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Reading Barcodes
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Take the following steps to start a project:
Start Visual Studio .NET.
Choose File->New->Project... from the menu.
In the New Project dialog box, Choose either "Visual C# Projects" or "Visual Basic Projects" in the Projects Type List, and choose "Windows Application" (or "Windows Forms Application" in Visual Studio 2010) in the Templates List.
Type the project name as "ReadingBarcodes" in the Project Name field, and then choose OK. If desired, type a new location for your project or select a directory using the Browse button, and then choose OK.
In the "Solution Explorer" window, right-click on the "References" folder, and select "Add Reference..." from the context menu. In the Add Reference dialog box, select the ".NET" tab and browse to the "C:\LEADTOOLS 18\Bin\DotNet\Win32" folder (or "C:\LEADTOOLS 18\Bin\DotNet4\Win32" if you are going to use .NET 4) and select the following DLLs:
Click the Select button and then press the OK button to add the above DLLs to the application.
Switch to Form1 code view (right-click Form1 in the solution explorer then select View Code ) and add the following lines at the beginning of the file:
[Visual Basic]
Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.Forms
Imports Leadtools.Barcode
[C#]
using Leadtools;
using Leadtools.Codecs;
using Leadtools.Forms;
using Leadtools.Barcode;
Drag and drop two buttons in Form1. Change the following properties:
| Property | Value |
|---|---|
| Name | loadImageButton |
| Text | Load image |
| Name | readBarcodesButton |
| Text | Read barcodes |
Add the following private variables to Form1
[Visual Basic]
Private barcodeEngineInstance As BarcodeEngine ' The barcode engine
Private theImage As RasterImage ' The current loaded image
Private imageFileName As String ' Last file name we loaded, this is used in the "Writing Barcodes" tutorial
[C#]
private BarcodeEngine barcodeEngineInstance; // The barcode engine
private RasterImage theImage; // The current loaded image
private string imageFileName; // Last file name we loaded, this is used in the "Writing Barcodes" tutorial
Add the following initialization code to Form1
[Visual Basic]
Protected Overrides Sub OnLoad(ByVal e As EventArgs)
' Use the developer and license file by LEADTOOLS
Dim MY_LICENSE_FILE As String = "d:\temp\TestLic.lic"
Dim MY_DEVELOPER_KEY As String = "xyz123abc"
RasterSupport.SetLicense(MY_LICENSE_FILE, MY_DEVELOPER_KEY)
' Create the BarcodeEngine instance
barcodeEngineInstance = New BarcodeEngine()
MyBase.OnLoad(e)
End Sub
[C#]
protected override void OnLoad(EventArgs e)
{
// Replace the keys with unlock support string provided by LEADTOOLS, or use the evaluation kernel
// Unlock reading 1D barcodes
string MY_LICENSE_FILE = "d:\\temp\\TestLic.lic";
string MY_DEVELOPER_KEY = "xyz123abc";
RasterSupport.SetLicense(MY_LICENSE_FILE, MY_DEVELOPER_KEY);
// Create the BarcodeEngine instance
barcodeEngineInstance = new BarcodeEngine();
base.OnLoad(e);
}
Add the following clean up code to Form1
[Visual Basic]
Protected Overrides Sub OnFormClosed(ByVal e As FormClosedEventArgs)
' Delete our resources
If Not theImage Is Nothing Then
theImage.Dispose()
End If
MyBase.OnFormClosed(e)
End Sub
[C#]
protected override void OnFormClosed(FormClosedEventArgs e)
{
// Delete our resources
if(theImage != null)
{
theImage.Dispose();
}
base.OnFormClosed(e);
}
Add the following code to loadImageButton click procedure:
[Visual Basic]
Private Sub loadImageButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles loadImageButton.Click
Dim fileName As String = "C:\Users\Public\Documents\LEADTOOLS Images\Barcode1.tif"
' Or comment out the following to load your own file
' Using dlg As New OpenFileDialog
' If dlg.ShowDialog(Me) = System.Windows.Forms.DialogResult.OK Then
' fileName = dlg.FileName
' Else
