Using the Fast TWAIN Feature (C++ Builder)

Take the following steps to start a project and to add some code that acquires images using Fast Twain:

1.	Start C++ Builder 4.0.
2.	On the Project pull-down menu, use Import Type library… and select the LEAD RasterTwain Object Library (14.5). Press OK.
3.	On the Project pull-down menu, use Import Type library… and select the LEAD Raster Object Library (14.5). Press OK.
4.	On the Project pull-down menu, use Import Type library… and select the LEAD RasterIO Object Library (14.5). Press OK.
5.	Add the following code to the private section of Unit1.h:

LEADTwainCapability* pTwainCap;
LEADRasterTwain* pRasterTwain;
int nRet;

6.	Handle the Form1 OnCreate event, and code the FormCreate procedure as follows:

void __fastcall TForm1::FormCreate(TObject *Sender)
{
   CoCreateInstance (CLSID_LEADRasterTwainCapability, NULL, CLSCTX_ALL, IID_ICapability, (void **)&pTwainCap);
   CoCreateInstance(CLSID_LEADRasterTwain, NULL, CLSCTX_ALL, IID_ILEADRasterTwain, (void**)&pRasterTwain);
   pRasterTwain->UnlockSupport ( L_SUPPORT_DOCUMENT, AnsiToOLESTR ( "TestKey" ) ) ;
   pRasterTwain->InitSession ( (long)Handle ) ;
   pRasterTwain->EnableMethodErrors = False;
   rbMemory->Checked= True;
}

7.	Handle the Form1 OnClose event, and code the FormClose procedure as follows:

void __fastcall TForm1::FormClose(TObject *Sender, TCloseAction &Action)
{
   pRasterTwain->EndSession ( ) ;
   if ( pTwainCap )
      pTwainCap->Release ( ) ;

   if ( pRasterTwain )
      pRasterTwain->Release ( ) ;
}

8.	At the top of Form1, add check box and name it as follows:
	Name	Caption
	chkUseBufferSize	Use Buffer Size
9.	Add 2 radio buttons, and name them as follows:
	Name	Caption
	rbNative	Native Mode
	rbMemory	Memory Mode
10.	Add 1 button, and name it as follows:
	Name	Caption
	btnAcquire	Fast Acquire
11.	Add 2 Edit boxes, and name them as follows:

edtBufferSize
edtFName

12.	Handle the btnAcquire control's OnClick event, and code the btnAcquireClick procedure as follows. In online help, you can use the Edit pull-down menu to copy the block of code.

void __fastcall TForm1::btnAcquireClick(TObject *Sender)
{
   if ( rbMemory->Checked )
   {
      pRasterTwain->FastTransferMode = L_LTWAIN_BUFFER_MODE ;
     pRasterTwain->FastFormat = FILE_CCITT_GROUP4 ;
   }
   else
   {
      pRasterTwain->FastTransferMode = L_LTWAIN_NATIVE_MODE ;
      pRasterTwain->FastFormat = FILE_TIF;
   }

   pRasterTwain->FastBitsPerPixel = 1;
   pRasterTwain->FastUsePreferredBufferSize = chkUseBufferSize->Checked;
   if ( pRasterTwain->FastUsePreferredBufferSize )
      pRasterTwain->FastBufferSize = StrToInt(edtBufferSize->Text);

   nRet= pRasterTwain->AcquireMulti ( AnsiToOLESTR ( edtFName->Text.c_str() ), (long)(L_LTWAIN_SHOW_USER_INTERFACE | L_LTWAIN_USE_THREAD_MODE), (TOLEBOOL)true );
   if ( nRet == 0 )
      ShowMessage ( "Fast Scanning process done successfully..." ) ;
   else
    ShowMessage ( "AcquireMulti failed, Error = " + IntToStr ( nRet ) ) ;
}

13.	In the Unit1.h file include these files.

#include "LTRASTERTWAINLib_TLB.h"
#include "LTRASTERLib_TLB.h"
#include "LTRASTERIOLib_TLB.h"

14.	Save your project and run your program to test it.