DocumentViewerView Object

Summary

Manages the main content view in this document viewer.

Syntax
TypeScript
JavaScript
function lt.Document.Viewer.DocumentViewerView 
	implements IDisposable 
class lt.Document.Viewer.DocumentViewerView() 
	implements IDisposable 

Remarks

The DocumentViewerView object can be accessed by the DocumentViewer.View property.

This class manages the main content to view the pages of the current LEADDocument set in the document viewer.

The class creates an instance of ImageViewer for viewing the pages. Virtualization is used to load and cache the image data to keep the application user interface responsive, support documents with a large number of pages, and minimize the resources used. Both raster and SVG viewing modes are supported.

The class also handles the user's page interactions, such as the pan, zoom, and magnify interactive modes; inertia scrolling, page layouts and fit modes, and annotation container rendering.

When the Document Viewer is Created

  1. A new instance of DocumentViewerView is created and set in the DocumentViewer.View property.

  2. A new instance of the ImageViewer control is created and added as a child control to DocumentViewerCreateOptions.ViewContainer. This image viewer will be used to view the Raster or SVG image data of the pages when a LEADDocument is set in the viewer. This control can be accessed by using the ImageViewer property of this class. Refer to the property for information on how this ImageViewer is initialized.

  3. The interactive modes are initialized and added to ImageViewer.InteractiveModes.

When the Document Viewer is Destroyed

  1. The ImageViewer control is removed from the parent DocumentViewerCreateOptions.ThumbnailsContainer container.

  2. All resources are freed.

When a new Document is Set

The following behavior occurs when a new LEADDocument object is set in the DocumentViewer object using the DocumentViewer.SetDocument method. Behavior depends on the conditions under which the LEADDocument object is set.

  • If a previous document was set in the document viewer

  • If the new document set is null (the application just closed this document), then no further action is required.

  • If a new document is being set, then the following behavior occurs

    • PreferredItemType is checked, and if SVG viewing is requested, then DocumentImages.IsSvgViewingPreferred is checked and ItemType is updated accordingly.

    • An ImageViewerItem is created for each page in the document. The value of ImageViewerItem.ImageSize is set to the value of DocumentPage.Size of each page. The item is "empty" and does not contain image data. This is updated in the next step.

    • An internal worker handles the loading and caching of the image data of the pages in the background to keep the user interface of the application responsive. This worker is also used to minimize the resources used when loading a document with a large amount of image data and a large number of pages by prioritizing loading the data for visible pages while discarding the data for pages that are no longer used.

    • The Operation event occurs while the virtualizer is loading and discarding image data, and when rendering place holders for pages that do not have their data loaded yet. Refer to Document Viewer Operations for more information on the specific details and how to customize the behavior.

Commands

The DocumentViewerView Object handles the following commands:

  • All interactive modes are added to the ImageViewer created by this part. This includes panning, zooming, and magnifying glass operations as well as the page links, annotations, and text selection modes.

  • Multiple ImageViewerViewLayout objects such as single, vertical, double, and horizontal are created and can be used by the view.

  • Rendering of the image data of the pages as well as the current text selection and annotation container rendering.

Refer to Document Viewer Commands and Document Viewer Operations for more information on the above and how to set and customize the behavior.

Example

In this example, clicking the example button will add a callback for the render of each document page to draw the page number over the document page image.

View.ts
ViewerInitializer.ts
View.js
ViewerInitializer.js
View.html
examples.css
import { ViewerInitializer } from "../utilities/ViewerInitializer"; 
 
export class ViewTSExample { 
   public run = () => { 
      new ViewerInitializer(this.addViewHook); 
   } 
 
   addViewHook = (documentViewer: lt.Document.Viewer.DocumentViewer) => { 
      // Get the view 
      const view = documentViewer.view; 
      // Get its image viewer 
      const imageViewer = view.imageViewer; 
 
      // Hook to the PostRender 
      imageViewer.postRenderItem.add((sender, e) => { 
         // Get the image viewer item for the page 
         const item = e.item; 
 
