L_TwainGetDeviceEventData
#include "lttwn.h"
L_LTTWN_API L_INT L_TwainGetDeviceEventData(hSession, pDeviceEvent)
HTWAINSESSION hSession; |
/* handle to an existing TWAIN session */ |
pTW_DEVICEEVENT pDeviceEvent; |
/* pointer to a structure */ |
Gets information for a specific device event.
Parameter |
Description |
hSession |
Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession function. |
pDeviceEvent |
Pointer to a TW_DEVICEEVENT structure that references the required device event capability. This structure must be allocated and will be filled with data corresponding to the required capability to get. |
Returns
SUCCESS |
The function was successful. |
< 1 |
An error occurred. Refer to Return Codes. |
Comments
This function should be called inside LTWAINDEVICEEVENTCALLBACK callback to get the device event information.
To get the status for each device event, call L_TwainSetDeviceEventCallback function.
To get the CAP_DEVICEEVENT capability values, call L_TwainGetDeviceEventCapability function.
To set the CAP_DEVICEEVENT capability values, call L_TwainSetDeviceEventCapability function.
To rest the CAP_DEVICEEVENT capability value to the default, call L_TwainResetDeviceEventCapability function.
For information about TW_DEVICEEVENT, refer to the TWAIN 1.9 specification from the site "http://www.twain.org/".
Required DLLs and Libraries
LTTWN For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application. |
See Also
Functions: |
L_TwainSetDeviceEventCallback, L_TwainSetDeviceEventCapability, L_TwainGetDeviceEventCapability, L_TwainResetDeviceEventCapability, LTWAINDEVICEEVENTCALLBACK |
Topics: |
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Example
float MyFix32ToFloat(TW_FIX32 * ptwFix) { float Floater = 0; Floater = (float)ptwFix->Whole + (float)ptwFix->Frac / (float)65536.0; return Floater; } L_INT EXT_CALLBACK DeviceEventCB(HTWAINSESSION hSession, L_VOID * /*pUserData*/) { TW_DEVICEEVENT twDevice; memset(&twDevice, 0, sizeof(TW_DEVICEEVENT)); L_INT nRet = L_TwainGetDeviceEventData(hSession, &twDevice); if (nRet != SUCCESS) return nRet; L_TCHAR szBuffer[MAX_PATH]; memset(szBuffer, 0, sizeof(szBuffer)); wsprintf(szBuffer, TEXT("Event = %d\nEvent Name =%s\n"), twDevice.Event, twDevice.DeviceName); MessageBox(NULL, szBuffer, TEXT("Notice!"), MB_OK); if (twDevice.Event == TWDE_CHECKBATTERY) { wsprintf(szBuffer, TEXT("Battery Minutes = %d\nBattery Percentage = %d\n"), twDevice.BatteryMinutes, twDevice.BatteryPercentage); MessageBox(NULL, szBuffer, TEXT("Notice!"), MB_OK); } else if (twDevice.Event == TWDE_CHECKPOWERSUPPLY) { wsprintf(szBuffer, TEXT("Power Supply =%d\n"), twDevice.PowerSupply); MessageBox(NULL, szBuffer, TEXT("Notice!"), MB_OK); } else if (twDevice.Event == TWDE_CHECKRESOLUTION) { wsprintf(szBuffer, TEXT("XResolution = %f\nYResolution = %f\n"), MyFix32ToFloat(&twDevice.XResolution), MyFix32ToFloat(&twDevice.YResolution)); MessageBox(NULL, szBuffer, TEXT("Notice!"), MB_OK); } else if (twDevice.Event == TWDE_CHECKFLASH) { wsprintf(szBuffer, TEXT("FlashUsed2 =%d\n"), twDevice.FlashUsed2); MessageBox(NULL, szBuffer, TEXT("Notice!"), MB_OK); } else if (twDevice.Event == TWDE_CHECKAUTOMATICCAPTURE) { wsprintf(szBuffer, TEXT("Automatic Capture =%d\nTime Before First Capture =%d\nTime Between Captures = %d\n"), twDevice.AutomaticCapture, twDevice.TimeBeforeFirstCapture, twDevice.TimeBetweenCaptures); MessageBox(NULL, szBuffer, TEXT("Notice!"), MB_OK); } return SUCCESS; } L_INT GetDeviceEventDataExample(HTWAINSESSION hSession) { BITMAPHANDLE MyBtmp; memset(&MyBtmp, 0, sizeof(BITMAPHANDLE)); L_TwainStartCapsNeg(hSession); L_TwainSetDeviceEventCallback(hSession, DeviceEventCB, NULL); L_TwainEndCapsNeg(hSession); L_TwainAcquire(hSession, &MyBtmp, sizeof(BITMAPHANDLE), NULL, LTWAIN_SHOW_USER_INTERFACE, NULL, NULL); return SUCCESS; }