说明：

自己写了一个饼状图的控件，可以旋转（如果嫌弃旋转范围太窄，可自行调节），可以出发点击事件。

注意：

如果视图放在scrollView，或者有特定手势存在的视图上的时候；会出现旋转不畅的现象，如果能
解决，自行解决；解决不了可以放弃旋转功能，或者放弃使用该控件。
ps：我是遇到了放在一个第三方的控件上，无论我怎么调整都被它影响，所以在公司app中，我放弃了
旋转功能

代码：

/**********************************/
/*********     饼状图     **********/
/**********************************/

class XJJPCItem {
var title: String?
var description: String?
var id: Int = 0
var scale: CGFloat = 0
var lineWidth: CGFloat = 1
var lineColor: UIColor?
var strockColor: UIColor?
var strockWidth: CGFloat = 1
var fillColor: UIColor?

//记录值，不用传入
var startAngle: CGFloat?
var endAngle: CGFloat?
var isSelected: Bool = false

init(_ title: String?,
     description: String?,
     id: Int?,
     scale: CGFloat?,
     lineWidth: CGFloat?,
     lineColor: UIColor?,
     strockColor: UIColor?,
     strockWidth: CGFloat?,
     fillColor: UIColor?) {
    self.title = title
    self.description = description
    self.id = id ?? 0
    self.scale = scale ?? 0
    self.lineWidth = lineWidth ?? 1
    self.lineColor = lineColor
    self.strockColor = strockColor
    self.strockWidth = strockWidth ?? 1
    self.fillColor = fillColor
}
}

class XJJPCView: UIView {
var touchUpBlock: ((_ id: Int) -> Void)?

var dataSource: [XJJPCItem]? {
    didSet {
        guard let data = dataSource else {return}
        self.source = data
        self.setNeedsDisplay()
    }
}

var defaultAngle: CGFloat = -1 / 4//以pi_2为基础设置，-1/4即为：-pi/2
var offset: CGFloat?//位移量，用于手势滑动

//文字属性
var textFont: UIFont!
var textColor: UIColor!

override init(frame: CGRect) {
    super.init(frame: frame)
    self.initUI()
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touche: UITouch in touches {
        let point: CGPoint = touche.location(in: self)
        self.tap(point)
    }
}

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touche: UITouch in touches {
        let point: CGPoint = touche.location(in: self)
        let previous: CGPoint = touche.previousLocation(in: self)
        if (point.x - previous.x) > 1 || (point.y - previous.y) > 1 {
            self.move(point, previous)
        }
    }
}

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    
}

//移动
private func move(_ point: CGPoint, _ previous: CGPoint) {
    let center: CGPoint = CGPoint(x: self.bounds.width / 2, y: self.bounds.height / 2)
    let x: CGFloat = point.x - center.x
    let y: CGFloat = point.y - previous.y
    let per_angle: CGFloat = pi_2 / 100
    if x > 0 {
        self.diff_angle += per_angle * (y / 10)
    }else {
        self.diff_angle += -per_angle * (y / 10)
    }
    self.setNeedsDisplay()
}

//点击
private func tap(_ point: CGPoint) {
    let center: CGPoint = CGPoint(x: self.bounds.width / 2, y: self.bounds.height / 2)
    let x: Double = Double(point.x - center.x)
    let y: Double = Double(point.y - center.y)
    let lenght: Double = sqrt(x * x + y * y)
    let angle: CGFloat = CGFloat(acos(x / lenght))
    let d_angle: CGFloat = (y >= 0) ? angle : -angle
    let a = self.angleTranslate(d_angle)
    
    if let r = self.sectorRadius {
        let _r = Double(r)
        if x > _r || x < -_r || y > _r || y < -_r {
            return
        }
    }
    
    self.source.forEach {[weak self] (item) in
        guard let sself = self else {return}
        item.isSelected = false
        if let b = item.startAngle, let c = item.endAngle {
            if b > c {
                if (a > b && a <= pi_2) || (a < c && a > 0) {
                    sself.touchUpBlock?(item.id)
                    item.isSelected = true
                }
            }else {
                if a > b, a < c {
                    sself.touchUpBlock?(item.id)
                    item.isSelected = true
                }
            }
        }
        sself.setNeedsDisplay()
    }
}

private let pi_2 = CGFloat(Double.pi * 2)
private var sectorRadius: CGFloat?//扇形区域半径

private var diff_angle: CGFloat = 0//旋转时的变化量

private var source: [XJJPCItem] = []

private func initUI() {
    self.backgroundColor = UIColor.clear
    self.textFont = UIFont.boldSystemFont(ofSize: 13)
    self.textColor = #colorLiteral(red: 0.2549019754, green: 0.2745098174, blue: 0.3019607961, alpha: 1)
}

//将角度转化为0~pi_2之间的值
private func angleTranslate(_ angle: CGFloat) -> CGFloat {
    if angle < 0 {
        let multiple: Int = Int(-angle / pi_2) + 1
        return angle + pi_2 * CGFloat(multiple)
    }else if angle > pi_2 {
        let multiple = Int(angle / pi_2)
        return angle - pi_2 * CGFloat(multiple)
    }
    
    return angle
}

override func draw(_ rect: CGRect) {
    super.draw(rect)
    guard let current = UIGraphicsGetCurrentContext() else {return}
    
    current.clear(rect)
    current.setFillColor(UIColor.clear.cgColor)
    current.fill(rect)
    
    self.drawOnContext(current)
}

//根据数据画出图形
private func drawOnContext(_ context: CGContext) {
    guard source.count > 0 else {return}
    
    let center: CGPoint = CGPoint(x: self.bounds.width / 2, y: self.bounds.height / 2)
    let r: CGFloat = self.bounds.height / 5 * 3 / 2
    var start: CGFloat = 0
    var end: CGFloat = 0
    
