我有一条由
UIBezierPath
画的线:
let line = CAShapeLayer()
line.path = UIBezierPath(arcCenter: center,
radius: radius,
startAngle: CGFloat(114.0/180.0) * .pi,
endAngle: .pi,
clockwise: true).cgPath
line.lineWidth = LINE_WIDTH
line.strokeColor = UIColor.red.withAlphaComponent(0.9).cgColor
line.fillColor = UIColor.clear.cgColor
我尝试通过添加一些新的
CAShapeLayer()
来绕过拐角:
let corner = CAShapeLayer()
corner.path = UIBezierPath(arcCenter: coordByCorner(114.0*1.00035),
radius: LINE_WIDTH/2,
startAngle: CGFloat(114.0/180.0) * .pi,
endAngle: CGFloat(114.0/180.0 + 1) * .pi,
clockwise: false).cgPath
corner.strokeColor = UIColor.clear.cgColor
corner.fillColor = UIColor.red.withAlphaComponent(0.9).cgColor
line.addSublayer(corner)
但我认为这是一个不好的变体,当我改变图层的颜色时,颜色会随着时间间隔的不同而变化。
此外,这一切看起来像这样:
P.S.: 1.00035 是为了消除层与层之间的间隙。阿尔法需要是< 1.0 (0.1 - 0.9). So how to do this while keeping the alpha?
问题通过添加kCALineCapRound解决
let line = CAShapeLayer()
line.path = UIBezierPath(arcCenter: center,
radius: radius,
startAngle: CGFloat(114.0/180.0) * .pi,
endAngle: .pi,
clockwise: true).cgPath
line.lineWidth = LINE_WIDTH
line.strokeColor = UIColor.red.withAlphaComponent(0.9).cgColor
line.fillColor = UIColor.clear.cgColor
line.lineCap = kCALineCapRound // this parameter solve my problem
这样做的一个简单方法是创建向内移动所需
cornerRadius
的路径,用两倍粗的线抚摸它并应用圆线连接样式。
let layer = CAShapeLayer()
layer.strokeColor = UIColor.lightGray.cgColor
layer.fillColor = UIColor.lightGray.cgColor
layer.lineWidth = 2.0 * cornerRadius
layer.lineJoin = kCALineJoinRound
layer.path = getSemicirclePath(
arcCenter: arcCenter,
radius: radius,
cornerRadius: cornerRadius
)
func getSemicirclePath(arcCenter: CGPoint, radius: CGFloat, cornerRadius: CGFloat) -> CGPath {
let path = UIBezierPath(
arcCenter: CGPoint(x: arcCenter.x, y: arcCenter.y - cornerRadius),
radius: radius - cornerRadius,
startAngle: .pi,
endAngle: 2.0 * .pi,
clockwise: true
)
path.close()
return path.cgPath
}
这里是示例结果:
根据当前版本的另一种方式
line.path.lineCapStyle = .round
.path 是 UIBezierPath
参考:https://developer.apple.com/documentation/uikit/uibezierpath/1624347-linecapstyle