Question

我画一个圆圈，只要圆圈只有一种颜色，就可以发挥得很好。但我需要有两种颜色，其中位置0为绿色，位置360为红色。位置180应该是半绿半红。

这是绘制我的圈子的代码

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()

你知道如何应用渐变吗？

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，然后将该路径设置为渐变图层上的遮罩。

毫无疑问，使用Core Graphics和混合模式也可以做到这一点。

UIBeziepath与颜色渐变

1 个答案: