posted July 11, 2001 08:41 AM            

Note I preserved their header comments which indicate that there is not a restriction on the redistribution of the header or the library - they claim no rights or ownership of the work (see below).

I have only tested a few of the functions - twain_acquirenative, twain_freenative, twain_easyversion, twain_isavailable. It is very possible that I made some mistakes in the translation so use/test at your own risk. The functions mentioned above seem to work just fine.

The dll, headers, etc can be downloaded from www.dosadi.com.

--Don

'
'  eztwain.bas
'
'  translated from 
'  EZTWAIN.H - interface to Easy TWAIN library from www.dosadi.com 
'  by Don Dickinson
'  ddickinson@usinternet.com
'  dickinson.basicguru.com
'
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
'  BELOW ARE THE HEADER NOTES FROM EZTWAIN.H
'
'
'  1.13     09/08/99 Documented correct return codes of AcquireToFilename.
'                    - No code changes -
'  1.12     09/14/98 Added Fix32ToFloat, allow MSG_OPENDS triplet.
'                    Added SetXferMech, XferMech.
'  1.11     08/17/98 Added ToFix32, SetContrast, SetBrightness.
'                    Modified TWAIN_ToFix32 to round away-from-zero.
'  1.09beta 07/27/98 Reverted from 1.08 to 1.06 and worked forward again.
'  1.06     08/21/97 correction to message hook, fixed 32-bit exports
'  1.05     11/06/96 32-bit conversion
'  1.04     05/03/95 added: WriteNativeToFile, WriteNativeToFilename,
' 					      FreeNative, SetHideUI, GetHideUI, SetCurrentUnits,
' 					      GetCurrentUnits, SetCurrentResolution, SetBitDepth,
' 					      SetCurrentPixelType, SetCapOneValue.
'  1.0a	    06/23/94 first alpha version
'  0.0      05/11/94 created
'
'  EZTWAIN 1.x is not a product, and is not the work of any company involved
'  in promoting or using the TWAIN standard.  This code is sample code,
'  provided without charge, and you use it entirely at your own risk.
'  No rights or ownership is claimed by the author, or by any company
'  or organization.  There are no restrictions on use or (re)distribution.
'
' Download from:    www.dosadi.com 
'
' Support contact:  support@dosadi.com
'
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
'
#if not %def(%EZTWAIN_BAS)
%EZTWAIN_BAS = 1
#include "win32api.inc"
Declare Function TWAIN_AcquireNative Lib "EZTW32.DLL" Alias "TWAIN_AcquireNative" _
      ( ByVal hwndApp as Long, ByVal wPizTypes as DWord ) as Long
'
'  The minimal use of EZTWAIN.DLL is to just call this routine, with 0 for
'  both params.  EZTWAIN creates a window if hwndApp is 0.
' 
'  Acquires a single image, from the currently selected Data Source, using
'  Native-mode transfer. It waits until the source closes (if it's modal) or
'  forces the source closed if not.  The return value is a handle to the
'  acquired image.  Only one image can be acquired per call.
' 
'  Under Windows, the return value is a global memory handle - applying
'  GlobalLock to it will return a (huge) pointer to the DIB, which
'  starts with a BITMAPINFOHEADER.
'  NOTE: You are responsible for disposing of the returned DIB - these things
'  can eat up your Windows memory fast!  See TWAIN_FreeNative below.
' 
'  The image type can be restricted using the following masks.  A mask of 0
'  means 'any pixel type is welcome'.
'  Caution: You should not assume that the source will honor a pixel type
'  restriction!  If you care, check the parameters of the DIB.
'
%TWAIN_BW		 = &h0001	'  1-bit per pixel, B&W 	(== TWPT_BW)
%TWAIN_GRAY		 = &h0002	'  1,4, or 8-bit grayscale  (== TWPT_GRAY)
%TWAIN_RGB		 = &h0004	'  24-bit RGB color         (== TWPT_RGB)
%TWAIN_PALETTE	 = &h0008	'  1,4, or 8-bit palette    (== TWPT_PALETTE)
%TWAIN_ANYTYPE	 = &h0000	'  any of the above
Declare Sub TWAIN_FreeNative Lib "EZTW32.DLL" Alias "TWAIN_FreeNative" ( ByVal hdib as Long )
'
'  Release the memory allocated to a native format image, as returned by
'  TWAIN_AcquireNative. (If you are coding in C or C++, this is just a call
'  to GlobalFree.)
'  If you use TWAIN_AcquireNative and don't free the returned image handle,
'  it stays around taking up Windows (virtual) memory until your application
'  terminates.  Memory required per square inch:
'              1 bit B&W       8-bit grayscale     24-bit color
'  100 dpi      1.25KB              10KB               30KB
