Take the following steps to create and run a program that shows how to interactively draw zones on an OCR page and how to recognize these zones. Remember, the purpose of the tutorials is to provide you with a quick and easy way to generate an OCR program:

1. Start Visual Studio 2005 or 2008

2. Choose File->New->Project from the menu

3. In the New Project dialog box, choose either "Visual C# Projects" or "Visual Basic Projects" in the Projects Type List, and choose "Windows Application" in Visual Studio 2005 or "Windows Forms Application" in Visual Studio 2008 from the Templates List

4. Type the project name as "OcrTutorial2" 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.

5. 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 LEADTOOLS For .NET "\LEAD Technologies\LEADTOOLS 16.5\Bin\DotNet\Win32" folder and select the following DLLs:

   • Leadtools.dll
   • Leadtools.Codecs.dll
   • Leadtools.WinForms.dll
   • Leadtools.Forms.dll
   • Leadtools.Forms.DocumentWriters.dll
   • Leadtools.Forms.Ocr.dll
   • Leadtools.Forms.Ocr.Plus.dll
   • Leadtools.Codecs.Bmp.dll
   • Leadtools.Codecs.Cmp.dll
   • Leadtools.Codecs.Tif.dll
   • Leadtools.Codecs.Fax.dll

   Note: The Leadtools.Codecs.*.dll references added are for the BMP, JPG, CMP, TIF and FAX image file formats. Add any additional file format codec DLL if required in your application.

6. Drag and drop a text box to your form. Leave the name as default (textBox1) and change the following properties:

   Property	Value
   Dock	Top
   Multiline	True
   ScrollBars	Both
   Size	460, 100

7. If you have not added the RasterImageViewer control to the Visual Studio toolbox, then select Tools->Choose Toolbox Items... from the menu, in the dialog box that show up, select the .NET Framework Components tab, click the Browse button and browse to LEADTOOLS For .NET "\LEAD Technologies\LEADTOOLS 16.5\Bin\DotNet\Win32" folder and select Leadtools.WinForms.dll. Hit OK to add the Leadtools.WinForms controls to your Visual Studio Toolbox (Including the RasterImageViewer control).

8. Drag and drop an instance of the RasterImageViewer control to your form. Leave the name as default "rasterImageViewer1" and change the following properties:

   Property	Value
   Dock	Fill
   InteractiveMode	None
   UseDpi	True

9. Using the Visual Studio designer, right click on rasterImageViewer1 and select Properties. Select the Events tab and add handlers to the following events:

   Event	Handler
   MouseDown	rasterImageViewer1_MouseDown
   MouseMove	rasterImageViewer1_MouseMove
   MouseUp	rasterImageViewer1_MouseUp
   KeyDown	rasterImageViewer1_KeyDown

10. 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 after any Imports or using section if there are any:

    [Visual Basic]

    
    Imports Leadtools
    Imports Leadtools.WinForms
    Imports Leadtools.Forms
    Imports Leadtools.Forms.DocumentWriters
    Imports Leadtools.Forms.Ocr
         

    [C#]

    
    using Leadtools;
    using Leadtools.WinForms
    using Leadtools.Forms;
    using Leadtools.Forms.DocumentWriters;
    using Leadtools.Forms.Ocr;
         

11. Add the following private variable to the Form1 class:

    [Visual Basic]

    
    ' The OCR engine instance
    Private _ocrEngine As IOcrEngine
     ' The OCR document
    Private _ocrDocument As IOcrDocument
    ' Are we currently rubber banding
    Private _isRubberBanding As Boolean
    ' The current rubber band rectangle
    Private _rubberBandingRectangle As Rectangle
    ' Flag to indicates if the rubber band rectangle is drawn
    Private _isRubberBandingRectangleDrawn As Boolean
    ' Did we clip the cursor?
    Private _saveClipRectangle As Rectangle
         

    [C#]

    
    // The OCR engine instance
    private IOcrEngine _ocrEngine;
    // The OCR document
    private IOcrDocument _ocrDocument;
    // Are we currently rubber banding
    private bool _isRubberBanding;
    // The current rubber band rectangle
    private Rectangle _rubberBandingRectangle;
    // Flag to indicates if the rubber band rectangle is drawn
    private bool _isRubberBandingRectangleDrawn;
    // Did we clip the cursor?
    private Rectangle _saveClipRectangle;
         

