绘制的圆未对齐

我在一个操场上尝试了您的代码,其中包含以下视图:

let clock = ClockView(frame: CGRect(x: 0, y: 0, width: 500, height: 400))

结果是:

您的问题是这一行:

ctx?.addArc(center: CGPoint(x: rect.midY, y: rect.midY), radius: rad, startAngle: 0, endAngle: endAngle, clockwise: true)

您正在使用 rect.midY 作为视图的水平中心,我假设您的视图不是方形的。将其更改为 rect.midX :

ctx?.addArc(center: CGPoint(x: rect.midX, y: rect.midY), radius: rad, startAngle: 0, endAngle: endAngle, clockwise: true)

其他问题:

1. sides 未定义。我只是把它设置为 60 来编译它。

2. 您使用的值为 48 在你的时间里 60 一小时后。

   更改:

   secondMarkers(ctx!, rect.midX, rect.midY, rad, 48, UIColor.white)
   

   致:

   secondMarkers(ctx!, rect.midX, rect.midY, rad, 60, UIColor.white)
   

3. 您需要一个更长的分隔符 5 滴答声,不是 4 .

   更改:

   if counter % 4 == 0 {
   

   致:

   if counter % 5 == 0 {
   

根据建议的更改,现在的结果是:

以下是完整的代码:

class ClockView: UIView {

    let sides = 60

    override func draw(_ rect:CGRect)

    {
        let ctx = UIGraphicsGetCurrentContext()

        let rad = rect.width / 4

        let endAngle = CGFloat.pi * 2

        ctx?.addArc(center: CGPoint(x: rect.midX, y: rect.midY), radius: rad, startAngle: 0, endAngle: endAngle, clockwise: true)

        ctx?.setFillColor(UIColor.gray.cgColor)

        ctx?.setStrokeColor(UIColor.white.cgColor)

        ctx?.setLineWidth(4.0)

        ctx?.drawPath(using: .fillStroke)

        secondMarkers(ctx!, rect.midX, rect.midY, rad, 60, UIColor.white)
    }

    func degree2Radian(a:CGFloat)-> CGFloat {
        let b = CGFloat.pi * a/180
        return b
    }

    func secondMarkers(_ ctx: CGContext,_ x: CGFloat,_ y: CGFloat,_ radius: CGFloat,_ tickCount: Int,_ color: UIColor) {
        let points = circleCircumferencePoints(tickCount,x,y,radius)

        var divider: CGFloat = 1/8
        var counter = 0
        for p in points {
            if counter % 5 == 0 {
                divider = 1/4
            }
            else {
                divider = 1/8
            }

            let xn = p.x + divider*(x-p.x)
            let yn = p.y + divider*(y-p.y)

            let path = CGMutablePath()
            path.move(to: CGPoint(x: p.x, y: p.y))
            path.addLine(to: CGPoint(x: xn, y: yn))
            path.closeSubpath()

            ctx.addPath(path)
            counter += 1
        }

        let cgcolor = color.cgColor
        ctx.setStrokeColor(cgcolor)
        ctx.setLineWidth(3.0)
        ctx.strokePath()
    }

    func circleCircumferencePoints(_ tickCount:Int,_ x:CGFloat,_ y:CGFloat,_ radius:CGFloat,_ adjustment:CGFloat=0)->[CGPoint] {
        let angle = degree2Radian(a: 360/CGFloat(tickCount))
        let cx = x
        let cy = y
        let r  = radius
        var i = tickCount
        var points = [CGPoint]()
        while points.count <= sides {
            let xpo = cx - r * cos(angle * CGFloat(i)+degree2Radian(a: adjustment))
            let ypo = cy - r * sin(angle * CGFloat(i)+degree2Radian(a: adjustment))
            points.append(CGPoint(x: xpo, y: ypo))
            i -= 1;
        }
        return points
    }
}

let clock = ClockView(frame: CGRect(x: 0, y: 0, width: 500, height: 400))