beginUndo Method

Summary

Creates a new undo node in this AnnAutomation object.

Syntax
TypeScript
JavaScript
AnnAutomation.prototype.beginUndo = function() 
beginUndo(): void; 
Remarks

Use BeginUndo, EndUndo and CancelUndo to programmatically add a node to the undo stack maintained by this AnnAutomation. Typically, you add an undo node as follows:

  1. Call the BeginUndo method before making any changes to create a new node.

  2. Perform any changes to the AnnAutomation object.

  3. Call the EndUndo method to commit this undo node into the undo stack of the AnnAutomation object.

  4. In case of errors (typically in a catch statement), call the CancelUndo method to remove the node and cancel the operation.

You do not need to manually call BeginUndo, EndUndo or CancelUndo when calling methods from this AnnAutomation object. The AnnAutomation object does this internally for you. For example, when you call the DeleteSelectedObjects method to delete the object(s) currently being edited, the AnnAutomation object will perform the above sequence internally to add the undo node.

Use the UndoCapacity property to get or set the number of user actions that can be reversed using the Undo method, or re-applied using the Redo method. The default value for the UndoCapacity property is 10 actions.

For information about undoing or redoing automation operations, refer to Undoing Annotation Automation Operations.

Example

The following example will manually add a new rectangle object to an automation object and then start editing it.

BeginUndo.ts
AutomationHelper.ts
BeginUndo.js
AutomationHelper.js
BeginUndo.html
import { AutomationHelper } from "../utilities/AutomationHelper"; 
 
export class AnnAutomation_BeginUndoExample { 
   private automation: lt.Annotations.Automation.AnnAutomation = null; 
 
   constructor() { 
      const helper = new AutomationHelper(); 
      helper.run(this.updateAutomation); 
      document.getElementById('exampleButton').onclick = () => this.run(this.automation); 
   } 
 
   private updateAutomation = (automation) => this.automation = automation; 
 
   private run = (automation: lt.Annotations.Automation.AnnAutomation) => { 
      automation.beginUndo(); 
 
      try { 
         // add a new rectangle object 
         const rectObj: lt.Annotations.Engine.AnnRectangleObject = new lt.Annotations.Engine.AnnRectangleObject(); 
         rectObj.rect = lt.LeadRectD.create(100, 100, 800, 800); 
         rectObj.stroke = lt.Annotations.Engine.AnnStroke.create(lt.Annotations.Engine.AnnSolidColorBrush.create("blue"), 
            lt.LeadLengthD.create(1)); 
         rectObj.fill = lt.Annotations.Engine.AnnSolidColorBrush.create("yellow"); 
         automation.container.children.add(rectObj); 
 
         // Invalidate it 
         automation.invalidate(lt.LeadRectD.get_empty()); 
 
         // Select this object 
         automation.selectObject(rectObj); 
 
         // commit the undo node 
         automation.endUndo(); 
      } 
      catch (ex) { 
         // in case of errors, cancel the undo node 
         automation.cancelUndo(); 
         alert(ex.message); 
         return; 
      } 
 
      alert("Object has been added as is now selected. Next will call //Undo// to undo the operation"); 
      automation.undo(); 
      alert("Operation has been undone. Next will call //Redo// to redo the operation"); 
      automation.redo(); 
      alert("Object should be back and selected"); 
   } 
} 
export class AutomationHelper { 
   private automation: lt.Annotations.Automation.AnnAutomation = null; 
 
   constructor() { 
      lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/v200/LEADTOOLSEVAL.txt", "EVAL", null); 
   } 
 
   public run(callback?: (automation: lt.Annotations.Automation.AnnAutomation) => void): void { 
      // Create the viewer 
      const imageViewerDiv = document.getElementById("imageViewerDiv"); 
      const createOptions: lt.Controls.ImageViewerCreateOptions = new lt.Controls.ImageViewerCreateOptions(imageViewerDiv); 
      const viewer: lt.Controls.ImageViewer = new lt.Controls.ImageViewer(createOptions); 
      viewer.autoCreateCanvas = true; 
 
