Access VBA/VB 通用扫描仪开发模块代码
Attribute VB_Name = "mdlTwain"
'*******************************************************************************
'
' Description: VB Module for accessing TWAIN compatible scanner (VB 5, 6)
'
' Author: Lumir Mik (lmik@seznam.cz)
'
' Version: 1.0
'
' License: Free to any use. If you change some part of this code, please,
' mention it here.
' Receive it as my contribution to free programmer sources
' in which I found much help and inspiration.
'
' There are 3 public functions in this module:
'
' 1. PopupSelectSourceDialog
' shows TWAIN dialog for selecting default source for acquisition
'
' 2. TransferWithoutUI
' transfers one image from TWAIN data source without showing
' the data source user interface (silent transfer). The programmer
' can set following attributes of the image:
' - resolution (DPI)
' - colour depth - monochromatic, grey, fullcolour
' - image size and position on the scanner glass
' - left, top, right, bottom (in inches).
' The image is saved into the BMP file.
'
' 3. TransferWithUI
' transfers one image from TWAIN data source using the data
' source user interface to set image attributes.
' The image is saved into the BMP file.
'
'*******************************************************************************
Option Explicit
'-----------------------------
' Declaration for TWAIN_32.DLL
'-----------------------------
Private Declare Function DSM_Entry Lib "Twain_32.dll" _
(ByRef pOrigin As Any, _
ByRef pDest As Any, _
ByVal DG As Long, _
ByVal DAT As Integer, _
ByVal MSG As Integer, _
ByRef pData As Any) As Integer
Private Type TW_VERSION
MajorNum As Integer ' TW_UINT16
MinorNum As Integer ' TW_UINT16
Language As Integer ' TW_UINT16
Country As Integer ' TW_UINT16
Info(1 To 34) As Byte ' TW_STR32
End Type
Private Type TW_IDENTITY
Id As Long ' TW_UINT32
Version As TW_VERSION ' TW_VERSION
ProtocolMajor As Integer ' TW_UINT16
ProtocolMinor As Integer ' TW_UINT16
SupportedGroups1 As Integer ' TW_UINT32
SupportedGroups2 As Integer
Manufacturer(1 To 34) As Byte ' TW_STR32
ProductFamily(1 To 34) As Byte ' TW_STR32
ProductName(1 To 34) As Byte ' TW_STR32
End Type
Private Type TW_USERINTERFACE
ShowUI As Integer ' TW_BOOL
ModalUI As Integer ' TW_BOOL
hParent As Long ' TW_HANDLE
End Type
Private Type TW_PENDINGXFERS
Count As Integer ' TW_UINT16
Reserved1 As Integer ' TW_UINT32
Reserved2 As Integer
End Type
Private Type TW_ONEVALUE
ItemType As Integer ' TW_UINT16
Item1 As Integer ' TW_UINT32
Item2 As Integer
End Type
Private Type TW_CAPABILITY
Cap As Integer ' TW_UINT16
ConType As Integer ' TW_UINT16
hContainer As Long ' TW_HANDLE
End Type
Private Type TW_FIX32
Whole As Integer ' TW_INT16
Frac As Integer ' TW_UINT16
End Type
Private Type TW_FRAME
Left As TW_FIX32 ' TW_FIX32
Top As TW_FIX32 ' TW_FIX32
Right As TW_FIX32 ' TW_FIX32
Bottom As TW_FIX32 ' TW_FIX32
End Type
Private Type TW_IMAGELAYOUT
Frame As TW_FRAME ' TW_FRAME
DocumentNumber As Long ' TW_UINT32
PageNumber As Long ' TW_UINT32
FrameNumber As Long ' TW_UINT32
End Type
Private Type TW_EVENT
pEvent As Long ' TW_MEMREF
TWMessage As Integer ' TW_UINT16
End Type
Private Const DG_CONTROL = 1
Private Const DG_IMAGE = 2
Private Const MSG_GET = 1
Private Const MSG_SET = 6
Private Const MSG_XFERREADY = 257
Private Const MSG_CLOSEDSREQ = 258
Private Const MSG_OPENDSM = 769
Private Const MSG_CLOSEDSM = 770
Private Const MSG_OPENDS = 1025
Private Const MSG_CLOSEDS = 1026
Private Const MSG_USERSELECT = 1027
Private Const MSG_DISABLEDS = 1281
Private Const MSG_ENABLEDS = 1282
Private Const MSG_PROCESSEVENT = 1537
Private Const MSG_ENDXFER = 1793
Private Const DAT_CAPABILITY = 1
Private Const DAT_EVENT = 2
Private Const DAT_IDENTITY = 3
Private Const DAT_PARENT = 4
Private Const DAT_PENDINGXFERS = 5
Private Const DAT_USERINTERFACE = 9
Private Const DAT_IMAGELAYOUT = 258
Private Const DAT_IMAGENATIVEXFER = 260
Private Const TWRC_SUCCESS = 0
