ReadBarcode(RasterImage,LogicalRectangle,BarcodeSymbology[],BarcodeReadOptions[]) Method

Read one barcode from an image with a symbology from a specified group and options.

Syntax

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

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

'Declaration

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

'Usage

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

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

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

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

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

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

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. You can 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.
options: An array of BarcodeReadOptions that specifies the options to use. This can be null (Nothing in Visual Basic), where the current default options is used. Otherwise, the method will use the option that corresponds to the symbologies being read, if the array does not contain specific options for a symbologies being read, then the default version will be used.

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).

Remarks

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.

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. Use 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.

Example

This example shows how to use this method to read any UPC barcode used to identify products from a rotated 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_ReadBarcodeExample4()
   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)
         ' Rotate the image by 90, so default option of reading horizonal barcodes will not work
         Console.WriteLine("Rotating the image by 90 degrees")
         Dim rotate As New RotateCommand(90 * 100, RotateCommandFlags.Resize, RasterColor.FromKnownColor(RasterKnownColor.White))
         rotate.Run(image)

         ' 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 using default options
         Console.WriteLine("Reading barcodes using default options")
         Dim barcode As BarcodeData = reader.ReadBarcode(image, LogicalRectangle.Empty, upcSymbologies, Nothing)

         ' Show its location and data if found
         ' This will print out "Not 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

         ' Now get the options we used previously, and change the 1D linear barcode read options
         ' to search for barcodes in both horizontal and vertical directions
         ' Note: Same options are used for UPCA and UPCE, so we only need one options class
         Dim oneDReadOptions As OneDBarcodeReadOptions = DirectCast(reader.GetDefaultOptions(BarcodeSymbology.UPCA), OneDBarcodeReadOptions)

         ' Change the read direction
         oneDReadOptions.SearchDirection = BarcodeSearchDirection.HorizontalAndVertical

         ' Try again using our options
         Console.WriteLine("Reading barcodes using our options")
         barcode = reader.ReadBarcode(image, LogicalRectangle.Empty, upcSymbologies, New BarcodeReadOptions() {oneDReadOptions})

         ' Show its location and data if found
         ' This will find the barcode and print its information now
         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_ReadBarcodeExample4()
{
   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))
      {
         // Rotate the image by 90, so default option of reading horizonal barcodes will not work
         Console.WriteLine("Rotating the image by 90 degrees");
         RotateCommand rotate = new RotateCommand(90 * 100, RotateCommandFlags.Resize, RasterColor.FromKnownColor(RasterKnownColor.White));
         rotate.Run(image);

         // 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 using default options
         Console.WriteLine("Reading barcodes using default options");
         BarcodeData barcode = reader.ReadBarcode(image, LogicalRectangle.Empty, upcSymbologies, null);

         // Show its location and data if found
         // This will print out "Not 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");
         }

         // Now get the options we used previously, and change the 1D linear barcode read options
         // to search for barcodes in both horizontal and vertical directions
         // Note: Same options are used for UPCA and UPCE, so we only need one options class
         OneDBarcodeReadOptions oneDReadOptions = reader.GetDefaultOptions(BarcodeSymbology.UPCA) as OneDBarcodeReadOptions;

         // Change the read direction
         oneDReadOptions.SearchDirection = BarcodeSearchDirection.HorizontalAndVertical;

         // Try again using our options
         Console.WriteLine("Reading barcodes using our options");
         barcode = reader.ReadBarcode(image, LogicalRectangle.Empty, upcSymbologies, new BarcodeReadOptions[] { oneDReadOptions });

         // Show its location and data if found
         // This will find the barcode and print its information now
         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_ReadBarcodeExample4(RasterImage image)
{
   // Create a Barcode engine
   BarcodeEngine engine = new BarcodeEngine();
   // Get the Barcode reader instance
   BarcodeReader reader = engine.Reader;

   RasterCodecs codecs = new RasterCodecs();

   // Rotate the image by 90, so default option of reading horizonal barcodes will not work
   Console.WriteLine("Rotating the image by 90 degrees");
   RotateCommand rotate = new RotateCommand(90 * 100, RotateCommandFlags.Resize, RasterColor.FromKnownColor(RasterKnownColor.White));
   rotate.Run(image);

   // 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 using default options
   Console.WriteLine("Reading barcodes using default options");
   BarcodeData barcode = reader.ReadBarcode(image, LogicalRectangle.Empty, upcSymbologies, null);

   // Show its location and data if found
   // This will print out "Not 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");
   }

   // Now get the options we used previously, and change the 1D linear barcode read options
   // to search for barcodes in both horizontal and vertical directions
   // Note: Same options are used for UPCA and UPCE, so we only need one options class
   OneDBarcodeReadOptions oneDReadOptions = reader.GetDefaultOptions(BarcodeSymbology.UPCA) as OneDBarcodeReadOptions;

   // Change the read direction
   oneDReadOptions.SearchDirection = BarcodeSearchDirection.HorizontalAndVertical;

   // Try again using our options
   Console.WriteLine("Reading barcodes using our options");
   barcode = reader.ReadBarcode(image, LogicalRectangle.Empty, upcSymbologies, new BarcodeReadOptions[] { oneDReadOptions });

   // Show its location and data if found
   // This will find the barcode and print its information now
   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_ReadBarcodeExample4(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()

   ' Rotate the image by 90, so default option of reading horizonal barcodes will not work
   Console.WriteLine("Rotating the image by 90 degrees")
   Dim rotate As RotateCommand = New RotateCommand(90 * 100, RotateCommandFlags.Resize, RasterColor.FromKnownColor(RasterKnownColor.White))
   rotate.Run(image)

   ' 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 using default options
   Console.WriteLine("Reading barcodes using default options")
   Dim barcode As BarcodeData = reader.ReadBarcode(image, LogicalRectangle.Empty, upcSymbologies, Nothing)

   ' Show its location and data if found
   ' This will print out "Not 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

   ' Now get the options we used previously, and change the 1D linear barcode read options
   ' to search for barcodes in both horizontal and vertical directions
   ' Note: Same options are used for UPCA and UPCE, so we only need one options class
   Dim oneDReadOptions As OneDBarcodeReadOptions = TryCast(reader.GetDefaultOptions(BarcodeSymbology.UPCA), OneDBarcodeReadOptions)

   ' Change the read direction
   oneDReadOptions.SearchDirection = BarcodeSearchDirection.HorizontalAndVertical

   ' Try again using our options
   Console.WriteLine("Reading barcodes using our options")
   barcode = reader.ReadBarcode(image, LogicalRectangle.Empty, upcSymbologies, New BarcodeReadOptions() {oneDReadOptions})

   ' Show its location and data if found
   ' This will find the barcode and print its information now
   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

Requirements

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)
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