#include "ltwrappr.h"

virtual L_INT LBitmap::WindowLevelExt(nLowBit, nHighBit, pLUT, uLUTLength, uFlags)

L_INT nLowBit;

low bit to use

L_INT nHighBit;

high bit to use


lookup table

L_UINT uLUTLength;

number of entries

L_UINT uFlags;

flag that indicates which functions use pLUT

Sets up the paint or paint and image processing functions' window leveling options for a specific bitmap.

Parameter Description
nLowBit Value indicating the low bit used for leveling. 0 <= nLowBit <= nHighBit <= (11 for 12-bit grayscale or 15 for 16-bit grayscale).
nHighBit Value indicating the high bit used for leveling. 0 <= nLowBit <= nHighBit <= (11 for 12-bit grayscale or 15 for 16-bit grayscale).
pLUT Optional lookup table that can be used to implement a user defined conversion. For every intensity value between 0 and 2 raised to the power of (nHighBit - nLowBit + 1)-1 there should be a corresponding entry in the lookup table that contains an RGB quad. If pLUT is NULL, the conversion is a normal shift (right or left) and the painted bitmap is 8-bit grayscale. If pLUT is not NULL, the painted bitmap is a 24-bit bitmap.
uLUTLength Value indicating the number of entries pointed to by pLUT.
uFlags Flag that indicates whether pLUT is used by the paint and image processing functions or only by the paint functions.  Possible values are:
  Value Meaning
  WINDOWLEVEL_PAINT [0x00] pLUT is used only by the paint functions.
  WINDOWLEVEL_PAINT_AND_PROCESSING [0x01] pLUT is used for both paint and image processing routines.



The function was successful.

< 1

An error occurred. Refer to Return Codes.


Provides "on demand" window leveling for the paint functions and does not alter the image data. To convert the image data to a window leveled bitmap, use LBitmap::WindowLevelBitmapExt.

If WINDOWLEVEL_PAINT_PROCESSING is specified, then all image processing functions will take the pLUT into account.

For information on saving bitmaps that have been window leveled, refer to Saving Window-Leveled Bitmaps.

LEADTOOLS supports two types of LUTs for 10-16-bit grayscale images (8-bit LUT and 16-bit LUT).  Typical grayscale image display and processing is done using an 8-bit LUT.  But, you can also use a 16-bit LUT, which offers more precision.  Some special video cards and monitors also support display of grayscale images using a 16-bit LUT.

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

See Also


LBitmap::WindowLevel, LBitmap::WindowLevelBitmapExt, LPaint::PaintDC, LPaint::PaintDCBuffer, LPaint::PaintRgnDC, LPaint::PaintRgnDCBuffer, LPaintEffect::PaintRgnDCEffect, Class Members, LBitmap::Deskew, LBitmap::DeskewExt


Raster Image Functions: Palettes


Raster Image Functions:Displaying and Printing


Grayscale Images


Saving Window-Leveled Bitmaps


Color Halftones and Halftone Images


Raster Image Functions: Working with Color Halftones, Halftones, and Grayscale Images


Raster Image Functions: Processing an Image


#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName 
L_INT LBitmap__WindowLevelExtExample() 
   L_INT nRet; 
   LBitmap LeadBitmap; 
   nRet =LeadBitmap.Load(MAKE_IMAGE_PATH(TEXT("image1.cmp")), 0,ORDER_BGR); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet =LeadBitmap.WindowLevelExt(1, 5, NULL, 0, 0); 
   if(nRet !=SUCCESS) 
      return nRet; 
   return SUCCESS; 

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