如何在将文档加载到文档查看器之前使用Bates Stamp将水印添加到文档中

附件是一个用JS和C＃编写的VS2017项目，允许用户在使用Bates Stamp Annotation加载文档之前对其进行水印：
https://www.leadtools.com/help/l ... /annbatesstamp.html
https://www.leadtools.com/help/l ... sstampcomposer.html

该项目正在使用Document Viewer Demo的DocumentService的修改版本，以及Document Viewer演示中随附的Tutorial1项目的修改版本。

要运行此项目，请从安装中下载并将其解压缩到此文件夹：
C：\ LEADTOOLS 19 \ Examples \ JS \ Documents

运行结果截图


以下是相关代码：

在DocumentsService的FactoryController.cs文件中，我添加了一个新的接口URI的POST方法。 该方法将使用URI并创建一个水印图像，并将其保存到文档查看器缓存中，然后将客户端返回给DocumentCache ID，然后将其称为Document Factory的LoadFromCache方法。

服务控制器代码：

1. [HttpPost]
   
2. public string ApplyWatermark(Uri uri)
   
3. {
   
4.    string documentId = "";
   
5. 
   
6.    using (RasterCodecs codecs = new RasterCodecs())
   
7.    using (WebClient client = new WebClient())
   
8.    {
   
9.       var bytes = client.DownloadData(uri.ToString());
   
10.       using (MemoryStream ms = new MemoryStream(bytes))
    
11.       {
    
12.          ms.Position = 0;
    
13.          codecs.Options.Load.AllPages = true;
    
14.          using (RasterImage image = codecs.Load(ms))
    
15.          using (RasterImage watermarkImage = AddWatermark(image))
    
16.          {
    
17.             using (MemoryStream outputStream = new MemoryStream())
    
18.             {
    
19.                codecs.Save(watermarkImage, outputStream, RasterImageFormat.RasPdfJpeg411, 24);
    
20.                var loadOptions = new LoadDocumentOptions()
    
21.                {
    
22.                   Cache = ServiceHelper.Cache,
    
23.                   CachePolicy = ServiceHelper.CreatePolicy(),
    
24.                   MimeType = "application/pdf"
    
25.                };
    
26.                using (var document = DocumentFactory.LoadFromStream(outputStream, loadOptions))
    
27.                {
    
28.                   document.AutoDeleteFromCache = false;
    
29.                   documentId = document.DocumentId;
    
30.                   document.SaveToCache();
    
31.                }
    
32.             }
    
33.          }
    
34.       }
    
35.    }
    
36. 
    
37.    return documentId;
    
38. }

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以下是使用Bates Stamping将水印应用于RasterImage的每个页面的相关代码：

1. private RasterImage AddWatermark(RasterImage image)
   
2. {
   
3.    using (AnnBatesStampComposer batesStampComposer = new AnnBatesStampComposer())
   
4.    {
   
5.       AnnBatesStampComposer.RenderingEngine = new AnnWinFormsRenderingEngine();
   
6.       AnnContainer batesStampContainer = new AnnContainer();
   
7.       batesStampContainer.Mapper.MapResolutions(image.XResolution, image.YResolution, image.XResolution, image.YResolution);
   
8.       batesStampContainer.Size = batesStampContainer.Mapper.SizeToContainerCoordinates(LeadSizeD.Create(image.Width, image.Height));
   
9. 
   
10.       using (AnnBatesStamp batesStamp = new AnnBatesStamp())
    
11.       {
    
12.          batesStamp.HorizontalAlignment = AnnHorizontalAlignment.Left;
    
13.          batesStamp.VerticalAlignment = AnnVerticalAlignment.Top;
    
14.          batesStamp.Logo.Opacity = 0.5;
    
15.          batesStamp.Logo.Angle = -45;
    
16.          batesStamp.Logo.StretchLogo = true;
    
17. 
    
18.          string imageFile = HostingEnvironment.ApplicationPhysicalPath + "Resources\\Images\\watermark.png";
    
19.          batesStamp.Logo.Picture = new AnnPicture(imageFile);
    
20.          batesStampComposer.Stamps.Add(batesStamp);
    
21.          batesStampComposer.TargetContainers.Add(batesStampContainer);
    
22. 
    
23.          RasterImage watermarkedImage = null;
    
24.          for (int i = 1; i <= image.PageCount; i++)
    
25.          {
    
26.             image.Page = i;
    
27.             if (watermarkedImage == null)
    
28.                watermarkedImage = AnnBatesStampComposer.RenderingEngine.RenderOnImage(batesStampContainer, image).Clone();
    
29.             else
    
30.                watermarkedImage.AddPage(AnnBatesStampComposer.RenderingEngine.RenderOnImage(batesStampContainer, image).Clone());
    
31.          }
    
32.          return watermarkedImage;
    
33.       }
    
34.    }
    
35. }

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这里是客户端的Javascript代码与相关的Ajax调用来调用这个方法：

1. var _this = this;
   
2. var documentViewer = null;
   
3. window.onload = function () {
   
4.     var createOptions = new lt.Documents.UI.DocumentViewerCreateOptions();
   
5.     createOptions.viewCreateOptions.useElements = true;
   
6.     createOptions.thumbnailsCreateOptions.useElements = true;
   
7.     createOptions.thumbnailsContainer = document.getElementById("thumbnails");
   
8.     createOptions.viewContainer = document.getElementById("documentViewer");
   
9.     _this.documentViewer = lt.Documents.UI.DocumentViewerFactory.createDocumentViewer(createOptions);
   
10. 
    
11.     _this.documentViewer.commands.run(lt.Documents.UI.DocumentViewerCommands.interactivePanZoom);
    
12.     _this.documentViewer.view.preferredItemType = lt.Documents.UI.DocumentViewerItemType.svg;
    
13.     _this.documentViewer.thumbnails.imageViewer.viewHorizontalAlignment = lt.Controls.ControlAlignment.center;
    
14. 
    
15.     lt.Documents.DocumentFactory.serviceHost = "http://localhost:19001"; // or wherever your host is
    
16.     lt.Documents.DocumentFactory.servicePath = ""; // the path to the root of the service, which is nothing for this example
    
17.     lt.Documents.DocumentFactory.serviceApiPath = "api"; // Routing occurs at "/api", unless you change the routing in the DocumentsService
    
18. 
    
19.     var url = "http://demo.leadtools.com/images/pdf/leadtools.pdf";
    
20. 
    
21.     $.ajax({
    
22.         type: 'POST',
    
23.         contentType: "application/json; charset=utf-8",
    
24.         url: "http://localhost:19001/api/Factory/ApplyWatermark?uri=" + url,
    
25.         success: function (cacheId) {
    
26.             // Call the "LoadFromUri" and pass success and failure callbacks to the promise
    
27.             lt.Documents.DocumentFactory.loadFromCache(cacheId)
    
28.                 .done(function (document) {
    
29.                 // Set the document in the viewer
    
30.                 documentViewer.setDocument(document);
    
31.             });
    
32.         }
    
33.     });
    
34. };

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