LBitmapBase::GrayScale

#include "ltwrappr.h"

virtual L_INT LBitmapBase::GrayScale(nBitsPerPixel=8)

L_INT nBitsPerPixel;

/* number of bits per pixel */

Converts a 1-, 4-, 8-, 16-, 24-, or 32-bit bitmap to an 8-bit, 12-bit, 16-bit or 32-bit grayscale bitmap. Support for 12 ,16 and 32-bit grayscale images is available only in the Document/Medical toolkits.

Parameter	Description
nBitsPerPixel	Value indicating the number of bits in the destination bitmap. Valid values are 8, 12, 16, or 32.

Returns

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

Comments

The resulting bitmap can be an 8-bit, 12-bit, ,16-bit or 32-bit grayscale bitmap. Once the function is complete, the Order member of the bitmap handle is set to ORDER_GRAY.

When converting to 12-bit , 16-bit, or 32-bit grayscale, a Lookup table is not used. When converting to 8-bit grayscale, a Lookup table is used to get the RGB for each input pixel. The grayscale value corresponding to that RGB triple is used in the destination bitmap.

To update a status bar or detect a user interrupt during execution of this function, refer to LBase::EnableStatusCallBack.

This function does not support signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this function.

Required DLLs and Libraries

LTDIS
LTFIL

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

Element:	LBitmapBase::IsGrayScale, LBitmapBase::ConvertToGrayScale, Class Members
Topics:	Raster Image Functions: Doing Color Expansion or Reduction
	Color Halftones and Halftone Images
	Raster Image Functions: Working with Color Halftones, Halftones, and Grayscale Images

Example

L_INT LBitmapBase__GrayScaleExample()
{
   L_INT nRet;
   LBitmapBase MyBitmap;
   MyBitmap.SetFileName(TEXT("C:\\Program Files\\LEAD Technologies, Inc\\LEADTOOLS 15.0\\Images\\image1.cmp"));
   nRet =MyBitmap.Load(24);
   if(nRet !=SUCCESS)
      return nRet;
   if(MyBitmap.IsGrayScale()==GRAY_NO)
      nRet = MyBitmap.GrayScale(8);
   return nRet;
}