ReadBarcode(RasterImage,LogicalRectangle,BarcodeSymbology[]) Method

C#
Visual Basic
WinRT C#
Java
Objective-C
WinRT JavaScript
C++

public BarcodeData ReadBarcode( 
   RasterImage image,
   LogicalRectangle searchBounds,
   BarcodeSymbology[] symbologies
)

'Declaration

Public Overloads Function ReadBarcode( _
   ByVal image As RasterImage, _
   ByVal searchBounds As LogicalRectangle, _
   ByVal symbologies() As BarcodeSymbology _
) As BarcodeData

'Usage

Dim instance As BarcodeReader
Dim image As RasterImage
Dim searchBounds As LogicalRectangle
Dim symbologies() As BarcodeSymbology
Dim value As BarcodeData
 
value = instance.ReadBarcode(image, searchBounds, symbologies)

public BarcodeData ReadBarcode( 
   RasterImage image,
   LogicalRectangle searchBounds,
   BarcodeSymbology[] symbologies
)

- (nullable LTBarcodeData *)readBarcode:(LTRasterImage *)image 
                           searchBounds:(LeadRect)searchBounds 
                            symbologies:(nullable NSArray<NSNumber *> *)symbologies 
                                  error:(NSError **)error

public BarcodeData readBarcode(
  RasterImage image, 
  LeadRect searchBounds, 
  BarcodeSymbology[] symbologies
)

 function Leadtools.Barcode.BarcodeReader.ReadBarcode(RasterImage,LogicalRectangle,BarcodeSymbology[])( 
   image ,
   searchBounds ,
   symbologies 
)

public:
BarcodeData^ ReadBarcode( 
   RasterImage^ image,
   LogicalRectangle searchBounds,
   array<BarcodeSymbology>^ symbologies
)

Parameters

image: A RasterImage object that contains the image data. Must not be null (Nothing in Visual Basic).
searchBounds: A LogicalRectangle that specifies the region of interest area in the image where the barcode search and detection is performed. Specify LogicalRectangle.Empty to indicate that the search must be performed on the whole image.
symbologies: An array of BarcodeSymbology enumeration members that specifies the barcode symbologies (types) to search for.

Return Value

An instance of BarcodeData or one of its derived classes that contains the symbology, data, location and any rotation angle of the barcode found. If no barcodes can be found, then this method will return null (Nothing in Visual Basic).

For more information on barcode reading, refer to BarcodeReader.

Use this method if you want to read a single barcode from a known group. For example, to read a barcode that can be of any UPC type, pass an array of BarcodeSymbology.UPCA and BarcodeSymbology.UPCE.

This method will use the default read options set in this BarcodeReader for all the items in symbologies.

LEADTOOLS barcode read engine is optimized for speed and can search for multiple similar symbologies at the same time. This method simply returns the first barcode that is detected correctly using the symbologies and current options.

The ReadSymbology event will occur before and after attempting to read any symbology. The read options being used whether the default or specified will be set in the BarcodeReadSymbologyEventArgs.Options property of the event data.

If symbologies is null (Nothing in Visual Basic), then this method will use all the currently available symbologies. If this parameter contains an empty array, then no barcode will be detected and null (Nothing in Visual Basic) will be returned.

The BarcodeReader provides the following barcode read methods:

Method	Description
ReadBarcode(RasterImage image, LogicalRectangle searchBounds, BarcodeSymbology symbology) and ReadBarcode(RasterImage image, LogicalRectangle searchBounds, BarcodeSymbology symbology, BarcodeReadOptions options)	Read one barcode from an image with specified symbology and default or specific options. Use these methods if you want to read a single barcode from the image, for example, a QR symbol by specifying BarcodeSymbology.QR or if you want to read any barcode found regardless of its type by using BarcodeSymbology.Unknown.
ReadBarcode(RasterImage image, LogicalRectangle searchBounds, BarcodeSymbology[] symbologies) and ReadBarcode(RasterImage image, LogicalRectangle searchBounds, BarcodeSymbology[] symbologies, BarcodeReadOptions[] options)	Read one barcode from an image with a symbology from a specified group and default or specific options. Uses these methods if you want to read a single barcode from a known group. For example, to read a barcode that can be of any UPC type, pass an array of BarcodeSymbology.UPCA and BarcodeSymbology.UPCE.
ReadBarcodes(RasterImage image, LogicalRectangle searchBounds, int maximumBarcodes, BarcodeSymbology[] symbologies) and ReadBarcodes(RasterImage image, LogicalRectangle searchBounds, int maximumBarcodes, BarcodeSymbology[] symbologies, BarcodeReadOptions[] options)	Read multiple barcodes from an image with symbologies from a specified group and default or specific options. Use these methods if you want to read multiple barcodes of the same or multiple symbologies.

This example shows how to use this method to read any UPC barcode used to identify products from an image.

