在
pre-release documentation,似乎没有Swift版本的CGPathApply.有等同还是替代?我试图获取CGPath的所有子路径,以便我可以从不同的起始点重新绘制.
Swift 3.0
在Swift 3.0中,您可以使用CGPath.apply,如下所示:
let path: CGPath = ... // or let path: CGMutablePath path.apply(info: nil) { (_,elementPointer) in let element = elementPointer.pointee let command: String let pointCount: Int switch element.type { case .movetoPoint: command = "moveto"; pointCount = 1 case .addLinetoPoint: command = "lineto"; pointCount = 1 case .addQuadCurvetoPoint: command = "quadCurveto"; pointCount = 2 case .addCurvetoPoint: command = "curveto"; pointCount = 3 case .closeSubpath: command = "close"; pointCount = 0 } let points = Array(UnsafeBufferPointer(start: element.points,count: pointCount)) Swift.print("\(command) \(points)") }
Swift 2.2
通过添加@convention(c),您现在可以直接从Swift调用CGPathApply.这是一个需要魔法的包装:
extension CGPath { func forEach(@noescape body: @convention(block) (CGpathelement) -> Void) { typealias Body = @convention(block) (CGpathelement) -> Void func callback(info: UnsafeMutablePointer<Void>,element: UnsafePointer<CGpathelement>) { let body = unsafeBitCast(info,Body.self) body(element.memory) } print(sizeofValue(body)) let unsafeBody = unsafeBitCast(body,UnsafeMutablePointer<Void>.self) CGPathApply(self,unsafeBody,callback) } }
(请注意,我的代码中没有提及@convention(c),而是在Core Graphics模块的CGPathApply声明中使用.)
使用示例
let path = UIBezierPath(roundedRect: CGRectMake(0,200,100),cornerRadius: 15) path.CGPath.forEach { element in switch (element.type) { case CGpathelementType.MovetoPoint: print("move(\(element.points[0]))") case .AddLinetoPoint: print("line(\(element.points[0]))") case .AddQuadCurvetoPoint: print("quadCurve(\(element.points[0]),\(element.points[1]))") case .AddCurvetoPoint: print("curve(\(element.points[0]),\(element.points[1]),\(element.points[2]))") case .CloseSubpath: print("close()") } }
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