#include "l_bitmap.h"

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


pointer to the bitmap handle

L_UINT uBitmapStructSize;

size, in bytes, of the structure

L_HWND hWnd;

window handle




pointer to info structure

L_UINT uInfoStructSize;

size, in bytes, of the structure

CAPTURECALLBACK pfnCaptureCallback;

optional callback function

L_VOID * pUserData;

pointer to more parameters for the callback

Captures an image of a window handle.

Parameter Description
pBitmap Pointer to a bitmap handle that references the captured data.
uBitmapStructSize Value that represents the size, in bytes, of the structure pointed to by pBitmap parameter, for versioning. Use sizeof (BITMAPHANDLE).
hWnd Handle of the window to capture.
wctCaptureType Flag that indicates the capture type. Possible values are:
  Value Meaning
  CAPTURE_CLIENT_AREA [0x01] Captures the client area of the window.
  CAPTURE_WINDOW [0x02] Capture the complete window.
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.
uInfoStructSize Value that represents the size, in bytes, of the structure pointed to by pCaptureInfo parameter, for versioning. Use sizeof(LEADCAPTUREINFO).
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.

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.



The function was successful.

< 1

An error occurred. Refer to Return Codes.


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


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


L_SetCaptureOption, L_SetCaptureOptionDlg, CAPTURECALLBACK, L_StopCapture


Screen Capture C API Function Groups: Capture Functions


Implementing Screen Capture


#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName 
static L_INT EXT_CALLBACK pfnCaptureCallback(pBITMAPHANDLE pBitmap, pLEADCAPTUREINFO pCaptureInfo, L_VOID* 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) 
   /* 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); 
   return nRet; 

Help Version 19.0.2017.10.27
Products | Support | Contact Us | Copyright Notices
© 1991-2017 LEAD Technologies, Inc. All Rights Reserved.
LEADTOOLS Screen Capture C API Help