Private Const TWRC_CHECKSTATUS = 2
Private Const TWRC_DSEVENT = 4
Private Const TWRC_NOTDSEVENT = 5
Private Const TWRC_XFERDONE = 6
Private Const TWLG_CZECH = 45
Private Const TWCY_CZECHOSLOVAKIA = 42
Private Const TWON_PROTOCOLMAJOR = 1
Private Const TWON_ONEVALUE = 5
Private Const TWON_PROTOCOLMINOR = 9
'-------------------------
' Declaration for WIN32API
'-------------------------
Private Declare Sub CopyMemory Lib "kernel32.dll" Alias "RtlMoveMemory" _
(ByVal pDest As Long, _
ByVal pSource As Long, _
ByVal Length As Long)
Private Declare Sub ZeroMemory Lib "kernel32.dll" Alias "RtlZeroMemory" _
(ByVal pDest As Long, _
ByVal Length As Long)
Private Declare Function GlobalFree Lib "kernel32.dll" _
(ByVal hMem As Long) As Long
Private Declare Function GlobalLock Lib "kernel32.dll" _
(ByVal hMem As Long) As Long
Private Declare Function GlobalUnlock Lib "kernel32.dll" _
(ByVal hMem As Long) As Long
Private Declare Function GlobalAlloc Lib "kernel32.dll" _
(ByVal wFlags As Long, _
ByVal dwBytes As Long) As Long
Private Declare Function GetMessage Lib "user32.dll" Alias "GetMessageA" _
(ByRef lpMsg As MSG, _
ByVal hwnd As Long, _
ByVal wMsgFilterMin As Long, _
ByVal wMsgFilterMax As Long) As Long
Private Declare Function TranslateMessage Lib "user32.dll" _
(ByRef lpMsg As MSG) As Long
Private Declare Function DispatchMessage Lib "user32.dll" Alias "DispatchMessageA" _
(ByRef lpMsg As MSG) As Long
Private Declare Function CreateWindowEx Lib "user32.dll" Alias "CreateWindowExA" _
(ByVal dwExStyle As Long, _
ByVal lpClassName As String, _
ByVal lpWindowName As String, _
ByVal dwStyle As Long, _
ByVal x As Long, _
ByVal y As Long, _
ByVal nWidth As Long, _
ByVal nHeight As Long, _
ByVal hWndParent As Long, _
ByVal hMenu As Long, _
ByVal hInstance As Long, _
ByVal lpParam As Long) As Long
Private Declare Function DestroyWindow Lib "user32.dll" _
(ByVal hwnd As Long) As Long
Private Type BITMAPFILEHEADER
bfType As Integer
bfSize As Long
bfReserved1 As Integer
bfReserved2 As Integer
bfOffBits As Long
End Type
Private Type BITMAPINFOHEADER
biSize As Long
biWidth As Long
biHeight As Long
biPlanes As Integer
biBitCount As Integer
biCompression As Long
biSizeImage As Long
biXPelsPerMeter As Long
biYPelsPerMeter As Long
biClrUsed As Long
biClrImportant As Long
End Type
Private Type RGBQUAD
rgbBlue As Byte
rgbGreen As Byte
rgbRed As Byte
rgbReserved As Byte
End Type
Private Type POINTAPI
x As Long
y As Long
End Type
Private Type MSG
hwnd As Long
message As Long
wParam As Long
lParam As Long
time As Long
pt As POINTAPI
End Type
Private Const GHND = 66
'----------------------------
' Declaration for this Module
'----------------------------
Private m_tAppID As TW_IDENTITY
Private m_tSrcID As TW_IDENTITY
Private m_lHndMsgWin As Long
Public Enum TWAIN_MDL_COLOURTYPE
BW = 0 ' TWPT_BW
GREY = 1 ' TWPT_GRAY
RGB = 2 ' TWPT_RGB
End Enum
Private Enum TWAIN_MDL_CAPABILITY
XFERCOUNT = 1 ' CAP_XFERCOUNT
PIXELTYPE = 257 ' ICAP_PIXELTYPE
INDICATORS = 4107 ' CAP_INDICATORS
UICONTROLLABLE = 4110 ' CAP_UICONTROLLABLE
PHYSICALWIDTH = 4369 ' ICAP_PSYSICALWIDTH
PHYSICALHEIGHT = 4370 ' ICAP_PSYSICALHEIGHT
XRESOLUTION = 4376 ' ICAP_XRESOLUTION
YRESOLUTION = 4377 ' ICAP_YRESOLUTION
BITDEPTH = 4395 ' ICAP_BITDEPTH
End Enum
Private Enum TWAIN_MDL_ITEMYPE
INT16 = 1 ' TW_INT16 short
UINT16 = 4 ' TW_UINT16 unsigned short
BOOL = 6 ' TW_BOOL unsigned short
FIX32 = 7 ' TW_FIX32 structure
End Enum
Public Function TransferWithoutUI(ByVal sngResolution As Single, _
ByVal tColourType As TWAIN_MDL_COLOURTYPE, _
ByVal sngImageLeft As Single, _
ByVal sngImageTop As Single, _
ByVal sngImageRight As Single, _
ByVal sngImageBottom As Single, _
ByVal sBMPFileName As String) As Long
'----------------------------------------------------------------------------
' Function transfers one image from Twain data source without showing
' the data source user interface (silent transfer).
