Available in LEADTOOLS Imaging Pro, Vector, Document, and Medical Imaging toolkits. |
Note: The purpose of this TWAIN tutorial is to provide you a quick and easy way to generate a TWAIN program. For more in depth TWAIN programming, refer to the TWAIN demo.
To Get or Set a TWAIN capability using LEADTOOLS:
1. |
Create a new directory in the \Examples\CDLL directory called TwainCap |
2. |
Copy everything in the SimpleLoad directory into the TwainCap directory. |
3. |
Compile the project as it is and run SimpleLoad.exe to familiarize yourself with the basic program. |
4. |
In the Imports.cpp, add the following lines: |
#if defined(WIN64)
…
…
#else
…
…
#pragma comment(lib, "..\\..\\..\\Lib"L_VER_DESIGNATOR"\\CDLL\\Win32\\Lttwn_u.lib")
#endif // #if defined(WIN64)
5. |
Add the following line in StdAfx.h in the TwainCap directory: |
#include "..\..\..\include\lttwn.h"
6. |
Define the following global variables in Ezfunc.h in the TwainCap directory: |
HTWAINSESSION hSession;
TW_CAPABILITY twCap;
L_UINT uItemValue;
Also, add the following defines:
#define IDM_SELECT_SOURCE 200
#define IDM_GET_CAPABILITY 201
#define IDM_SET_CAPABILITY 202
#define IDM_SET_BRIGHTNESS 203
#define IDM_ACQUIRE 204
7. |
Edit EZFUNC.RC file in the TwainCap directory and add the following lines: |
#include "EZFUNC.H"
MAIN_MENU MENU
BEGIN
MENUITEM "Select Source" IDM_SELECT_SOURCE
MENUITEM "Get Capability" IDM_GET_CAPABILITY
MENUITEM "Set Capability" IDM_SET_CAPABILITY
MENUITEM "Set Brightness" IDM_SET_BRIGHTNESS
MENUITEM "Acquire" IDM_ACQUIRE
END
8. |
In the InitApplication function change the line: |
wcWindowClass.lpszMenuName = NULL; /* No menu */
to be
wcWindowClass.lpszMenuName = TEXT("MAIN_MENU");
9. |
In the MainWndProc function, before the handling of the WM_PALETTECHANGED message, add the following code: |
case WM_COMMAND:
{
switch (LOWORD(wParam))
{
case IDM_SELECT_SOURCE:
{
}
break;
case IDM_GET_CAPABILITY:
{
}
break;
case IDM_SET_CAPABILITY:
{
}
break;
case IDM_SET_BRIGHTNESS:
{
}
break;
case IDM_ACQUIRE:
{
}
break;
}
}
break;
10. |
In the WM_CREATE message handler add the following code at the end of it (after SendMessage (hWnd, WM_QUERYNEWPALETTE, 0, 0L);): |
APPLICATIONDATA AppData;
AppData.uStructSize = sizeof(APPLICATIONDATA);
AppData.hWnd = hWnd;
lstrcpy (AppData.szManufacturerName, TEXT("LEAD Technologies, Inc."));
lstrcpy (AppData.szAppProductFamily, TEXT("LEAD Test Applications"));
lstrcpy (AppData.szVersionInfo, TEXT("Version 1.0"));
lstrcpy (AppData.szAppName, TEXT("TWAIN Test Application"));
nRet = L_TwainInitSession(&hSession, &AppData);
if (nRet != SUCCESS)
return FALSE;
nRet = L_TwainStartCapsNeg(hSession);
if(nRet != SUCCESS)
return FALSE;
11. |
In the WM_DESTROY message handler add the following code at the end of it (before the PostQuitMessage (0);): |
