#include "ltwrappr.h"

virtual L_INT LBitmap::GetUserLookupTable (pLookupTable, uLookupLen, apUserPoint, uUserPointCount, puPointCount, uFlags = 0)

L_UINT * pLookupTable;

lookup table

L_UINT uLookupLen;

lookup table length

POINT *apUserPoint;

array of points

L_UINT uUserPointCount;

number of points in the array

L_UINT *puPointCount;

pointer to a variable to be updated

L_UINT32 uFlags;


Updates the lookup table, based on a curve that passes through the specified points.

Parameter Description
pLookupTable Pointer to the lookup table to be filled by this function. The length of the lookup table is specified in the uLookupLen parameter.
uLookupLen Length of the lookup table pointed to by the pLookupTable parameter. Possible values are:
  Value Meaning
  65536 16-bit / sample image
  4096 12-bit / sample image
  256 8-bit / sample image


Pointer to an array of POINT structures that contain the points on the curve used to update the lookup table.


Number of points in the apUserPoint array.


Pointer to a variable to be updated with the number of entries in the lookup table that were actually updated.


Reserved for future use. Must be 0.



The function was successful.

< 1

An error occurred. Refer to Return Codes.


This function will update the lookup table array using the best curve that passes through the points specified in the apUserPoint parameter. The points in the array may be sorted or not. In most cases, this function is used with the LBitmap::RemapIntensity 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.

See Also


LBitmap::AdjustTint, LBitmap::GammaCorrectExt, LBitmap::GetFunctionalLookupTable, LBitmap::RemapIntensity


Changing Brightness and Contrast


Raster Image Functions: Modifying Intensity Values


Raster Image Functions: Changing Brightness and Contrast


L_INT LBitmap__GetUserLookupTableExample(LBitmap & Bitmap, L_TCHAR * pszFile) 
   L_INT nRet; 
   L_UINT LookupTable[256]; 
   POINT apUserPoint[3] = { {0, 0}, {128, 150}, {255, 255} }; 
   nRet =Bitmap.Load(pszFile, 24, ORDER_BGR); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet =Bitmap.GetUserLookupTable(LookupTable, 256, apUserPoint, 3, NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet =Bitmap.RemapIntensity((L_INT*)LookupTable, 256, CHANNEL_MASTER); 
   if(nRet !=SUCCESS) 
      return nRet; 
   return SUCCESS; 

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