iOS - 镂空、裁剪效果实现

裁剪部分区域

利用 mask view 实现，遮罩层实现

裁剪

• UIView 实现

        // img_w: 原始图片宽度
        // img_h: 原始图片高度
        let cutView = UIView.init(frame: CGRect.init(x: 0,
                                                     y: 0,
                                                     width: img_w * 0.5,
                                                     height: img_h * 0.5))
        // 这里需要有一个颜色，不能为透明
        cutView.backgroundColor = .red
        imageView.mask = cutView

• CALayer 实现

        // img_w: 原始图片宽度
        // img_h: 原始图片高度
        let cutView = CALayer.init()
        cutView.frame = CGRect.init(x: 0,
                                                     y: 0,
                                                     width: img_w * 0.5,
                                                     height: img_h * 0.5)
        cutView.backgroundColor = UIColor.red.cgColor
        imageView.layer.mask = cutView

镂空部分区域

使用 CAShapeLayer 实现

镂空

        let shapeLayer = CAShapeLayer.init()

        // maskPath: 为黑色方形蒙版路径
        // hollowOutPath: 为黑色蒙版中间镂空的圆形路径
        let shapeLayer = CAShapeLayer.init()
        let maskPath = UIBezierPath.init(rect: CGRect.init(x: 20, y: 20, width: img_w - 40, height: img_h - 40))
        let hollowOutPath = UIBezierPath.init(arcCenter: CGPoint.init(x: img_w * 0.5, y: img_h * 0.5),
                                           radius: img_w * 0.5 * 0.5 * 0.5,
                                           startAngle: 0,
                                           endAngle: 2 * CGFloat(Double.pi),
                                           clockwise: true)
        maskPath.append(hollowOutPath)

        maskPath.usesEvenOddFillRule = true
        shapeLayer.fillRule = .evenOdd
        // 蒙版的颜色
        shapeLayer.fillColor = UIColor.black.withAlphaComponent(0.6).cgColor
        shapeLayer.path = maskPath.cgPath

        let maskView = UIView.init(frame: CGRect.init(x: 0, y: 0, width: img_w, height: img_h))
        maskView.layer.addSublayer(shapeLayer)

        imageView.addSubview(maskView)