    self.sectorRadius = r
    
    var currentAngle: CGFloat = defaultAngle * pi_2 + diff_angle
    
    for item in source {
        start = currentAngle
        end = start + item.scale * pi_2
        let text: String = (item.title ?? "") + ": \(item.scale)"
        
        self.creatSector(context, center, r, start, end, item.strockWidth, item.strockColor ?? #colorLiteral(red: 0.2392156869, green: 0.6745098233, blue: 0.9686274529, alpha: 1), item.fillColor ?? #colorLiteral(red: 0.4666666687, green: 0.7647058964, blue: 0.2666666806, alpha: 1))
        let result = self.creatLine(context, center, r, start, item.scale * pi_2, item.lineColor ?? #colorLiteral(red: 0.2549019754, green: 0.2745098174, blue: 0.3019607961, alpha: 1), item.lineWidth)
        self.creatText(context, text, result.0, result.1)
        
        if item.isSelected == true {
            self.creatSelectSector(context, center, r + 5, start, end, 10, item.strockColor ?? #colorLiteral(red: 0.2392156869, green: 0.6745098233, blue: 0.9686274529, alpha: 1), item.fillColor ?? #colorLiteral(red: 0.4666666687, green: 0.7647058964, blue: 0.2666666806, alpha: 1))
        }
        
        currentAngle = end
        
        item.startAngle = self.angleTranslate(start)
        item.endAngle = self.angleTranslate(end)
    }
}

//画扇形
private func creatSector(_ context: CGContext,
                         _ center: CGPoint,
                         _ radius: CGFloat,
                         _ startAngle: CGFloat,
                         _ endAngle: CGFloat,
                         _ strockWidth: CGFloat,
                         _ strockColor: UIColor,
                         _ fillColor: UIColor) {
    
    context.move(to: center)
    context.addArc(center: center, radius: radius, startAngle: startAngle, endAngle: endAngle, clockwise: false)
    context.setStrokeColor(strockColor.cgColor)
    context.setFillColor(fillColor.cgColor)
    context.setLineWidth(strockWidth)
    context.closePath()
    
    context.drawPath(using: .fillStroke)
}

//选中状态圆弧
private func creatSelectSector(_ context: CGContext,
                               _ center: CGPoint,
                               _ radius: CGFloat,
                               _ startAngle: CGFloat,
                               _ endAngle: CGFloat,
                               _ strockWidth: CGFloat,
                               _ strockColor: UIColor,
                               _ fillColor: UIColor) {
    let s_color: UIColor = fillColor.withAlphaComponent(0.4)
    
    context.addArc(center: center, radius: radius, startAngle: startAngle, endAngle: endAngle, clockwise: false)
    context.setStrokeColor(s_color.cgColor)
    context.setLineWidth(strockWidth)
    
    context.drawPath(using: .stroke)
}

//找到圆弧上直线经过的点，并返回圆心到这一点所在直线的任意一点，通过scale实现
private func findPoint(_ center: CGPoint,
                       _ radius: CGFloat,
                       _ startAngle: CGFloat,
                       _ moveAngle: CGFloat,
                       _ scale: CGFloat) -> CGPoint {
    let angle: CGFloat = startAngle + moveAngle / 2
    let o_x: CGFloat = radius * cos(angle)
    let o_y: CGFloat = radius * sin(angle)
    let c_x: CGFloat = center.x + o_x * scale
    let c_y: CGFloat = center.y + o_y * scale
    
    return CGPoint(x: c_x, y: c_y)
}

//画线
private func creatLine(_ context: CGContext,
                       _ center: CGPoint,
                       _ radius: CGFloat,
                       _ startAngle: CGFloat,
                       _ moveAngle: CGFloat,
                       _ lineColor: UIColor,
                       _ lineWidth: CGFloat) -> (CGPoint, Bool) {
    let centerAngle: CGFloat = self.angleTranslate(startAngle + moveAngle / 2)
    let isLeft: Bool = (centerAngle > pi_2 / 4) && (centerAngle < pi_2 / 4 * 3)
    let start: CGPoint = self.findPoint(center, radius, startAngle, moveAngle, 0.8)
    let middle: CGPoint = self.findPoint(center, radius, startAngle, moveAngle, 1.2)
    let diff: CGFloat = 1 - fabs(middle.x - center.x) / (radius * 1.2)
    let end: CGPoint = CGPoint(x: middle.x + (isLeft ? -20 : 20) * diff, y: middle.y)
    
    context.move(to: start)
    context.addLine(to: middle)
    context.addLine(to: end)
    context.setLineWidth(lineWidth)
    context.setStrokeColor(lineColor.cgColor)
    
    context.drawPath(using: .stroke)
    
    return (end, isLeft)
}

//写文字
private func creatText(_ context: CGContext, _ text: String, _ position: CGPoint, _ isLeft: Bool) {
    let style = NSMutableParagraphStyle()
    style.lineBreakMode = .byWordWrapping
    style.alignment = .center
    
    /*之前的写法
     let dic: [String : Any] = [
     NSFontAttributeName: textFont,
     NSForegroundColorAttributeName: textColor,
     NSParagraphStyleAttributeName: style,
     ]
     */
    
    let dic: [NSAttributedStringKey : Any] = [
        .font: textFont,
        .foregroundColor: textColor,
        .paragraphStyle: style,
        ]
    let size = text.size(withAttributes: dic)
    let x: CGFloat = isLeft ? (position.x - size.width) : position.x
    let y: CGFloat = position.y - size.height / 2
    let rect = CGRect(x: x,  y: y, width: size.width, height: size.height)
    text.draw(in: rect, withAttributes: dic)
}

}