12. Add the following code to the Form1 constructor (in Visual Basic, you can copy/paste the whole Sub New code from here):

    [Visual Basic]

    
    Sub New()
       ' This call is required by the Windows Form Designer.
       InitializeComponent()
    
       ' Add any initialization after the InitializeComponent() call.
       ' Unlock the OCR support
       RasterSupport.Unlock(RasterSupportType.OcrPlus, "Replace with your own key here")
    
       ' Unlock Document support (For ScaleToGray)
       RasterSupport.Unlock(RasterSupportType.Document, "Replace with your own key here")
    
       ' Initialize the OCR engine
       _ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Plus, False)
    
       ' Startup the engine
       _ocrEngine.Startup(Nothing, Nothing, Nothing, Nothing)
    
       ' Create the OCR document
       _ocrDocument = _ocrEngine.DocumentManager.Create()
    
       ' Load an image into the OCR document
       Dim fileName As String = "C:\Users\Public\Documents\LEADTOOLS Images\Ocr1.tif"
       Dim page As IOcrPage = _ocrDocument.Pages.AddPage(fileName, Nothing)
    
       ' Enable ScaleToGray painting on the viewer
       ' This will greatly enhance how the image looks
       Dim props As RasterPaintProperties = RasterImageViewer1.PaintProperties
       props.PaintDisplayMode = props.PaintDisplayMode Or RasterPaintDisplayModeFlags.ScaleToGray
       RasterImageViewer1.PaintProperties = props
    
       ' We cannot handle the LostFocus event from the designer, so we will do it here
       AddHandler RasterImageViewer1.LostFocus, AddressOf rasterImageViewer1_LostFocus
    
       ' Show this image in the viewer
       RasterImageViewer1.Image = page.GetRasterImage()
    
       Text = "Use +/-/Enter on the keyboard to zoom in/out on the image. Use the mouse to draw a zone and recognize it"
    End Sub
         

    [C#]

    
    public Form1()
    {
       InitializeComponent();
    
       // Unlock the OCR support
       RasterSupport.Unlock(RasterSupportType.OcrPlus, "Replace with your own key here");
    
       // Unlock Document support (For ScaleToGray)
       RasterSupport.Unlock(RasterSupportType.Document, "Replace with your own key here");
    
       // Initialize the OCR engine
       _ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Plus, false);
    
       // Startup the engine
       _ocrEngine.Startup(null, null, null, null);
    
       // Create the OCR document
       _ocrDocument = _ocrEngine.DocumentManager.Create();
    
       // Load an image into the OCR document
       string fileName = @"C:\Users\Public\Documents\LEADTOOLS Images\Ocr1.tif";
       IOcrPage page = _ocrDocument.Pages.AddPage(fileName, null);
    
       // Enable ScaleToGray painting on the viewer
       // This will greatly enhance how the image looks
       RasterPaintProperties props = rasterImageViewer1.PaintProperties;
       props.PaintDisplayMode |= RasterPaintDisplayModeFlags.ScaleToGray;
       rasterImageViewer1.PaintProperties = props;
    
       // We cannot handle the LostFocus event from the designer, so we will do it here
       rasterImageViewer1.LostFocus += new EventHandler(rasterImageViewer1_LostFocus);
    
       // Show this image in the viewer
       rasterImageViewer1.Image = page.GetRasterImage();
    
       Text = "Use +/-/Enter on the keyboard to zoom in/out on the image. Use the mouse to draw a zone and recognize it";
    }
         

13. Override the Form1 closed event to add the code necessary to shutdown the OCR engine when the application terminates:

    [Visual Basic]

    
    Protected Overrides Sub OnFormClosed(ByVal e As FormClosedEventArgs)
       ' Destroy the document
       _ocrDocument.Dispose()
    
       ' Shutdown and dispose the engine
       _ocrEngine.Dispose()
    
       MyBase.OnFormClosed(e)
    End Sub
         

    [C#]

    
    protected override void OnFormClosed(FormClosedEventArgs e)
    {
       // Destroy the document
       _ocrDocument.Dispose();
    
       // Shutdown and dispose the engine
       _ocrEngine.Dispose();
    
       base.OnFormClosed(e);
    }
         

14. Add the following code to rasterImageViewer1MouseDown event handler:

    [Visual Basic]

    
    Private Sub RasterImageViewer1_MouseDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles RasterImageViewer1.MouseDown
       RasterImageViewer1.Focus()
    
