LBitmap::WindowLevelBitmap

#include "ltwrappr.h"

virtual L_INT LBitmap::WindowLevelBitmap(nLowBit, nHighBit, pLUT, uLUTLength, nOrderDst)

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 */

Converts a 12 or 16-bit grayscale image to an 8-bit grayscale or a 24-bit RGB bitmap. This function is available in Document/Medical toolkits only.

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.
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.

Returns

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

Comments

This function will convert the class object's bitmap to a window leveled bitmap. To implement window leveling without affecting the image, use LBitmap::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 only in the Document/Medical toolkits.

This function supports signed data images.

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

Required DLLs and Libraries

LTDIS
LTFIL
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.

See Also

Functions:	LBitmap::WindowLevel, Class Members
Topics:	Raster Image Functions: Palettes
	Grayscale Images
	Saving Window-Leveled Bitmaps

Example

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

L_INT LBitmap__WindowLevelBitmapExample()
{
   L_UINT32 x;
   L_INT nLowBit;
   L_INT nHighBit;
   L_INT nLow;
   L_INT nHigh;
   L_UINT32 nSize;
   RGBQUAD * ptmp;
   RGBQUAD * pLUT;
   LBitmap LeadBitmap;
   /* Change the bitmap to 16-bit grayscale */
   LeadBitmap.GrayScale(16 );
   LeadBitmap.GetMinMaxBits(&nLowBit, &nHighBit);
   LeadBitmap.GetMinMaxVal(&nLow, &nHigh);
   nSize = (L_UINT32)(1L<<(nHighBit - nLowBit + 1));
   pLUT = (RGBQUAD *)GlobalAlloc(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++;
   }
   LeadBitmap.WindowLevel(nLowBit, nHighBit,
                        (RGBQUAD *)pLUT, nSize, ORDER_BGR);
   GlobalFreePtr(pLUT);
   return SUCCESS;
}