'  200 dpi        5KB               40KB              120KB
'  300 dpi      11.25KB             90KB              270KB
'  400 dpi       20KB              160KB              480KB
' 
Declare Function TWAIN_AcquireToClipboard Lib "EZTW32.DLL" Alias "TWAIN_AcquireToClipboard" _
      ( ByVal hwndApp as Long, ByVal wPixTypes as Dword ) as Long
'
'  Like AcquireNative, but puts the resulting image, if any, into the system
'  clipboard.  Under Windows, this will put a CF_DIB item in the clipboard
'  if successful.  If this call fails, the clipboard is either empty or
'  contains the old contents.
'  A return value of 1 indicates success, 0 indicates failure.
' 
'  Useful for environments like Visual Basic where it is hard to make direct
'  use of a DIB handle.  In fact, TWAIN_AcquireToClipboard uses
'  TWAIN_AcquireNative for all the hard work.
'
Declare Function TWAIN_AcquireToFilename Lib "EZTW32.DLL" Alias "TWAIN_AcquireToFilename" _
      ( ByVal hwndApp as Long, zFile as Asciiz ) as Long
'
'  Acquire an image and write it to a .BMP (Windows Bitmap) file.
'  The file name and path in pszFile are used.  If pszFile is NULL or
'  points to an empty string, the user is prompted with a Save File dialog.
'  Return values:
'  0 success
'  -1 Acquire failed OR user cancelled File Save dialog
'  -2 file open error (invalid path or name, or access denied)
'  -3 (weird) unable to lock DIB - probably an invalid handle.
'  -4 writing BMP data failed, possibly output device is full
'
Declare Function TWAIN_SelectImageSource Lib "EZTW32.DLL" Alias "TWAIN_SelectImageSource" _
      ( ByVal hwnd as Long ) as Long
'
'  This is the routine to call when the user chooses the "Select Source..."
'  menu command from your application's File menu.  Your app has one of
'  these, right?  The TWAIN spec calls for this feature to be available in
'  your user interface, preferably as described.
'  Note: If only one TWAIN device is installed on a system, it is selected
'  automatically, so there is no need for the user to do Select Source.
'  You should not require your users to do Select Source before Acquire.
' 
'  This function posts the Source Manager's Select Source dialog box.
'  It returns after the user either OK's or CANCEL's that dialog.
'  A return of 1 indicates OK, 0 indicates one of the following:
'    a) The user cancelled the dialog
'    b) The Source Manager found no data sources installed
'    c) There was a failure before the Select Source dialog could be posted
'  -- details --
'  Only sources that can return images (that are in the DG_IMAGE group) are
'  displayed.  The current default source will be highlighted initially.
'  In the standard implementation of "Select Source...", your application
'  doesn't need to do anything except make this one call.
' 
'  If you want to be meticulous, disable your "Acquire" and "Select Source"
'  menu items or buttons if TWAIN_IsAvailable() returns 0 - see below.
'
' --------- Basic TWAIN Inquiries
Declare Function TWAIN_IsAvailable Lib "EZTW32.DLL" Alias "TWAIN_IsAvailable" () as Long
'
'  Call this function any time to find out if TWAIN is installed on the
'  system.  It takes a little time on the first call, after that it's fast,
'  just testing a flag.  It returns 1 if the TWAIN Source Manager is
'  installed & can be loaded, 0 otherwise. 
'
Declare Function TWAIN_EasyVersion Lib "EZTW32.DLL" Alias "TWAIN_EasyVersion" () as Long
'
'  Returns the version number of EZTWAIN.DLL, multiplied by 100.
'  So e.g. version 2.01 will return 201 from this call.
'
Declare Function TWAIN_State Lib "EZTW32.DLL" Alias "TWAIN_State" () as Long
'
'  Returns the TWAIN Protocol State per the spec.
'
%TWAIN_PRESESSION		   = 1	'  source manager not loaded
%TWAIN_SM_LOADED			= 2	'  source manager loaded
%TWAIN_SM_OPEN			   = 3	'  source manager open
%TWAIN_SOURCE_OPEN		= 4	'  source open but not enabled
%TWAIN_SOURCE_ENABLED	= 5	'  source enabled to acquire
%TWAIN_TRANSFER_READY	= 6	'  image ready to transfer
%TWAIN_TRANSFERRING		= 7	'  image in transit
' --------- DIB handling utilities ---------
Declare Function TWAIN_DibDepth Lib "EZTW32.DLL" Alias "TWAIN_DibDepth" _
      ( ByVal hdib as Long ) as Long
Declare Function TWAIN_DibWidth Lib "EZTW32.DLL" Alias "TWAIN_DibWidth" _
      ( ByVal hdib as Long ) as Long
            
Declare Function TWAIN_DibHeight Lib "EZTW32.DLL" Alias "TWAIN_DibHeight" _
      ( ByVal hdib as Long ) as Long
      
Declare Function TWAIN_DibNumColors Lib "EZTW32.DLL" Alias "TWAIN_DibNumColors" _
      ( ByVal hdib as Long ) as Long
Declare Function TWAIN_RowSize Lib "EZTW32.DLL" Alias "TWAIN_RowSize" _
      ( ByVal hdib as Long ) as Long
      
Declare Sub TWAIN_ReadRow Lib "EZTW32.DLL" Alias "TWAIN_ReadRow" _
      ( ByVal hdib as Long, ByVal nRow as Long, prow as Any )
'
'  Read row n of the given DIB into buffer at prow.
'  Caller is responsible for ensuring buffer is large enough.
'  Row 0 is the *top* row of the image, as it would be displayed.
'
Declare Function TWAIN_CreateDibPalette Lib "EZTW32.DLL" Alias "TWAIN_CreateDibPalette" _
      ( ByVal hdib as Long ) as Long
'
'  Create and return a logical palette to be used for drawing the DIB.
'  For 1, 4, and 8-bit DIBs the palette contains the DIB color table.
'  For 24-bit DIBs, a default halftone palette is returned.
'
Declare Sub TWAIN_DrawDibToDC Lib "EZTW32.DLL" Alias "TWAIN_DrawDibToDC" _
      ( ByVal hDC as Long, ByVal dx as Long, ByVal dy as Long, _
        ByVal w as Long, ByVal h as Long, ByVal hdib as Long, _
        ByVal sx as Long, ByVal sy as Long )
'
'  Draws a DIB on a device context.
'  You should call CreateDibPalette, select that palette
'  into the DC, and do a RealizePalette(hDC) first.
'
' --------- BMP file utilities
Declare Function TWAIN_WriteNativeToFilename Lib "EZTW32.DLL" Alias "TWAIN_WriteNativeToFilename" _
      ( ByVal hdib as Long, zFile as Asciiz ) as Long
'      
'  Writes a DIB handle to a .BMP file
' 
'  hdib		= DIB handle, as returned by TWAIN_AcquireNative
'  pszFile	= far pointer to NUL-terminated filename
'  If pszFile is NULL or points to a null string, prompts the user
'  for the filename with a standard file-save dialog.
' 
'  Return values:
' 	 0	success
' 	-1	user cancelled File Save dialog
' 	-2	file open error (invalid path or name, or access denied)
' 	-3	(weird) unable to lock DIB - probably an invalid handle.
' 	-4	writing BMP data failed, possibly output device is full
'
Declare Function TWAIN_WriteNativeToFile Lib "EZTW32.DLL" Alias "TWAIN_WriteNativeToFile" _
      ( ByVal hdib as Long, ByVal hFile as Long ) as Long
'
'  Writes a DIB to a file in .BMP format.
' 
'  hdib		= DIB handle, as returned by TWAIN_AcquireNative
'  fh		= file handle, as returned by _open, _lopen or OpenFile
' 
'  Return value as for TWAIN_WriteNativeToFilename
'
Declare Function TWAIN_LoadNativeFromFilename Lib "EZTW32.DLL" Alias "TWAIN_LoadNativeFromFilename" _
      ( zFile as Asciiz ) as Long
'
'  Load a .BMP file and return a DIB handle (as from AcquireNative.)
'  Accepts a filename (including path & extension).
'  If pszFile is NULL or points to a null string, the user is prompted.
'  Returns a DIB handle if successful, otherwise NULL.
'
Declare Function TWAIN_LoadNativeFromFile Lib "EZTW32.DLL" Alias "TWAIN_LoadNativeFromFile" _
      ( ByVal fh as Long ) as Long
'
'  Like LoadNativeFromFilename, but takes an already open file handle.
'
Declare Sub TWAIN_SetHideUI Lib "EZTW32.DLL" Alias "TWAIN_SetHideUI" _
      ( ByVal fHide as Long )
      