' Return
' End If
' End Using
' Load the image
Using codecs As New RasterCodecs
Dim newImage As RasterImage = codecs.Load(fileName, 0, CodecsLoadByteOrder.BgrOrGray, 1, 1)
' Delete old image if any
If Not theImage Is Nothing Then
theImage.Dispose()
End If
theImage = newImage
imageFileName = fileName
End Using
End Sub
[C#]
private void loadImageButton_Click(object sender, EventArgs e)
{
string fileName = @"C:\Users\Public\Documents\LEADTOOLS Images\Barcode1.tif";
// Or comment out the following to load your own file
//using(OpenFileDialog dlg = new OpenFileDialog())
//{
// if(dlg.ShowDialog(this) == System.Windows.Forms.DialogResult.OK)
// {
// fileName = dlg.FileName;
// }
// else
// {
// return;
// }
//}
// Load the image
using(RasterCodecs codecs = new RasterCodecs())
{
string fileName = @"C:\Users\Public\Documents\LEADTOOLS Images\Barcode1.tif"
RasterImage newImage = codecs.Load(fileName, 0, CodecsLoadByteOrder.BgrOrGray, 1, 1);
// Delete old image if any
if(theImage != null)
{
theImage.Dispose();
}
theImage = newImage;
imageFileName = fileName;
}
}
Add the following code to readBarcodesButton click procedure:
[Visual Basic]
Private Sub readBarcodesButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles readBarcodesButton.Click
If theImage Is Nothing
MessageBox.Show("Load an image first")
Return
End If
Try
' Read all the barcodes
' The first parameter is the image from which to read the barcodes.
' The second parameter is the search rectangle. Pass an empty rectangle to indicate the entire image.
' The third parameter is the maximum number of barcodes to read. Pass 0 for all found in the image.
' The last parameter is an array of the BarcodeSymbology we are interested in. Pass null (or Nothing)
' to indicate that we do not care, and want all available barcodes to be read (found in the image and supported by
' the current unlock support mechanism)
Dim dataArray() As BarcodeData = barcodeEngineInstance.Reader.ReadBarcodes(theImage, LogicalRectangle.Empty, 0, Nothing)
Dim sb As New StringBuilder()
sb.AppendFormat("{0} barcode(s) found", dataArray.Length)
sb.AppendLine()
For i As Integer = 0 To dataArray.Length - 1
Dim data As BarcodeData = dataArray(i)
sb.AppendFormat("Symbology: {0}, Location: {1}, Data: {2}", data.Symbology.ToString(), data.Bounds.ToString(), data.Value)
sb.AppendLine()
Next
MessageBox.Show(sb.ToString())
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
End Sub
[C#]
private void readBarcodesButton_Click(object sender, EventArgs e)
{
if(theImage == null)
{
MessageBox.Show("Load an image first");
return;
}
try
{
// Read all the barcodes
// The first parameter is the image we want to read the barcodes from
// The second parameter is the search rectangle. Pass an empty rectangle to indicate the entire image.
// The third parameter is the maximum number of barcodes to read. Pass 0 for all barcodes found in the image.
// Last parameter is an array of the BarcodeSymbology we are interested in. Pass null (or Nothing)
// to indicate that we do not care, and want all barcodes available to be read(that have been found in the image and are supported by
// the current unlock support mechanism)
BarcodeData[] dataArray = barcodeEngineInstance.Reader.ReadBarcodes(theImage, LogicalRectangle.Empty, 0, null);
StringBuilder sb = new StringBuilder();
sb.AppendFormat("{0} barcode(s) found", dataArray.Length);
sb.AppendLine();
for(int i = 0; i < dataArray.Length; i++)
{
BarcodeData data = dataArray[i];
sb.AppendFormat("Symbology: {0}, Location: {1}, Data: {2}", data.Symbology.ToString(), data.Bounds.ToString(), data.Value);
sb.AppendLine();
}
MessageBox.Show(sb.ToString());
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
Build, and Run the program to test it. Click "Load Image" to load the image and "Read Barcodes" to search for and show the 1D barcodes that have been read.
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