'
' Input values
' - sngResolution (Single) - resolution of the image in DPI
' (dots per inch)
' - tColourType (UDT) - colour depth of the imaged - monochromatic (BW),
' colours of grey (GREY), full colours (COLOUR)
' - sngImageLeft, sngImageTop, sngImageRight, sngImageBottom (Single) -
' values determine the rectangle on the scanner glass that will
' be scanned (default units are inches) - if you set Right and Bottom
' values to 0, the module sets maximum values the scanner driver allows
' (the bottom right corner of the scanner glass)
' - sBMPFileName (String) - the file name of the saved image
'
' Function returns 0 if OK, 1 if an error occurs
'----------------------------------------------------------------------------
Dim lRtn As Long
Dim lTmp As Long
Dim blTwainOpen As Boolean
Dim lhDIB As Long
On Local Error GoTo ErrPlace
'-------------------------------
' Open Twain Data Source Manager
'-------------------------------
lRtn = OpenTwainDSM()
If lRtn Then GoTo ErrPlace
blTwainOpen = True
'-----------------------
' Open Twain Data Source
'-----------------------
lRtn = OpenTwainDS()
If lRtn Then GoTo ErrPlace
'-----------------------------------------------------------
' Set all important attributes of the image and the transfer
'-----------------------------------------------------------
'----------------------------------------------------------------------
' Set image size and position
' If sngImageRight or sngImageBottom is 0 put physical width and height
' of the scanner into these values
'----------------------------------------------------------------------
If (sngImageRight = 0) Or (sngImageBottom = 0) Then
lRtn = TwainGetOneValue(PHYSICALWIDTH, sngImageRight)
If lRtn Then GoTo ErrPlace
lRtn = TwainGetOneValue(PHYSICALHEIGHT, sngImageBottom)
If lRtn Then GoTo ErrPlace
End If
lRtn = SetImageSize(sngImageLeft, sngImageTop, sngImageRight, sngImageBottom)
If lRtn Then GoTo ErrPlace
'-----------------------------------------------
' Set the image resolution in DPI - both X and Y
'-----------------------------------------------
lRtn = TwainSetOneValue(XRESOLUTION, FIX32, sngResolution)
If lRtn Then GoTo ErrPlace
lRtn = TwainSetOneValue(YRESOLUTION, FIX32, sngResolution)
If lRtn Then GoTo ErrPlace
'--------------------------
' Set the image colour type
'--------------------------
lRtn = TwainSetOneValue(PIXELTYPE, UINT16, tColourType)
If lRtn Then GoTo ErrPlace
'----------------------------------------------------------------
' If the colour type is fullcolour, set the bitdepth of the image
' - 24 bits, 32 bits, ...
'----------------------------------------------------------------
If tColourType = RGB Then lRtn = TwainSetOneValue(BITDEPTH, UINT16, 24)
'---------------------------------------------------
' Set number of images you want to transfer (just 1)
'---------------------------------------------------
lRtn = TwainSetOneValue(XFERCOUNT, INT16, 1)
If lRtn Then GoTo ErrPlace
'----------------------------------------------------
' TRANSFER the image with UI disabled.
' If successful, lhDIB is filled with handle to DIB
'----------------------------------------------------
lRtn = TwainTransfer(False, lhDIB)
If lRtn Then GoTo ErrPlace
'------------------
' Close Data Source
'------------------
lRtn = CloseTwainDS()
If lRtn Then GoTo ErrPlace
'--------------------------
' Close Data Source Manager
'--------------------------
lRtn = CloseTwainDSM()
If lRtn Then GoTo ErrPlace
blTwainOpen = False
'----------------------------------
' Save DIB handle into the BMP file
'----------------------------------
lRtn = SaveDIBToFile(lhDIB, sBMPFileName)
If lRtn Then GoTo ErrPlace
TransferWithoutUI = 0
Exit Function
ErrPlace:
If lhDIB Then lRtn = GlobalFree(lhDIB)
If blTwainOpen Then lRtn = CloseTwainDS(): lRtn = CloseTwainDSM()
TransferWithoutUI = 1
End Function
Public Function TransferWithUI(ByVal sBMPFileName As String) As Long
'-------------------------------------------------------------------
' Function transfers one image from Twain data source using the data
' source user interface to set image attributes.