      // PanZoom interactive mode 
      const panZoom: lt.Controls.ImageViewerPanZoomInteractiveMode = new lt.Controls.ImageViewerPanZoomInteractiveMode(); 
 
      // Create an instance of the Automation control object that works with LEADTOOLS ImageViewer 
      const imageViewerAutomationControl: lt.Demos.Annotations.ImageViewerAutomationControl = new lt.Demos.Annotations.ImageViewerAutomationControl(); 
      // Attach our image viewer 
      imageViewerAutomationControl.imageViewer = viewer; 
 
      // Set the image viewer interactive mode 
      const automationInteractiveMode: lt.Demos.Annotations.AutomationInteractiveMode = new lt.Demos.Annotations.AutomationInteractiveMode(); 
      automationInteractiveMode.automationControl = imageViewerAutomationControl; 
 
      // Set the image URL 
      viewer.imageUrl = "http://demo.leadtools.com/images/png/pngimage.png"; 
 
      // Create and set up the automation manager using the HTML5 rendering engine 
      const renderingEngine: lt.Annotations.Rendering.AnnHtml5RenderingEngine = new lt.Annotations.Rendering.AnnHtml5RenderingEngine(); 
      const manager: lt.Annotations.Automation.AnnAutomationManager = lt.Annotations.Automation.AnnAutomationManager.create(renderingEngine); 
 
      // Create only the line and rectangle automation objects 
      this.createMyAutomationObjects(manager); 
 
      // You can instruct the manager to create the default (all) automation objects. 
      // comment out the call to CreateMyAutomationObjects and call this instead: 
      //manager.createDefaultObjects(); 
 
      // Add the objects to the objects select element 
      const currentObjectIdSelect = document.getElementById("currentObjectIdSelect") as HTMLSelectElement; 
      // Add the PanZoom option 
      currentObjectIdSelect.options[currentObjectIdSelect.options.length] = new Option("Pan/Zoom", lt.Annotations.Engine.AnnObject.none.toString()); 
 
      const automationObjCount: number = manager.objects.count; 
      for (let i = 0; i < automationObjCount; i++) { 
         // Get the object 
         const automationObj: lt.Annotations.Automation.AnnAutomationObject = manager.objects.item(i); 
 
         // Add its name to the select element 
         const name: string = automationObj.name; 
         const id: number = automationObj.id; 
         currentObjectIdSelect.options[currentObjectIdSelect.options.length] = new Option(name, id.toString()); 
      } 
 
      // Hook to its change event 
      currentObjectIdSelect.addEventListener("change", () => { 
         // Get the object ID 
         const id: number = parseInt(currentObjectIdSelect.options[currentObjectIdSelect.selectedIndex].value); 
 
         // Set it as the current object in the manager 
         manager.currentObjectId = id; 
 
         // If this is the "Pan/Zoom" option, then back to pan zoom, otherwise, set our automation control 
         if (id == lt.Annotations.Engine.AnnObject.none) { 
            viewer.defaultInteractiveMode = panZoom; 
         } 
         else { 
            viewer.defaultInteractiveMode = automationInteractiveMode; 
         } 
      }); 
 
      // When the current object ID changes, we need to update our select 
      manager.add_currentObjectIdChanged((sender, e) => { 
         const currentObjectId: number = manager.currentObjectId; 
         for (let i = 0; i < currentObjectIdSelect.options.length; i++) { 
            const id: number = parseInt(currentObjectIdSelect.options[i].value); 
            if (id === currentObjectId) { 
               currentObjectIdSelect.selectedIndex = i; 
               break; 
            } 
         } 
      }); 
 
      // Pan zoom by default 
      viewer.defaultInteractiveMode = panZoom; 
 
      // Set up the automation (will create the container as well) 
      const automation: lt.Annotations.Automation.AnnAutomation = new lt.Annotations.Automation.AnnAutomation(manager, imageViewerAutomationControl); 
      this.automation = automation; 
      // Add handler to update the container size when the image size changes 
      viewer.itemChanged.add((sender, e) => { 
         const container: lt.Annotations.Engine.AnnContainer = automation.container; 
         container.size = container.mapper.sizeToContainerCoordinates(viewer.imageSize); 
 
