Question

我想为圆弧创建一个内部阴影，但是我得到了一个半圆而不是阴影（请参见下图）。

我的代码是：

let rect = self.bounds
let segmentArcPath = UIBezierPath()
segmentArcPath.addArc(withCenter: rect.center,
                      radius: (rect.height - insetShadow) / 2,
                      startAngle: -.pi/2,
                      endAngle: value * 2 * .pi - .pi/2,
                      clockwise: true)

shadowPath = segmentArcPath.cgPath

我曾尝试添加两条路径（不关闭阴影），但未成功：

let rect = self.bounds
let segmentArcPath = UIBezierPath()
segmentArcPath.addArc(withCenter: rect.center,
                      radius: (rect.height - insetShadow) / 2,
                      startAngle: internalStrokeStart,
                      endAngle: internalStrokeEnd,
                      clockwise: true)

let segmentArcPath2 = UIBezierPath()
segmentArcPath2.addArc(withCenter: rect.center,
                      radius: (rect.height - insetShadow) / 2 - 5,
                      startAngle: internalStrokeStart,
                      endAngle: internalStrokeEnd,
                      clockwise: false)

segmentArcPath.append(segmentArcPath2)
shadowPath = segmentArcPath.cgPath

如何创建上图所示的阴影？你有什么提示吗？

Answer 1

按照@vacawama的建议：

仅创建一个UIBezierPath。绘制外圆弧后，绘制5 朝向弧线中心的单位线，然后调用addArc以添加内弧到同一路径

let rect = self.bounds
let outerRadius = (rect.height - insetShadow) / 2
let segmentArcPath = UIBezierPath()
segmentArcPath.addArc(withCenter: rect.center,
                      radius: outerRadius,
                      startAngle: internalStrokeStart,
                      endAngle: internalStrokeEnd,
                      clockwise: true)
let innerCircleRadius = outerRadius - 2
let startPointXInnerCircle = cos(internalStrokeEnd) * innerCircleRadius + rect.center.x
let startPointYInnerCircle = sin(internalStrokeEnd) * innerCircleRadius + rect.center.y

segmentArcPath.addLine(to: CGPoint(x: startPointXInnerCircle, y: startPointYInnerCircle))

segmentArcPath.addArc(withCenter: rect.center,
                      radius: innerCircleRadius,
                      startAngle: internalStrokeEnd,
                      endAngle: internalStrokeStart,
                      clockwise: false)

shadowPath = segmentArcPath.cgPath

带有Swift的局部阴影的内部阴影

1 个答案: