virtual L_INT LBitmap::WindowLevelBitmap(nLowBit, nHighBit, pLUT, uLUTLength, nOrderDst, uFlags = 0)
Converts a 12 or 16-bit grayscale image to an 8-bit grayscale or a 24-bit RGB bitmap.
Value indicating the low bit used for leveling. 0 <= nLowBit <= nHighBit <= (11 for 12-bit grayscale or 15 for 16-bit grayscale).
Value indicating the high bit used for leveling. 0 <= nLowBit <= nHighBit <= (11 for 12-bit grayscale or 15 for 16-bit grayscale).
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.
Value indicating the number of entries pointed to by pLUT.
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. |
Reserved for future use. Must be 0.
Value | Meaning |
---|---|
SUCCESS | The function was successful. |
< 1 | An error occurred. Refer to Return Codes. |
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.
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.
For information on saving bitmaps that have been window leveled, refer to Saving Window-Leveled Bitmaps.
Win32, x64.
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;
}
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