ToolTipView.swift

final class TooltipView: UIView {
    private var option: Option!

    init(option: Option) {
        self.option = option
        super.init(frame: .zero)
        configure()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    private let titleLabel = PaddingLabel()
    
    override func draw(_ rect: CGRect) {
        let top: CGFloat = rect.minY + option.arrowHeight + option.lineWidth
        let left: CGFloat = rect.minX + option.arrowWidth + option.lineWidth
        let right: CGFloat = rect.maxX - option.arrowWidth - option.lineWidth
        let bottom: CGFloat = rect.maxY - option.arrowHeight - option.lineWidth
        
        let topLeft = CGPoint(x: left + option.radius, y: top + option.radius)
        let topRight = CGPoint(x: right - option.radius, y: top + option.radius)
        let bottomLeft = CGPoint(x: left + option.radius, y: bottom - option.radius)
        let bottomRight = CGPoint(x: right - option.radius, y: bottom - option.radius)

        let path = UIBezierPath()

        path.addArc(
            withCenter: topLeft,
            radius: option.radius,
            startAngle: .pi,
            endAngle: 3 * .pi / 2,
            clockwise: true
        )
        switch option.arrowPosition {
        case let .top(normalizedArrowPointX):
            let centerX = rect.width * normalizedArrowPointX
            path.addLine(to: CGPoint(x: centerX - option.arrowWidth / 2, y: top))
            path.addLine(to: CGPoint(x: centerX, y: rect.minY))
            path.addLine(to: CGPoint(x: centerX + option.arrowWidth / 2 , y: top))
        default: break
        }
        
        path.addLine(to: CGPoint(x: topRight.x, y: top))
        path.addArc(
            withCenter: topRight,
            radius: option.radius,
            startAngle: -.pi / 2,
            endAngle: 0,
            clockwise: true
        )
        
        switch option.arrowPosition {
        case let .right(normalizedArrowPointY):
            let centerY = rect.height * normalizedArrowPointY
            path.addLine(to: CGPoint(x: right, y: centerY - option.arrowHeight / 2))
            path.addLine(to: CGPoint(x: rect.maxX, y: centerY))
            path.addLine(to: CGPoint(x: right, y: centerY + option.arrowHeight / 2))
        default: break
        }

        path.addLine(to: CGPoint(x: right, y: bottomRight.y))
        path.addArc(
            withCenter: bottomRight,
            radius: option.radius,
            startAngle: 0,
            endAngle: .pi / 2,
            clockwise: true
        )
        
        switch option.arrowPosition {
        case let .bottom(normalizedArrowPointX):
            let centerX = rect.width * normalizedArrowPointX
            path.addLine(to: CGPoint(x: centerX + option.arrowWidth / 2, y: bottom))
            path.addLine(to: CGPoint(x: centerX, y: rect.maxY))
            path.addLine(to: CGPoint(x: centerX - option.arrowWidth / 2 , y: bottom))
        default: break
        }

        path.addLine(to: CGPoint(x: bottomLeft.x, y: bottom))
        path.addArc(
            withCenter: bottomLeft,
            radius: option.radius,
            startAngle: .pi / 2,
            endAngle: .pi,
            clockwise: true
        )
        
        switch option.arrowPosition {
        case let .left(normalizedArrowPointY):
            let centerY = rect.height * normalizedArrowPointY
            path.addLine(to: CGPoint(x: left, y: centerY + option.arrowHeight / 2))
            path.addLine(to: CGPoint(x: rect.minX, y: centerY))
            path.addLine(to: CGPoint(x: left, y: centerY - option.arrowHeight / 2))
        default: break
        }
        
        path.addLine(to: CGPoint(x: left, y: topLeft.y))
        option.fillColor.setFill()
        option.strokeColor.setStroke()
        path.lineWidth = option.lineWidth
        path.fill()
        path.stroke()
    }
}

private extension TooltipView {
    func configure() {
        addSubview(titleLabel)
        titleLabel.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            titleLabel.leftAnchor.constraint(equalTo: leftAnchor, constant: option.arrowWidth + option.lineWidth),
            titleLabel.rightAnchor.constraint(equalTo: rightAnchor, constant: -option.arrowWidth - option.lineWidth),
            titleLabel.topAnchor.constraint(equalTo: topAnchor, constant: option.arrowHeight+option.lineWidth),
            titleLabel.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -option.arrowHeight-option.lineWidth),
        ])
        
        titleLabel.attributedText = option.attributeText
        titleLabel.padding = option.padding
    }
}

enum ArrowPosition {
    case top(normalizedPointX: CGFloat)
    case bottom(normalizedPointX: CGFloat)
    case left(normalizedPointY: CGFloat)
    case right(normalizedPointY: CGFloat)
}

struct Option {
    let fillColor: UIColor
    let strokeColor: UIColor
    let attributeText: NSAttributedString
    let padding: UIEdgeInsets
    let arrowWidth: CGFloat
    let arrowHeight: CGFloat
    let radius: CGFloat
    let lineWidth: CGFloat
    let arrowPosition: ArrowPosition
    
    init(
        fillColor: UIColor = UIColor(hex: "f59542"),
        strokeColor: UIColor = .white,
        attributeText: NSAttributedString = NSAttributedString(
        string: "Tootlip",
        attributes: [
            .foregroundColor: UIColor.white,
            .font: UIFont.systemFont(ofSize: 14),
        ]),
        padding: UIEdgeInsets = UIEdgeInsets(top: 2, left: 4, bottom: 2, right: 4),
        arrowWidth: CGFloat = 7,
        arrowHeight: CGFloat = 4.5,
        radius: CGFloat = 4,
        lineWidth: CGFloat = 2,
        arrowPosition: ArrowPosition = .bottom(normalizedPointX: 0.6)
    ) {
        self.fillColor = fillColor
        self.strokeColor = strokeColor
        self.attributeText = attributeText
        self.padding = padding
        self.arrowWidth = arrowWidth
        self.arrowHeight = arrowHeight
        self.radius = radius
        self.lineWidth = lineWidth
        self.arrowPosition = arrowPosition
    }
}

final class PaddingLabel: UILabel {
    var padding: UIEdgeInsets = .zero
    
    override func drawText(in rect: CGRect) {
        super.drawText(in: rect.inset(by: padding))
    }

    override var intrinsicContentSize: CGSize {
        var size = super.intrinsicContentSize
        size.width += padding.left + padding.right
        size.height += padding.top + padding.bottom
        return size
    }
}

Example

    let toolTip = TooltipView(option: Option(
        fillColor: UIColor(0xf59542)
        attributeText: NSAttributedString(
            string: "Top: #f59542",
            attributes: [
                .foregroundColor: UIColor.white,
                .font: UIFont.systemFont(ofSize: 14),
            ]
        ),
        padding: UIEdgeInsets(top: 2, left: 4, bottom: 2, right: 4),
        arrowPosition: .bottom(normalizedPointX: 0.4)
    ))