       ' Cancel rubber banding if it is on
       If (_isRubberBanding) Then
          EndRubberBanding()
       Else
          If (e.Button = MouseButtons.Left) Then
             ' See if the click is on the image
             Dim rect As Rectangle = RasterImageViewer1.PhysicalViewRectangle
             If (rect.Contains(e.X, e.Y)) Then
                ' Start the rubber banding
                BeginRubberBanding(Rectangle.FromLTRB(e.X, e.Y, e.X, e.Y))
             End If
          End If
       End If
    End Sub
         

    [C#]

    
    private void rasterImageViewer1_MouseDown(object sender, MouseEventArgs e)
    {
       rasterImageViewer1.Focus();
    
       // Cancel rubber banding if it is on
       if(_isRubberBanding)
          EndRubberBanding();
       else
       {
          if(e.Button == MouseButtons.Left)
          {
             // See if the click is on the image
             Rectangle rect = rasterImageViewer1.PhysicalViewRectangle;
             if(rect.Contains(e.X, e.Y))
             {
                // Start the rubber banding
                BeginRubberBanding(Rectangle.FromLTRB(e.X, e.Y, e.X, e.Y));
             }
          }
       }
    }
         

15. Add the following code to the rasterImageViewer1MouseMove event handler:

    [Visual Basic]

    
    Private Sub RasterImageViewer1_MouseMove(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles RasterImageViewer1.MouseMove
       ' If we are rubber banding, erase the old rectangle, update the position and draw the new rectangle
       If (_isRubberBanding) Then
          DrawRubberBandRectangle()
    
          _rubberBandingRectangle = Rectangle.FromLTRB( _
             _rubberBandingRectangle.Left, _
             _rubberBandingRectangle.Top, _
             e.X, _
             e.Y)
    
          DrawRubberBandRectangle()
       End If
    End Sub
         

    [C#]

    
    private void rasterImageViewer1_MouseMove(object sender, MouseEventArgs e)
    {
       // If we are rubber banding, erase the old rectangle, update the position and draw the new rectangle
       if(_isRubberBanding)
       {
          DrawRubberBandRectangle();
    
          _rubberBandingRectangle = Rectangle.FromLTRB(
             _rubberBandingRectangle.Left,
             _rubberBandingRectangle.Top,
             e.X,
             e.Y);
    
          DrawRubberBandRectangle();
       }
    }
         

16. Add the following code to the rasterImageViewer1MouseUp event handler:

    [Visual Basic]

    
    Private Sub RasterImageViewer1_MouseUp(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles RasterImageViewer1.MouseUp
       ' If we are rubber banding, end it
       If (_isRubberBanding) Then
          EndRubberBanding()
    
          Dim bounds As RectangleF = _rubberBandingRectangle
    
          ' This rectangle is in physical coordinates, convert it to logical
          Using matrix As System.Drawing.Drawing2D.Matrix = RasterImageViewer1.GetTransformWithDpi()
             Dim t As New Transformer(matrix)
             bounds = t.RectangleToLogical(bounds)
          End Using
    
          ' Add the zone and recognize it
          AddAndRecognizeZone(bounds)
       End If
    End Sub
         

    [C#]

    
    private void rasterImageViewer1_MouseUp(object sender, MouseEventArgs e)
    {
       // If we are rubber banding, end it
       if(_isRubberBanding)
       {
          EndRubberBanding();
    
          RectangleF bounds = _rubberBandingRectangle;
    
          // This rectangle is in physical coordinates, convert it to logical
          using(System.Drawing.Drawing2D.Matrix matrix = rasterImageViewer1.GetTransformWithDpi())
          {
             Transformer t = new Transformer(matrix);
             bounds = t.RectangleToLogical(bounds);
          }
    
          // Add the zone and recognize it
          AddAndRecognizeZone(bounds);
       }
    }
         

17. Add the following code to the rasterImageViewer1LostFocus event handler:

    [Visual Basic]

    
    Private Sub RasterImageViewer1_LostFocus(ByVal sender As System.Object, ByVal e As System.EventArgs)
       ' If we are rubber banding, cancel it
       If (_isRubberBanding) Then
          EndRubberBanding()
       End If
    End Sub
         

    [C#]

    
    private void rasterImageViewer1_LostFocus(object sender, EventArgs e)
    {
       // If we are rubber banding, cancel it
       if(_isRubberBanding)
          EndRubberBanding();
    }
         