'
' Input values
' - sBMPFileName (String) - the file name of the saved image
'
' Function returns 0 if OK, 1 if an error occurs
'-------------------------------------------------------------
Dim lRtn As Long
Dim blTwainOpen As Boolean
Dim lhDIB As Long
On Local Error GoTo ErrPlace
'-------------------------------
' Open Twain Data Source Manager
'-------------------------------
lRtn = OpenTwainDSM()
If lRtn Then GoTo ErrPlace
blTwainOpen = True
'-----------------------
' Open Twain Data Source
'-----------------------
lRtn = OpenTwainDS()
If lRtn Then GoTo ErrPlace
'----------------------------------------------------
' TRANSFER the image with UI enabled.
' If successful, lhDIB is filled with handle to DIB
'----------------------------------------------------
lRtn = TwainTransfer(True, lhDIB)
If lRtn Then GoTo ErrPlace
'------------------
' Close Data Source
'------------------
lRtn = CloseTwainDS()
If lRtn Then GoTo ErrPlace
'--------------------------
' Close Data Source Manager
'--------------------------
lRtn = CloseTwainDSM()
If lRtn Then GoTo ErrPlace
blTwainOpen = False
'----------------------------------
' Save DIB handle into the BMP file
'----------------------------------
lRtn = SaveDIBToFile(lhDIB, sBMPFileName)
If lRtn Then GoTo ErrPlace
TransferWithUI = 0
Exit Function
ErrPlace:
If lhDIB Then lRtn = GlobalFree(lhDIB)
If blTwainOpen Then lRtn = CloseTwainDS(): lRtn = CloseTwainDSM()
TransferWithUI = 1
End Function
Public Function PopupSelectSourceDialog() As Long
'------------------------------------------------------------------
' Function shows the Twain dialog for selecting default data source
'
' Function returns 0 if OK, 1 if an error occurs
'------------------------------------------------------------------
Dim iRtn As Integer
Dim lRtn As Long
On Local Error GoTo ErrPlace
'-------------------------------
' Open Twain Data Source Manager
'-------------------------------
lRtn = OpenTwainDSM()
If lRtn Then GoTo ErrPlace
'----------------------------------------------------
' Popup "Select source" dialog
' DG_CONTROL, DAT_IDENTITY, MSG_USERSELECT
'----------------------------------------------------
iRtn = DSM_Entry(m_tAppID, ByVal 0&, DG_CONTROL, DAT_IDENTITY, _
MSG_USERSELECT, m_tSrcID)
If iRtn <> TWRC_SUCCESS Then
lRtn = CloseTwainDSM()
GoTo ErrPlace
End If
'--------------------------------
' Close Twain Data Source Manager
'--------------------------------
lRtn = CloseTwainDSM()
If lRtn Then GoTo ErrPlace
PopupSelectSourceDialog = 0
Exit Function
ErrPlace:
PopupSelectSourceDialog = 1
End Function
Private Function OpenTwainDSM() As Long
Dim iRtn As Integer
On Local Error GoTo ErrPlace
'----------------------------------------------------
' Create window that will receive all TWAIN messages
' Message loop can be found in TwainTransfer function
'----------------------------------------------------
m_lHndMsgWin = CreateWindowEx(0&, "#32770", "TWAIN_MSG_WINDOW", 0&, _
10&, 10&, 150&, 50&, 0&, 0&, 0&, 0&)
If m_lHndMsgWin = 0 Then GoTo ErrPlace
'------------------------------------------------------------
' Introduce yourself to TWAIN - MajorNum, MinorNum, Language,
' Country, Manufacturer, ProductFamily, ProductName, etc.
'------------------------------------------------------------
Call ZeroMemory(VarPtr(m_tAppID), Len(m_tAppID))
With m_tAppID
.Version.MajorNum = 1
.Version.Language = TWLG_CZECH
.Version.Country = TWCY_CZECHOSLOVAKIA
.ProtocolMajor = TWON_PROTOCOLMAJOR
.ProtocolMinor = TWON_PROTOCOLMINOR
.SupportedGroups1 = DG_CONTROL Or DG_IMAGE
End With
Call CopyMemory(VarPtr(m_tAppID.Manufacturer(1)), _
StrPtr(StrConv("LMik", vbFromUnicode)), _
Len("LMik"))
Call CopyMemory(VarPtr(m_tAppID.ProductFamily(1)), _
StrPtr(StrConv("VB Module", vbFromUnicode)), _
Len("VB Module"))
Call CopyMemory(VarPtr(m_tAppID.ProductName(1)), _
StrPtr(StrConv("VB Module for TWAIN", vbFromUnicode)), _
Len("VB Module for TWAIN"))
'--------------------------------------
' Open Data Source Manager
' DG_CONTROL, DAT_PARENT, MSG_OPENDSM
'--------------------------------------
iRtn = DSM_Entry(m_tAppID, ByVal 0&, DG_CONTROL, DAT_PARENT, MSG_OPENDSM, _
m_lHndMsgWin)
If iRtn <> TWRC_SUCCESS Then GoTo ErrPlace
OpenTwainDSM = 0
Exit Function
ErrPlace:
OpenTwainDSM = 1
End Function
Private Function OpenTwainDS() As Long
Dim iRtn As Integer
On Local Error GoTo ErrPlace
'----------------------------------------------------------------------
' Open Data Source
' DG_CONTROL, DAT_IDENTITY, MSG_OPENDS
'
' The default data source is opened. If you want user to select the new
' default one, call public function PopupSelectSourceDialog.
