[Swift]iOS开发:使用模拟器绘制图片并保存到电脑本地

func renderImage(){
        let W:CGFloat = 120
        UIGraphicsBeginImageContextWithOptions(CGSize(width:W,height:W), false, UIScreen.main.scale)
        //在当前上下文上绘图
        let ctx = UIGraphicsGetCurrentContext()
        ctx?.setFillColor(UIColor(red: 138/255, green: 201/255, blue: 1, alpha: 1).cgColor)
        ctx?.addArc(center: CGPoint(x:W/2,y:W/2), radius: W/2, startAngle: 0, endAngle: .pi*2, clockwise: true)
        ctx?.clip()
        ctx?.fill(CGRect(origin: .zero, size: CGSize(width: W, height: W)))
        //获取画好的图片
        let img = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        let imageView = UIImageView(frame: CGRect(origin: .zero, size: CGSize(width: 120, height: 120)))
        imageView.center = view.center
        imageView.image = img
        view.addSubview(imageView)

        //打印工程所在文件路径
        print(NSHomeDirectory())
        //获取本地缓存文件路径
        let cachPath = NSSearchPathForDirectoriesInDomains(.cachesDirectory, .userDomainMask, true)
        //设置保存路径
        let path = cachPath[0] + "/img.png"
        //将图片转换为png图片数据
        let imgData = UIImagePNGRepresentation(img!)
        do {
            //写入到指定路径
            try imgData?.write(to: URL(fileURLWithPath: path))
        }
        catch{

        }
    }