18. Add the following code to the rasterImageViewer1KeyDown event handler:

    [Visual Basic]

    
    Private Sub RasterImageViewer1_KeyDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles RasterImageViewer1.KeyDown
       ' Zoom in and out using the mouse keys
       Const zoomRatio As Double = 1.2
       Dim scaleFactor As Double = RasterImageViewer1.ScaleFactor
    
       Select Case (e.KeyCode)
          Case Keys.Add, Keys.Oemplus
             ' Zoon in
             scaleFactor *= zoomRatio
             e.Handled = True
    
          Case Keys.Subtract, Keys.OemMinus
             ' Zone out
             scaleFactor /= zoomRatio
             e.Handled = True
    
          Case Keys.Enter
             scaleFactor = 1
             e.Handled = True
       End Select
    
       Const minimumScaleFactor As Double = 0.05
       Const maximumScaleFactor As Double = 11
    
       scaleFactor = Math.Max(minimumScaleFactor, Math.Min(maximumScaleFactor, scaleFactor))
    
       ' Check if scale factor has changed
       If (scaleFactor <> RasterImageViewer1.ScaleFactor) Then
          RasterImageViewer1.BeginUpdate()
    
          ' Yes, zoom keeping the center of the image
    
          ' Get what you see in physical coordinates
          Dim rc As Rectangle = Rectangle.Intersect(RasterImageViewer1.PhysicalViewRectangle, RasterImageViewer1.ClientRectangle)
          ' Get the center of what you see in physical coordinates
          Dim center As New PointF(rc.Left + rc.Width \ 2, rc.Top + rc.Height \ 2)
          Using matrix As System.Drawing.Drawing2D.Matrix = RasterImageViewer1.GetTransformWithDpi()
             Dim t As New Transformer(matrix)
             ' Get the center of what you see in logical coordinates
             center = t.PointToLogical(center)
          End Using
    
          RasterImageViewer1.ScaleFactor = scaleFactor
    
          ' Bring the original center into the view center
          Using matrix As System.Drawing.Drawing2D.Matrix = RasterImageViewer1.GetTransformWithDpi()
             Dim t As New Transformer(matrix)
             ' Get the center of what you saw before the zoom in physical coordinates
             center = t.PointToPhysical(center)
          End Using
    
          ' Bring the old center into the center of the view
          RasterImageViewer1.CenterAtPoint(Point.Round(center))
    
          RasterImageViewer1.EndUpdate()
       End If
    End Sub
         

    [C#]

    
    private void rasterImageViewer1_KeyDown(object sender, KeyEventArgs e)
    {
       // Zoom in and out using the mouse keys
       const double zoomRatio = 1.2;
       double scaleFactor = rasterImageViewer1.ScaleFactor;
    
       switch(e.KeyCode)
       {
          case Keys.Add:
          case Keys.Oemplus:
             // Zoon in
             scaleFactor *= zoomRatio;
             e.Handled = true;
             break;
    
          case Keys.Subtract:
          case Keys.OemMinus:
             // Zone out
             scaleFactor /= zoomRatio;
             e.Handled = true;
             break;
    
          case Keys.Enter:
             scaleFactor = 1;
             e.Handled = true;
             break;
       }
    
       const double minimumScaleFactor = 0.05;
       const double maximumScaleFactor = 11;
    
       scaleFactor = Math.Max(minimumScaleFactor, Math.Min(maximumScaleFactor, scaleFactor));
    
       // Check if scale factor has changed
       if(scaleFactor != rasterImageViewer1.ScaleFactor)
       {
          rasterImageViewer1.BeginUpdate();
    
          // Yes, zoom keeping the center of the image
    
          // Get what you see in physical coordinates
          Rectangle rc = Rectangle.Intersect(rasterImageViewer1.PhysicalViewRectangle, rasterImageViewer1.ClientRectangle);
          // Get the center of what you see in physical coordinates
          PointF center = new PointF(rc.Left + rc.Width / 2, rc.Top + rc.Height / 2);
          using(System.Drawing.Drawing2D.Matrix matrix = rasterImageViewer1.GetTransformWithDpi())
          {
             Transformer t = new Transformer(matrix);
             // Get the center of what you see in logical coordinates
             center = t.PointToLogical(center);
          }
    
          rasterImageViewer1.ScaleFactor = scaleFactor;
    
