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readBarcodes Method

Summary

Reads the barcodes found on this page.

Syntax

TypeScript

JavaScript

DocumentPage.prototype.readBarcodes = function( 
   bounds, 
   maximumBarcodes, 
   symbologies 
)

readBarcodes( 
   bounds: LeadRectD, 
   maximumBarcodes: number, 
   symbologies: BarcodeSymbology[] 
): JQueryPromise<BarcodeData[]>;

Parameters

bounds

Search area in page coordinates. If this value is Empty, then the entire page is searched for barcodes.

maximumBarcodes

Maximum number of barcodes to read. Use -1 to read all the barcodes found.

symbologies

Barcode symbologies to search for. If this value is null or an empty array, then all barcode symbologies are searched for.

Return Value

A Promise object that may resolve successfully to an array of objects of type BarcodeData containing the data for each barcode found. An empty array is returned if no barcodes were found on the page.

Remarks

This method uses the engine set in the service. If the engine value is null then no barcodes are read and this method returns an empty array.

The readBarcodes method calls getImageUrl and then reads the barcodes found.

Since the search area and options used can differ greatly from one call to the another, the document will never save the barcodes found in the cache. Each call to readBarcodes will re-read all the barcodes from the page image.

Example

Barcode.ts

DocumentHelper.ts

Barcode.js

DocumentHelper.js

Barcode.html

import { DocumentHelper } from "../../utilities/DocumentHelper"; 
 
export class LEADDocument_BarcodesExample { 
   public constructor() { 
      lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/js/LEADTOOLSEVAL.txt", "EVAL", null); 
      DocumentHelper.initFactory(); 
   } 
 
   public run = (buttonID: string) => { 
      const exampleButton = document.getElementById(buttonID); 
      exampleButton.onclick = this.readBarcodes; 
   } 
 
   readBarcodes = () => { 
      const url = "https://demo.leadtools.com/images/tiff/barcodes.tif"; 
      const loadDocumentOptions = new lt.Document.LoadDocumentOptions(); 
 
      DocumentHelper.log("Loading document..."); 
      lt.Document.DocumentFactory.loadFromUri(url, loadDocumentOptions) 
         .done((document: lt.Document.LEADDocument) => { 
            DocumentHelper.log("Done. Reading barcodes..."); 
            // Read all the barcodes in the first page 
            const docPage = document.pages.item(0); 
            docPage.readBarcodes(lt.LeadRectD.empty, 0, null) 
               .done((barcodes) => { 
                  DocumentHelper.log("Number of barcodes read: " + barcodes.length + " (data in console)", barcodes); 
               }) 
               .fail(DocumentHelper.showServiceError); 
         }) 
         .fail(DocumentHelper.showServiceError); 
   } 
}

export class DocumentHelper { 
   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); 
   } 
 
   static log = (message: string, data?: any) => { 
      const outputElement = document.getElementById("output"); 
      if (outputElement) { 
         const time = (new Date()).toLocaleTimeString(); 
         const textElement = document.createElement("p"); 
         textElement.innerHTML = (outputElement.childElementCount + 1) + " [" + time + "]: " + message; 
         outputElement.insertBefore(textElement, outputElement.firstChild); 
      } 
 
      if (!data) 
         console.log(message); 
      else 
         console.log(message, data); 
   } 
 
   static initFactory = () => { 
      // 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"; 
   } 
}

import { DocumentHelper } from "../../utilities/DocumentHelper"; 
 
export class LEADDocument_BarcodesExample { 
   constructor() { 
      lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/js/LEADTOOLSEVAL.txt", "EVAL", null); 
      DocumentHelper.initFactory(); 
   } 
 
   run = (buttonID) => { 
      const exampleButton = document.getElementById(buttonID); 
      exampleButton.onclick = this.readBarcodes; 
   } 
 
   readBarcodes = () => { 
      const url = "https://demo.leadtools.com/images/tiff/barcodes.tif"; 
      const loadDocumentOptions = new lt.Document.LoadDocumentOptions(); 
 
      DocumentHelper.log("Loading document..."); 
      lt.Document.DocumentFactory.loadFromUri(url, loadDocumentOptions) 
         .done((document) => { 
            DocumentHelper.log("Done. Reading barcodes..."); 
            // Read all the barcodes in the first page 
            const docPage = document.pages.item(0); 
            docPage.readBarcodes(lt.LeadRectD.empty, 0, null) 
               .done((barcodes) => { 
                  DocumentHelper.log("Number of barcodes read: " + barcodes.length + " (data in console)", barcodes); 
               }) 
               .fail(DocumentHelper.showServiceError); 
         }) 
         .fail(DocumentHelper.showServiceError); 
   } 
}

export class DocumentHelper { 
   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); 
   } 
 
   static log = (message, data) => { 
      const outputElement = document.getElementById("output"); 
      if (outputElement) { 
         const time = (new Date()).toLocaleTimeString(); 
         const textElement = document.createElement("p"); 
         textElement.innerHTML = (outputElement.childElementCount + 1) + " [" + time + "]: " + message; 
         outputElement.insertBefore(textElement, outputElement.firstChild); 
      } 
 
      if (!data) 
         console.log(message); 
      else 
         console.log(message, data); 
   } 
 
   static initFactory = () => { 
      // 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"; 
   } 
}

<!doctype html> 
<html lang="en"> 
<title>Document Example | Barcodes</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> 
      <button type="button" id="exampleButton">Run Example</button> 
   </div> 
   <div id="output"></div> 
   <div> 
      <img id="img" /> 
   </div> 
</body> 
 
<script> 
   window.onload = () => { 
      const example = new window.examples.LEADDocument.Barcodes(); 
      example.run("exampleButton"); 
   }; 
</script> 
</html>