         // Create new canvas data provider for the new image 
         const canvasDataProvider: lt.Demos.Annotations.CanvasDataProvider = new lt.Demos.Annotations.CanvasDataProvider(viewer.activeItem.canvas); 
         imageViewerAutomationControl.automationDataProvider = canvasDataProvider; 
 
      }); 
 
      // Set up this automation as the active one 
      this.automation.active = true; 
 
      if(callback) 
         callback(this.automation); 
   } 
 
   private createMyAutomationObjects(manager): void { 
      // Get the automation objects collection 
      const automationObjects = manager.objects; 
 
      // Set up the select automation object 
      const selectAutomationObj: lt.Annotations.Automation.AnnAutomationObject = new lt.Annotations.Automation.AnnAutomationObject(); 
      selectAutomationObj.id = lt.Annotations.Engine.AnnObject.selectObjectId; 
      selectAutomationObj.name = "Select"; 
      selectAutomationObj.drawDesignerType = lt.Annotations.Designers.AnnRectangleDrawDesigner; 
      selectAutomationObj.editDesignerType = lt.Annotations.Designers.AnnSelectionEditDesigner; 
      selectAutomationObj.runDesignerType = null; 
 
      // Create the object template for it 
      const selectObj: lt.Annotations.Engine.AnnSelectionObject = new lt.Annotations.Engine.AnnSelectionObject(); 
      selectObj.stroke = lt.Annotations.Engine.AnnStroke.create(lt.Annotations.Engine.AnnSolidColorBrush.create("darkgreen"), lt.LeadLengthD.create(2)); 
      selectAutomationObj.objectTemplate = selectObj; 
 
      // Add it to the automation objects of the manager 
      automationObjects.add(selectAutomationObj); 
 
      // Set up the line automation object 
      const lineAutomationObj: lt.Annotations.Automation.AnnAutomationObject = new lt.Annotations.Automation.AnnAutomationObject(); 
      lineAutomationObj.id = lt.Annotations.Engine.AnnObject.lineObjectId; 
      lineAutomationObj.name = "Line"; 
      lineAutomationObj.drawDesignerType = lt.Annotations.Designers.AnnLineDrawDesigner; 
      lineAutomationObj.editDesignerType = lt.Annotations.Designers.AnnPolylineEditDesigner; 
      lineAutomationObj.runDesignerType = lt.Annotations.Designers.AnnRunDesigner; 
 
      // Create the object template for it, use the default stroke 
      const lineObj: lt.Annotations.Engine.AnnPolylineObject = new lt.Annotations.Engine.AnnPolylineObject(); 
      lineAutomationObj.objectTemplate = lineObj; 
 
      // Add it to the automation objects of the manager 
      automationObjects.add(lineAutomationObj); 
 
      // Set up the rectangle automation object 
      const rectAutomationObj: lt.Annotations.Automation.AnnAutomationObject = new lt.Annotations.Automation.AnnAutomationObject(); 
      rectAutomationObj.id = lt.Annotations.Engine.AnnObject.rectangleObjectId; 
      rectAutomationObj.name = "Rectangle"; 
      rectAutomationObj.drawDesignerType = lt.Annotations.Designers.AnnRectangleDrawDesigner; 
      rectAutomationObj.editDesignerType = lt.Annotations.Designers.AnnRectangleEditDesigner; 
      rectAutomationObj.runDesignerType = lt.Annotations.Designers.AnnRunDesigner; 
 
      // Create the object template for it, use the default stroke and fill 
      const rectObj: lt.Annotations.Engine.AnnRectangleObject = new lt.Annotations.Engine.AnnRectangleObject(); 
      rectAutomationObj.set_objectTemplate(rectObj); 
 