          // Bring the original center into the view center
          using(System.Drawing.Drawing2D.Matrix matrix = rasterImageViewer1.GetTransformWithDpi())
          {
             Transformer t = new Transformer(matrix);
             // Get the center of what you saw before the zoom in physical coordinates
             center = t.PointToPhysical(center);
          }
    
          // Bring the old center into the center of the view
          rasterImageViewer1.CenterAtPoint(Point.Round(center));
    
          rasterImageViewer1.EndUpdate();
       }
    }
         

19. Add the following private methods to Form1 to handle the rubber banding:

    [Visual Basic]

    
    ' Begins the rubber banding operation
    Private Sub BeginRubberBanding(ByVal rect As Rectangle)
       _rubberBandingRectangle = rect
    
       _isRubberBanding = True
       RasterImageViewer1.Capture = True
    
       ' Clip the cursor
       ClipCursor(True)
    
       DrawRubberBandRectangle()
    End Sub
    
    ' Ends the rubber banding operation
    Private Sub EndRubberBanding()
       ' Stop clipping the cursor
       ClipCursor(False)
    
       RasterImageViewer1.Capture = False
       _isRubberBanding = False
    
       If (_isRubberBandingRectangleDrawn) Then
          DrawRubberBandRectangle()
       End If
    End Sub
    
    ' Draws the rubberband rectangle on the viewer
    Private Sub DrawRubberBandRectangle()
       Dim rect As Rectangle = FixRectangle(_rubberBandingRectangle)
       rect.Width = rect.Width + 1
       rect.Height = rect.Height + 1
       rect = RasterImageViewer1.RectangleToScreen(rect)
       ControlPaint.DrawReversibleFrame(rect, Color.Transparent, FrameStyle.Thick)
    
       _isRubberBandingRectangleDrawn = Not _isRubberBandingRectangleDrawn
    End Sub
    
    ' Clips the mouse cursor on the dimension of the image in the viewer
    Private Sub ClipCursor(ByVal clip As Boolean)
       If (clip) Then
          Dim rect As Rectangle = Rectangle.Intersect(FixRectangle(RasterImageViewer1.PhysicalViewRectangle), RasterImageViewer1.ClientRectangle)
          rect = RasterImageViewer1.RectangleToScreen(rect)
          Dim prnt As Control = RasterImageViewer1.Parent
          Do While (Not prnt Is Nothing)
             rect = Rectangle.Intersect(rect, RasterImageViewer1.Parent.RectangleToScreen(RasterImageViewer1.Parent.ClientRectangle))
             If (TypeOf prnt Is Form) Then
                Dim f As Form = CType(Parent, Form)
                If (f.IsMdiChild) Then
                   If (Not f.Owner Is Nothing) Then
                      rect = Rectangle.Intersect(rect, f.Owner.RectangleToScreen(f.Owner.ClientRectangle))
                   ElseIf (Not f.Parent Is Nothing) Then
                      rect = Rectangle.Intersect(rect, f.Parent.RectangleToScreen(f.Parent.ClientRectangle))
                   End If
                End If
             End If
    
             prnt = prnt.Parent
          Loop
    
          rect.Height = rect.Height + 1
          rect.Width = rect.Width + 1
    
          _saveClipRectangle = Cursor.Clip
          Cursor.Clip = rect
       Else
          Cursor.Clip = _saveClipRectangle
          _saveClipRectangle = Rectangle.Empty
       End If
    End Sub
    
    ' Fox the rectangle coordinates is inverted (its right or bottom value greater than its left or top)
    Private Shared Function FixRectangle(ByVal rect As Rectangle) As Rectangle
       If (rect.Left > rect.Right) Then
          rect = Rectangle.FromLTRB(rect.Right, rect.Top, rect.Left, rect.Bottom)
       End If
       If (rect.Top > rect.Bottom) Then
          rect = Rectangle.FromLTRB(rect.Left, rect.Bottom, rect.Right, rect.Top)
       End If
    
       Return rect
    End Function
         

    [C#]

    
    // Begins the rubber banding operation
    private void BeginRubberBanding(Rectangle rect)
    {
       _rubberBandingRectangle = rect;
    
       _isRubberBanding = true;
       rasterImageViewer1.Capture = true;
    
       // Clip the cursor
       ClipCursor(true);
    