Declare Function TWAIN_GetHideUI Lib "EZTW32.DLL" Alias "TWAIN_GetHideUI" () as Long
'
'  These functions control the 'hide source user interface' flag.
'  This flag is cleared initially, but if you set it non-zero, then when
'  a source is enabled it will be asked to hide its user interface.
'  Note that this is only a request - some sources will ignore it!
'  This affects AcquireNative, AcquireToClipboard, and EnableSource.
'  If the user interface is hidden, you will probably want to set at least
'  some of the basic acquisition parameters yourself - see
'  SetCurrentUnits, SetBitDepth, SetCurrentPixelType and
'  SetCurrentResolution below.
'
' --------- Application Registration
Declare Sub TWAIN_RegisterApp Lib "EZTW32.DLL" Alias "TWAIN_RegisterApp" _
      ( ByVal nMajorNum as Long, ByVal nMinorNum as Long, _
        ByVal nLanguage as Long, ByVal nCountry as Long, _
        zVersion as Asciiz, zMfg as Asciiz, zProduct as Asciiz ) 
        ' 
'  TWAIN_RegisterApp can be called *AS THE FIRST CALL*, to register the
'  application. If this function is not called, the application is given a
'  'generic' registration by EZTWAIN.
'  Registration only provides this information to the Source Manager and any
'  sources you may open - it is used for debugging, and (frankly) by some
'  sources to give special treatment to certain applications.
' --------- Error Analysis and Reporting ------------------------------------
Declare Function TWAIN_GetResultCode Lib "EZTW32.DLL" Alias "TWAIN_GetResultCode" () as Dword
'
'  Return the result code (TWRC_xxx) from the last triplet sent to TWAIN
'
Declare Function TWAIN_GetConditionCode Lib "EZTW32.DLL" Alias "TWAIN_GetConditionCode" () as Dword
'
'  Return the condition code from the last triplet sent to TWAIN.
'  (To be precise, from the last call to TWAIN_DS below)
'  If a source is NOT open, return the condition code of the source manager.
'
Declare Sub TWAIN_ErrorBox Lib "EZTW32.DLL" Alias "TWAIN_ErrorBox" ( zMsg as Asciiz )
'
'  Post an error message dialog with an exclamation mark, OK button,
'  and the title 'TWAIN Error'.
'  pszMsg points to a null-terminated message string.
'
Declare Sub TWAIN_ReportLastError Lib "EZTW32.DLL" Alias "TWAIN_ReportLastError" ( zMsg as Asciiz )
'
'  Like TWAIN_ErrorBox, but if some details are available from
'  TWAIN about the last failure, they are included in the message box.
'
' --------- TWAIN State Control ------------------------------------
Declare Function TWAIN_LoadSourceManager Lib "EZTW32.DLL" Alias "TWAIN_LoadSourceManager" () as Long
'
'  Finds and loads the Data Source Manager, TWAIN.DLL.
'  If Source Manager is already loaded, does nothing and returns TRUE.
'  This can fail if TWAIN.DLL is not installed (in the right place), or
'  if the library cannot load for some reason (insufficient memory?) or
'  if TWAIN.DLL has been corrupted.
Declare Function TWAIN_OpenSourceManager Lib "EZTW32.DLL" Alias "TWAIN_OpenSourceManager" _
      ( ByVal hwnd as Long ) as Long
'
'  Opens the Data Source Manager, if not already open.
'  If the Source Manager is already open, does nothing and returns TRUE.
'  This call will fail if the Source Manager is not loaded.
'
Declare Function TWAIN_OpenDefaultSource Lib "EZTW32.DLL" Alias "TWAIN_OpenDefaultSource" () as Long
'
'  This opens the source selected in the Select Source dialog.
'  If a source is already open, does nothing and returns TRUE.
