L_GetUserLookUpTable

#include "l_bitmap.h"

L_LTIMGEFX_API L_INT L_GetUserLookUpTable (pLookupTable, uLookupLen, apUserPoint, uUserPointCount, puPointCount, uFlags)

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;	flags

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
apUserPoint	Pointer to an array of POINT structures that contain the points on the curve used to update the lookup table.
uUserPointCount	Number of points in the apUserPoint array.
puPointCount	Pointer to a variable to be updated with the number of entries in the lookup table that were actually updated.
uFlags	Reserved for future use. Must be 0.

Returns

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

Comments

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 L_RemapBitmapIntensity function.

Required DLLs and Libraries

LTIMGEFX

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.

Example

This example will brighten the loaded bitmap using the lookup table updated by the L_GetUserLookUpTable function.

#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName 
L_INT GetUserLookUpTableExample(L_VOID) 
{ 
   L_INT nRet; 
   L_UINT  LookupTable[256];  /* Array to hold lookup table*/ 
   BITMAPHANDLE LeadBitmap;  /*Bitmap handle to hold the loaded image */ 
   POINT  apUserPoint[3] = {{0,0},{128,150},{255,255}}; 
   /* Load the bitmap, force 24 bits per pixel */ 
   nRet = L_LoadBitmap (MAKE_IMAGE_PATH(TEXT("ImageProcessingDemo\\Image3.cmp")), &LeadBitmap, sizeof(BITMAPHANDLE), 24, ORDER_BGR, NULL, NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
   /*Get Lookup table where the array effected by user data function */ 
   nRet = L_GetUserLookUpTable (LookupTable, 256,apUserPoint, 3, NULL, 0); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet = L_RemapBitmapIntensity (&LeadBitmap, (L_INT *)LookupTable, 256,CHANNEL_MASTER); 
   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; 
   //free bitmap 
   if(LeadBitmap.Flags.Allocated) 
      L_FreeBitmap(&LeadBitmap); 
   return SUCCESS; 
}

Help Version 19.0.2017.10.27

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LEADTOOLS Raster Imaging C API Help

Introduction

Version History

Getting Started

LEADTOOLS Raster Imaging Features

Redistributables/Files To Be Included With Your Application

Functions:	L_GetFunctionalLookupTable, L_RemapBitmapIntensity, L_AdjustBitmapTint, L_GammaCorrectBitmapExt
Topics:	Changing Brightness and Contrast
	Raster Image Functions: Changing Brightness and Contrast
	Raster Image Functions: Modifying Intensity Values