Gets the overlay bitmap for the specified index.


#include "l_bitmap.h"

L_LTKRN_API L_INT L_GetOverlayBitmap (pBitmap, nIndex, pOverlayBitmap, uStructSize, uFlags)



Pointer to the bitmap handle referencing the main bitmap.

L_INT nIndex

The index of the overlay being retrieved. This index is zero-based.

pBITMAPHANDLE pOverlayBitmap

Pointer to the overlay bitmap handle to be updated with the overlay bitmap at the specified index. This cannot be NULL.

L_UINT uStructSize

Size of the BITMAPHANDLE structure pointed to by pOverlayBitmap. Pass sizeof(BITMAPHANDLE).

L_UINT uFlags

Flags that determine how to retrieve the bitmap. You cannot combine these flags. Possible values are:

Value Meaning
OVERLAY_COPY [0x0000] A copy of the overlay bitmap is retrieved from the overlay list.
OVERLAY_NOCOPY [0x0001] The actual overlay bitmap is retrieved. No copy is made. You should be careful when modifying the overlay bitmap because you can modify/invalidate the entry in the overlay bitmap list.
OVERLAY_MOVE [0x0003] The actual overlay bitmap is retrieved. The bitmap is also removed from the overlay list. This is recommended over OVERLAY_NOCOPY.


Value Meaning
SUCCESS The function was successful.
< 1 An error occurred. Refer to Return Codes.


This function can be used to get a copy of the overlay bitmap (OVERLAY_COPY) or to get the bitmap without making a copy (OVERLAY_NOCOPY or OVERLAY_MOVE).

The quickest way to get the overlay bitmap is to avoid making a copy. For more information on using OVERLAY_NOCOPY, refer to the "Comments" section of L_SetOverlayBitmap.

If OVERLAY_MOVE is set in uFlags, the overlay bitmap from the corresponding index will be invalidated.

pOverlayBitmap is assumed to be unallocated and uninitialized. It will be filled without freeing the existing data.

Required DLLs and Libraries


Win32, x64, Linux.

See Also




This example will get the overlay bitmaps and save them to separate files.

L_INT GetOverlayBitmapExample(HWND hWnd, pBITMAPHANDLE pBitmap) 
   L_INT          nRet; 
   BITMAPHANDLE   OverlayBitmap; 
   L_INT          i; 
   L_TCHAR        s[MAX_PATH]; 
   for(i = 0; i < MAX_OVERLAYS; i++) 
      // note that I am using OVERLAY_NOCOPY, so I should not free the overlay bitmap! 
      nRet = L_GetOverlayBitmap(pBitmap, i, &OverlayBitmap, sizeof(BITMAPHANDLE), OVERLAY_NOCOPY); 
      if(nRet == SUCCESS) 
         wsprintf(s, MAKE_IMAGE_PATH(TEXT("overlay%d_copy.cmp")), i); 
         nRet = L_SaveBitmap(s, &OverlayBitmap, FILE_LEAD1BIT, 1, 1, NULL); 
         if(nRet != SUCCESS) 
            MessageBox(hWnd, TEXT("Error saving file!"), s, MB_OK); 
            return nRet; 
         return nRet; 
   return SUCCESS; 

Help Version 22.0.2023.7.11
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LEADTOOLS Raster Imaging C API Help

Products | Support | Contact Us | Intellectual Property Notices
© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.