注意

在iOS中訪問(wèn)相冊(cè)，首先我們得獲取用戶(hù)授權(quán)，在iOS10之前不用再I(mǎi)nfo.plist寫(xiě)參數(shù)。
在iOS10 之后要自定義彈出的信息

Privacy - Photo Library Usage Description
Privacy - Camera Usage Description

獲取權(quán)限

    /// 獲取權(quán)限
    ///
    /// - Parameter accessBlock:  閉包回調(diào)
    func accessCameraAuthority(accessBlock:AccessBlock!)
    {
        let authStatus = AVCaptureDevice.authorizationStatus(forMediaType: AVMediaTypeVideo)
        if authStatus == AVAuthorizationStatus.notDetermined {
            // 請(qǐng)求授權(quán)
            AVCaptureDevice.requestAccess(forMediaType: AVMediaTypeAudio, completionHandler: { finish in
                if finish {
                    if (accessBlock) != nil
                    {
                        accessBlock(true)
                    }
                }
                else
                {
                    if (accessBlock) != nil
                    {
                        accessBlock(false)
                    }
                }
            })
        }
        else if authStatus == AVAuthorizationStatus.authorized
        {
            // 授權(quán)成功
            if (accessBlock) != nil
            {
                accessBlock(true)
            }
        }
        else
        {
            // 用戶(hù)拒絕授權(quán)
            if (accessBlock) != nil
            {
                accessBlock(false)
            }
        }
    }

當(dāng)返回true，我們就可以有訪問(wèn)權(quán)限了。
在iOS中截屏的方法如下：

    /// 截屏
    ///
    /// - Parameters:
    ///   - view: 要截屏的view
    /// - Returns: 一個(gè)UIImage
    func cutImageWithView(view:UIView) -> UIImage
    {
        // 參數(shù)①：截屏區(qū)域  參數(shù)②：是否透明  參數(shù)③：清晰度
        UIGraphicsBeginImageContextWithOptions(view.frame.size, true, UIScreen.main.scale)
        view.layer.render(in: UIGraphicsGetCurrentContext()!)
        let image:UIImage = UIGraphicsGetImageFromCurrentImageContext()!
        UIGraphicsEndImageContext();
        return image;
    }

這個(gè)方法是獲取當(dāng)前view的內(nèi)容，size的大小要巧妙的設(shè)置，比如你的view超出了看到的屏幕，你使用截圖下來(lái)，
就是一部分回事黑色的區(qū)域。你截取當(dāng)前能看到的，就widow就可以了。
我們?cè)谑褂煤芏郃PP的時(shí)候會(huì)截出很長(zhǎng)的圖，這個(gè)時(shí)候我們就用巧取得方式來(lái)獲取，方法如下：

     /// 截屏
    ///
    /// - Parameters:
    ///   - view: 要截屏的view
    /// - Returns: 一個(gè)UIImage
    func cutFullImageWithView(scrollView:UIScrollView) -> UIImage
    {
        // 記錄當(dāng)前的scrollView的偏移量和坐標(biāo)
        let currentContentOffSet:CGPoint = scrollView.contentOffset
        let currentFrame:CGRect = scrollView.frame;
        
        // 設(shè)置為zero和相應(yīng)的坐標(biāo)
        scrollView.contentOffset = CGPoint.zero
        scrollView.frame = CGRect.init(x: 0, y: 0, width: scrollView.frame.size.width, height: scrollView.frame.size.height)
        
        // 參數(shù)①：截屏區(qū)域  參數(shù)②：是否透明  參數(shù)③：清晰度
        UIGraphicsBeginImageContextWithOptions(scrollView.contentSize, true, UIScreen.main.scale)
        scrollView.layer.render(in: UIGraphicsGetCurrentContext()!)
        let image:UIImage = UIGraphicsGetImageFromCurrentImageContext()!
        