         // Build the text we want. The page number is the item index + 1 
         const pageNumber = imageViewer.items.indexOf(item) + 1; 
         const text = "Page " + pageNumber; 
 
         // Get the image transformation for this item 
         const transform = imageViewer.getItemImageTransform(e.item); 
 
         // Apply it to the context 
         const ctx = e.context; 
         ctx.save(); 
         ctx.transform(transform.m11, transform.m12, transform.m21, transform.m22, transform.offsetX, transform.offsetY); 
 
         // Render the text 
         ctx.fillStyle = "red"; 
         ctx.font = "60pt bold Times New Roman"; 
         ctx.fillText(text, 70, 70); 
         ctx.restore(); 
      }); 
 
      // Invalidate so our changes take effect the first time 
      view.invalidate(lt.LeadRectD.empty); 
   } 
} 
export class ViewerInitializer { 
   private callback: (viewer: lt.Document.Viewer.DocumentViewer) => void = null; 
 
   constructor(callback?: (viewer: lt.Document.Viewer.DocumentViewer) => void) { 
      this.callback = callback; 
      this.init(); 
   } 
 
   public static showServiceError = (jqXHR, statusText, errorThrown) => { 
      alert('Error returned from service. See the console for details.') 
      const serviceError = lt.Document.ServiceError.parseError(jqXHR, statusText, errorThrown); 
      console.error(serviceError); 
   } 
 
   private init = () => { 
      this.initFactory(); 
      this.testConnection(); 
   } 
 
   private initFactory = () => { 
      lt.RasterSupport.setLicenseUri('https://demo.leadtools.com/licenses/v200/LEADTOOLSEVAL.txt', 'EVAL', null); 
 
      // To communicate with the DocumentsService, it must be running! 
      // Change these parameters to match the path to the service. 
      lt.Document.DocumentFactory.serviceHost = 'http://localhost:40000'; 
      lt.Document.DocumentFactory.servicePath = ''; 
      lt.Document.DocumentFactory.serviceApiPath = 'api'; 
   } 
 
   private testConnection = () => { 
      const serviceStatus = document.getElementById('serviceStatus'); 
      serviceStatus.innerHTML = 'Connecting to service: ' + lt.Document.DocumentFactory.serviceUri; 
 
      lt.Document.DocumentFactory.verifyService() 
         .done((serviceData) => { 
            serviceStatus.innerHTML = 'Service connection verified!'; 
            this.createDocumentViewer(); 
         }) 
         .fail((jqXHR, statusText, errorThrown) => { 
            serviceStatus.innerHTML = 'Service connection unavailable.'; 
            ViewerInitializer.showServiceError(jqXHR, statusText, errorThrown); 
         }); 
   } 
 
   private createDocumentViewer = () => { 
      // Initialize the user interface 
      const interactiveSelect = document.getElementById('interactiveSelect'); 
 
      const panZoomOption = document.createElement('option'); 
      panZoomOption.innerHTML = 'Pan / Zoom'; 
      panZoomOption.value = lt.Document.Viewer.DocumentViewerCommands.interactivePanZoom; 
      interactiveSelect.appendChild(panZoomOption); 
 
      const textOption = document.createElement('option'); 
      textOption.value = lt.Document.Viewer.DocumentViewerCommands.interactiveSelectText; 
      textOption.innerHTML = 'Select Text'; 
      interactiveSelect.appendChild(textOption); 
 
      let documentViewer: lt.Document.Viewer.DocumentViewer = null; 
      interactiveSelect.onchange = (e) => documentViewer.commands.run((e.target as HTMLSelectElement).value, null); 
 
      const annotationsSelect = document.getElementById('annotationsSelect'); 
 
      const annSelectOption = document.createElement('option'); 
      annSelectOption.innerHTML = 'Select Annotation'; 
      annSelectOption.value = lt.Annotations.Engine.AnnObject.selectObjectId.toString(); 
      annotationsSelect.appendChild(annSelectOption); 
 
