L_DefaultDithering

#include "l_bitmap.h"

L_LTKRN_API L_INT L_DefaultDithering(uMethod)

L_UINT uMethod;

/* dithering method to use */

Specifies the default dithering method to use when converting an image from 64, 48, 32, 24, or 16 bits per pixel to 8 bits per pixel or fewer.

Parameter	Description
uMethod	The dithering method to use. Valid values are:
	Value	Meaning
	NO_DITHERING	[0] Use no dithering.
	FLOYD_STEIN_DITHERING	[1] Use the Floyd-Steinberg method.
	BURKES_DITHERING	[3] Use the Burkes method.
	STUCKI_DITHERING	[2] Use the Stucki method.
	SIERRA_DITHERING	[4] Use the Sierra method.
	STEVENSON_ARCE_DITHERING	[5] Use the Stevenson-Arce method.
	JARVIS_DITHERING	[6] Use the Jarvis method.
	ORDERED_DITHERING	[7] Use ordered dithering, which is faster than other methods but is lower in quality.
	CLUSTERED_DITHERING	[8] Use clustered dithering.

Returns

SUCCESS	The function was successful.
< 0	An error occurred. Refer to Return Codes.

Comments

Some LEADTOOLS functions automatically dither an image when necessary for display. Those functions use the default dithering method that this function specifies.

For general information about dithering, refer to Color Resolution and Dithering.

Required DLLs and Libraries

LTKRN

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 2000 / XP/Vista, Windows CE.

See Also

Functions:	L_ColorResBitmap, L_CreateUserMatchTable,
	L_SetUserMatchTable, L_FreeUserMatchTable
Topics:	Raster Image Functions: Doing Color Expansion or Reduction
	Raster Image Functions: Doing Color Space Conversions
	Raster Image Functions: Palettes
	Color Resolution and Dithering
	Color Halftone and Halftone Images

Example

This example sets NO_DITHERING as the default before loading a 24-bit image at 8 bits per pixel. This overrides the normal default, which is to use Floyd-Steinberg dithering.

 L_INT DefaultDitheringExample(HWND          hWnd,
                                              pBITMAPHANDLE pBitmap ) 
{
   L_INT nRet;
   /* Set the default dithering */
   nRet = L_DefaultDithering(NO_DITHERING);
   if(nRet != SUCCESS)
      return nRet;
   /* Load the bitmap at 8 bits per pixel */
   if(pBitmap->Flags.Allocated)
      L_FreeBitmap(pBitmap);
   nRet = L_LoadBitmap (TEXT("%UserProfile%\\My Documents\\LEADTOOLS Images\\IMAGE3.CMP"), pBitmap, sizeof(BITMAPHANDLE), 8, 0, NULL, NULL);
   if(nRet != SUCCESS)
      return nRet;
   /* Update the paint palette */
   SendMessage (hWnd, WM_QUERYNEWPALETTE, 0, 0L);

   return SUCCESS;
}