'----------------------------------------------------------------------
Call ZeroMemory(VarPtr(m_tSrcID), Len(m_tSrcID))
iRtn = DSM_Entry(m_tAppID, ByVal 0&, DG_CONTROL, DAT_IDENTITY, MSG_OPENDS, _
m_tSrcID)
If iRtn <> TWRC_SUCCESS Then GoTo ErrPlace
OpenTwainDS = 0
Exit Function
ErrPlace:
OpenTwainDS = 1
End Function
Private Function CloseTwainDS() As Long
Dim iRtn As Integer
On Local Error GoTo ErrPlace
'----------------------------------------
' Close Data Source
' DG_CONTROL, DAT_IDENTITY, MSG_CLOSEDS
'----------------------------------------
iRtn = DSM_Entry(m_tAppID, ByVal 0&, DG_CONTROL, DAT_IDENTITY, _
MSG_CLOSEDS, m_tSrcID)
If iRtn <> TWRC_SUCCESS Then GoTo ErrPlace
CloseTwainDS = 0
Exit Function
ErrPlace:
CloseTwainDS = 1
End Function
Private Function CloseTwainDSM() As Long
Dim lRtn As Long
Dim iRtn As Integer
On Local Error GoTo ErrPlace
'---------------------------------------
' Close Data Source Manager
' DG_CONTROL, DAT_PARENT, MSG_CLOSEDSM
'---------------------------------------
iRtn = DSM_Entry(m_tAppID, ByVal 0&, DG_CONTROL, DAT_PARENT, MSG_CLOSEDSM, _
m_lHndMsgWin)
If iRtn <> TWRC_SUCCESS Then
lRtn = DestroyWindow(m_lHndMsgWin)
GoTo ErrPlace
End If
'---------------------------
' Destroy the message window
'---------------------------
lRtn = DestroyWindow(m_lHndMsgWin)
If lRtn = 0 Then GoTo ErrPlace
CloseTwainDSM = 0
Exit Function
ErrPlace:
CloseTwainDSM = 1
End Function
Private Function SetImageSize(ByRef sngLeft As Single, _
ByRef sngTop As Single, _
ByRef sngRight As Single, _
ByRef sngBottom As Single) As Long
Dim tImageLayout As TW_IMAGELAYOUT
Dim lRtn As Long
Dim iRtn As Integer
On Local Error GoTo ErrPlace
'-------------------------------------------------------------------
' Set the size of the image - in default units
' DG_IMAGE, DAT_IMAGELAYOUT, MSG_SET
'
' If you do not select any units the INCHES are selected as default.
' The values of Single type are converted into TWAIN TW_FIX32.