      const annLineOption = document.createElement('option'); 
      annLineOption.innerHTML = 'Line Object'; 
      annLineOption.value = lt.Annotations.Engine.AnnObject.lineObjectId.toString(); 
      annotationsSelect.appendChild(annLineOption); 
 
      const annRectOption = document.createElement('option'); 
      annRectOption.innerHTML = 'Rectangle Object'; 
      annRectOption.value = lt.Annotations.Engine.AnnObject.rectangleObjectId.toString(); 
      annotationsSelect.appendChild(annRectOption); 
      annotationsSelect.onchange = (e) => { 
         const value = +(e.currentTarget as HTMLSelectElement).value; 
         documentViewer.annotations.automationManager.currentObjectId = value; 
      } 
 
      // Init the document viewer, pass along the panels 
      const createOptions = new lt.Document.Viewer.DocumentViewerCreateOptions(); 
      // We are not going to use elements mode in this example 
      createOptions.viewCreateOptions.useElements = false; 
      createOptions.thumbnailsCreateOptions.useElements = false; 
 
      // The middle panel for the view 
      createOptions.viewContainer = document.getElementById('viewer'); 
      // The left panel for the thumbnails 
      createOptions.thumbnailsContainer = document.getElementById('thumbnails'); 
      // The right panel is for bookmarks 
      createOptions.bookmarksContainer = document.getElementById('bookmarks'); 
      createOptions.useAnnotations = true; 
 
      // Create the document viewer 
      documentViewer = lt.Document.Viewer.DocumentViewerFactory.createDocumentViewer(createOptions); 
 
      // We prefer SVG viewing 
      documentViewer.view.preferredItemType = lt.Document.Viewer.DocumentViewerItemType.svg; 
 
      // Create html5 rendering engine 
      documentViewer.annotations.automationManager.renderingEngine = new lt.Annotations.Rendering.AnnHtml5RenderingEngine(); 
      // Initialize documentViewer annotations 
      documentViewer.annotations.initialize(); 
 
      documentViewer.annotations.automationManager.currentObjectIdChanged.add(function (sender, e) { 
         // When done drawing, the manager will return to the select object; so we need force the annotationsSelect element to return to the select object option 
         (annotationsSelect as HTMLSelectElement).value = sender.currentObjectId; 
      }); 
 
      this.loadDefaultDoc(documentViewer, interactiveSelect as HTMLSelectElement) 
   } 
 
   private loadDefaultDoc = (viewer: lt.Document.Viewer.DocumentViewer, interactiveSelect: HTMLSelectElement) => { 
      // Load a PDF document 
      const url = 'https://demo.leadtools.com/images/pdf/leadtools.pdf'; 
      lt.Document.DocumentFactory.loadFromUri(url, null) 
         .done((doc: lt.Document.LEADDocument) => { 
            const ready = () => { 
               viewer.setDocument(doc); 
               const panZoom = lt.Document.Viewer.DocumentViewerCommands.interactivePanZoom; 
               interactiveSelect.value = panZoom; 
               viewer.commands.run(panZoom, null); 
               if(this.callback) 
                  this.callback(viewer); 
            } 
 
            if (doc.isStructureSupported && !doc.structure.isParsed) 
               doc.structure.parse() 
                  .done(ready) 
                  .fail(ViewerInitializer.showServiceError); 
            else 
               ready(); 
         }) 
         .fail(ViewerInitializer.showServiceError); 
   } 
} 
import { ViewerInitializer } from "../utilities/ViewerInitializer"; 
 
export class ViewJSExample { 
   constructor() { } 
 
   run = () => { 
      new ViewerInitializer(this.addViewHook); 
   } 
 
   addViewHook = (documentViewer) => { 
      // Get the view 
      const view = documentViewer.view; 
      // Get its image viewer 
      const imageViewer = view.imageViewer; 
 
      // Hook to the PostRender 
      imageViewer.postRenderItem.add(function (sender, e) { 
         // Get the image viewer item for the page 
         const item = e.item; 
 
