L_WindowLevelBitmap
#include "l_bitmap.h"
L_INT EXT_FUNCTION L_WindowLevelBitmap (pBitmap, nLowBit, nHighBit, pLUT, uLUTLength, nOrderDst)
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pBITMAPHANDLE pBitmap; |
/* pointer to the bitmap handle */ |
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L_INT nLowBit; |
/* low bit to use */ |
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L_INT nHighBit; |
/* high bit to use */ |
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RGBQUAD L_HUGE *pLUT; |
/* lookup table */ |
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L_UINT uLUTLength; |
/* number of entries */ |
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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.
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Parameter |
Description |
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pBitmap |
Pointer to the bitmap handle referencing the bitmap to be leveled. |
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nLowBit |
Value indicating the low bit used for leveling. 0 <= nLowBit <= nHighBit <= (11 for 12-bit grayscale or 15 for 16-bit grayscale). |
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nHighBit |
Value indicating the high bit used for leveling. 0 <= nLowBit <= nHighBit <= (11 for 12-bit grayscale or 15 for 16-bit grayscale). |
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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. |
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uLUTLength |
Value indicating the number of entries pointed to by pLUT. |
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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: |
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Value |
Meaning |
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ORDER_RGB |
[0] The input colors are in red-green-blue order. |
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ORDER_BGR |
[1] The input colors are in blue-green-red order. |
Returns
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SUCCESS |
The function was successful. |
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< 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 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
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LTIMG 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
Windows 95 / 98 / Me, Windows 2000 / XP.
See Also
Example
This example window levels the bitmap with a custom palette. The image data is changed in this example.
void TestFunction(HWND hWnd, pBITMAPHANDLE pBitmap)
{
L_UINT32 x;
RGBQUAD L_HUGE* ptmp;
RGBQUAD L_HUGE* pLUT;
L_INT nLowBit;
L_INT nHighBit;
L_INT nLow;
L_INT nHigh;
L_UINT32 nSize;
/* Change the bitmap to 16-bit grayscale */
L_GrayScaleBitmap(pBitmap, 16 );
L_GetMinMaxBits(pBitmap, &nLowBit, &nHighBit);
L_GetMinMaxVal(pBitmap, &nLow, &nHigh);
nSize = (L_UINT32)(1L<<(pBitmap->HighBit - pBitmap->LowBit + 1));
pLUT = (RGBQUAD L_HUGE*)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++;
}
L_WindowLevelBitmap ( pBitmap, nLowBit, nHighBit,
(RGBQUAD L_HUGE*)pLUT, nSize, ORDER_BGR);
GlobalFreePtr(pLUT);
}