'-------------------------------------------------------------------
lRtn = FloatToFix32(sngLeft, tImageLayout.Frame.Left)
If lRtn Then GoTo ErrPlace
lRtn = FloatToFix32(sngTop, tImageLayout.Frame.Top)
If lRtn Then GoTo ErrPlace
lRtn = FloatToFix32(sngRight, tImageLayout.Frame.Right)
If lRtn Then GoTo ErrPlace
lRtn = FloatToFix32(sngBottom, tImageLayout.Frame.Bottom)
If lRtn Then GoTo ErrPlace
iRtn = DSM_Entry(m_tAppID, m_tSrcID, DG_IMAGE, DAT_IMAGELAYOUT, MSG_SET, _
tImageLayout)
If (iRtn <> TWRC_SUCCESS) And (iRtn <> TWRC_CHECKSTATUS) Then GoTo ErrPlace
SetImageSize = 0
Exit Function
ErrPlace:
SetImageSize = 1
End Function
Private Function TwainTransfer(ByRef blShowUI As Boolean, _
ByRef lDIBHandle As Long) As Long
Dim tUI As TW_USERINTERFACE
Dim tPending As TW_PENDINGXFERS
Dim lhDIB As Long
Dim tEvent As TW_EVENT
Dim tMSG As MSG
Dim lRtn As Long
Dim iRtn As Integer
On Local Error GoTo ErrPlace
'---------------------------------------------
' Set tUI.ShowUI to 1 (show UI) or 0 (hide UI)
'---------------------------------------------
With tUI
.ShowUI = IIf(blShowUI = True, 1, 0)
.ModalUI = 1
.hParent = m_lHndMsgWin
End With
'----------------------------------------------
' Enable Data Source User Interface
' DG_CONTROL, DAT_USERINTERFACE, MSG_ENABLEDS
'----------------------------------------------
iRtn = DSM_Entry(m_tAppID, m_tSrcID, DG_CONTROL, DAT_USERINTERFACE, _
MSG_ENABLEDS, tUI)
If iRtn <> TWRC_SUCCESS Then GoTo ErrPlace
'-----------------------------------------------------------------
' Process events in the message loop
' DG_CONTROL, DAT_EVENT, MSG_PROCESSEVENT
'
' There are two messages we are interested in in this message loop
' - MSG_XFERREADY - the data source is ready to transfer
' - MSG_CLOSEDSREQ - the data source requests to close itself
'-----------------------------------------------------------------
While GetMessage(tMSG, 0&, 0&, 0&)
Call ZeroMemory(VarPtr(tEvent), Len(tEvent))
tEvent.pEvent = VarPtr(tMSG)
iRtn = DSM_Entry(m_tAppID, m_tSrcID, DG_CONTROL, DAT_EVENT, _
MSG_PROCESSEVENT, tEvent)
Select Case tEvent.TWMessage
Case MSG_XFERREADY
GoTo MSGGET
Case MSG_CLOSEDSREQ
GoTo MSGDISABLEDS
End Select
lRtn = TranslateMessage(tMSG)
lRtn = DispatchMessage(tMSG)
Wend
MSGGET:
'----------------------------------------------------
' Start transfer
' DG_IMAGE, DAT_IMAGENATIVEXFER, MSG_GET
'
' If transfer is successful you get the handle to DIB
'----------------------------------------------------
iRtn = DSM_Entry(m_tAppID, m_tSrcID, DG_IMAGE, DAT_IMAGENATIVEXFER, _
MSG_GET, lhDIB)
If iRtn <> TWRC_XFERDONE Then
iRtn = DSM_Entry(m_tAppID, m_tSrcID, DG_CONTROL, DAT_PENDINGXFERS, _
MSG_ENDXFER, tPending)
iRtn = DSM_Entry(m_tAppID, m_tSrcID, DG_CONTROL, DAT_USERINTERFACE, _
MSG_DISABLEDS, tUI)
GoTo ErrPlace
End If
'--------------------------------------------
' End transfer
' DG_CONTROL, DAT_PENDINGXFERS, MSG_ENDXFER
'--------------------------------------------
iRtn = DSM_Entry(m_tAppID, m_tSrcID, DG_CONTROL, DAT_PENDINGXFERS, _
MSG_ENDXFER, tPending)
If iRtn <> TWRC_SUCCESS Then
iRtn = DSM_Entry(m_tAppID, m_tSrcID, DG_CONTROL, DAT_USERINTERFACE, _
MSG_DISABLEDS, tUI)
GoTo ErrPlace
End If
MSGDISABLEDS:
'-----------------------------------------------
' Disable Data Source
' DG_CONTROL, DAT_USERINTERFACE, MSG_DISABLEDS
'-----------------------------------------------
iRtn = DSM_Entry(m_tAppID, m_tSrcID, DG_CONTROL, DAT_USERINTERFACE, _
MSG_DISABLEDS, tUI)
If iRtn <> TWRC_SUCCESS Then GoTo ErrPlace
lDIBHandle = lhDIB
TwainTransfer = 0
Exit Function
ErrPlace:
If lhDIB Then lRtn = GlobalFree(lhDIB)
lDIBHandle = 0
TwainTransfer = 1
End Function
Private Function SaveDIBToFile(ByRef lhDIB As Long, _
ByRef sFileName As String) As Long
'---------------------------------------------------------------------------
' Function saves the handle to DIB (device independent bitmap) into BMP file
'---------------------------------------------------------------------------
Dim tBFH As BITMAPFILEHEADER