         // Build the text we want. The page number is the item index + 1 
         const pageNumber = imageViewer.items.indexOf(item) + 1; 
         const text = "Page " + pageNumber; 
 
         // Get the image transformation for this item 
         const transform = imageViewer.getItemImageTransform(e.item); 
 
         // Apply it to the context 
         const ctx = e.context; 
         ctx.save(); 
         ctx.transform(transform.m11, transform.m12, transform.m21, transform.m22, transform.offsetX, transform.offsetY); 
 
         // Render the text 
         ctx.fillStyle = "red"; 
         ctx.font = "60pt bold Times New Roman"; 
         ctx.fillText(text, 70, 70); 
         ctx.restore(); 
      }); 
 
      // Invalidate so our changes take effect the first time 
      view.invalidate(lt.LeadRectD.empty); 
   } 
} 
export class ViewerInitializer { 
   constructor(callback) { 
      this.callback = callback; 
      this.init(); 
   } 
 
   static showServiceError = (jqXHR, statusText, errorThrown) => { 
      alert("Error returned from service. See the console for details.") 
      const serviceError = lt.Document.ServiceError.parseError(jqXHR, statusText, errorThrown); 
      console.error(serviceError); 
   } 
 
   init = () => { 
      this.initFactory(); 
      this.testConnection(); 
   } 
 
   initFactory = () => { 
      lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/v200/LEADTOOLSEVAL.txt", "EVAL", null); 
 
      // To communicate with the DocumentsService, it must be running! 
      // Change these parameters to match the path to the service. 
      lt.Document.DocumentFactory.serviceHost = "http://localhost:40000"; 
      lt.Document.DocumentFactory.servicePath = ""; 
      lt.Document.DocumentFactory.serviceApiPath = "api"; 
   } 
 
   testConnection = () => { 
      const serviceStatus = document.getElementById("serviceStatus"); 
      serviceStatus.innerHTML = "Connecting to service: " + lt.Document.DocumentFactory.serviceUri; 
 
      lt.Document.DocumentFactory.verifyService() 
         .done((serviceData) => { 
            serviceStatus.innerHTML = "Service connection verified!"; 
            this.createDocumentViewer(); 
         }) 
         .fail((jqXHR, statusText, errorThrown) => { 
            serviceStatus.innerHTML = "Service connection unavailable."; 
            ViewerInitializer.showServiceError(jqXHR, statusText, errorThrown); 
         }); 
   } 
 
   createDocumentViewer = () => { 
      // Initialize the user interface 
      const interactiveSelect = document.getElementById("interactiveSelect"); 
 
      const panZoomOption = document.createElement("option"); 
      panZoomOption.innerHTML = "Pan / Zoom"; 
      panZoomOption.value = lt.Document.Viewer.DocumentViewerCommands.interactivePanZoom; 
      interactiveSelect.appendChild(panZoomOption); 
 
      const textOption = document.createElement("option"); 
      textOption.value = lt.Document.Viewer.DocumentViewerCommands.interactiveSelectText; 
      textOption.innerHTML = "Select Text"; 
      interactiveSelect.appendChild(textOption); 
 
      let documentViewer = null; 
      interactiveSelect.onchange = (e) => documentViewer.commands.run(e.target.value, null); 
 
      const annotationsSelect = document.getElementById("annotationsSelect"); 
 
      const annSelectOption = document.createElement("option"); 
      annSelectOption.innerHTML = "Select Annotation"; 
      annSelectOption.value = lt.Annotations.Engine.AnnObject.selectObjectId.toString(); 
      annotationsSelect.appendChild(annSelectOption); 
 
      const annLineOption = document.createElement("option"); 
      annLineOption.innerHTML = "Line Object"; 
      annLineOption.value = lt.Annotations.Engine.AnnObject.lineObjectId.toString(); 
      annotationsSelect.appendChild(annLineOption); 
 
      const annRectOption = document.createElement("option"); 
      annRectOption.innerHTML = "Rectangle Object"; 
      annRectOption.value = lt.Annotations.Engine.AnnObject.rectangleObjectId.toString(); 
      annotationsSelect.appendChild(annRectOption); 
      annotationsSelect.onchange = (e) => { 
         const value = +e.currentTarget.value; 
         documentViewer.annotations.automationManager.currentObjectId = value; 
      } 
 