        // 重新設(shè)置原來(lái)的參數(shù)
        scrollView.contentOffset = currentContentOffSet
        scrollView.frame = currentFrame
        
        UIGraphicsEndImageContext();
        
        return image;
    }

這里是保證他是scrllView，來(lái)切換相應(yīng)的offset和frame，來(lái)截取屏幕。有一點(diǎn)要注意，比如你的是tableView，下面的數(shù)據(jù)中的圖片沒(méi)有加載出來(lái)，也是肯定不會(huì)顯示的。
接下來(lái)就是把截圖保存到相冊(cè)，下面是保存到系統(tǒng)相冊(cè)：

    func writeImageToAlbum(image:UIImage)
    {
        UIImageWriteToSavedPhotosAlbum(image, self, #selector(image(image:didFinishSavingWithError:contextInfo:)), nil)
    }
    
    func image(image: UIImage, didFinishSavingWithError error: NSError?, contextInfo:UnsafeRawPointer)
    {
        if let e = error as NSError?
        {
            print(e)
        }
        else
        {
            UIAlertController.init(title: nil,
                                   message: "保存成功！",
                                   preferredStyle: UIAlertControllerStyle.alert).show(self, sender: nil);
        }
    }

寫(xiě)入到指定的相冊(cè)，這里看到的是先寫(xiě)入相冊(cè)，再移動(dòng)到指定的相冊(cè)

       // 看有沒(méi)有指定的相冊(cè)
        let library = ALAssetsLibrary.init()
        let albumGroups = NSMutableArray()
        
        library.enumerateGroups(withTypes: ALAssetsGroupType(ALAssetsGroupAll), using:
            {
                oneGroup,pointer in
                albumGroups.add(oneGroup! as ALAssetsGroup)
        },
                                failureBlock:
            {
                error in
        })
        
        var haveCustomAlbum = false
        for albumGroup in albumGroups
        {
            let groupName:String = (albumGroup as! ALAssetsGroup).value(forProperty: ALAssetsGroupPropertyName) as! String
            print(groupName)
            if groupName == "指定相冊(cè)"
            {
                haveCustomAlbum = true
            }
        }

如果有指定相冊(cè)直接寫(xiě)入沒(méi)有就去創(chuàng)建

// 這里是創(chuàng)建相冊(cè)
if !haveCustomAlbum
        {
            library.addAssetsGroupAlbum(withName: "指定相冊(cè)",
                                        resultBlock:
                {alAsetGroup in
                    if alAsetGroup != nil
                    {
                        print("創(chuàng)建相冊(cè)成功");
                    }
            },
                                        failureBlock:
                {error in
                    print("創(chuàng)建相冊(cè)失敗");
            })
        }

下面是寫(xiě)入到指定的相冊(cè)，下面的image，group和library都是上面獲取到的

func writeImageToCustomAlbumFinish(image:UIImage,library:ALAssetsLibrary,alAsetGroup:ALAssetsGroup)
    {
        // 首先寫(xiě)入到寫(xiě)到相冊(cè) 這里也可以用PHPhotoLibrary來(lái)做
        library.writeImage(toSavedPhotosAlbum: image.cgImage, orientation:.up, completionBlock:
            { url,error in
                if (error != nil)
                {
                    // 取到asset
                    library.asset(for: url, resultBlock:
                        {
                            aAlAset in
                            if aAlAset != nil
                            {
                                // 添加到group
                                alAsetGroup.add(aAlAset)
                            }
                    },
                                  failureBlock:
                        {
                            error in
                    })
                }
        })
    }

拼圖

func combinTwoImage(image1:UIImage,image2:UIImage) -> UIImage
    {
        let width = max(image1.size.width, image2.size.width)
        let height = image1.size.height + image2.size.height
        let offScreenSize = CGSize.init(width: width, height: height)
        
        UIGraphicsBeginImageContext(offScreenSize);
        
        let rect = CGRect.init(x:0, y:0, width:width, height:image1.size.height)
        image1.draw(in: rect)
        
        let rect2 = CGRect.init(x:0, y:image1.size.height, width:width, height:image2.size.height)
        image1.draw(in: rect2)
        
        let image:UIImage = UIGraphicsGetImageFromCurrentImageContext()!
        
        UIGraphicsEndImageContext();
        
        return image;
    }