[Swift]iOS开发之UIBezierPath画曲线

用过任何绘图软件的朋友对Bezier曲线都不会陌生，就是钢笔工具～下面来看看Bezier曲线的画法，首先定义startPoint、endPoint和controlPoint

let startPoint = CGPointMake(100, 100)
let endPoint = CGPointMake(300, 100)
let controlPoint = CGPointMake(150, 50)

 再定义path和layer

let path = UIBezierPath()
let layer = CAShapeLayer()

 设置Bezier曲线的起点、终点和控制点

path.moveToPoint(startPoint)
path.addQuadCurveToPoint(endPoint, controlPoint: controlPoint)

 最后添加layer到view

layer.path = path.CGPath
layer.fillColor = UIColor.clearColor().CGColor
layer.strokeColor = UIColor.blackColor().CGColor
        
view.layer.addSublayer(layer)

 运行我们可以看到⬇️图效果

为了更好地理解Bezier曲线，我们为它添加起点终点和控制点的layer

let slayer = CALayer()
let elayer = CALayer()
let clayer = CALayer()
        
slayer.frame = CGRectMake(startPoint.x, startPoint.y, 5, 5)
elayer.frame = CGRectMake(endPoint.x, endPoint.y, 5, 5)
clayer.frame = CGRectMake(controlPoint.x, controlPoint.y, 5, 5)
        
slayer.backgroundColor = UIColor.redColor().CGColor
elayer.backgroundColor = UIColor.redColor().CGColor
clayer.backgroundColor = UIColor.redColor().CGColor

view.layer.addSublayer(slayer)
view.layer.addSublayer(elayer)
view.layer.addSublayer(clayer)

 Run

是不是赶脚很熟悉，就是钢笔工具的赶脚嘛～接下来可以自己调节controlPoint试试～

还可以添加两个控制点，更改fillcolor

clayer2.frame = CGRectMake(controlPoint2.x, controlPoint2.y, 5, 5)