      // Init the document viewer, pass along the panels 
      const createOptions = new lt.Document.Viewer.DocumentViewerCreateOptions(); 
      // We are not going to use elements mode in this example 
      createOptions.viewCreateOptions.useElements = false; 
      createOptions.thumbnailsCreateOptions.useElements = false; 
 
      // The middle panel for the view 
      createOptions.viewContainer = document.getElementById("viewer"); 
      // The left panel for the thumbnails 
      createOptions.thumbnailsContainer = document.getElementById("thumbnails"); 
      // The right panel is for bookmarks 
      createOptions.bookmarksContainer = document.getElementById("bookmarks"); 
      createOptions.useAnnotations = true; 
 
      // Create the document viewer 
      documentViewer = lt.Document.Viewer.DocumentViewerFactory.createDocumentViewer(createOptions); 
 
      // We prefer SVG viewing 
      documentViewer.view.preferredItemType = lt.Document.Viewer.DocumentViewerItemType.svg; 
 
      // Create html5 rendering engine 
      documentViewer.annotations.automationManager.renderingEngine = new lt.Annotations.Rendering.AnnHtml5RenderingEngine(); 
      // Initialize documentViewer annotations 
      documentViewer.annotations.initialize(); 
 
      documentViewer.annotations.automationManager.currentObjectIdChanged.add(function (sender, e) { 
         // When done drawing, the manager will return to the select object; so we need force the annotationsSelect element to return to the select object option 
         annotationsSelect.value = sender.currentObjectId; 
      }); 
 
      this.loadDefaultDoc(documentViewer, interactiveSelect) 
   } 
 
   loadDefaultDoc = (viewer, interactiveSelect) => { 
      // Load a PDF document 
      const url = "https://demo.leadtools.com/images/pdf/leadtools.pdf"; 
      lt.Document.DocumentFactory.loadFromUri(url, null) 
         .done((doc) => { 
            const ready = () => { 
               viewer.setDocument(doc); 
               const panZoom = lt.Document.Viewer.DocumentViewerCommands.interactivePanZoom; 
               interactiveSelect.value = panZoom; 
               viewer.commands.run(panZoom, null); 
               if(this.callback) 
                  this.callback(viewer); 
            } 
 
            if (doc.isStructureSupported && !doc.structure.isParsed) 
               doc.structure.parse() 
                  .done(ready) 
                  .fail(ViewerInitializer.showServiceError); 
            else 
               ready(); 
         }) 
         .fail(ViewerInitializer.showServiceError); 
   } 
} 
<!doctype html> 
<html lang="en"> 
<title>DocViewer Example | DocumentViewer</title> 
 
<head> 
   <script src="https://code.jquery.com/jquery-2.2.4.min.js" 
      integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44=" crossorigin="anonymous"></script> 
 
   <script src="../LT/Leadtools.js"></script> 
   <script src="../LT/Leadtools.Controls.js"></script> 
   <script src="../LT/Leadtools.Annotations.Engine.js"></script> 
   <script src="../LT/Leadtools.Annotations.Designers.js"></script> 
   <script src="../LT/Leadtools.Annotations.Rendering.Javascript.js"></script> 
   <script src="../LT/Leadtools.Annotations.Automation.js"></script> 
   <script src="../LT/Leadtools.ImageProcessing.Main.js"></script> 
   <script src="../LT/Leadtools.ImageProcessing.Color.js"></script> 
   <script src="../LT/Leadtools.ImageProcessing.Core.js"></script> 
   <script src="../LT/Leadtools.ImageProcessing.Effects.js"></script> 
   <script src="../LT/Leadtools.Document.js"></script> 
   <script src="../LT/Leadtools.Document.Viewer.js"></script> 
   <link rel="stylesheet" type="text/css" href="../css/examples.css"> 
 
