HitTestZone Method

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.Ocr 
Imports Leadtools.Forms 
Imports Leadtools.Document.Writer 
Imports Leadtools.WinForms 
Imports Leadtools.Drawing 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Color 
 
' Assume Form1 is a Windows.Forms form in your application 
 
' The OCR engine we are using 
Private _ocrEngine As IOcrEngine 
' The OCR page we are using 
Private _ocrPage As IOcrPage 
 
' Our raster image viewer instance 
Private _viewer As RasterImageViewer 
 
Public Sub New() 
   InitializeComponent() 
 
   ' Initialize the raster image viewer 
   ' Turn on use DPI, center the image, add border padding and frame shadow to show that our calculations will be 
   ' independent on all of those extra options 
   _viewer = New RasterImageViewer() 
   _viewer.Dock = DockStyle.Fill 
   _viewer.BackColor = SystemColors.AppWorkspace 
   _viewer.UseDpi = True 
   _viewer.BorderPadding.All = 8 
   _viewer.FrameSize = New SizeF(1, 1) 
   _viewer.FrameShadowSize = New SizeF(2, 2) 
   _viewer.SizeMode = RasterPaintSizeMode.Normal 
   _viewer.HorizontalAlignMode = RasterPaintAlignMode.Center 
   _viewer.VerticalAlignMode = RasterPaintAlignMode.Center 
   _viewer.AutoDisposeImages = True 
   _viewer.InteractiveMode = RasterViewerInteractiveMode.None 
 
   ' Turn on scale to gray painting in the viewer 
   Dim props As RasterPaintProperties = _viewer.PaintProperties 
   props.PaintDisplayMode = props.PaintDisplayMode Or RasterPaintDisplayModeFlags.ScaleToGray 
   _viewer.PaintProperties = props 
 
   ' Subscribe to the viewer events we need 
   AddHandler _viewer.KeyDown, AddressOf _viewer_KeyDown 
   AddHandler _viewer.MouseDown, AddressOf _viewer_MouseDown 
   AddHandler _viewer.PostImagePaint, AddressOf _viewer_PostImagePaint 
 
   Controls.Add(_viewer) 
   _viewer.BringToFront() 
 
   ' Create and startup the OCR engine 
   _ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.LEAD, False) 
   _ocrEngine.Startup(Nothing, Nothing, Nothing, LEAD_VARS.OcrLEADRuntimeDir) 
 
   ' Load an image into the OCR document 
   Dim tifFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.tif") 
   _ocrPage = _ocrEngine.CreatePage(_ocrEngine.RasterCodecsInstance.Load(tifFileName, 1), OcrImageSharingMode.AutoDispose) 
 
   ' Do auto zone 
   _ocrPage.AutoZone(Nothing) 
 
   ' AutoZone does not specify a name for the zones, so loop through all the zones and set their names 
   ' to a unique value. We will use the name in the paint code later 
   Dim ocrZones As IOcrZoneCollection = _ocrPage.Zones 
   For i As Integer = 0 To ocrZones.Count - 1 
      Dim ocrZone As OcrZone = ocrZones(i) 
 
      ' Construct the name from the ID 
      ocrZone.Name = String.Format("Zone {0}", ocrZone.Id) 
 
      ocrZones(i) = ocrZone 
   Next 
 
   ' Show the same image in the viewer 
   _viewer.Image = _ocrPage.GetRasterImage() 
 
   ' Note, the image we got from GetRasterImage is a copy of the image in the engine 
   ' Since we set the AutoDisposeImages of the viewer to "true", the image will be disposed 
   ' when the viewer is disposed at application termination 
 
   Text = "+ to zoom in, - to zoom out, enter to return to 100%. Select the zones with the mouse" 
End Sub 
 
Protected Overrides Sub OnFormClosed(e As FormClosedEventArgs) 
   ' Dispose the page 
   _ocrPage.Dispose() 
 
   ' Shutdown the OCR engine 
   _ocrEngine.Dispose() 
 
   MyBase.OnFormClosed(e) 
End Sub 
 
Private Sub _viewer_KeyDown(sender As Object, e As KeyEventArgs) 
   Const zoomRatio As Double = 1.2 
   Dim scaleFactor As Double = _viewer.ScaleFactor 
 
   Select Case e.KeyCode 
      Case Keys.Add, Keys.Oemplus 
         ' Zoom in 
         scaleFactor *= zoomRatio 
         e.Handled = True 
         Exit Select 
 
      Case Keys.Subtract, Keys.OemMinus 
         ' Zoom out 
         scaleFactor /= zoomRatio 
         e.Handled = True 
         Exit Select 
 
      Case Keys.Enter 
         scaleFactor = 1 
         e.Handled = True 
         Exit Select 
   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 <> _viewer.ScaleFactor Then 
      _viewer.BeginUpdate() 
 
      ' Yes, zoom keeping the center of the image 
 
      ' Get what you see in physical coordinates 
      Dim rc As Rectangle = Rectangle.Intersect(_viewer.PhysicalViewRectangle, _viewer.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) 
      Dim t As New Transformer(_viewer.Transform) 
      ' Get the center of what you see in logical coordinates 
      center = t.PointToLogical(center) 
 