      // Add it to the automation objects of the manager 
      automationObjects.add(rectAutomationObj); 
 
      const textAutomationObj: lt.Annotations.Automation.AnnAutomationObject = new lt.Annotations.Automation.AnnAutomationObject(); 
      textAutomationObj.id = lt.Annotations.Engine.AnnObject.textObjectId; 
      textAutomationObj.name = "Text"; 
      textAutomationObj.drawDesignerType = lt.Annotations.Designers.AnnRectangleDrawDesigner; 
      textAutomationObj.editDesignerType = lt.Annotations.Designers.AnnTextEditDesigner; 
      textAutomationObj.runDesignerType = lt.Annotations.Designers.AnnRunDesigner; 
 
      // Create the object template for it, use the default stroke, fill, text and font 
      const textObj: lt.Annotations.Engine.AnnTextObject = new lt.Annotations.Engine.AnnTextObject(); 
      textAutomationObj.objectTemplate = textObj; 
 
      // Add it to the automation objects of the manager 
      automationObjects.add(textAutomationObj); 
   } 
} 
import { AutomationHelper } from "../utilities/AutomationHelper"; 
 
export class AnnAutomation_BeginUndoExample { 
   automation = null; 
 
   constructor() { 
      const helper = new AutomationHelper(); 
      helper.run(this.updateAutomation); 
      document.getElementById('exampleButton').onclick = () => this.run(this.automation); 
   } 
 
   updateAutomation = (automation) => this.automation = automation; 
 
   run = (automation) => { 
      automation.beginUndo(); 
 
      try { 
         // add a new rectangle object 
         const rectObj = new lt.Annotations.Engine.AnnRectangleObject(); 
         rectObj.rect = lt.LeadRectD.create(100, 100, 800, 800); 
         rectObj.stroke = lt.Annotations.Engine.AnnStroke.create(lt.Annotations.Engine.AnnSolidColorBrush.create("blue"), 
            lt.LeadLengthD.create(1)); 
         rectObj.fill = lt.Annotations.Engine.AnnSolidColorBrush.create("yellow"); 
         automation.container.children.add(rectObj); 
 
         // Invalidate it 
         automation.invalidate(lt.LeadRectD.get_empty()); 
 
         // Select this object 
         automation.selectObject(rectObj); 
 
         // commit the undo node 
         automation.endUndo(); 
      } 
      catch (ex) { 
         // in case of errors, cancel the undo node 
         automation.cancelUndo(); 
         alert(ex.message); 
         return; 
      } 
 
      alert("Object has been added as is now selected. Next will call //Undo// to undo the operation"); 
      automation.undo(); 
      alert("Operation has been undone. Next will call //Redo// to redo the operation"); 
      automation.redo(); 
      alert("Object should be back and selected"); 
   } 
} 
export class AutomationHelper { 
   automation = null; 
 
   constructor() { 
      lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/v200/LEADTOOLSEVAL.txt", "EVAL", null); 
   } 
 
   run(callback) { 
      // Create the viewer 
      const imageViewerDiv = document.getElementById("imageViewerDiv"); 
      const createOptions = new lt.Controls.ImageViewerCreateOptions(imageViewerDiv); 
      const viewer = new lt.Controls.ImageViewer(createOptions); 
      viewer.autoCreateCanvas = true; 
 
      // PanZoom interactive mode 
      const panZoom = new lt.Controls.ImageViewerPanZoomInteractiveMode(); 
 
      // Create an instance of the Automation control object that works with LEADTOOLS ImageViewer 
      const imageViewerAutomationControl = new lt.Demos.Annotations.ImageViewerAutomationControl(); 
      // Attach our image viewer 
      imageViewerAutomationControl.imageViewer = viewer; 
 
      // Set the image viewer interactive mode 
      const automationInteractiveMode = new lt.Demos.Annotations.AutomationInteractiveMode(); 
      automationInteractiveMode.automationControl = imageViewerAutomationControl; 
 
      // Set the image URL 
      viewer.imageUrl = "http://demo.leadtools.com/images/png/pngimage.png"; 
 
      // Create and set up the automation manager using the HTML5 rendering engine 
      const renderingEngine = new lt.Annotations.Rendering.AnnHtml5RenderingEngine(); 
      const manager = lt.Annotations.Automation.AnnAutomationManager.create(renderingEngine); 
 
