iOS Swift 内阴影

前言:

原作者地址：https://github.com/Mstic/inner_shadow

我这是从原作者改写过来的Swift版本。

花了点时间搜了一下iOS内阴影相关的文章。结果项目里没有用上，背景用的是一个图片拉伸的。

代码地址：

代码地址：https://gitee.com/yuency/Autolayout
示例代码类名 【InnerShadowView】【InnerShadowViewController】

效果图：

内阴影.PNG

上代码！

InnerShadowView.swift

import UIKit

class InnerShadowView: UIView {
    override func draw(_ rect: CGRect) {
        let context = UIGraphicsGetCurrentContext()
        var r: CGFloat = 0, g: CGFloat = 0, b: CGFloat = 0, a: CGFloat = 0
        backgroundColor?.getRed(&r, green: &g, blue: &b, alpha: &a)
        let color = UIColor(red: r, green: g, blue: b, alpha: a)
        let shadow = NSShadow()
        shadow.shadowColor = UIColor(cgColor: layer.shadowColor ?? UIColor.black.cgColor)
        shadow.shadowOffset = layer.shadowOffset
        shadow.shadowBlurRadius = layer.shadowRadius
        let rectanglePath = UIBezierPath(roundedRect: bounds, cornerRadius: layer.cornerRadius)
        color.setFill()
        context?.saveGState()
        context?.clip(to: rectanglePath.bounds)
        context?.setShadow(offset: .zero, blur: 0, color: nil)
        context?.setAlpha((shadow.shadowColor as! UIColor).cgColor.alpha)
        context?.beginTransparencyLayer(auxiliaryInfo: nil)
        let opaqueShadow = (shadow.shadowColor as! UIColor)
        context?.setShadow(offset: shadow.shadowOffset, blur: shadow.shadowBlurRadius, color: opaqueShadow.cgColor)
        context?.setBlendMode(.sourceOut)
        context?.beginTransparencyLayer(auxiliaryInfo: nil)
        opaqueShadow.setFill()
        rectanglePath.fill()
        context?.endTransparencyLayer()
        context?.endTransparencyLayer() //这句不多余
        context?.restoreGState()
    }
}

调用示例：

import UIKit

class InnerShadowViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
        
        //使用
        let shadowView_1 = InnerShadowView(frame: CGRect(x: 100, y: 100, width: 200, height: 200))
        shadowView_1.backgroundColor = UIColor.white
        shadowView_1.layer.cornerRadius = 100
        shadowView_1.clipsToBounds = true
        shadowView_1.layer.shadowColor = UIColor.black.cgColor
        shadowView_1.layer.shadowOffset = CGSize(width: 5, height: 5)
        shadowView_1.layer.shadowRadius = 20
        self.view.addSubview(shadowView_1)
        
        let shadowView_2 = InnerShadowView(frame: CGRect(x: 100, y: 333, width: 200, height: 200))
        shadowView_2.backgroundColor = UIColor.white
        shadowView_2.layer.shadowColor = UIColor.black.cgColor
        shadowView_2.layer.shadowOffset = CGSize(width: 0, height: 0)
        shadowView_2.layer.shadowRadius = 20
        self.view.addSubview(shadowView_2)

        let shadowView_3 = InnerShadowView(frame: CGRect(x: 100, y: 600, width: 200, height: 100))
        shadowView_3.backgroundColor = UIColor.white
        shadowView_3.layer.cornerRadius = 50
        shadowView_3.clipsToBounds = true
        shadowView_3.layer.shadowColor = UIColor.black.cgColor
        shadowView_3.layer.shadowOffset = CGSize(width: 0, height: 0)
        shadowView_3.layer.shadowRadius = 20
        self.view.addSubview(shadowView_3)
    }
}

结语

有待改进，设置阴影的透明度。