'  Fails if the source manager is not loaded and open.
'
Declare Function TWAIN_EnableSource Lib "EZTW32.DLL" Alias "TWAIN_EnableSource" _
      ( ByVal hwnd as Long ) as Long
'
'  Enables the open Data Source. This posts the source's user interface
'  and allows image acquisition to begin.  If the source is already enabled,
'  this call does nothing and returns TRUE.
'
Declare Function TWAIN_DisableSource Lib "EZTW32.DLL" Alias "TWAIN_DisableSource" () as Long
'
'  Disables the open Data Source, if any.
'  This closes the source's user interface.
'  If there is not an enabled source, does nothing and returns TRUE.
'
Declare Function TWAIN_CloseSource Lib "EZTW32.DLL" Alias "TWAIN_CloseSource" () as Long
'
'  Closes the open Data Source, if any.
'  If the source is enabled, disables it first.
'  If there is not an open source, does nothing and returns TRUE.
'
Declare Function TWAIN_CloseSourceManager Lib "EZTW32.DLL" Alias "TWAIN_CloseSourceManager" _
      ( ByVal hwnd as Long ) as Long
'       
'  Closes the Data Source Manager, if it is open.
'  If a source is open, disables and closes it as needed.
'  If the Source Manager is not open, does nothing and returns TRUE.
'
Declare Function TWAIN_UnloadSourceManager Lib "EZTW32.DLL" Alias "TWAIN_UnloadSourceManager" () as Long
'
'  Unloads the Data Source Manager i.e. TWAIN.DLL - releasing
'  any associated memory or resources.
'  This call will fail if the Source Manager is open, otherwise
'  it always succeeds and returns TRUE.
'
Declare Function TWAIN_MessageHook Lib "EZTW32.DLL" Alias "TWAIN_MessageHook" _
      ( ptrMsg as Any ) as Long
'
'  This function detects Windows messages that should be routed
'  to an enabled Data Source, and picks them off.  In a full TWAIN
'  app, TWAIN_MessageHook is called inside the main GetMessage loop.
'  The skeleton code looks like this:  
' 		MSG msg;
'   	while (GetMessage((LPMSG)&msg, NULL, 0, 0)) {
' 			if (!TWAIN_MessageHook ((LPMSG)&msg)) {
' 				TranslateMessage ((LPMSG)&msg);
' 				DispatchMessage ((LPMSG)&msg);
' 			}
' 		} '  while
'
Declare Function TWAIN_WaitForNativeXfer Lib "EZTW32.DLL" Alias "TWAIN_WaitForNativeXfer" _
      ( ByVal hwnd as Long ) as Long
Declare Sub TWAIN_ModalEventLoop Lib "EZTW32.DLL" Alias "TWAIN_ModalEventLoop" ()
'
'  Process messages until termination, source disable, or image transfer.
'
Declare Function TWAIN_EndXfer Lib "EZTW32.DLL" Alias "TWAIN_EndXfer" () as Long
Declare Function TWAIN_AbortAllPendingXfers Lib "EZTW32.DLL" Alias "TWAIN_AbortAllPendingXfers" () as Long
Declare Function TWAIN_WriteDibToFile Lib "EZTW32.DLL" Alias "TWAIN_WriteDibToFile" _
      ( lpDIB as BITMAPINFOHEADER, ByVal hFile as Long ) as Long
'
'  Writes a DIB to a file in .BMP format.
'  Returns TRUE if successful, FALSE otherwise.
'  (Likely causes of failure: device full, or permission denied to write to file or device
'  lpDIB	= pointer to DIB, as from GlobalLock of DIB handle
'  fh		= file handle, as returned by C _open or Windows _lopen or OpenFile
'  For example of use, see TWAIN_WriteNativeToFilename in EZTWAIN.C
'
' --------- High-level Capability Negotiation Functions --------
Declare Function TWAIN_NegotiateXferCount Lib "EZTW32.DLL" Alias "TWAIN_NegotiateXferCount" _
      ( ByVal nXFers as Long ) as Long
'
'  Negotiate with open Source the number of images application will accept.
'  This is only allowed in State 4 (TWAIN_SOURCE_OPEN)
'  nXfers = -1 means any number