Dim tBIH As BITMAPINFOHEADER
Dim tRGB As RGBQUAD
Dim lpDIB As Long
Dim lDIBSize As Long
Dim bDIBits() As Byte
Dim iFileNum As Integer
Dim lRtn As Long
On Local Error GoTo ErrPlace
If sFileName = "" Then GoTo ErrPlace
If Dir(sFileName, vbNormal Or vbHidden Or vbSystem) <> "" Then
Call SetAttr(sFileName, vbNormal)
Call Kill(sFileName)
End If
lpDIB = GlobalLock(lhDIB)
If lpDIB = 0 Then GoTo ErrPlace
Call CopyMemory(VarPtr(tBIH), lpDIB, Len(tBIH))
lDIBSize = Len(tBIH) + (tBIH.biClrUsed * Len(tRGB)) + _
(((tBIH.biWidth * tBIH.biBitCount + 31) \ 32) * 4 * tBIH.biHeight)
ReDim bDIBits(1 To lDIBSize) As Byte
Call CopyMemory(VarPtr(bDIBits(1)), lpDIB, lDIBSize)
lRtn = GlobalUnlock(lhDIB)
lRtn = GlobalFree(lhDIB)
lhDIB = 0
With tBFH
.bfType = 19778 ' "BM"
.bfSize = Len(tBFH) + lDIBSize
.bfOffBits = Len(tBFH) + Len(tBIH) + (tBIH.biClrUsed * Len(tRGB))
End With
iFileNum = FreeFile
Open sFileName For Binary As #iFileNum
Put #iFileNum, , tBFH
Put #iFileNum, , bDIBits()
Close #iFileNum
SaveDIBToFile = 0
Exit Function
ErrPlace:
lRtn = GlobalUnlock(lhDIB)
lRtn = GlobalFree(lhDIB)
lhDIB = 0
SaveDIBToFile = 1
End Function
Private Function TwainSetOneValue(ByVal Cap As TWAIN_MDL_CAPABILITY, _
ByVal ItemType As TWAIN_MDL_ITEMYPE, _
ByRef Item As Variant) As Long
'-----------------------------------------------------------------------
' There are four types of containers that TWAIN defines for capabilities
' (TW_ONEVALUE, TW_ARRAY, TW_RANGE and TW_ENUMERATION)
' This module deals with one of them only - TW_ONEVALUE (single value)
' To set some capability you have to fill TW_ONEVALUE fields and use
' the triplet DG_CONTROL DAT_CAPABILITY MSG_SET
' The macros that convert some data types are used here as well
'-----------------------------------------------------------------------
On Local Error GoTo ErrPlace
Dim tCapability As TW_CAPABILITY
Dim tOneValue As TW_ONEVALUE
Dim lhOneValue As Long
Dim lpOneValue As Long
Dim lRtn As Long
Dim iRtn As Integer
Dim tFix32 As TW_FIX32
Dim iTmp As Integer
tCapability.ConType = TWON_ONEVALUE
tCapability.Cap = Cap
tOneValue.ItemType = ItemType
Select Case ItemType
Case INT16
tOneValue.Item1 = CInt(Item)
Case UINT16, BOOL
If ToUnsignedShort(CLng(Item), iTmp) Then GoTo ErrPlace
Call CopyMemory(VarPtr(tOneValue.Item1), VarPtr(iTmp), 2&)
Case FIX32
If FloatToFix32(CSng(Item), tFix32) Then GoTo ErrPlace
Call CopyMemory(VarPtr(tOneValue.Item1), VarPtr(tFix32), 4&)
End Select
lhOneValue = GlobalAlloc(GHND, Len(tOneValue))
lpOneValue = GlobalLock(lhOneValue)
Call CopyMemory(lpOneValue, VarPtr(tOneValue), Len(tOneValue))
lRtn = GlobalUnlock(lhOneValue)
tCapability.hContainer = lhOneValue
iRtn = DSM_Entry(m_tAppID, m_tSrcID, DG_CONTROL, DAT_CAPABILITY, MSG_SET, _
tCapability)
If iRtn <> TWRC_SUCCESS Then
lRtn = GlobalFree(lhOneValue)
GoTo ErrPlace
End If
lRtn = GlobalFree(lhOneValue)
TwainSetOneValue = 0
Exit Function
ErrPlace:
TwainSetOneValue = 1
End Function
Private Function TwainGetOneValue(ByVal Cap As TWAIN_MDL_CAPABILITY, _
ByRef Item As Variant) As Long
'-----------------------------------------------------------------------
' There are four types of containers that TWAIN defines for capabilities
' (TW_ONEVALUE, TW_ARRAY, TW_RANGE and TW_ENUMERATION)
' This module deals with one of them only - TW_ONEVALUE (single value)
' To get some capability you have to fill TW_ONEVALUE fields and use
' the triplet DG_CONTROL DAT_CAPABILITY MSG_GET
' The macros that convert some data types are used here as well
'-----------------------------------------------------------------------
On Local Error GoTo ErrPlace
Dim tCapability As TW_CAPABILITY
Dim tOneValue As TW_ONEVALUE
Dim tFix32 As TW_FIX32
Dim lpOneValue As Long
Dim lRtn As Long
Dim iRtn As Integer
tCapability.ConType = TWON_ONEVALUE
tCapability.Cap = Cap
iRtn = DSM_Entry(m_tAppID, m_tSrcID, DG_CONTROL, DAT_CAPABILITY, MSG_GET, _
tCapability)
If iRtn <> TWRC_SUCCESS Then GoTo ErrPlace
lpOneValue = GlobalLock(tCapability.hContainer)
