ios - 为CAShapeLayer添加渐变

我得到了这个CAShapeLayer在图表中为我画一条线：

open func generateLayer(path: UIBezierPath) -> CAShapeLayer {
    let lineLayer = CAShapeLayer()
    lineLayer.lineJoin = lineJoin.CALayerString
    lineLayer.lineCap = lineCap.CALayerString
    lineLayer.fillColor = UIColor.clear.cgColor
    lineLayer.lineWidth = lineWidth
    lineLayer.strokeColor = lineColors.first?.cgColor ?? UIColor.white.cgColor

    lineLayer.path = path.cgPath

    if dashPattern != nil {
        lineLayer.lineDashPattern = dashPattern as [NSNumber]?
    }

    if animDuration > 0 {
        lineLayer.strokeEnd = 0.0
        let pathAnimation = CABasicAnimation(keyPath: "strokeEnd")
        pathAnimation.duration = CFTimeInterval(animDuration)
        pathAnimation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
        pathAnimation.fromValue = NSNumber(value: 0 as Float)
        pathAnimation.toValue = NSNumber(value: 1 as Float)
        pathAnimation.autoreverses = false
        pathAnimation.isRemovedOnCompletion = false
        pathAnimation.fillMode = kCAFillModeForwards

        pathAnimation.beginTime = CACurrentMediaTime() + CFTimeInterval(animDelay)
        lineLayer.add(pathAnimation, forKey: "strokeEndAnimation")

    } else {
        lineLayer.strokeEnd = 1
    }

    return lineLayer
}

现在，我想用渐变色而不是单色来画这条线。这是我想出的，但是不幸的是，它并没有为我划清界限。如果没有此添加的代码（lineColors.count == 1），则只能使用一种颜色正确绘制线条。

fileprivate func show(path: UIBezierPath) {
    let lineLayer = generateLayer(path: path)
    layer.addSublayer(lineLayer)

    if lineColors.count > 1 {
        let gradientLayer = CAGradientLayer()
        gradientLayer.startPoint = CGPoint(x: 0.0, y: 0.5)
        gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.5)
        gradientLayer.frame = self.bounds
        gradientLayer.colors = lineColors
        gradientLayer.mask = lineLayer
        layer.addSublayer(gradientLayer)
    }
}

最佳答案

好吧，事实证明我正在为这个行搜索一个多小时：

gradientLayer.colors = lineColors

我忘了将此数组中的UIColors对象映射到CGColorRef对象...
这行为我修复了它：

gradientLayer.colors = lineColors.map({$0.cgColor})

关于ios - 为CAShapeLayer添加渐变，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/46365733/