如何在 UIBezierPath Swift 中绘制这样的曲线？

Question

我正在尝试开发一个背景如下所示的屏幕：

在这里，我正在尝试开发灰色弯曲背景，它也填充了屏幕的下部。 我对UIBezierPath很陌生，我试过这个：

class CurvedView: UIView {

//MARK:- Data Types

//MARK:- View Setup

override func draw(_ rect: CGRect) {
    
    let fillColor: UIColor = .blue
    let path = UIBezierPath()
    let y:CGFloat = 0
    
    print(rect.height)
    print(rect.width)
    
    path.move(to: CGPoint(x: .zero, y: 100))
    path.addLine(to: CGPoint(x: 60, y: 100))
    path.addCurve(to: .init(x: 100, y: 0), controlPoint1: .init(x: 125, y: 80), controlPoint2: .init(x: 50, y: 80))
    
    path.close()
    fillColor.setFill()
    path.fill()
    
}

override init(frame: CGRect) {
    super.init(frame: frame)
    self.backgroundColor = .init(hex: "#dfe1e3")
}

required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    self.backgroundColor = .init(hex: "#dfe1e3")
    
}
}

这段代码给了我这个：

我遵循了很多教程，但我没有得到确切的理解。 我知道对于这条曲线，我必须移动到(0,100) ，然后添加一条线，然后添加一条曲线，十延长线添加一条曲线，然后直线下曲线，然后直线并关闭。 但是，当我开始时，你可以看到蓝线没有覆盖上部。 谁能帮帮我吗？

Answer 1

这是我创建的一些示例，您可以更改值以使其更类似于您想要的

这是曲线中控制点如何工作的指南

注意：我在 viewDidload 中调用了这段代码

let path = UIBezierPath()
        let fillColor = UIColor.blue
        
        let y: CGFloat = UIScreen.main.bounds.size.height
        let x: CGFloat = UIScreen.main.bounds.size.width
        let height: CGFloat = 200
        
        path.move(to: CGPoint(x: 0, y: y)) // bottom left
        path.addLine(to: CGPoint(x: 0, y: y - 20)) // top left
        path.addCurve(to: CGPoint(x: x, y: y - height), controlPoint1: CGPoint(x: x * 2 / 3, y: y), controlPoint2: CGPoint(x: x * 5 / 6, y: y - height * 6 / 5)) // curve to top right
        path.addLine(to: CGPoint(x: x, y: y)) // bottom right
        path.close() // close the path from bottom right to bottom left

        let shapeLayer = CAShapeLayer()
    shapeLayer.path = path.cgPath
    shapeLayer.fillColor = fillColor.cgColor

    view.layer.addSublayer(shapeLayer)

Answer 2

参考@aiwiguna

class CurvedView: UIView {

//MARK:- Data Types

//MARK:- View Setup

override func draw(_ rect: CGRect) {
    
  
    let path = UIBezierPath()
  
    
    let fillColor = UIColor.blue
            
            let y: CGFloat = UIScreen.main.bounds.size.height
            let x: CGFloat = UIScreen.main.bounds.size.width
            let height: CGFloat = 200
            
            path.move(to: CGPoint(x: 0, y: y)) // bottom left
            path.addLine(to: CGPoint(x: 0, y: y - 20)) // top left
            path.addCurve(to: CGPoint(x: x, y: y - height), controlPoint1: CGPoint(x: x * 2 / 3, y: y), controlPoint2: CGPoint(x: x * 5 / 6, y: y - height * 6 / 5)) // curve to top right
            path.addLine(to: CGPoint(x: x, y: y)) // bottom right
            path.close() // close the path from bottom right to bottom left

            let shapeLayer = CAShapeLayer()
        shapeLayer.path = path.cgPath
        shapeLayer.fillColor = fillColor.cgColor

    
    path.close()
    fillColor.setFill()
    path.fill()
    
}

override init(frame: CGRect) {
    super.init(frame: frame)
    self.backgroundColor = .red
}

required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    self.backgroundColor = .yellow
    
}
}