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L_GrayScaleBitmap

#include "l_bitmap.h"

L_LTKRN_API L_INT L_GrayScaleBitmap(pBitmap, nBitsPerPixel)

Converts a 1-, 4-, 8-, 16-, 24-, or 32-bit bitmap to an 8-bit, 12-bit, 16-bit, or 32-bit grayscale bitmap. Support for 12, 16 and 32-bit grayscale images is available in the Document and Medical Imaging toolkits.

Parameters

pBITMAPHANDLE pBitmap

Pointer to the bitmap handle referencing the bitmap to be converted.

L_INT nBitsPerPixel

Value indicating the number of bits in the destination bitmap. Valid values are 8, 12, 16, or 32.

Returns

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

Comments

The resulting bitmap can be an 8-bit, 12-bit, 16-bit or 32-bit grayscale bitmap. Once the function is complete, the Order member of the bitmap handle is set to ORDER_GRAY.

When converting to 12-bit, 16-bit or 32-bit grayscale, a Lookup table is not used. When converting to 8-bit grayscale, a Lookup table is used to get the RGB for each input pixel. The grayscale value corresponding to that RGB triple is used in the destination bitmap.

To update a status bar or detect a user interrupt during execution of this function, refer to L_SetStatusCallback.

Required DLLs and Libraries

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

Platforms

Win32, x64, Linux.

Functions

L_IsGrayScaleBitmap

Topics

Example

For complete sample code, refer to the FEATURE2 example. This example loads a bitmap and changes it to 8-bit grayscale.

L_INT GrayScaleBitmapExample(L_VOID) 
{ 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle to hold the loaded image. */ 
 
   /* Load the bitmap, keeping the bits per pixel of the file */ 
   nRet = L_LoadBitmap (MAKE_IMAGE_PATH(TEXT("IMAGE1.CMP")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   /* Change the bitmap to grayscale */ 
   nRet = L_GrayScaleBitmap(&LeadBitmap, 8 ); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   nRet = L_SaveBitmap(MAKE_IMAGE_PATH(TEXT("Result.BMP")), &LeadBitmap, FILE_BMP, 24, 0, NULL); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   L_FreeBitmap(&LeadBitmap); 
   return SUCCESS; 
}

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