      // Create only the line and rectangle automation objects 
      this.createMyAutomationObjects(manager); 
 
      // You can instruct the manager to create the default (all) automation objects. 
      // comment out the call to CreateMyAutomationObjects and call this instead: 
      //manager.createDefaultObjects(); 
 
      // Add the objects to the objects select element 
      const currentObjectIdSelect = document.getElementById("currentObjectIdSelect"); 
      // Add the PanZoom option 
      currentObjectIdSelect.options[currentObjectIdSelect.options.length] = new Option("Pan/Zoom", lt.Annotations.Engine.AnnObject.none.toString()); 
 
      const automationObjCount = manager.objects.count; 
      for (let i = 0; i < automationObjCount; i++) { 
         // Get the object 
         const automationObj = manager.objects.item(i); 
 
         // Add its name to the select element 
         const name = automationObj.name; 
         const id = automationObj.id; 
         currentObjectIdSelect.options[currentObjectIdSelect.options.length] = new Option(name, id.toString()); 
      } 
 
      // Hook to its change event 
      currentObjectIdSelect.addEventListener("change", () => { 
         // Get the object ID 
         const id = parseInt(currentObjectIdSelect.options[currentObjectIdSelect.selectedIndex].value); 
 
         // Set it as the current object in the manager 
         manager.currentObjectId = id; 
 
         // If this is the "Pan/Zoom" option, then back to pan zoom, otherwise, set our automation control 
         if (id == lt.Annotations.Engine.AnnObject.none) { 
            viewer.defaultInteractiveMode = panZoom; 
         } 
         else { 
            viewer.defaultInteractiveMode = automationInteractiveMode; 
         } 
      }); 
 
      // When the current object ID changes, we need to update our select 
      manager.add_currentObjectIdChanged((sender, e) => { 
         const currentObjectId = manager.currentObjectId; 
         for (let i = 0; i < currentObjectIdSelect.options.length; i++) { 
            const id = parseInt(currentObjectIdSelect.options[i].value); 
            if (id === currentObjectId) { 
               currentObjectIdSelect.selectedIndex = i; 
               break; 
            } 
         } 
      }); 
 
      // Pan zoom by default 
      viewer.defaultInteractiveMode = panZoom; 
 
      // Set up the automation (will create the container as well) 
      const automation = new lt.Annotations.Automation.AnnAutomation(manager, imageViewerAutomationControl); 
      this.automation = automation; 
      // Add handler to update the container size when the image size changes 
      viewer.itemChanged.add((sender, e) => { 
         const container = automation.container; 
         container.size = container.mapper.sizeToContainerCoordinates(viewer.imageSize); 
 
         // Create new canvas data provider for the new image 
         const canvasDataProvider = new lt.Demos.Annotations.CanvasDataProvider(viewer.activeItem.canvas); 
         imageViewerAutomationControl.automationDataProvider = canvasDataProvider; 
 
      }); 
 
      // Set up this automation as the active one 
      this.automation.active = true; 
 
      if(callback) 
         callback(this.automation); 
   } 
 
   createMyAutomationObjects(manager) { 
      // Get the automation objects collection 
      const automationObjects = manager.objects; 
 
      // Set up the select automation object 
      const selectAutomationObj = new lt.Annotations.Automation.AnnAutomationObject(); 
      selectAutomationObj.id = lt.Annotations.Engine.AnnObject.selectObjectId; 
      selectAutomationObj.name = "Select"; 
      selectAutomationObj.drawDesignerType = lt.Annotations.Designers.AnnRectangleDrawDesigner; 
      selectAutomationObj.editDesignerType = lt.Annotations.Designers.AnnSelectionEditDesigner; 
      selectAutomationObj.runDesignerType = null; 
 
      // Create the object template for it 
      const selectObj = new lt.Annotations.Engine.AnnSelectionObject(); 
      selectObj.stroke = lt.Annotations.Engine.AnnStroke.create(lt.Annotations.Engine.AnnSolidColorBrush.create("darkgreen"), lt.LeadLengthD.create(2)); 
      selectAutomationObj.objectTemplate = selectObj; 
 
