File Transfer

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The File Transfer Mode transfers the image data from the Source to a data file, or if the Source is acquiring multiple pages, a series of data files.

With DTWAIN there are two types of File Transfer Modes: DTWAIN Mode, and Source Mode. With DTWAIN Mode, any TWAIN device can acquire images to a file or series of files. In Source Mode, DTWAIN uses the Source's internal file transfer protocol. There are many devices that do not have internal file transfer support, so the DTWAIN Mode is the only choice for these particular Sources.

DTWAIN has file-naming options for multi-page acquisitions. For example, DTWAIN can generate the file names, your application can provide the names, or the user can provide a file name for each acquired page.

DTWAIN Mode

Using DTWAIN mode, the image(s) are transferred to files where the application can choose the file format that the image(s) will be saved to. The supported formats are:

•	Windows BMP

•

PCX

•	DCX (multipage PCX)

•

GIF

•	TIFF (single-page and multi-page TIFFs with the following compressions: no compression, Group 3 Fax, Group 4 Fax, JPEG, Packbits, Flate, LZW)

•

PNG

•	JPEG (the quality factor of the file can be set by the application, as well as whether the file is a progressive JPEG file)

•

JPEG-2000

•	Targa (TGA)

•	Windows Metafile (WMF)

•	Windows Enhanced Metafile (EMF)

•	Windows Icon (ICO) (Vista and non-Vista compatible)

•	Adobe Photoshop (PSD)

•	Adobe Portable Document Format (PDF) *

•	Adobe Postscript Level 1, 2, or 3*

•	Text (using a supported OCR engine).

•	Wireless Bitmap (WBMAP)

When using DTWAIN mode, the File Transfer can use either Native or Buffered mode when transferring the image data from the Source to DTWAIN.

Source Mode

If the Source supports file transfers, DTWAIN can transfer files using the Source's internal file transfer mechanism instead of using DTWAIN to simulate file transfers. This mode is advantageous since the Source is responsible for creating the image files, and that the Source may support file formats that DTWAIN mode does not support. The disadvantage is that many Sources do not support this mode of image transfer. There are DTWAIN functions to query the Source's file transfer support, so you can adjust your application accordingly.

The function that acquires images using the File Transfer Mode is DTWAIN_AcquireFile.and DTWAIN_AcquireFileEx

* PDFand Postscript file support is available only in DTWAIN/PDF.

Issues with JPEG-in-TIFF (TIFF-JPEG) files

If you're saving the file to TIFF-JPEG format, please note that DTWAIN saves these files in the new TIFF-JPEG format, as opposed to the older, buggy TIFF-JPEG format that many viewers still support. If you have an image viewer that only views TIFF-JPEG files that have been saved in the old format, please contact the creator of the software and kindly suggest that they support the newer TIFF-JPEG format. The older format has been officially been out of support from Adobe, the creators of the TIFF format. All viewers should now use the newer format.