L_CountLUTColors

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#include "l_bitmap.h"

L_LTIMGCOR_API L_INT L_CountLUTColors(pLUT, ulLLUTLen, pNumberOfEntries, pFirstIndex, uFlags);

RGBQUAD *pLUT;	/* lookup table */
L_UINT ulLLUTLen;	/* LUT length */
L_UINT *pNumberOfEntries;	/* pointer to a variable to be updated */
L_INT *pFirstIndex;	/* pointer to a variable to be updated */
L_UINT uFlags;	/* flags */

Gets the total number of entries between the start color and the end color, and the index of the last occurrence of the start color. The start and end colors are determined internally.

Parameter	Description
pLUT	Pointer to a lookup table.
ulLLUTLen	LUT length.
pNumberOfEntries	Pointer to a variable to be updated with total number of entries in start to end color.
pFirstIndex	Pointer to a variable to be updated with index of the last occurrence of the start color.
uFlags	Flag that indicates the LUT is belong to signed or unsigned image. Possible values are:
	Value	Meaning
	COUNT_LUT_UNSIGNED	[0x0001] Belong to signed image.
	COUNT_LUT_SIGNED	[0x0002] Belong to unsigned image.

Returns

SUCCESS	LUT is Linear (success).
0	LUT is not linear (fail).
<0	An error occurred. Refer to Return Codes.

Comments

Suppose you have a LUT with 4096 colors, the first 200 colors are black and the last 30 are white, the rest of the colors between black and white are gray. This is what the function will provide :

pNumberOfEntries :	3868.
pFirstIndex :	199.

In more detail this is:

Total number of entries: 4096 (0 4095)

First index of the end color: 4095 30 + 1 (+1 to add the first index of the end color to the range)

Number of occurrences of the starting color: 200 (0 199)

The last index of the start color: 199

Total number of entries: (4095 30 + 1) 199 + 1

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

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.

See Also

Functions:	L_WindowLevelExt, L_WindowLevel, L_WindowLevelFillLUT, L_GetUserLookUpTable, L_RemapBitmapIntensity, L_ApplyLinearVOILUT
Topics:	Raster Image Functions: Palettes

Example

Gets bitmap pLUT total number of entries in start to end colors and the index of the last occurrence of the start color.

L_INT CountLUTColorsExample(pBITMAPHANDLE pBitmap, L_UINT * pNumberOfEntries, L_INT * pFirstIndex)
{
   return L_CountLUTColors(pBitmap->pLUT, pBitmap->LUTLength, pNumberOfEntries, pFirstIndex, pBitmap->Flags.Signed? COUNT_LUT_SIGNED : COUNT_LUT_UNSIGNED);
}