L_TwainEndCapsNeg(hSession);
L_TwainEndSession(&hSession);
12. |
In the IDM_SELECT_SOURCE menu handler add the following code: |
case IDM_SELECT_SOURCE:
{
nRet = L_TwainSelectSource(hSession, NULL);
}
break;
13. |
In the IDM_GET_CAPABILITY menu handler add the following code: |
case IDM_GET_CAPABILITY:
{
L_INT nItemType;
twCap.Cap = ICAP_XFERMECH;
twCap.ConType = TWON_DONTCARE16;
twCap.hContainer = NULL;
L_TwainGetCapability(hSession, &twCap, LTWAIN_CAPABILITY_GETCURRENT);
L_TwainGetNumericContainerItemType(&twCap, &nItemType);
if (nItemType == TWTY_UINT16)
L_TwainGetNumericContainerUINTValue(&twCap, 0, &uItemValue);
else
MessageBox(hWnd, TEXT("Returned bad item type"), TEXT("Get Item Type"), MB_OK);
}
break;
14. |
In the IDM_SET_CAPABILITY menu handle add the following code: |
case IDM_SET_CAPABILITY:
{
if (uItemValue != TWSX_NATIVE)
{
TW_CAPABILITY twSetCap;
twSetCap.Cap = ICAP_XFERMECH;
twSetCap.ConType = TWON_ONEVALUE;
L_TwainCreateNumericContainerOneValue(&twSetCap, TWAINNUMERICTYPE_TW_UINT16, TWSX_NATIVE);
L_TwainSetCapability(hSession, &twSetCap, LTWAIN_CAPABILITY_SET);
L_TwainFreeContainer(&twSetCap);
}
else
MessageBox(hWnd, TEXT("The Transfer mode is Native"), TEXT("Set Capability"), MB_OK);
}
break;
15. |
In the IDM_SET_BRIGHTNESS menu handle add the following code: |
case IDM_SET_BRIGHTNESS:
{
TW_CAPABILITY twBrightnessCap;
TW_FIX32 twFix32;
pTW_ONEVALUE ptwOneVal;
twBrightnessCap.Cap = ICAP_BRIGHTNESS;
twBrightnessCap.ConType = TWON_ONEVALUE;
nRet = L_TwainGetCapability (hSession, &twBrightnessCap, LTWAIN_CAPABILITY_GETCURRENT);
if (nRet == SUCCESS)
{
ptwOneVal = (pTW_ONEVALUE)GlobalLock(twCap.hContainer);
memcpy(&twFix32, (void *)&ptwOneVal->Item, sizeof(TW_FIX32));
GlobalUnlock(twBrightnessCap.hContainer);
GlobalFree(twBrightnessCap.hContainer);
twBrightnessCap.hContainer = NULL;
if (twFix32.Whole != 128)
{
twFix32.Whole = 128;
twFix32.Frac = 0;
}
twBrightnessCap.Cap = ICAP_BRIGHTNESS;
twBrightnessCap.ConType = TWON_ONEVALUE;
twBrightnessCap.hContainer = GlobalAlloc(GHND, sizeof(TW_ONEVALUE) + sizeof(TW_FIX32));
ptwOneVal = (pTW_ONEVALUE)GlobalLock(twCap.hContainer);
ptwOneVal->ItemType = TWTY_FIX32;
memcpy((void *)&ptwOneVal->Item, &twFix32, sizeof(TW_FIX32));
GlobalUnlock(twBrightnessCap.hContainer);
L_TwainSetCapability (hSession, &twBrightnessCap, LTWAIN_CAPABILITY_SET);
}
}
break;
16. |
In the IDM_ACQUIRE menu handler add the following code: |
case IDM_ACQUIRE:
{
L_TwainEndCapsNeg(hSession);
if (LeadBitmap.Flags.Allocated)
{
L_FreeBitmap(&LeadBitmap);
L_InitBitmap(&LeadBitmap, sizeof(BITMAPHANDLE), 0, 0, 0);
L_TwainAcquire(hSession, &LeadBitmap, sizeof(BITMAPHANDLE), NULL, LTWAIN_SHOW_USER_INTERFACE, NULL, NULL);
}
}
break;
17. |
Compile and test the program. |