#include "l_bitmap.h"

L_LTIMGCOR_API L_INT L_ConvertBitmapUnsignedToSigned(pBitmap, uFlags)


pointer to the bitmap handle

L_UINT uFlags;


Converts an unsigned bitmap to signed.

Parameter Description
pBitmap Pointer to the bitmap handle referencing the bitmap.
uFlags Flag that indicates how to process bits outside the low bit to high bit range. Possible values are:
  Value Meaning
  PROCESS_RANGE_ONLY [0x0001] Shift data by adding half the range to each pixel without changing bits outside the (LowBit-HighBit) range.
  PROCESS_OUTSIDE_RANGE [0x0002] Shift data by adding half the range to each pixel and set to zero all bits outside the (LowBit-HighBit) range.



The function was successful.

< 1

An error occurred. Refer to Return Codes.


This function updates pBitmap->MaxVal and pBitmap-> MinVal with new values that reflect the bitmap's new signed data. In addition, the pBitmap->Flags.Signed value will be set to one.

This function supports 12 and 16-bit grayscale images. Support for 12 and 16-bit grayscale images is available in the Document and Medical Imaging toolkits.

This function does not support 32-bit grayscale images. It returns the error code ERROR_GRAY32_UNSUPPORTED if a 32-bit grayscale image is passed to this function.

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.


Win32, x64, Linux.

See Also


L_ClearNegativePixels, L_ConvertBitmapSignedToUnsigned


Processing an Image


Raster Image Functions: Getting and Setting Pixel Values


L_INT ConvertBitmapUnsignedToSignedExample(L_VOID) 
   L_INT nRet; 
   /* Bitmap handle to hold the loaded image. */ 
   BITMAPHANDLE LeadBitmap; 
   LOADFILEOPTION LoadFileOption; 
   /* enable negative pixels to be loaded from TIFF files */ 
   nRet = L_GetDefaultLoadFileOption(&LoadFileOption, sizeof(LOADFILEOPTION)); 
   if(nRet != SUCCESS) 
      return nRet; 
   LoadFileOption.Flags |= ELO_SIGNED; 
   /* Load the bitmap, as 16-bit grayscale un-signed */ 
   nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("clean.tif")), &LeadBitmap,sizeof(BITMAPHANDLE), 16, ORDER_GRAY, &LoadFileOption, NULL); 
   if(nRet != SUCCESS) 
      return nRet; 
   /* convert bitmap to signed */ 
      nRet = L_ConvertBitmapUnsignedToSigned(&LeadBitmap, PROCESS_RANGE_ONLY); 
      if(nRet != SUCCESS) 
         return nRet; 
   return SUCCESS; 
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