#include "l_bitmap.h"

L_LTKRN_API L_INT L_ChangeBitmapCompression(pBitmap, nComp)


pointer to the bitmap handle

L_INT nComp;

compression type

Compresses of decompresses a bitmap.

Parameter Description
pBitmap Pointer to the bitmap handle referencing the bitmap to compress or decompress.
nComp Flag that indicates the type of compression to use on the bitmap. Possible values are:
  Value Meaning
  COMP_NONE [0] No compression. This option can be used to decompress compressed or super compressed bitmaps.
  COMP_RLE [1] 1-bit RLE compression. This compression is very fast and Lossless. For more information, refer to Speeding Up 1-Bit Documents. This is the same as passing TYPE_COMPRESSED to L_AllocateBitmap.
  COMP_SUPER [2] Super compression. This is available for 1-bit, 8-bit, and 24-bit bitmaps only. The 24-bit and 8-bit compression is lossy, while the 1-bit compression is lossless.



The function was successful.

< 1

An error occurred. Refer to Return Codes.


This function should be used instead of L_ToggleBitmapCompression.

Required DLLs and Libraries

LFCMP (for 24-bit Super compression)
LFFAX (for 1-bit Super compression)

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.


Win32, x64, Linux.

See Also


L_AllocateBitmap, L_CreateBitmap


Super Compressed Bitmaps


Speeding up 1-Bit Documents


Raster Image Functions: Compression Functions


This function toggles bitmap compression.

L_INT ChangeBitmapCompressionExample(HWND  hWnd, pBITMAPHANDLE   pBitmap) 
   L_INT     nRet = 0; 
   L_TCHAR   s[100]; 
   if(pBitmap->BitsPerPixel == 1 || pBitmap->BitsPerPixel == 8 || pBitmap->BitsPerPixel == 24) 
      wsprintf(s, TEXT("BEFORE - ImageSize: %ld bytes, Type: %s"), pBitmap->Size, (pBitmap->Flags.SuperCompressed ? TEXT("SUPERCOMP") : TEXT("UNCOMP"))); 
      MessageBox(hWnd, s, TEXT("ChangeBitmapCompression"), MB_OK); 
      nRet = L_ChangeBitmapCompression(pBitmap, pBitmap->Flags.SuperCompressed ? COMP_NONE : COMP_SUPER); 
      if(nRet == SUCCESS) 
         wsprintf(s, TEXT("AFTER - ImageSize: %ld bytes, Type: %s"), pBitmap->Size, (pBitmap->Flags.SuperCompressed ? TEXT("SUPERCOMP") : TEXT("UNCOMP"))); 
         wsprintf(s, TEXT("L_ChangeBitmapCompression Failed")); 
         return nRet; 
      MessageBox(hWnd, s, TEXT("ChangeBitmapCompression"), MB_OK); 
   return SUCCESS; 

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