Visual Basic Sample Program
The following Visual Basic example all that is required to do the following:
Check if TWAIN is installed.
Initialize the DTWAIN Dynamic Link Library.
Select a Source
Acquire a page using the Native transfer mode
Save page to a BMP file called "test.bmp"
Shut down any open TWAIN Source's and DTWAIN itself
Private Sub ExampleFunction()
Dim SelectedSource As Long
Dim RetVal As Long
Dim ErrStatus As Long
Rem Check for Twain
if DTWAIN_IsTwainAvailable Then
Rem Initialize DTWAIN
open a TWAIN Source
SelectedSource = DTWAIN_SelectSource
Rem Acquire to a BMP file
RetVal = DTWAIN_AcquireFile(SelectedSource, "test.bmp", DTWAIN_BMP,_
DTWAIN_USENATIVE + DTWAIN_USENAME, DTWAIN_PT_DEFAULT, 1, 1, 1,_
Shut down DTWAIN
That's all there is to it! The Visual Basic project just adds the DTWAIN32.BAS interface file to define the DTWAIN functions so that Visual Basic will recognize the functions such as DTWAIN_SysInitialize.
The documentation that comes with the DynaRithmic TWAIN Library discusses functions such as DTWAIN_AcquireFile in depth. It wasn't discussed here, but the goal of this small example is to show how simple it is to acquire images from a TWAIN device and save them to a file.
To acquire to the other file types other than BMP, the parameter that specifies DTWAIN_BMP can be any of the other file types such as DTWAIN_GIF, DTWAIN_JPEG, etc.. Therefore just 5 calls can save a file to any of many file types by just changing the third parameter to DTWAIN_AcquireFile
We will boldly challenge you to try to implement TWAIN image retrieval without DTWAIN, especially if you use Visual Basic. You will realize that you will save weeks of programming using DTWAIN than if you tried to implement this yourself.