'
Declare Function TWAIN_NegotiatePixelTypes Lib "EZTW32.DLL" Alias "TWAIN_NegotiatePixelTypes" _
      ( ByVal wPixTypes as Dword ) as Long
'
'  Negotiate with the source to restrict pixel types that can be acquired.
'  This tries to restrict the source to a *set* of pixel types,
'  See TWAIN_AcquireNative above for some mask constants.
'  --> This is only allowed in State 4 (TWAIN_SOURCE_OPEN)
'  A parameter of 0 (TWAIN_ANYTYPE) causes no negotiation & no restriction.
'  You should not assume that the source will honor your restrictions, even
'  if this call succeeds!
'
Declare Function TWAIN_GetCurrentUnits Lib "EZTW32.DLL" Alias "TWAIN_GetCurrentUnits" () as Long
'
'  Ask the source what its current unit of measure is.
'  If anything goes wrong, this function just returns TWUN_INCHES (0).
'
Declare Function TWAIN_SetCurrentUnits Lib "EZTW32.DLL" Alias "TWAIN_SetCurrentUnits" _
      ( ByVal nUnits as Long ) as Long
'
'  Set the current unit of measure for the source.
'  Unit of measure codes are in TWAIN.H, but TWUN_INCHES is 0.
'
Declare Function TWAIN_GetBitDepth Lib "EZTW32.DLL" Alias "TWAIN_GetBitDepth" () as Long
'
'  Get the current bitdepth, which can depend on the current PixelType.
'  Bit depth is per color channel e.g. 24-bit RGB has bit depth 8.
'  If anything goes wrong, this function returns 0.
'
Declare Function TWAIN_SetBitDepth Lib "EZTW32.DLL" Alias "TWAIN_SetBitDepth" _
      ( ByVal nBits as Long ) as Long
'
'  (Try to) set the current bitdepth (for the current pixel type).
'
Declare Function TWAIN_GetPixelType Lib "EZTW32.DLL" Alias "TWAIN_GetPixelType" () as Long
'
'  Ask the source for the current pixel type.
'  If anything goes wrong (it shouldn't), this function returns 0 (TWPT_BW).
'
Declare Function TWAIN_SetCurrentPixelType Lib "EZTW32.DLL" Alias "TWAIN_SetCurrentPixelType" _
      ( ByVal nPixType as Long ) as Long
'
'  (Try to) set the current pixel type for acquisition.
'  This is only allowed in State 4 (TWAIN_SOURCE_OPEN)
'  The source may select this pixel type, but don't assume it will.
'
Declare Function TWAIN_GetCurrentResolution Lib "EZTW32.DLL" Alias "TWAIN_GetCurrentResolution" () as Double
'
'  Ask the source for the current (horizontal) resolution.
'  Resolution is in dots per current unit! (See TWAIN_GetCurrentUnits above)
'  If anything goes wrong (it shouldn't) this function returns 0.0
'
Declare Function TWAIN_GetYResolution Lib "EZTW32.DLL" Alias "TWAIN_GetYResolution" () as Double
'
'  Returns the current vertical resolution, in dots per *current unit*.
'  In the event of failure, returns 0.0.
'
Declare Function TWAIN_SetCurrentResolution Lib "EZTW32.DLL" Alias "TWAIN_SetCurrentResolution" _
      ( ByVal dRes as Double ) as Long
'
'  (Try to) set the current resolution for acquisition.
'  Resolution is in dots per current unit! (See TWAIN_GetCurrentUnits above)
'  This is only allowed in State 4 (TWAIN_SOURCE_OPEN)
'  Note: The source may select this resolution, but don't assume it will.
'
Declare Function TWAIN_SetContrast Lib "EZTW32.DLL" Alias "TWAIN_SetContrast" _
      ( ByVal dCon as Double ) as Long
'
'  (Try to) set the current contrast for acquisition.
'  The TWAIN standard says that the range for this cap is -1000 ... +1000
'
Declare Function TWAIN_SetBrightness Lib "EZTW32.DLL" Alias "TWAIN_SetBrightness" _
      ( ByVal dBri as Double ) as Long
'      
'  (Try to) set the current brightness for acquisition.
