Official Website:http://www.twain.org
一、简介
二、使用步骤
1. 打开 DSM (Data Source Manager: 数据源管理器)
2. 选择 DS (Data Source: 数据源)
3. 打开 DS
4. 设置参数
5. 显示扫描界面
6. 获取图像
7. 关闭扫描界面
8. 关闭 DS
9. 关闭数据源
三、CTwainHelper 助手类
- 调用 CTwainHelper::Initialize() 确定是否有可用的设备。
- 在窗口消息循环中，调用 CTwainHelper::ProcessMessage() 处理 TWAIN 消息。
- 要获取图像时，调用 CTwainHelper::GetImage()。
- 如果图像已准备好 (如用户确定扫描图像)，窗口会收到 WM_COMMAND 消息，wParam 为 IDC_TwainHelper。此时应用程序可以调用 CTwainHelper::TransferImage() 获取图像到文件中。
四、后话
Open the Source Manager (State 2 to 3)
Select the Source (during State 3)
Open the Source (State 3 to 4)
Negotiate Capabilities with the Source (during State 4)
Request the Acquisition of Data from the Source (State 4 to 5)
Recognize that the Data Transfer is Ready (State 5 to 6)
Start and Perform the Transfer (State 6 to 7)
Conclude the Transfer (State 7 to 6 to 5)
Disconnect the TWAIN Session (State 5 to 1 in sequence)
VC++ Call Twain
Header
#ifndef __TWAINCPP_
#define __TWAINCPP_
#include "Twain.h"
#define TWCPP_ANYCOUNT (-1)
#define TWCPP_CANCELTHIS (1)
#define TWCPP_CANCELALL (2)
#define TWCPP_DOTRANSFER (0)
class CTwain
{
public:
void Deskew(LPSTR lpFilename);
CTwain(HWND hWnd = NULL);
virtual ~CTwain();
BOOL InitTwain(HWND hWnd);
void ReleaseTwain();
/*
This routine must be implemented by the dervied class
After setting the required values in the m_AppId structure,
the derived class should call the parent class implementation
Refer Pg: 51 of the Twain Specification version 1.8
*/
virtual void GetIdentity();
virtual BOOL SelectSource();
virtual BOOL OpenSource(TW_IDENTITY *pSource=NULL);
virtual int ShouldTransfer(TW_IMAGEINFO& info) { return TWCPP_DOTRANSFER;};
void SetPara(int nFileFormat,LPCTSTR lpFileName,int nAD,int nPage,int nStep,BOOL bDeskdw);
void GetPara(UINT &nPage);
BOOL ProcessMessage(MSG msg);
BOOL SelectDefaultSource();
BOOL IsValidDriver() const;
BOOL SourceSelected() const {return m_bSourceSelected;} ;
BOOL DSMOpen() const;
BOOL DSOpen() const;
BOOL SourceEnabled() const { return m_bSourceEnabled;};
BOOL ModalUI() const { return m_bModalUI; };
TW_INT16 GetRC() const { return m_returnCode; };
TW_STATUS GetStatus() const { return m_Status; };
BOOL SetImageCount(TW_INT16 nCount = 1);
BOOL Acquire(int numImages=1);
void DoFileTransfer();
void CloseDSM();
protected:
BOOL CallTwainProc(pTW_IDENTITY pOrigin,pTW_IDENTITY pDest,
TW_UINT32 DG,TW_UINT16 DAT,TW_UINT16 MSG,
TW_MEMREF pData);
void CloseDS();
BOOL GetCapability(TW_CAPABILITY& twCap,TW_UINT16 cap,TW_UINT16 conType=TWON_DONTCARE16);
BOOL GetCapability(TW_UINT16 cap,TW_UINT32& value);
BOOL SetCapability(TW_UINT16 cap,TW_UINT16 value,BOOL sign=FALSE);
BOOL SetCapability(TW_CAPABILITY& twCap);
BOOL EnableSource(BOOL showUI = TRUE);
BOOL GetImageInfo(TW_IMAGEINFO& info);
virtual BOOL DisableSource();
virtual BOOL CanClose() { return TRUE; };
void TranslateMessage(TW_EVENT& twEvent);
void TransferImage();
BOOL EndTransfer();
void CancelTransfer();
BOOL ShouldContinue();
BOOL GetImage(TW_IMAGEINFO& info);
// virtual void CopyImage(HANDLE hBitmap,TW_IMAGEINFO& info)=0;
protected:
HINSTANCE m_hTwainDLL;
DSMENTRYPROC m_pDSMProc;
TW_IDENTITY m_AppId;
TW_IDENTITY m_Source;
TW_STATUS m_Status;
TW_INT16 m_returnCode;
HWND m_hMessageWnd;
BOOL m_bSourceSelected;
BOOL m_bDSMOpen;
BOOL m_bDSOpen;
BOOL m_bSourceEnabled;
BOOL m_bModalUI;Cpp
#include "stdafx.h"
#include "twaincpp.h"
#include "showpic.h"
#include "tiff2pdfdll.h"
CTwain::CTwain(HWND hWnd)
{
m_hTwainDLL = NULL;
m_pDSMProc = NULL;
m_bSourceSelected = FALSE;
m_bDSOpen = m_bDSMOpen = FALSE;
m_bSourceEnabled = FALSE;
m_bModalUI = TRUE;
m_nImageCount = TWCPP_ANYCOUNT;
if(hWnd)
{
InitTwain(hWnd);
}
}
CTwain::~CTwain()
{
ReleaseTwain();
}
/*
初始化TWAIN 接口. 构造函数中已经调用，不过如果调用了ReleaseTwain的话就需要再次调用.
