HitTestZone Method

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Ocr; 
using Leadtools.Forms.Common; 
using Leadtools.Document.Writer; 
using Leadtools.WinForms; 
using Leadtools.Drawing; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
 
// Assume Form1 is a Windows.Forms form in your application 
 
// The OCR engine we are using 
private IOcrEngine _ocrEngine; 
// The OCR page we are using 
private IOcrPage _ocrPage; 
 
// Our raster image viewer instance 
private RasterImageViewer _viewer; 
 
public Form1() 
{ 
   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 
   RasterPaintProperties props = _viewer.PaintProperties; 
   props.PaintDisplayMode |= RasterPaintDisplayModeFlags.ScaleToGray; 
   _viewer.PaintProperties = props; 
 
   // Subscribe to the viewer events we need 
   _viewer.KeyDown += new KeyEventHandler(_viewer_KeyDown); 
   _viewer.MouseDown += new MouseEventHandler(_viewer_MouseDown); 
   _viewer.PostImagePaint += new PaintEventHandler(_viewer_PostImagePaint); 
 
   Controls.Add(_viewer); 
   _viewer.BringToFront(); 
 
   // Create and startup the OCR engine 
   _ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.LEAD); 
   _ocrEngine.Startup(null, null, null, LEAD_VARS.OcrLEADRuntimeDir); 
 
   // Load an image into the OCR document 
   string tifFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.tif"); 
   _ocrPage = _ocrEngine.CreatePage(_ocrEngine.RasterCodecsInstance.Load(tifFileName, 1), OcrImageSharingMode.AutoDispose); 
 
   // Do auto zone 
   _ocrPage.AutoZone(null); 
 
   // 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 
   IOcrZoneCollection ocrZones = _ocrPage.Zones; 
   for (int i = 0; i < ocrZones.Count; i++) 
   { 
      OcrZone ocrZone = ocrZones[i]; 
 
      // Construct the name from the ID 
      ocrZone.Name = string.Format("Zone {0}", ocrZone.Id); 
 
      ocrZones[i] = ocrZone; 
   } 
 
   // 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"; 
} 
 
protected override void OnFormClosed(FormClosedEventArgs e) 
{ 
   // Dispose the page 
   _ocrPage.Dispose(); 
 
   // Shutdown the OCR engine 
   _ocrEngine.Dispose(); 
 
   base.OnFormClosed(e); 
} 
 
private void _viewer_KeyDown(object sender, KeyEventArgs e) 
{ 
   const double zoomRatio = 1.2; 
   double scaleFactor = _viewer.ScaleFactor; 
 
   switch (e.KeyCode) 
   { 
      case Keys.Add: 
      case Keys.Oemplus: 
         // Zoom 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 != _viewer.ScaleFactor) 
   { 
      _viewer.BeginUpdate(); 
 
      // Yes, zoom keeping the center of the image 
 
      // Get what you see in physical coordinates 
      Rectangle rc = Rectangle.Intersect(_viewer.PhysicalViewRectangle, _viewer.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); 
      Transformer t = 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(); 
   } 
} 
 
private void _viewer_MouseDown(object sender, MouseEventArgs e) 
{ 
   // Perform hit-testing on the zones 
   if (_ocrEngine != null && _ocrEngine.IsStarted && _ocrPage != null && e.Button == MouseButtons.Left) 
   { 
      // Get the transform of the viewer 
      // Use the transform that takes the DPI into consideration since we turned that on 
      using (Matrix matrix = _viewer.GetTransformWithDpi()) 
      { 
         Transformer t = new Transformer(matrix); 
 
         // Convert the mouse click coordinates from physical (viewer) to logical (image) 
         PointF point = 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. 
         LeadPoint lPoint = new LeadPoint((int)point.X, (int)point.Y); 
         int zoneIndex = _ocrPage.HitTestZone(lPoint); 
         if (zoneIndex != -1) 
         { 
            // We hit a zone, loop through all the zones, unselect all but the hit tested zone 
            for (int index = 0; index < _ocrPage.Zones.Count; index++) 
            { 
               // 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 
 
               OcrZone ocrZone = _ocrPage.Zones[index]; 
 
               if (index != zoneIndex) 
                  ocrZone.Name = null; 
               else 
                  ocrZone.Name = "Selected"; 
 
               _ocrPage.Zones[index] = ocrZone; 
            } 
 
            // Re-paint the viewer to show the new zones 
            _viewer.Invalidate(); 
         } 
      } 
   } 
} 
 
private void _viewer_PostImagePaint(object sender, PaintEventArgs e) 
{ 
   // Draw the zones on the viewer in their correct location 
   if (_ocrEngine != null && _ocrEngine.IsStarted && _ocrPage != null) 
   { 
      // Get the transform of the viewer 
      // Use the transform that takes the DPI into consideration since we turned that on 
      using (Matrix matrix = _viewer.GetTransformWithDpi()) 
      { 
         Transformer t = new Transformer(matrix); 
 
         Pen normalPen = new Pen(Color.Blue, 1); 
         Pen selectedPen = new Pen(Color.Red, 2); 
         selectedPen.DashStyle = DashStyle.Dash; 
 
         foreach (OcrZone ocrZone in _ocrPage.Zones) 
         { 
            // Get the zone bounds in pixels 
            // You can also use _ocrPage.GetZoneBoundsInPixels here 
            RectangleF zoneBounds = new RectangleF(ocrZone.Bounds.Left, ocrZone.Bounds.Top, ocrZone.Bounds.Width, ocrZone.Bounds.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") 
               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); 
 
            // 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) 
            SizeF labelSize = e.Graphics.MeasureString(ocrZone.Name, Font); 
            RectangleF labelRectangle = 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); 
         } 
      } 
   } 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 
   public const string OcrLEADRuntimeDir = @"C:\LEADTOOLS22\Bin\Common\OcrLEADRuntime"; 
}