[英]Add gradient to CAShapeLayer
I got this CAShapeLayer drawing a line in a chart for me: 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
}
Now I'd like to draw this line with a gradient instead of a single color. 现在,我想用渐变色而不是单色来画这条线。 This is what I came up with, but unfortunately it does not draw the line for me.
这就是我想出的,但是不幸的是,这并没有为我划清界限。 Without this added code (lineColors.count == 1) the line is drawn correctly with a single color.
没有此添加的代码(lineColors.count == 1),线条将正确地以单一颜色绘制。
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)
}
}
Well turns out I was searching more than an hour for this line: 好吧,我在这条线上搜索了一个多小时:
gradientLayer.colors = lineColors
I forgot to map the UIColors objects in this array to CGColorRef objects... This line fixed it for me: 我忘了将此数组中的UIColors对象映射到CGColorRef对象...这一行为我修复了它:
gradientLayer.colors = lineColors.map({$0.cgColor})
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