如何绘制环绕圆形按钮的圆形矩形? [英] How to draw rounded rect that wraps around circular button?

问题描述

我想使用贝塞尔曲线路径快速设计以下屏幕快照的曲线的突出显示部分.

I want to design the highlighted portion of curve of the below screen snapshot using bezier path in swift.

推荐答案

这只是一个三角函数，用于找出右下角该按钮周围的弧形，例如

It’s just a little trigonometry to figure out the arcs around that button in the bottom right hand corner, e.g.

func updatePath() {
    let buttonCenter = CGPoint(x: bounds.maxX - circleRadius, y: bounds.maxY - circleRadius)

    circleShapeLayer.path = UIBezierPath(arcCenter: buttonCenter, radius: circleRadius, startAngle: 0, endAngle: .pi * 2, clockwise: true).cgPath // red

    let angle1 = acos((circleRadius - cornerRadius) / (circleRadius + spaceRadius + cornerRadius))
    let angle2 = acos((circleRadius - bottomDistance - cornerRadius) / (circleRadius + spaceRadius + cornerRadius))

    let arc1Center = CGPoint(x: bounds.maxX - cornerRadius,
                             y: buttonCenter.y - (circleRadius + cornerRadius + spaceRadius) * sin(angle1))

    let path = UIBezierPath()

    path.move(to: CGPoint(x: bounds.maxX, y: bounds.minY + cornerRadius))
    path.addArc(withCenter: arc1Center, radius: cornerRadius, startAngle: 0, endAngle: .pi / 2 + (.pi / 2 - angle1), clockwise: true) // blue
    path.addArc(withCenter: buttonCenter, radius: circleRadius + spaceRadius, startAngle: 2 * .pi - angle1, endAngle: .pi / 2 + angle2, clockwise: false) // green

    let arc2Center = CGPoint(x: buttonCenter.x - (circleRadius + cornerRadius + spaceRadius) * sin(angle2), y: bounds.maxY - bottomDistance - cornerRadius)

    path.addArc(withCenter: arc2Center, radius: cornerRadius, startAngle: -(.pi / 2 - angle2), endAngle: .pi / 2, clockwise: true) // yellow
    path.addArc(withCenter: CGPoint(x: bounds.minX + cornerRadius, y: bounds.maxY - (bottomDistance + cornerRadius)), radius: cornerRadius, startAngle: .pi / 2, endAngle: .pi, clockwise: true) // cyan
    path.addArc(withCenter: CGPoint(x: bounds.minX + cornerRadius, y: bounds.minY + cornerRadius), radius: cornerRadius, startAngle: .pi, endAngle: .pi * 3 / 2, clockwise: true) // white
    path.addArc(withCenter: CGPoint(x: bounds.maxX - cornerRadius, y: bounds.minY + cornerRadius), radius: cornerRadius, startAngle: .pi * 3 / 2, endAngle: 2 * .pi, clockwise: true) // black
    path.close()

    backgroundShapeLayer.path = path.cgPath
}

屈服:

或者，如果您想匹配上述笔画，则在上面的代码中将其用颜色编码为注释:

Or, if you want to match the above strokes, here it is color coded to the comments in the code above:

例如:

@IBDesignable
class BackgroundView: UIView {
    @IBInspectable var cornerRadius:   CGFloat = 10 { didSet { setNeedsLayout() } }
    @IBInspectable var spaceRadius:    CGFloat = 10 { didSet { setNeedsLayout() } }
    @IBInspectable var circleRadius:   CGFloat = 50 { didSet { setNeedsLayout() } }
    @IBInspectable var bottomDistance: CGFloat = 30 { didSet { setNeedsLayout() } }

    private let backgroundShapeLayer: CAShapeLayer = {
        let shapeLayer = CAShapeLayer()
        shapeLayer.fillColor = UIColor.white.cgColor
        shapeLayer.strokeColor = UIColor.clear.cgColor
        return shapeLayer
    }()

    private let circleShapeLayer: CAShapeLayer = {
        let shapeLayer = CAShapeLayer()
        shapeLayer.fillColor = UIColor.white.cgColor
        shapeLayer.strokeColor = UIColor.clear.cgColor
        return shapeLayer
    }()

    override init(frame: CGRect = .zero) {
        super.init(frame: frame)
        configure()
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        configure()
    }

    override func layoutSubviews() {
        super.layoutSubviews()
        updatePath()
    }
}

private extension BackgroundView {

    func configure() {
        layer.addSublayer(circleShapeLayer)
        layer.addSublayer(backgroundShapeLayer)
    }

    func updatePath() {
        let buttonCenter = CGPoint(x: bounds.maxX - circleRadius, y: bounds.maxY - circleRadius)

        circleShapeLayer.path = UIBezierPath(arcCenter: buttonCenter, radius: circleRadius, startAngle: 0, endAngle: .pi * 2, clockwise: true).cgPath

        let angle1 = acos((circleRadius - cornerRadius) / (circleRadius + spaceRadius + cornerRadius))
        let angle2 = acos((circleRadius - bottomDistance - cornerRadius) / (circleRadius + spaceRadius + cornerRadius))

        let arc1Center = CGPoint(x: bounds.maxX - cornerRadius,
                                 y: buttonCenter.y - (circleRadius + cornerRadius + spaceRadius) * sin(angle1))

        let path = UIBezierPath()

        path.move(to: CGPoint(x: bounds.maxX, y: bounds.minY + cornerRadius))
        path.addArc(withCenter: arc1Center, radius: cornerRadius, startAngle: 0, endAngle: .pi / 2 + (.pi / 2 - angle1), clockwise: true)
        path.addArc(withCenter: buttonCenter, radius: circleRadius + spaceRadius, startAngle: 2 * .pi - angle1, endAngle: .pi / 2 + angle2, clockwise: false)

        let arc2Center = CGPoint(x: buttonCenter.x - (circleRadius + cornerRadius + spaceRadius) * sin(angle2), y: bounds.maxY - bottomDistance - cornerRadius)

        path.addArc(withCenter: arc2Center, radius: cornerRadius, startAngle: -(.pi / 2 - angle2), endAngle: .pi / 2, clockwise: true)
        path.addArc(withCenter: CGPoint(x: bounds.minX + cornerRadius, y: bounds.maxY - (bottomDistance + cornerRadius)), radius: cornerRadius, startAngle: .pi / 2, endAngle: .pi, clockwise: true)
        path.addArc(withCenter: CGPoint(x: bounds.minX + cornerRadius, y: bounds.minY + cornerRadius), radius: cornerRadius, startAngle: .pi, endAngle: .pi * 3 / 2, clockwise: true)
        path.addArc(withCenter: CGPoint(x: bounds.maxX - cornerRadius, y: bounds.minY + cornerRadius), radius: cornerRadius, startAngle: .pi * 3 / 2, endAngle: 2 * .pi, clockwise: true)
        path.close()

        backgroundShapeLayer.path = path.cgPath
    }
}

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