最好的特点就是可以自定义路径，设置圆角和描边都很方便，以下为代码和效果，均在playground中实现
1、首先实现一个圆角矩形，并对此路径描边，为其绘制一个轮廓。
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//: Playground - noun: a place where people can playimport UIKit
class MyView : UIView{
override func drawRect(rect: CGRect) {
var pathRect = UIEdgeInsetsInsetRect(self.bounds, UIEdgeInsetsMake(1, 1, 1, 1))
var path = UIBezierPath(roundedRect: pathRect, cornerRadius: 10)
path.lineWidth = 4
UIColor.greenColor().setFill()
UIColor.blackColor().setStroke()
path.fill()
path.stroke()
}
}let viewRect = CGRect(x: 0, y: 0, width: 100, height: 100)
let myEmptyView = MyView(frame:viewRect)
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tips：所有绘制操作都是按照调用顺序进行的。在本段代码中，我在填充矩形后再对其进行描边。如果交换对path.fill()和path.stroke()的调用顺序，将会得到一个稍有不同的结果，绿色填充将会略微覆盖黑色描边，效果图如下。
2、下面自定义一条路径，确定几个点，然后像画笔一样连线！
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//: Playground - noun: a place where people can playimport UIKit
class MyView : UIView{
override func drawRect(rect: CGRect) {
var bezierPath = UIBezierPath()
//创建一个矩形，它的所有边都内缩5%
var drawingRect = CGRectInset(self.bounds, self.bounds.size.width*0.05, self.bounds.size.height*0.05)
//确定组成绘画的点
var topLeft = CGPointMake(CGRectGetMinX(drawingRect), CGRectGetMinY(drawingRect))
var topRight = CGPointMake(CGRectGetMaxX(drawingRect), CGRectGetMinY(drawingRect))
var bottomLeft = CGPointMake(CGRectGetMinX(drawingRect), CGRectGetMaxY(drawingRect))
var bottomRight = CGPointMake(CGRectGetMaxX(drawingRect), CGRectGetMaxY(drawingRect))
var center = CGPointMake(CGRectGetMidX(drawingRect), CGRectGetMinY(drawingRect))
//开始绘制
bezierPath.moveToPoint(topLeft)
bezierPath.addLineToPoint(topRight)
bezierPath.addLineToPoint(bottomLeft)
bezierPath.addCurveToPoint(bottomRight, controlPoint1: center, controlPoint2: center)
//使路径闭合，结束绘制
bezierPath.closePath()
//设定颜色，并绘制它们
UIColor.redColor().setFill()
UIColor.blackColor().setStroke()
bezierPath.fill()
bezierPath.stroke()
}
}let viewRect = CGRect(x: 0, y: 0, width: 100, height: 100)
let myEmptyView = MyView(frame:viewRect)
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3、多条子路径也可以。
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//: Playground - noun: a place where people can playimport UIKit
class MyView : UIView{
override func drawRect(rect: CGRect) {
//创建一条空Bezier路径
let bezierPath = UIBezierPath()
//为两个组成部分定义矩形
let squareRect = CGRectInset(rect, rect.size.width*0.45, rect.size.height*0.05)
let circleRect = CGRectInset(rect, rect.size.width*0.3, rect.size.height*0.3)
let cornerRadius : CGFloat = 20
//创建路径
let circlePath = UIBezierPath(ovalInRect: circleRect)
let squarePath = UIBezierPath(roundedRect: squareRect, cornerRadius: cornerRadius)
//将它们添加到主路径
squarePath.appendPath(circlePath)
bezierPath.appendPath(squarePath)
//设定颜色并绘制它们
UIColor.redColor().setFill()
//绘制路径
bezierPath.fill()
}
}let viewRect = CGRect(x: 0, y: 0, width: 100, height: 100)
let myEmptyView = MyView(frame:viewRect)
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以上就是UIBezierPath的基本用法，用好了将是绘制图形的又一利器。