LEADTOOLS Thunk Server

IMPORTANT: The following discussion is for the LEADTOOLS Plus, Professional and Arabic engines only. The LEADTOOLS Advantage engine supports multi-threading and x64 platform natively and does not require the use of a "thunk server".

The various OCR engines supported by LEAD were designed to work in the following environment:

1. 32-bit process
2. Single-threaded application

In the past, this enforced many restrictions on how you can use the LEADTOOLS OCR engines, for example, you could not use OCR in a server environment where multi-threading is a must, also you could not develop a 64-bit application and link it to the LEADTOOLS OCR class library.

LEAD developed the LEADTOOLS Thunk Server framework to work around these restrictions and enable the OCR engines to work in following environments:

1. Multi-threaded 32-bit applications
2. Link from a 64-bit process

The LEADTOOLS Thunk Server framework works in the background to isolate the OCR engine in a separate process and marshal the various method calls and data back and forth between the engine and your application. To use the LEADTOOLS thunk server in your .NET application, all you have to do is pass true to the useThunkServer parameter to the OcrEngineManager.CreateEngine method. The rest of your application code will remain unaffected. For more information and example code, refer to OcrEngineManager.

Distribution Files

Additional files need to be included in distribution files for your application if you chose to use the LEADTOOLS Thunk Server framework.

If your application is based on the LEADTOOLS .NET class library (Leadtools.Forms.Ocr), then you need to distribute the following files as part of your application:

File	Description
LtThunkServer.exe	COM+ thunk server
LtDocthunku.dll	Helper for the LEADTOOLS OCR Plus Engine
LtDocthunk2u.dll	Helper for the LEADTOOLS OCR Professional Engine
LtDocthunkaru.dll	Helper for the LEADTOOLS OCR Arabic Engine

If your application is based on the LEADTOOLS CDLL library (Ltdoc and Ltdoc2), then you need the above plus the following as part of the distribution files of your application:

File	Description
LtThunkutlu.dll	32-bit helper DLL for the LEADTOOLS CDLL framework
LtThunkutlx.dll	64-bit helper DLL for the LEADTOOLS CDLL framework

Starting the LEADTOOLS Thunk Server

The LEADTOOLS Thunk Server is based on COM+ technology. You should register the server as part of the setup procedure for your application. Perform the following steps to register the LEADTOOLS Thunk Server that ships with the LEADTOOLS .NET Class Library:

1. Go to Windows Command prompt

2. Run the following command:

   "C:\Program Files (x86)\LEAD Technologies\LEADTOOLS 16.5\Bin\Common\OCR Thunk\LtThunkServer.exe" /regserver

Your application should perform something similar to the above as part of the setup procedure.

Reference