Using the Fast TWAIN Feature (Visual Basic)

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

1.	Start Visual Basic.
2.	Add the LEAD RasterTwain Object Library and LEAD Raster Variant Object Library to your project.
	On the Project pull-down menu, use the References option, and select the LEAD RasterTwain Object Library.
	On the Project pull-down menu, use the References option, and select the LEAD Raster Variant Object Library.
3.	Add the LEAD Main Control to your project. On the Project pull-down menu, use the Components option, and select the LEAD Main ActiveX Control.
4.	Add the following code to the general declarations section of your project:

Public TwainCap As New LEADTwainCapability_U
Public WithEvents RasterTwain As LEADRasterTwain_U
Public nXferMode As Integer
Public nRet As Integer

5.	Add the following code to the main form's Load procedure:

Set RasterTwain = New LEADRasterTwain_U
RasterTwain.InitSession hWnd
RasterTwain.EnableMethodErrors = False
optMemory.Value = True

6.	Add the following code to the main form's Unload procedure:

RasterTwain.EndSession

7.	At the top of your main form, add 1 check box
	Name	Caption
	chkUseBufferSize	Use Buffer Size
8.	Add the following radio buttons:
	Name	Caption
	optNative	Native Mode
	optMemory	Memory Mode
9.	Add the following button:
	Name	Caption
	cmdAcquire	Fast Acquire
10.	Add the two text boxes and name them as follows:

txtBufferSize

txtFName

11.	Code the Fast Acquire control's Click procedure as follows. In online help, you can use the Edit pull-down menu to copy the block of code.

If optMemory.Value = True Then
   RasterTwain.FastTransferMode = L_LTWAIN_BUFFER_MODE
   RasterTwain.FastFormat = FILE_CCITT_GROUP4
Else
   RasterTwain.FastTransferMode = L_LTWAIN_NATIVE_MODE
   RasterTwain.FastFormat = FILE_TIF
End If

RasterTwain.FastBitsPerPixel = 1
RasterTwain.FastUsePreferredBufferSize = chkUseBufferSize.Value
RasterTwain.FastBufferSize = Val(txtBufferSize.Text)

nRet = RasterTwain.AcquireMulti(txtFName.Text, L_LTWAIN_SHOW_USER_INTERFACE Or L_LTWAIN_USE_THREAD_MODE, True)
If nRet = 0 Then
   MsgBox "Fast Scanning process completed successfully..."
Else
   MsgBox "The AcquireMulti method failed, Error = " + Str(nRet)
End If

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