遮罩图像视图 Swift 5答案

【问题标题】：Mask over the image view Swift 5遮罩图像视图 Swift 5
【发布时间】：2021-08-28 10:28:45
【问题描述】：

我一直在尝试使用 Swift 5.2 从 this question 实现 this answer 我只看到模糊的图像并且没有出现蒙版。有人可以指出我在那里缺少什么或如何将其从 Swift 3 转换为 Swift 5 吗？

这是一个游乐场代码。

import UIKit
import PlaygroundSupport

let generalFrame = CGRect(x: 0, y: 0, width: 500, height: 500)
let containerView = UIView(frame: generalFrame)
containerView.backgroundColor = UIColor.black;
PlaygroundPage.current.liveView = containerView

let parentView = UIView(frame: generalFrame)
containerView.addSubview(parentView)
let url = URL(string: "https://static.pexels.com/photos/168066/pexels-photo-168066-large.jpeg")
let data = try Data(contentsOf: url!);
let imageView = UIImageView(frame:parentView.bounds)
imageView.image = UIImage(data: data)
imageView.contentMode = .scaleAspectFill

let maskView = UIView(frame:parentView.bounds)
maskView.backgroundColor = UIColor.black
maskView.layer.mask = {() -> CALayer in
    var  roundedRect = CGRect (
        x: 0.0,
        y: 0.0,
        width: parentView.bounds.size.width * 0.5,
        height: parentView.bounds.size.width * 0.5
    );
    roundedRect.origin.x = parentView.frame.size.width / 2 - roundedRect.size.width / 2;
    roundedRect.origin.y = parentView.frame.size.height / 2 - roundedRect.size.height / 2;
    let cornerRadius = roundedRect.size.height / 2.0;
    let path = UIBezierPath(rect:parentView.bounds)
    let croppedPath = UIBezierPath(roundedRect: roundedRect, cornerRadius: cornerRadius)
    path.append(croppedPath)
    path.usesEvenOddFillRule = true
    let maskLayer = CAShapeLayer()
    maskLayer.path = path.cgPath;
    maskLayer.fillRule = CAShapeLayerFillRule.evenOdd
    return maskLayer
}()

let blurView = UIBlurEffect(style: .light)
let effectView = UIVisualEffectView(effect: blurView)

effectView.frame = generalFrame
effectView.mask = maskView

parentView.addSubview(imageView)
parentView.addSubview(effectView)

【问题讨论】：

标签： ios swift3 swift5

【解决方案1】：

我设法让这个工作。修复方法是对 UIVisualEffectView 应用掩码：

let maskLayer = CAShapeLayer()
effectView.layer.mask = maskLayer


import UIKit
import PlaygroundSupport

let generalFrame = CGRect(x: 0, y: 0, width: 500, height: 500)
let containerView = UIView(frame: generalFrame)
containerView.backgroundColor = UIColor.black;
PlaygroundPage.current.liveView = containerView

let parentView = UIView(frame: generalFrame)
containerView.addSubview(parentView)

let url = URL(string: "https://static.pexels.com/photos/168066/pexels-photo-168066-large.jpeg")
let data = try Data(contentsOf: url!);
let imageView = UIImageView(frame:parentView.bounds)

imageView.image = UIImage(data: data)
imageView.contentMode = .scaleAspectFill

var roundedRect = CGRect (
    x: 0.0,
    y: 0.0,
    width: parentView.bounds.size.width * 0.5,
    height: parentView.bounds.size.width * 0.5
);
roundedRect.origin.x = parentView.frame.size.width / 2 - roundedRect.size.width / 2;
roundedRect.origin.y = parentView.frame.size.height / 2 - roundedRect.size.height / 2;
let cornerRadius = roundedRect.size.height / 2.0;
let path = UIBezierPath(rect:parentView.bounds)
let croppedPath = UIBezierPath(roundedRect: roundedRect, cornerRadius: cornerRadius)
path.append(croppedPath)
path.usesEvenOddFillRule = true

let maskLayer = CAShapeLayer()
maskLayer.path = path.cgPath;
maskLayer.fillRule = CAShapeLayerFillRule.evenOdd

let blurView = UIBlurEffect(style: .light)
let effectView = UIVisualEffectView(effect: blurView)
effectView.frame = generalFrame
effectView.layer.mask = maskLayer

parentView.addSubview(imageView)
parentView.addSubview(effectView)

【讨论】：