'  The TWAIN standard says that the range for this cap is -1000 ... +1000
'
Declare Function TWAIN_SetXferMech Lib "EZTW32.DLL" Alias "TWAIN_SetXferMech" _
      ( ByVal mech as Long ) as Long
Declare Function TWAIN_XferMech Lib "EZTW32.DLL" Alias "TWAIN_XferMech" () as Long
'
'  (Try to) set or get the transfer mode - one of the following:
'
%XFERMECH_NATIVE    = 0
%XFERMECH_FILE      = 1
%XFERMECH_MEMORY    = 2
'
' --------- Low-level Capability Negotiation Functions --------
'
'  Setting a capability is valid only in State 4 (TWAIN_SOURCE_OPEN)
'  Getting a capability is valid in State 4 or any higher state.
'
Declare Function TWAIN_SetCapOneValue Lib "EZTW32.DLL" Alias "TWAIN_SetCapOneValue" _
      ( ByVal cap as dword, ByVal itemType as dword, byVal itemVal as Long ) as Long
'
'  Do a DAT_CAPABILITY/MSG_SET, on capability 'Cap' (e.g. ICAP_PIXELTYPE,
'  CAP_AUTOFEED, etc.) using a TW_ONEVALUE container with the given item type
'  and value.  The item value must fit into 32 bits.
'  Returns TRUE (1) if successful, FALSE (0) otherwise.
'
Declare Function TWAIN_GetCapCurrent Lib "EZTW32.DLL" Alias "TWAIN_GetCapCurrent" _
      ( ByVal cap as dword, ByVal itemType as dword, pVal as Any ) as Long
'
'  Do a DAT_CAPABILITY/MSG_GETCURRENT on capability 'Cap'.
'  Copy the current value out of the returned container into *pVal.
'  If the operation fails (the source refuses the request), or if the
'  container is not a ONEVALUE or ENUMERATION, or if the item type of the
'  returned container is incompatible with the expected TWTY_ type in nType,
'  returns FALSE.  If this function returns FALSE, *pVal is not touched.
'
Declare Function TWAIN_ToFix32 Lib "EZTW32.DLL" Alias "TWAIN_ToFix32" _
      ( ByVal d as Double ) as Long
'
'  Convert a floating-point value to a 32-bit TW_FIX32 value that can be passed
'  to e.g. TWAIN_SetCapOneValue
'
Declare Function TWAIN_Fix32ToFloat Lib "EZTW32.DLL" Alias "TWAIN_Fix32ToFloat" _
      ( ByVal nfix as Long ) as Double
'
'  Convert a TW_FIX32 value (as returned from some capability inquiries)
'  to a double (floating point) value.
' --------- Lowest-level functions for TWAIN protocol --------
Declare Function TWAIN_DS Lib "EZTW32.DLL" Alias "TWAIN_DS" _
      ( ByVal dg as Dword, ByVal dat as dword, ByVal msg as Dword, pData as Any ) as Long
'
'  Passes the triplet (DG, DAT, MSG, pData) to the open data source if any.
'  Returns 1 (TRUE) if the result code is TWRC_SUCCESS, 0 (FALSE) otherwise.
'  The last result code can be retrieved with TWAIN_GetResultCode(), and the corresponding
'  condition code can be retrieved with TWAIN_GetConditionCode().
'  If no source is open this call will fail, result code TWRC_FAILURE, condition code TWCC_NODS.
'
Declare Function TWAIN_Mgr Lib "EZTW32.DLL" Alias "TWAIN_Mgr" _
      ( ByVal dg as Dword, ByVal dat as Dword, ByVal msg as DWord, pData as Any) as Long
'
'int EZTAPI TWAIN_Mgr(unsigned long DG, unsigned DAT, unsigned MSG, void FAR *pData);
'
'  Passes a triplet to the Data Source Manager (DSM).
'  Returns 1 (TRUE) if the result code is TWRC_SUCCESS, 0 (FALSE) otherwise.
'  The last result code can be retrieved with TWAIN_GetResultCode(), and the corresponding
'  condition code can be retrieved with TWAIN_GetConditionCode().
'  If the Source Manager is not open, this call will fail, and set the result code to TWRC_FAILURE,
'  with a condition code of TWCC_SEQERROR (triplet out of sequence).
#endif