C#
Visual Basic
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Copy Code

Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.Forms
Imports Leadtools.Barcode
Imports Leadtools.ImageProcessing

      
Public Sub BarcodeReader_ReadBarcodeExample3()
   Dim imageFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Barcode1.tif")
   ' Create a Barcode engine
   Dim engine As New BarcodeEngine()

   ' Get the Barcode reader instance
   Dim reader As BarcodeReader = engine.Reader

   Using codecs As New RasterCodecs()
      Using image As RasterImage = codecs.Load(imageFileName, 0, CodecsLoadByteOrder.BgrOrGray, 1, 1)
         ' In the US, UPC barcodes are used to identity products. So, create an array of UPC symbologies
         Dim upcSymbologies() As BarcodeSymbology = _
         { _
            BarcodeSymbology.UPCA, _
            BarcodeSymbology.UPCE _
         }

         ' Read the first UPC barcode from the image
         Dim barcode As BarcodeData = reader.ReadBarcode(image, LogicalRectangle.Empty, upcSymbologies)

         ' Show its location and data if found
         If Not IsNothing(barcode) Then
            Console.WriteLine("Found a {0} barcode at {1}, data:\n{2}", barcode.Symbology, barcode.Bounds, barcode.Value)
         Else
            Console.WriteLine("Not found")
         End If
      End Using
   End Using
End Sub

Public NotInheritable Class LEAD_VARS
Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class

using Leadtools;
using Leadtools.Codecs;
using Leadtools.Forms;
using Leadtools.Barcode;
using Leadtools.ImageProcessing;

      
public void BarcodeReader_ReadBarcodeExample3()
{
   string imageFileName = Path.Combine(LEAD_VARS.ImagesDir, "Barcode1.tif");
   // Create a Barcode engine
   BarcodeEngine engine = new BarcodeEngine();

   // Get the Barcode reader instance
   BarcodeReader reader = engine.Reader;

   using(RasterCodecs codecs = new RasterCodecs())
   {
      using(RasterImage image = codecs.Load(imageFileName, 0, CodecsLoadByteOrder.BgrOrGray, 1, 1))
      {
         // In the US, UPC barcodes are used to identity products. So, create an array of UPC symbologies
         BarcodeSymbology[] upcSymbologies =
         {
            BarcodeSymbology.UPCA,
            BarcodeSymbology.UPCE
         };

         // Read the first UPC barcode from the image
         BarcodeData barcode = reader.ReadBarcode(image, LogicalRectangle.Empty, upcSymbologies);

         // Show its location and data if found
         if(barcode != null)
         {
            Console.WriteLine("Found a {0} barcode at {1}, data:\n{2}", barcode.Symbology, barcode.Bounds, barcode.Value);
         }
         else
         {
            Console.WriteLine("Not found");
         }
      }
   }
}

static class LEAD_VARS
{
public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}

using Leadtools;
using Leadtools.Codecs;
using Leadtools.Forms;
using Leadtools.Barcode;
using Leadtools.ImageProcessing;
using Leadtools.Examples;

public void BarcodeReader_ReadBarcodeExample3(RasterImage image)
{
   // Create a Barcode engine
   BarcodeEngine engine = new BarcodeEngine();
   // Get the Barcode reader instance
   BarcodeReader reader = engine.Reader;

   RasterCodecs codecs = new RasterCodecs();

   // In the US, UPC barcodes are used to identity products. So, create an array of UPC symbologies
   BarcodeSymbology[] upcSymbologies =
   {
      BarcodeSymbology.UPCA,
      BarcodeSymbology.UPCE
   };

   // Read the first UPC barcode from the image
   BarcodeData barcode = reader.ReadBarcode(image, LogicalRectangle.Empty, upcSymbologies);

   // Show its location and data if found
   if(barcode != null)
   {
      Console.WriteLine("Found a {0} barcode at {1}, data:\n{2}", barcode.Symbology, barcode.Bounds, barcode.Value);
   }
   else
   {
      Console.WriteLine("Not found");
   }
}

Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.Forms
Imports Leadtools.Barcode
Imports Leadtools.ImageProcessing
Imports Leadtools.ImageProcessing.Color

Public Sub BarcodeReader_ReadBarcodeExample3(ByVal image As RasterImage)
   ' Create a Barcode engine
   Dim engine As BarcodeEngine = New BarcodeEngine()
   ' Get the Barcode reader instance
   Dim reader As BarcodeReader = engine.Reader

   Dim codecs As RasterCodecs = New RasterCodecs()

   ' In the US, UPC barcodes are used to identity products. So, create an array of UPC symbologies
   Dim upcSymbologies As BarcodeSymbology() = {BarcodeSymbology.UPCA, BarcodeSymbology.UPCE}

   ' Read the first UPC barcode from the image
   Dim barcode As BarcodeData = reader.ReadBarcode(image, LogicalRectangle.Empty, upcSymbologies)

   ' Show its location and data if found
   If Not barcode Is Nothing Then
      Console.WriteLine("Found a {0} barcode at {1}, data:" & Constants.vbLf & "{2}", barcode.Symbology, barcode.Bounds, barcode.Value)
   Else
      Console.WriteLine("Not found")
   End If
End Sub

Target Platforms

Reference

BarcodeReader Class
BarcodeReader Members
Overload List
ReadBarcode(RasterImage image, LogicalRectangle searchBounds, BarcodeSymbology symbology)
ReadBarcode(RasterImage image, LogicalRectangle searchBounds, BarcodeSymbology symbology, BarcodeReadOptions options)
ReadBarcode(RasterImage image, LogicalRectangle searchBounds, BarcodeSymbology[] symbologies, BarcodeReadOptions[] options)
ReadBarcodes(RasterImage image, LogicalRectangle searchBounds, int maximumBarcodes, BarcodeSymbology[] symbologies)
ReadBarcodes(RasterImage image, LogicalRectangle searchBounds, int maximumBarcodes, BarcodeSymbology[] symbologies, BarcodeReadOptions[] options)
Programming with LEADTOOLS Barcode
Supported Barcode Symbologies
Unlocking Barcode Support
Reading Barcodes Tutorial