// Assume Form1 is a Windwos.Forms form in your application
// The OCR engine we are using
private IOcrEngine _ocrEngine;
// The document we are using
private IOcrDocument _ocrDocument;
// Our raster image viewer instance
private RasterImageViewer _viewer;
public Form1()
{
InitializeComponent();
// Unlock the support needed for LEADTOOLS Plus OCR engine
RasterSupport.Unlock(RasterSupportType.Document, "Replace with your own key here");
RasterSupport.Unlock(RasterSupportType.OcrPlus, "Replace with your own key here");
RasterSupport.Unlock(RasterSupportType.OcrPlusPdfLeadOutput, "Replace with your own key here");
// 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.Plus, false);
_ocrEngine.Startup(null, null, null, null);
// Create the OCR document
_ocrDocument = _ocrEngine.DocumentManager.CreateDocument();
// Load an image into the OCR document
string tifFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.tif";
IOcrPage ocrPage = _ocrDocument.Pages.AddPage(tifFileName, null);
// 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 teh 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 document
_ocrDocument.Dispose();
// Shutdown the OCR engine
_ocrEngine.Shutdown();
_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:
// 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 != _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 && _ocrDocument != null && _ocrDocument.Pages.Count > 0 && 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 alternitave 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.
IOcrPage ocrPage = _ocrDocument.Pages[0];
int zoneIndex = ocrPage.HitTestZone(new LogicalPoint(point));
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].Selected = 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.Selected = false;
else
ocrZone.Selected = true;
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 && _ocrDocument != null && _ocrDocument.Pages.Count > 0)
{
// 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);
IOcrPage ocrPage = _ocrDocument.Pages[0];
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 = ocrZone.Bounds.ToRectangleF(ocrPage.DpiX, ocrPage.DpiY);
// 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.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);
}
}
}
} |
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