ios - 圆形贝塞尔曲线路径不正确

Question

我需要在 View 中绘制饼图。我已经正确绘制了背景路径。但是当我添加进度层时，路径绘制不正确。

这是我用来创建层并将它们添加到 View 的代码。

我也创建了一个要点。您也可以从那里看到完整的代码。 MultiColoredPie Gist

private lazy var pathLayers: [PieLayer] = {

        guard let data = self.data else { return [] }

        var previousPercentage: CGFloat = 0
        let sorted = data.sorted(by: { (data1, data2) -> Bool in
            return data1.percentage < data2.percentage
        })

        var layers: [PieLayer] = []
        for (index, item) in sorted.enumerated() {
            previousPercentage += item.percentage
            let layer = PieLayer()
            layer.index = index
            layer.lineCap = CAShapeLayerLineCap.square
            layer.fillColor = nil
            layer.strokeColor = item.color.cgColor
            layer.strokeEnd = previousPercentage //item.percentage
            layer.percentage = previousPercentage //item.percentage
            layers.append(layer)
        }
        return layers
}()

override func layoutSubviews() {
        super.layoutSubviews()
        self.addShapes()
}

func addShapes() {
        shapeLayer.path = commonPath.cgPath
        shapeLayer.lineWidth = lineWidth
        self.layer.addSublayer(shapeLayer)

        for layer in pathLayers.reversed() {
            print("\(layer.index) - \(layer.percentage)")
            layer.lineWidth = lineWidth
            layer.path = commonPath.cgPath
            self.layer.addSublayer(layer)
        }

}

我用这段代码创建路径，

private var commonPath: UIBezierPath {
        get {
            let x = self.frame.width/2
            let y = self.frame.height/2
            let center = CGPoint(x: x, y: y)
            let path = UIBezierPath(arcCenter: center, radius: CGFloat(x - lineWidth/2), startAngle: -90.degreesToRadians, endAngle: 270.degreesToRadians, clockwise: true)
            path.close()
            return path
        }
}

有人知道为什么会这样吗？ (而且似乎不是从 -90 开始的)

Answer 1

您应该设置适当的CGLineCap。你有 CGLineCap.square，但你需要 CGLineCap.butt

这里有更多信息:CGLineCap

换行

 layer.lineCap = CAShapeLayerLineCap.square

到:

 layer.lineCap = CAShapeLayerLineCap.butt