Call CopyMemory(VarPtr(tOneValue), lpOneValue, Len(tOneValue))
lRtn = GlobalUnlock(tCapability.hContainer)
lRtn = GlobalFree(tCapability.hContainer)
Select Case tOneValue.ItemType
Case INT16
Item = tOneValue.Item1
Case UINT16, BOOL
Item = FromUnsignedShort(tOneValue.Item1)
Case FIX32
Call CopyMemory(VarPtr(tFix32), VarPtr(tOneValue.Item1), 4&)
Item = Fix32ToFloat(tFix32)
End Select
TwainGetOneValue = 0
Exit Function
ErrPlace:
TwainGetOneValue = 1
End Function
Private Function ToUnsignedShort(ByRef lSrc As Long, _
ByRef iDst As Integer) As Long
'------------------------------------------------------------------------
' Sets number ranging from 0 to 65535 into 2-byte VB Integer
' (useful for communicating with other dll that uses unsigned data types)
'
' Function returns 0 is OK, 1 if an error occurs
'------------------------------------------------------------------------
On Local Error GoTo ErrPlace
If (lSrc < 0) Or (lSrc > 65535) Then GoTo ErrPlace
Call CopyMemory(VarPtr(iDst), VarPtr(lSrc), 2&)
' Another way
'iDst = IIf(lSrc > 32767, lSrc - 65536, lSrc)
ToUnsignedShort = 0
Exit Function
ErrPlace:
ToUnsignedShort = 1
End Function
Private Function FromUnsignedShort(ByRef iSrc As Integer) As Long
'------------------------------------------------------------------------
' Gets the 2-byte unsigned number from VB Integer data type
' (useful for communicating with other dll that uses unsigned data types)
'
' Function returns unsigned 2-byte value (in VB Long type)
'------------------------------------------------------------------------
Dim lTmp As Long
Call CopyMemory(VarPtr(lTmp), VarPtr(iSrc), 2&)
' Another way
'lTmp = IIf(iSrc < 0, iSrc + 65536, iSrc)
FromUnsignedShort = lTmp
End Function
Private Function ToUnsignedLong(ByRef sngSrc As Single, _
ByRef lDst As Long) As Long
'------------------------------------------------------------------------
' Sets number ranging from 0 to 4294967295 into 4-byte VB Long
' (useful for communicating with other dll that uses unsigned data types)
'
' Function returns 0 is OK, 1 if an error occurs
'------------------------------------------------------------------------
On Local Error GoTo ErrPlace
If (sngSrc < 0) Or (sngSrc > 4294967295#) Then GoTo ErrPlace
lDst = IIf(sngSrc > 2147483647, sngSrc - 4294967296#, sngSrc)
ToUnsignedLong = 0
Exit Function
ErrPlace:
ToUnsignedLong = 1
End Function
Private Function FromUnsignedLong(ByRef lSrc As Long) As Single
'------------------------------------------------------------------------
' Gets the 4-byte unsigned number from VB Long data type
' (useful for communicating with other dll that uses unsigned data types)
'
' Function returns unsigned 4-byte value (in VB Single type)
'------------------------------------------------------------------------
Dim sngTmp As Single
sngTmp = IIf(lSrc < 0, lSrc + 4294967296#, lSrc)
FromUnsignedLong = sngTmp
End Function
Private Function Fix32ToFloat(ByRef tFix32 As TW_FIX32) As Single
'----------------------------------------------------------------
' Converts TWAIN TW_FIX32 data structure into VB Single data type
' (needed for communicating with TWAIN)
'
' Function returns floating-point number in VB Single data type
'----------------------------------------------------------------
Dim sngTmp As Single
sngTmp = tFix32.Whole + CSng(FromUnsignedShort(tFix32.Frac) / 65536)
Fix32ToFloat = sngTmp
End Function
Private Function FloatToFix32(ByRef sngSrc As Single, _
ByRef tFix32 As TW_FIX32) As Long
'----------------------------------------------------------------
' Converts VB Single data type into TWAIN TW_FIX32 data structure
' (needed for communicating with TWAIN)
'
' Function returns 0 is OK, 1 if an error occurs
'----------------------------------------------------------------
On Local Error GoTo ErrPlace
tFix32.Whole = CInt(Fix(sngSrc))
Call ToUnsignedShort(CLng(sngSrc * 65536) And 65535, tFix32.Frac)
FloatToFix32 = 0
Exit Function
ErrPlace:
FloatToFix32 = 1
End Function
