带颜色渐变的UIBeziepath

Question

只要圆圈只有一种颜色，我正在绘制一个圆圈并发挥效果。但我需要两种颜色，其中位置0是绿色，位置360是红色。位置180应该是半绿半红。

这里，吸引了我的圈子

let center = CGPoint(x: bounds.midX, y: bounds.midY) 

     // Calculate the center difference between the end and start angle 
     let angleDiff: CGFloat = endAngle.toRads - startAngle.toRads 
     // Calculate how much we should draw depending on the value set 
     let arcLenPerValue = angleDiff/CGFloat(maxValue) 
     // The inner end angle some basic math is done 
     let innerEndAngle = arcLenPerValue * CGFloat(value) + startAngle.toRads 

     // The radius for style 1 is set below 
     // The radius for style 1 is a bit less than the outer, this way it looks like its inside the circle 
     var radiusIn = (max(bounds.width - outerRingWidth*2 - innerRingSpacing, bounds.height - outerRingWidth*2 - innerRingSpacing)/2) - innerRingWidth/2 

     // If the style is different, mae the radius equal to the outerRadius 
     if viewStyle >= 2 { 
      radiusIn = (max(bounds.width, bounds.height)/2) - (outerRingWidth/2) 
     } 


     // Start drawing 
     let innerPath = UIBezierPath(arcCenter: center, 
            radius: radiusIn, 
            startAngle: startAngle.toRads, 
            endAngle: innerEndAngle, 
            clockwise: true) 
     innerPath.lineWidth = innerRingWidth 
     innerPath.lineCapStyle = innerCapStyle 
     innerRingColor.setStroke() 
     innerPath.stroke() 

你知道如何运用渐变的代码？

Answer 1

路径通常使用单一颜色绘制。

如果要使用渐变绘制路径，可以创建CAShapeLayer并将路径安装到其中，然后使该路径成为渐变图层上的遮罩。

您无疑也可以使用Core Graphics和混合模式来做到这一点。