Converts the signed class object's bitmap to an unsigned one.


#include "ltwrappr.h"

virtual L_INT LBitmapBase::ConvertSignedToUnsigned(uShift, uFlags = 0)


L_UINT uShift

Flag that indicates how the shift will be done. Possible values are:

Value Meaning
SHIFT_ZERO_TO_CENTER [0] Shift by 32768 (16-bit images) or by 2048 (12-bit images)
SHIFT_MIN_TO_ZERO [1] Shift all image data to make minimum value in the image 0 and the maximum value to the maximum possible value (65535 for 16-bit, 4095 for 12-bit).
SHIFT_NEG_TO_ZERO [2] Set all the negative pixels to 0 and leave the positive pixels unchanged. (Achieves the same result as LBitmapBase::ClearNegativePixels).

L_UINT32 uFlags

Reserved for future use. Must be 0.


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


If the ELO_SIGNED flag has been set using LOADFILEOPTION, when a file is loaded, the bitmap may contain negative pixel values and LEADTOOLS will paint/process the image incorrectly. To use this bitmap correctly the negative pixels should be converted, if it contains negative pixels (if LBitmapBase::IsPixelsSigned returns TRUE).

If LBitmapBase::IsPixelsSigned returns TRUE, this function will shift the color values in the class object's bitmap according to the uShift parameter.

The function will also update the MinVal and MaxVal members of the BITMAPHANDLE.

This function supersedes LBitmapBase::ClearNegativePixels.

This function supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available only in the Document/Medical toolkits.

This function supports signed data images.

Required DLLs and Libraries


Win32, x64.

See Also




L_INT LBitmapBase__ConvertSignedToUnsignedExample(LBitmapBase & Bitmap, L_TCHAR * pszFile) 
   L_INT nRet; 
   LOADFILEOPTION LoadFileOption; 
   // Enable negative pixels 
   LoadFileOption.Flags |= ELO_SIGNED; 
   nRet =Bitmap.Load(pszFile, 0, ORDER_BGRORGRAY, &LoadFileOption); 
   if(nRet !=SUCCESS) 
      return nRet; 
   // Clear negative pixels if the bitmap is signed 
   if (Bitmap.IsPixelsSigned()) 
      return FAILURE;  
   return SUCCESS; 
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