public TesseractEngine(string dataPath, string language, EngineMode engineMode)
{
if (dataPath == null)
{
throw new ArgumentNullException(nameof(dataPath));
}
if (dataPath == string.Empty)
{
throw new ArgumentException("Data path is empty.", nameof(dataPath));
}
if (language == null)
{
throw new ArgumentNullException(nameof(language));
}
dataPath = dataPath.Trim();
if (dataPath.EndsWith("\\", StringComparison.Ordinal) || dataPath.EndsWith("/", StringComparison.Ordinal))
{
dataPath = dataPath.Substring(0, dataPath.Length - 1);
}
_handle = new HandleRef(this, Tesseract4.TessBaseAPICreate());
if (Tesseract4.TessBaseAPIInit2(_handle, dataPath, language, (int)engineMode) == 0)
{
return;
}
_handle = new HandleRef(this, IntPtr.Zero);
GC.SuppressFinalize(this);
throw new TesseractException("Failed to initialise tesseract engine.");
}
private void ReleaseUnmanagedResources()
{
if (_handle.Handle == IntPtr.Zero)
{
return;
}
Tesseract4.TessDeleteText(_handle.Handle);
_handle = new HandleRef(this, IntPtr.Zero);
}
public TesseractEngine(string dataPath, string language, EngineMode engineMode)
{
if (dataPath == null)
{
throw new ArgumentNullException(nameof(dataPath));
}
if (dataPath == string.Empty)
{
throw new ArgumentException("Data path is empty.", nameof(dataPath));
}
if (language == null)
{
throw new ArgumentNullException(nameof(language));
}
dataPath = dataPath.Trim();
if (dataPath.EndsWith("\\", StringComparison.Ordinal) || dataPath.EndsWith("/", StringComparison.Ordinal))
{
dataPath = dataPath.Substring(0, dataPath.Length - 1);
}
if (!Directory.Exists(dataPath))
{
if (Debugger.IsAttached)
{
dataPath = Path.Combine(Path.GetDirectoryName(Assembly.GetEntryAssembly()?.Location) ?? Directory.GetCurrentDirectory(), dataPath);
}
else
{
throw new TesseractException($"Tesseract data path does not exists. Current directory: {Directory.GetCurrentDirectory()}. Supplied data path: {dataPath}.");
}
}
_handle = new HandleRef(this, Tesseract4.TessBaseAPICreate());
if (Tesseract4.TessBaseAPIInit2(_handle, dataPath, language, (int)engineMode) == 0)
{
return;
}
_handle = new HandleRef(this, IntPtr.Zero);
GC.SuppressFinalize(this);
throw new TesseractException("Failed to initialise tesseract engine.");
}
public ITesseractResult Process(IPix image)
{
if (image == null)
{
throw new ArgumentNullException(nameof(image));
}
if (Interlocked.CompareExchange(ref _processCount, 1, 0) != 0)
{
throw new InvalidOperationException("Only one image can be processed at once. Please make sure you dispose of the page once your finished with it.");
}
try
{
const PageSegmentMode pageSegMode = PageSegmentMode.Auto;
Tesseract4.TessBaseAPISetPageSegMode(_handle, (int)pageSegMode);
Tesseract4.TessBaseAPISetImage2(_handle, image.HandleRef);
if (Tesseract4.TessBaseAPIRecognize(_handle, out var rec) != 0)
{
throw new TesseractException("Recognition of image failed.");
}
using var text = Text.Create(() => Tesseract4.TessBaseAPIGetUTF8Text(_handle));
using var hocrText = Text.Create(() => Tesseract4.TessBaseAPIGetHOCRText(_handle, 0));
return(new TesseractResult
{
Text = text.ToString(),
HocrText = $"{Tags.XhtmlBeginTag}{hocrText}{Tags.XhtmlEndTag}",
Confidence = null
});
}
finally
{
Tesseract4.TessBaseAPIClear(_handle);
Interlocked.Decrement(ref _processCount);
}
}