      // Add it to the automation objects of the manager 
      automationObjects.add(selectAutomationObj); 
 
      // Set up the line automation object 
      const lineAutomationObj = new lt.Annotations.Automation.AnnAutomationObject(); 
      lineAutomationObj.id = lt.Annotations.Engine.AnnObject.lineObjectId; 
      lineAutomationObj.name = "Line"; 
      lineAutomationObj.drawDesignerType = lt.Annotations.Designers.AnnLineDrawDesigner; 
      lineAutomationObj.editDesignerType = lt.Annotations.Designers.AnnPolylineEditDesigner; 
      lineAutomationObj.runDesignerType = lt.Annotations.Designers.AnnRunDesigner; 
 
      // Create the object template for it, use the default stroke 
      const lineObj = new lt.Annotations.Engine.AnnPolylineObject(); 
      lineAutomationObj.objectTemplate = lineObj; 
 
      // Add it to the automation objects of the manager 
      automationObjects.add(lineAutomationObj); 
 
      // Set up the rectangle automation object 
      const rectAutomationObj = new lt.Annotations.Automation.AnnAutomationObject(); 
      rectAutomationObj.id = lt.Annotations.Engine.AnnObject.rectangleObjectId; 
      rectAutomationObj.name = "Rectangle"; 
      rectAutomationObj.drawDesignerType = lt.Annotations.Designers.AnnRectangleDrawDesigner; 
      rectAutomationObj.editDesignerType = lt.Annotations.Designers.AnnRectangleEditDesigner; 
      rectAutomationObj.runDesignerType = lt.Annotations.Designers.AnnRunDesigner; 
 
      // Create the object template for it, use the default stroke and fill 
      const rectObj = new lt.Annotations.Engine.AnnRectangleObject(); 
      rectAutomationObj.set_objectTemplate(rectObj); 
 
      // Add it to the automation objects of the manager 
      automationObjects.add(rectAutomationObj); 
 
      const textAutomationObj = new lt.Annotations.Automation.AnnAutomationObject(); 
      textAutomationObj.id = lt.Annotations.Engine.AnnObject.textObjectId; 
      textAutomationObj.name = "Text"; 
      textAutomationObj.drawDesignerType = lt.Annotations.Designers.AnnRectangleDrawDesigner; 
      textAutomationObj.editDesignerType = lt.Annotations.Designers.AnnTextEditDesigner; 
      textAutomationObj.runDesignerType = lt.Annotations.Designers.AnnRunDesigner; 
 
      // Create the object template for it, use the default stroke, fill, text and font 
      const textObj = new lt.Annotations.Engine.AnnTextObject(); 
      textAutomationObj.objectTemplate = textObj; 
 
      // Add it to the automation objects of the manager 
      automationObjects.add(textAutomationObj); 
   } 
} 
<!doctype html> 
<html lang="en"> 
<title>Automation Example | EditText</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.Demos.js"></script> 
   <script src="../../LT/Leadtools.Demos.Annotations.Js"></script> 
   <style> 
      #imageViewerDiv { 
         border: 1px solid #000000; 
         width: 800px; 
         height: 800px; 
         background-color: #7F7F7F; 
      } 
   </style> 
   <!-- All demo files are bundled and appended to the window --> 
   <script src="../../bundle.js" type="text/javascript"></script> 
</head> 
 
<body> 
   <p>Either Pan/Zoom or Annotations mode. In annotations mode, draw new objects or edit them.</p> 
   <div> 
      <select id="currentObjectIdSelect"></select> 
      <input type="button" id="exampleButton" value="Example" /> 
      <label id="exampleLabel" /> 
   </div> 
   <div id="imageViewerDiv" /> 
</body> 
 
<script> 
   window.onload = () => { 
      const example = new window.examples.AnnAutomation.BeginUndo(); 
   }; 
</script> 
</html> 
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Leadtools.Annotations.Automation Assembly