      _viewer.ScaleFactor = scaleFactor 
 
      ' Bring the original center into the view center 
      t = New Transformer(_viewer.Transform) 
      ' 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 
      _viewer.CenterAtPoint(Point.Round(center)) 
 
      _viewer.EndUpdate() 
   End If 
End Sub 
 
Private Sub _viewer_MouseDown(sender As Object, e As MouseEventArgs) 
   ' Perform hit-testing on the zones 
   If _ocrEngine IsNot Nothing AndAlso _ocrEngine.IsStarted AndAlso _ocrPage IsNot Nothing AndAlso e.Button = MouseButtons.Left Then 
      ' Get the transform of the viewer 
      ' Use the transform that takes the DPI into consideration since we turned that on 
      Using matrix As Matrix = _viewer.GetTransformWithDpi() 
         Dim t As New Transformer(matrix) 
 
         ' Convert the mouse click coordinates from physical (viewer) to logical (image) 
         Dim point As New PointF(e.X, e.Y) 
         point = t.PointToLogical(point) 
 
         ' Hit test the zones 
         ' An alternative to calling HitTestZone is to loop through all the zones 
         ' and get the value of .Bounds in pixels, then check if the point is inside 
         ' the boundaries. 
         Dim lPoint As New LeadPoint(CInt(Math.Truncate(point.X)), CInt(Math.Truncate(point.Y))) 
         Dim zoneIndex As Integer = _ocrPage.HitTestZone(lPoint) 
         If zoneIndex <> -1 Then 
            ' We hit a zone, loop through all the zones, unselect all but the hit tested zone 
            For index As Integer = 0 To _ocrPage.Zones.Count - 1 
               ' Since OcrZone is a structure, we cannot simply do 
               ' ocrZone.Zones[index].Name = value 
               ' We have to get a copy of the structure, modify it and set it back 
 
               Dim ocrZone As OcrZone = _ocrPage.Zones(index) 
 
               If index <> zoneIndex Then 
                  ocrZone.Name = Nothing 
               Else 
                  ocrZone.Name = "Selected" 
               End If 
 
               _ocrPage.Zones(index) = ocrZone 
            Next 
 
            ' Re-paint the viewer to show the new zones 
            _viewer.Invalidate() 
         End If 
      End Using 
   End If 
End Sub 
 
Private Sub _viewer_PostImagePaint(sender As Object, e As PaintEventArgs) 
   ' Draw the zones on the viewer in their correct location 
   If _ocrEngine IsNot Nothing AndAlso _ocrEngine.IsStarted AndAlso _ocrPage IsNot Nothing Then 
      ' Get the transform of the viewer 
      ' Use the transform that takes the DPI into consideration since we turned that on 
      Using matrix As Matrix = _viewer.GetTransformWithDpi() 
         Dim t As New Transformer(matrix) 
 
         Dim normalPen As New Pen(Color.Blue, 1) 
         Dim selectedPen As New Pen(Color.Red, 2) 
         selectedPen.DashStyle = DashStyle.Dash 
 
         For Each ocrZone As OcrZone In _ocrPage.Zones 
            ' Get the zone bounds in pixels 
            ' You can also use _ocrPage.GetZoneBoundsInPixels here 
            Dim ltzoneBounds As LeadRect = ocrZone.Bounds 
            Dim zoneBounds As New RectangleF(ltzoneBounds.Left, ltzoneBounds.Top, ltzoneBounds.Width, ltzoneBounds.Height) 
 
            ' This rectangle is in image (logical) coordinates with top-left view perspective 
            ' Convert to the physical coordinates of the viewer 
            zoneBounds = t.RectangleToPhysical(zoneBounds) 
 
            ' Now draw this zone on the viewer surface 
            If ocrZone.Name = "Selected" Then 
               e.Graphics.DrawRectangle(selectedPen, zoneBounds.X, zoneBounds.Y, zoneBounds.Width - 1, zoneBounds.Height - 1) 
            Else 
               e.Graphics.DrawRectangle(normalPen, zoneBounds.X, zoneBounds.Y, zoneBounds.Width - 1, zoneBounds.Height - 1) 
            End If 
 
            ' Draw the zone name on the left hand corner of the zone 
            ' Note, in a real application you might want to have an option to show/hide the zone names (labels) 
            Dim labelSize As SizeF = e.Graphics.MeasureString(ocrZone.Name, Font) 
            Dim labelRectangle As New RectangleF(zoneBounds.X, zoneBounds.Y - labelSize.Height, labelSize.Width, labelSize.Height) 
            e.Graphics.FillRectangle(Brushes.Yellow, labelRectangle) 
            e.Graphics.DrawString(ocrZone.Name, Font, Brushes.Black, labelRectangle.X, labelRectangle.Y) 
         Next 
      End Using 
   End If 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" 
   Public Const OcrLEADRuntimeDir As String = "C:\LEADTOOLS 20\Bin\Common\OcrLEADRuntime" 
End Class