posted July 11, 2001 08:42 AM            

'
'  testtw.bas
'
'  twain test program
'
#compile exe
#dim all
#include "eztwain.bas"
Function PBMain()
   
   Dim hDIB as Long
   
   MsgBox "About to start"
   
   if TWAIN_IsAvailable() then
      MsgBox "Twain is available: " + Format$(TWAIN_EasyVersion())
      hDIB = TWAIN_AcquireNative(0, 0)
      if hDIB then
         MsgBox "Dib Received and saved as e:\test.bmp"
         if dir$("c:\test.bmp") <> "" then
            kill "c:\test.bmp"
         end if
         MsgBox Format$(TWAIN_WriteNativeToFilename(hdib, "c:\test.bmp"))
         TWAIN_FreeNative hDIB
      else
         MsgBox "No dib created"
      end if
   else
      MsgBox "Twain is not available"
   end if
   
End Function

posted February 02, 2006 05:19 PM            

Thanks to Don for the translation and nice sample code.
We've gone on from that free version of EZTwain (still available) to do a commercial EZTwain Pro with, of course, lots more features.
It is a superset: Don's sample code would run with our latest product.

As a result of interest from PB developers, the EZTwain Pro developer kit includes a full (machine-generated) PowerBASIC declaration file for all 300+ functions in EZTwain Pro.
If you need to scan a multipage document from a scanner into a PDF file with a half-dozen lines of code, or anything else involving a TWAIN scanner, check us out.
http://www.dosadi.com/eztwain3.htm