iOS实现简单长截图

素材狗 2023-03-30 23:00:01 文章分类：移动开发点击数：6次

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这篇文章主要为大家详细介绍了iOS实现简单长截图，文中示例代码介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们可以参考一下

本文实例为大家分享了iOS实现简易的长截图的具体代码，供大家参考，具体内容如下

长截图的实现原理：

实际上是将view的内容绘制成图片，再将各个view绘制出来的图片拼接出来。

具体代码：

将view绘制成图片

func getImage(in view:UIView?) -> UIImage? {
    guard let view = view else {return nil}
    let size = view.bounds.size
    UIGraphicsBeginImageContextWithOptions(size, false, UIScreen.main.scale)
    view.layer.render(in: UIGraphicsGetCurrentContext()!)
    view.layer.contents = nil
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image
}

1.绘制状态栏

// 先获取状态栏view
func getStatusBar() -> UIView? {
    if Float(UIDevice.current.systemVersion)! >= 13 {
        guard let statusBarManager = UIApplication.shared.keyWindow?.windowScene?.statusBarManager,
              let localStatusBar = statusBarManager.value(forKey: "createLocalStatusBar") as? NSObject,
              let statusBar = localStatusBar.value(forKey: "statusBar") as? UIView else {return nil}
        return statusBar
    } else {
        guard let statusBarWindow = UIApplication.shared.value(forKey: "statusBarWindow") as? UIWindow  else {return nil}
        let statusBar = statusBarWindow.value(forKey: "statusBar") as? UIView
        return statusBar
    }
}

// 再绘制成图片
let statusBarImage = getImage(in: getStatusBar())

2.绘制导航栏(如果有的话)

if let nav = vc.navigationController { // 表示有导航栏
    let navBar = nav.navigationBar
    let navBarImage = getImage(in: navBar)
}

在某些情况下，如自定义的导航栏，则需要另外自行获取view再来绘制

3.绘制ScrollView

绘制scrollview长图的时候，如果直接绘制的话，那么得到的图片就是scrollview的frame.size大小的图片，而没有滚动到的地方则不会绘制进去，所以要先将scrollview的size变成和contentSize一样

func getScrollViewImage(scrollView:UIScrollView?) -> UIImage? {
    if let scroll = scrollView {
        let saveOffset = scroll.contentOffset // 保存偏移量，用于绘制图片完成后还原
        let saveFrame = scroll.frame // 保存frame
        scroll.contentOffset = CGPoint.zero
        scroll.frame = CGRect(origin: saveFrame.origin, size: scroll.contentSize) // 设置size和contentSize一致
        
        UIGraphicsBeginImageContext(scroll.frame.size)
        UIGraphicsBeginImageContextWithOptions(CGSize(width: scroll.frame.size.width, height: scroll.frame.size.height), false, UIScreen.main.scale)
        scroll.layer.render(in: UIGraphicsGetCurrentContext()!)
        let scrollImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        
        scroll.contentOffset = saveOffset // 还原偏移量，否则绘制图片之后，scrollview偏移量不正确
        scroll.frame = saveFrame // 还原frame
        return scrollImage
    }
    return nil
}

到这里，其实最难的一步已经完成了，但是这个方法也不是完美的。当这个scrollview添加到父视图的时候是添加约束的方式来确定大小和位置的时候，使用这个方法绘制出来的图片大小没有问题，但是内容却可能只有屏幕上显示出来的部分多一点，其他部分是空白。具体原因我也不太清楚，只要在绘制成图片之前将约束移除，绘制之后再添加回来

func getScrollViewImage(scrollView:UIScrollView?) -> UIImage? {
    if let scroll = scrollView {
        let saveOffset = scroll.contentOffset // 保存偏移量，用于绘制图片完成后还原
        let saveFrame = scroll.frame // 保存frame
        scroll.contentOffset = CGPoint.zero
        scroll.frame = CGRect(origin: saveFrame.origin, size: scroll.contentSize) // 设置size和contentSize一致
        let layouts = scroll.superview!.constraints // 获取的是scrollview的父容器的约束，这才是约束scrollview大小和位置的正确约束
        scroll.superview?.removeConstraints(layouts)
        
        UIGraphicsBeginImageContext(scroll.frame.size)
        UIGraphicsBeginImageContextWithOptions(CGSize(width: scroll.frame.size.width, height: scroll.frame.size.height), false, UIScreen.main.scale)
        scroll.layer.render(in: UIGraphicsGetCurrentContext()!)
        let scrollImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        
        scroll.contentOffset = saveOffset // 还原偏移量，否则绘制图片之后，scrollview偏移量不正确
        scroll.frame = saveFrame // 还原frame
        scroll.superview?.addConstraints(layouts) // 还原约束
        return scrollImage
    }
    return nil
}

如果项目中集成了SnapKit的话可以用其给scrollview重新设置约束，绘制图片结束后在还原也可以

func getScrollViewImage(scrollView:UIScrollView?) -> UIImage? {
    if let scroll = scrollView {
        
        // ......

        let layouts = scroll.superview!.constraints // 获取的是scrollview的父容器的约束，这才是约束scrollview大小和位置的正确约束
        scroll.snp.remakeConstraints { (make) in
            make.top.left.right.equalTo(0)
            make.height.equalTo(scroll.contentSize.height)
        }
        
        // ...... 
        
        scroll.snp.removeConstraints()
        scroll.superview?.addConstraints(layouts) // 还原约束
        
        return scrollImage
    }
    return nil
}

4.拼接图片

已经得到了所需要的各个部分的元素，这里按照上下位置将其拼接起来

func combineImages(with upImage:UIImage?, and downImage:UIImage?) -> UIImage? {
    if upImage == nil {
        return downImage
    }
    if downImage == nil {
        return upImage
    }
    guard let up = upImage,
          let down = downImage else {return nil}
    let size = CGSize(width: up.size.width, height: up.size.height + down.size.height)
    UIGraphicsBeginImageContextWithOptions(size, false, UIScreen.main.scale)
    
    let upRect = CGRect(origin: CGPoint(x: 0, y: 0), size: up.size)
    up.draw(in: upRect)
    let downRect = CGRect(x: (up.size.width - down.size.width) / 2, y: upRect.origin.y + upRect.size.height, width: down.size.width, height: down.size.height)
    down.draw(in: downRect)
    
    let result = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return result
}