hWnd是接受Twain消息的窗口句柄，通常应该是主应用程序的窗口句柄
*/
BOOL CTwain::InitTwain(HWND hWnd)
{
char libName[512];
if(IsValidDriver())
{
return TRUE;
}
memset(&m_AppId,0,sizeof(m_AppId));
if(!IsWindow(hWnd))
{
return FALSE;
}
m_hMessageWnd = hWnd;
strcpy(libName,"TWAIN_32.DLL");
m_hTwainDLL = LoadLibrary(libName);
if(m_hTwainDLL != NULL)
{
if(!(m_pDSMProc = (DSMENTRYPROC)GetProcAddress(m_hTwainDLL,MAKEINTRESOURCE(1))))
{
FreeLibrary(m_hTwainDLL);
m_hTwainDLL = NULL;
}
}
if(IsValidDriver())
{
GetIdentity();
m_bDSMOpen= CallTwainProc(&m_AppId,NULL,DG_CONTROL,DAT_PARENT,MSG_OPENDSM,(TW_MEMREF)&m_hMessageWnd);
return TRUE;
}
else
{
return FALSE;
}
}
/*
释放Twain接口，除非不再使用Twain接口，否则就无需调用
*/
void CTwain::ReleaseTwain()
{
if(IsValidDriver())
{
CloseDSM();
FreeLibrary(m_hTwainDLL);
m_hTwainDLL = NULL;
m_pDSMProc = NULL;
}
}
/*
如果正确的装载了驱动程序，就返回TRUE
*/
BOOL CTwain::IsValidDriver() const
{
return (m_hTwainDLL && m_pDSMProc);
}
BOOL CTwain::CallTwainProc(pTW_IDENTITY pOrigin,pTW_IDENTITY pDest,
TW_UINT32 DG,TW_UINT16 DAT,TW_UINT16 MSG,
TW_MEMREF pData)
{
if(IsValidDriver())
{
USHORT ret_val;
ret_val = (*m_pDSMProc)(pOrigin,pDest,DG,DAT,MSG,pData);
m_returnCode = ret_val;
if(ret_val != TWRC_SUCCESS)
{
(*m_pDSMProc)(pOrigin,pDest,DG_CONTROL,DAT_STATUS,MSG_GET,&m_Status);
}
return (ret_val == TWRC_SUCCESS);
}
else
{
m_returnCode = TWRC_FAILURE;
return FALSE;
}
}
/*
设置Twain的一些入口参数
*/
void CTwain::GetIdentity()
{
// Expects all the fields in m_AppId to be set except for the id field.
m_AppId.Id = 0; // Initialize to 0 (Source Manager
m_AppId.Version.MajorNum = 1; //Your app's version number
m_AppId.Version.MinorNum = 5;
m_AppId.Version.Language = TWLG_USA;
m_AppId.Version.Country = TWCY_USA;
strcpy (m_AppId.Version.Info, "3.5");
m_AppId.ProtocolMajor = TWON_PROTOCOLMAJOR;
m_AppId.ProtocolMinor = TWON_PROTOCOLMINOR;
m_AppId.SupportedGroups = DG_IMAGE | DG_CONTROL;
strcpy (m_AppId.Manufacturer, "MICSS");
strcpy (m_AppId.ProductFamily, "Generic");
strcpy (m_AppId.ProductName, "Twain Test");
}
/*
调用此函数显示选择扫描设备窗口
*/
BOOL CTwain::SelectSource()
{
memset(&m_Source,0,sizeof(m_Source));
if(!SourceSelected())
{
SelectDefaultSource();
}
if(CallTwainProc(&m_AppId,NULL,DG_CONTROL,DAT_IDENTITY,MSG_USERSELECT,&m_Source))
{
m_bSourceSelected = TRUE;
}
return m_bSourceSelected;
}
/*
用于选择缺省扫描设备
*/
BOOL CTwain::SelectDefaultSource()
{
m_bSourceSelected = CallTwainProc(&m_AppId,NULL,DG_CONTROL,DAT_IDENTITY,MSG_GETDEFAULT,&m_Source);
return m_bSourceSelected;
}
/*
关闭数据源（即扫描仪）
*/
void CTwain::CloseDS()
{
if(DSOpen())
{
DisableSource();
CallTwainProc(&m_AppId,NULL,DG_CONTROL,DAT_IDENTITY,MSG_CLOSEDS,(TW_MEMREF)&m_Source);
m_bDSOpen = FALSE;
}
}
/*
关闭数据源管理器
*/
void CTwain::CloseDSM()
{
if(DSMOpen())
{
CloseDS();
CallTwainProc(&m_AppId,NULL,DG_CONTROL,DAT_PARENT,MSG_CLOSEDSM,(TW_MEMREF)&m
