L_WindowLevelBitmap

#include "l_bitmap.h"

L_LTIMGCOR_API L_INT L_WindowLevelBitmap (pBitmap, nLowBit, nHighBit, pLUT, uLUTLength, nOrderDst, uFlags)

pBITMAPHANDLE pBitmap;	pointer to the bitmap handle
L_INT nLowBit;	low bit to use
L_INT nHighBit;	high bit to use
RGBQUAD *pLUT;	lookup table
L_UINT uLUTLength;	number of entries
L_INT nOrderDst;	destination color order
L_UINT32 uFlags;	flags

Converts a 12 or 16-bit grayscale image to an 8-bit grayscale or a 24-bit RGB bitmap.

Parameter	Description
pBitmap	Pointer to the bitmap handle referencing the bitmap to be leveled.
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 output bitmap is 8-bit grayscale. If pLUT is not NULL, the output bitmap is a 24-bit bitmap.
uLUTLength	Value indicating the number of entries pointed to by pLUT.
nOrderDst	Value indicating the color order if the output bitmap will be 24-bit. If pLUT is NULL, this parameter is ignored. Possible values are:
	Value	Meaning
	ORDER_RGB	[0] The input colors are in red-green-blue order.
	ORDER_BGR	[1] The input colors are in blue-green-red order.
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 convert the bitmap to a window leveled bitmap. To implement window leveling without affecting the image, use L_WindowLevel.

The bitmap data is changed by this function.

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

This function is similar to L_WindowLevelBitmapExt, except that it uses 8-bit per component LUT instead of 16-bit per component LUT. If more precision is desired, you can use L_WindowLevelBitmapExt instead of L_WindowLevelBitmap.

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 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

LTIMGCOR

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 window levels the bitmap with a custom palette. The image data is changed in this example.

L_INT WindowLevelBitmapExample(pBITMAPHANDLE pBitmap) 
{ 
   /* Load an pass a 24-bit image */ 
   L_INT nRet; 
   L_UINT32 x; 
   RGBQUAD * ptmp; 
   RGBQUAD * pLUT; 
   L_INT nLowBit; 
   L_INT nHighBit; 
   L_INT nLow; 
   L_INT nHigh; 
   L_UINT32 nSize; 
   /* Change the bitmap to 16-bit grayscale */ 
   nRet = L_GrayScaleBitmap(pBitmap, 16 ); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet = L_GetMinMaxBits(pBitmap, &nLowBit, &nHighBit, 0); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet = L_GetMinMaxVal(pBitmap, &nLow, &nHigh, 0); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nSize = (L_UINT32)(1L<<(pBitmap->HighBit - pBitmap->LowBit + 1)); 
   pLUT = (RGBQUAD *)GlobalAllocPtr(GHND, nSize * sizeof(RGBQUAD)); 
   ptmp = pLUT; 
   /* fill the first half of the LUT with RED */ 
   for(x=0;x<nSize/2;x++) 
   { 
      ptmp->rgbRed       = 255; 
      ptmp->rgbGreen     = 0; 
      ptmp->rgbBlue      = 0; 
      ptmp->rgbReserved  = 0; 
      ptmp++; 
   } 
   /* fill the rest with gray values */ 
   for(x=nSize/2;x<nSize;x++) 
   { 
      ptmp->rgbRed       = (( L_UCHAR) ((L_UINT32) (x - nLow) * 255 / (nHigh - nLow))); 
      ptmp->rgbGreen     = ptmp->rgbRed; 
      ptmp->rgbBlue      = ptmp->rgbGreen; 
      ptmp->rgbReserved  = 0; 
      ptmp++; 
   } 
   nRet = L_WindowLevelBitmap ( pBitmap, nLowBit, nHighBit,(RGBQUAD *)pLUT, nSize, ORDER_BGR, 0); 
   if(nRet !=SUCCESS) 
      return nRet; 
   GlobalFreePtr(pLUT); 
   return SUCCESS; 
}

Help Version 19.0.2017.10.27

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_WindowLevelBitmapExt, L_WindowLevel, L_WindowLevelFillLUT, L_ChangeHueSatIntBitmap, L_ColorReplaceBitmap, L_ColorThresholdBitmap, L_AdaptiveContrastBitmap, L_ApplyMathLogicBitmap, L_ColorIntensityBalance, L_ColorizeGrayBitmap, L_ContBrightIntBitmap, L_DigitalSubtractBitmap, L_DynamicBinaryBitmap, L_EdgeDetectEffectBitmap, L_FunctionalLightBitmap, L_MultiScaleEnhancementBitmap, L_SelectBitmapData, L_ShiftBitmapData, L_WindowLevelExt, L_WindowLevelFillLUTExt
Topics:	Raster Image Functions: Palettes
	Color Halftone and Halftone Images
	Grayscale Images
	Saving Window-Leveled Bitmaps
	Raster Image Functions: Processing an Image