L_CaptureWindow

Summary

Captures an image of a window handle.

Syntax

L_LTSCR_API L_INT L_CaptureWindow(pBitmap, uBitmapStructSize, hWnd, wctCaptureType, pCaptureInfo, uInfoStructSize, pfnCaptureCallback, pUserData)

Parameters

pBITMAPHANDLE pBitmap

Pointer to a bitmap handle that references the captured data.

L_UINT uBitmapStructSize

Value that represents the size, in bytes, of the structure pointed to by pBitmap parameter, for versioning. Use sizeof (BITMAPHANDLE).

L_HWND hWnd

Handle of the window to capture.

WINDOWCAPTURETYPE wctCaptureType

Flag that indicates the capture type. Possible values are:

pLEADCAPTUREINFO pCaptureInfo

Pointer to the LEADCAPTUREINFO structure to be updated with information regarding the captured image's source. Pass NULL if you are not interested in extra information about the capture.

L_UINT uInfoStructSize

Value that represents the size, in bytes, of the structure pointed to by pCaptureInfo parameter, for versioning. Use sizeof(LEADCAPTUREINFO).

CAPTURECALLBACK pfnCaptureCallback

Optional callback function for additional processing.

If you do not provide a callback function, pass NULL as the value of this parameter.

If you do provide a callback function, pass the function pointer as the value of this parameter.

The callback function must adhere to the function prototype described in CAPTURECALLBACK function.

L_VOID * pUserData

Void pointer that you can use to pass one or more additional parameters that the callback function needs.

To use this feature, assign a value to a variable or create a structure that contains as many fields as you need. Then, in this parameter, pass the address of the variable or structure, casting it to L_VOID ;*. The callback function, which receives the address in its own pUserData parameter, can cast it to a pointer of the appropriate data type to access your variable or structure.

If the additional parameters are not needed, you can pass NULL in this parameter.

Returns

Comments

The callback can be used to do multiple captures, depending on the options set using L_SetCaptureOption function.

The hot key needs to be pressed to complete the capture.

Required DLLs and Libraries

• LTSCR
• 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_SetCaptureOption
• L_SetCaptureOptionDlg
• CAPTURECALLBACK
• L_StopCapture

Topics

• Screen Capture C API Function Groups: Capture Functions
• Implementing Screen Capture

Example

static L_INT EXT_CALLBACK pfnCaptureCallback(pBITMAPHANDLE pBitmap, pLEADCAPTUREINFO pCaptureInfo, L_VOID* pUserData) 
{ 
   UNREFERENCED_PARAMETER(pCaptureInfo); 
   UNREFERENCED_PARAMETER(pUserData); 
   /* save the captured image */ 
   return (L_SaveBitmap (MAKE_IMAGE_PATH(TEXT("test.bmp")), pBitmap, FILE_BMP, 0, 0, NULL)); 
} 
L_INT CaptureWindowExample (L_VOID) 
{ 
   BITMAPHANDLE Bitmap; 
   LEADCAPTUREINFO CaptureInfo; 
   /* Get the window handle */ 
   HWND hWnd = GetForegroundWindow(); 
   /*To call the L_CaptureWindow*/ 
   L_INT nRet = L_CaptureWindow(&Bitmap,  
 sizeof(BITMAPHANDLE), hWnd, CAPTURE_WINDOW, &CaptureInfo, sizeof(LEADCAPTUREINFO),  
 pfnCaptureCallback, NULL); 
    L_FreeBitmap(&Bitmap); 
   return nRet; 
}