .degrees(90))
    path.addLine(to: bottomRight)
    path.addLine(to: bottomLeft)
    
    return path
  }
}