       DrawRubberBandRectangle();
    }
    
    // Ends the rubber banding operation
    private void EndRubberBanding()
    {
       // Stop clipping the cursor
       ClipCursor(false);
    
       rasterImageViewer1.Capture = false;
       _isRubberBanding = false;
    
       if(_isRubberBandingRectangleDrawn)
          DrawRubberBandRectangle();
    }
    
    // Draws the rubberband rectangle on the viewer
    private void DrawRubberBandRectangle()
    {
       Rectangle rect = FixRectangle(_rubberBandingRectangle);
       rect.Width++;
       rect.Height++;
       rect = rasterImageViewer1.RectangleToScreen(rect);
       ControlPaint.DrawReversibleFrame(rect, Color.Transparent, FrameStyle.Thick);
    
       _isRubberBandingRectangleDrawn = !_isRubberBandingRectangleDrawn;
    }
    
    // Clips the mouse cursor on the dimension of the image in the viewer
    private void ClipCursor(bool clip)
    {
       if(clip)
       {
          Rectangle rect = Rectangle.Intersect(FixRectangle(rasterImageViewer1.PhysicalViewRectangle), rasterImageViewer1.ClientRectangle);
          rect = rasterImageViewer1.RectangleToScreen(rect);
          Control parent = rasterImageViewer1.Parent;
          while(parent != null)
          {
             rect = Rectangle.Intersect(rect, rasterImageViewer1.Parent.RectangleToScreen(rasterImageViewer1.Parent.ClientRectangle));
             if(parent is Form)
             {
                Form form = parent as Form;
                if(form.IsMdiChild)
                {
                   if(form.Owner != null)
                      rect = Rectangle.Intersect(rect, form.Owner.RectangleToScreen(form.Owner.ClientRectangle));
                   else if(form.Parent != null)
                      rect = Rectangle.Intersect(rect, form.Parent.RectangleToScreen(form.Parent.ClientRectangle));
                }
             }
    
             parent = parent.Parent;
          }
    
          rect.Height += 1;
          rect.Width += 1;
    
          _saveClipRectangle = Cursor.Clip;
          Cursor.Clip = rect;
       }
       else
       {
          Cursor.Clip = _saveClipRectangle;
          _saveClipRectangle = Rectangle.Empty;
       }
    }
    
    // Fox the rectangle coordinates is inverted (its right or bottom value greater than its left or top)
    private static Rectangle FixRectangle(Rectangle rect)
    {
       if(rect.Left > rect.Right)
          rect = Rectangle.FromLTRB(rect.Right, rect.Top, rect.Left, rect.Bottom);
       if(rect.Top > rect.Bottom)
          rect = Rectangle.FromLTRB(rect.Left, rect.Bottom, rect.Right, rect.Top);
    
       return rect;
    }
         

20. Add the following private method to Form1 to add the zone to the page, recognize and show the results:

    [Visual Basic]

    
    Private Sub AddAndRecognizeZone(ByVal bounds As RectangleF)
       Dim page As IOcrPage = _ocrDocument.Pages(0)
    
       ' First clear any previous zones from the page
       page.Zones.Clear()
    
       ' Add a zone with the given coordinates to the page
       Dim zone As New OcrZone()
       zone.Bounds = New LogicalRectangle(bounds)
       ' Leave the rest of the zone properties as default
    
       page.Zones.Add(zone)
    
       ' Recognize the page now and get the results as a string
       Dim txt As String = page.RecognizeText(Nothing)
    
       ' Put the results in the text box
       TextBox1.Text = txt
    End Sub
         

    [C#]

    
    private void AddAndRecognizeZone(RectangleF bounds)
    {
       IOcrPage page = _ocrDocument.Pages[0];
    
       // First clear any previous zones from the page
       page.Zones.Clear();
    
       // Add a zone with the given coordinates to the page
       OcrZone zone = new OcrZone();
       zone.Bounds = new LogicalRectangle(bounds);
       // Leave the rest of the zone properties as default
    
       page.Zones.Add(zone);
    
       // Recognize the page now and get the results as a string
       string txt = page.RecognizeText(null);
    
       // Put the results in the text box
       TextBox1.Text = txt;
    }
         

21. Build and Run the project to test it. After the program starts, you can use the +, - and Enter key to zoom in and out of the page. Use the mouse to draw a zone on the page, once a zone is drawn, the text inside will show up in the text box.

22. Save this project to use for testing other code samples.

Reference