Disk File Transfer Considerations

When the Disk File Transfer mode is used, the Data Source saves an image directly to a file. You must use the SetCapability Method and the IGTwainCtl Control.ImageFileName Property to set all parameters involved in using Disk File Transfer. For example, if you would like to set the filename or format type prior to acquiring an image using Disk File Transfer, do something like this example:

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Dim capOneValue As IGTWAINCapOneValue Set capOneValue = frmMain.IGTwainCtl1.CreateCapability(IG_TW_ON_ONEVALUE) capOneValue.ID = IG_TW_ICAP_IMAGEFILEFORMAT capOneValue.ItemType = AM_TID_META_UINT16 capOneValue.Value.ChangeType IG_DATA_LONG capOneValue.Value.Long = IG_FORMAT_TIF frmMain.IGTwainCtl1.SetCapability capOneValue, IG_TW_MSG_SET frmMain.IGTwainCtl1.ImageFileName = "ScanFile.tif"

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Dim capOneValue As IGTWAINCapOneValue
Set capOneValue =
frmMain.IGTwainCtl1.CreateCapability(IG_TW_ON_ONEVALUE)
capOneValue.ID = IG_TW_ICAP_IMAGEFILEFORMAT
capOneValue.ItemType = AM_TID_META_UINT16
capOneValue.Value.ChangeType IG_DATA_LONG
capOneValue.Value.Long = IG_FORMAT_TIF
frmMain.IGTwainCtl1.SetCapability capOneValue, IG_TW_MSG_SET
frmMain.IGTwainCtl1.ImageFileName = "ScanFile.tif"

Your choice of which file format to use for an image that is acquired and stored directly to a file is limited by two factors:

The file formats supported by your scanner's Device Driver
The file formats supported by TWAIN

The following formats are supported by TWAIN for image acquisition devices: TIFF, PICT, BMP, XBM, JPEG, FPX, PNG. Therefore, if you are using the Disk File Transfer, you are restricted to using a format that is both supported by TWAIN and supported by your Data Source.

If you do not specify a filename, the path to the temporary Windows directory will be used.