   <!-- All demo files are bundled and appended to the window --> 
   <script src="../bundle.js" type="text/javascript"></script> 
</head> 
 
 
<body> 
   <div class="container"> 
      <div class="toolbar"> 
         <div class="vcenter push-right"> 
            <button type="button" id="exampleButton">Run Example</button> 
         </div> 
         <div class="vcenter push-right"> 
            <label for="interactiveSelect">Interactive mode:</label> 
            <select id="interactiveSelect"></select> 
         </div> 
         <div class="vcenter push-right"> 
            <label for="annotationsSelect">Annotations objects:</label> 
            <select id="annotationsSelect"></select> 
         </div> 
         <div id="output" class="vcenter push-right"></div> 
         <div id="serviceStatus" class="vcenter push-right"></div> 
      </div> 
      <div class="docContainer"> 
         <div class="sidepanel" id="thumbnails"></div> 
         <div class="centerpanel" id="viewer"></div> 
         <div class="sidepanel" id="bookmarks"></div> 
      </div> 
   </div> 
</body> 
<script> 
   window.onload = () => { 
      const button = document.getElementById('exampleButton'); 
      button.onclick = () => { 
         const example = new window.examples.ViewExample(); 
         example.run(); 
      } 
   }; 
</script> 
 
</html> 
 /* 
   Remove default body styling. 
   Set the body to flex as a column; 
*/ 
body { 
   margin: 0; 
   display: flex; 
   flex-direction: column; 
} 
 
.container { 
   margin: 10px; 
   width: calc(100% - 20px); 
   height: calc(100vh - 20px); 
} 
 
.toolbar { 
   height: 5%; 
   width: 100%; 
   border-bottom: 2px solid #333; 
   flex-direction: row; 
   display: flex; 
} 
#bookmarks{ 
   overflow: hidden; 
} 
 
.vcenter { 
   margin-top: auto; 
   margin-bottom: auto; 
} 
 
.hcenter{ 
   margin-left: auto; 
   margin-right: auto; 
} 
 
.push-right{ 
   margin-left: 10px; 
} 
 
.docContainer{ 
   height: 95%; 
   width: 100%; 
   display: flex; 
   flex-direction: row; 
} 
 
.sidepanel{ 
   width: 15%; 
   height: 100%; 
} 
 
.centerpanel{ 
   width:100%; 
   height:100%; 
} 
 
 /* Styles for Elements Mode. */ 
 .lt-item, .lt-image-border { 
   /* Box Shadow (view, item, image border) */ 
   box-shadow: #333 2px 2px 5px 1px; 
 } 
 .lt-view,.lt-thumb-item { 
   /* View */ 
   margin: 5px; 
   padding: 5px; 
 } 
 .lt-item { 
   /* Item */ 
   border: 2px solid #6ecaab; 
   background-color: #b2decf; 
   padding: 10px; 
 } 
 .lt-image-border { 
   /* Image Border */ 
   border: 3px solid #444; 
   background-color: white; 
 } 
 .lt-thumb-item { 
   /* Thumbnail Item */ 
   border: 2px solid #6ecaab; 
   background-color: #b2decf; 
 } 
 .lt-thumb-item.lt-thumb-item-selected { 
   /* Selected Thumbnail Item */ 
   border: 2px solid #59b2ba; 
   background-color: #8ce1e1; 
 } 
 .lt-thumb-item-hovered { 
   /* Hovered Thumbnail Item */ 
   border: 2px solid #52b996; 
   background-color: #87c7b1; 
 } 
 .small-modal { 
   max-width: 200px; 
   width: 200px; 
 } 

Requirements

Target Platforms

Help Version 20.0.2019.10.14
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Leadtools.Document.Viewer Assembly