lverrdif(3)

LIBRARY ROUTINE
lverrdif - Perform dithering by four-direction error diffusion.

LIBRARY CALL
#include "vinclude.h"
int
lverrdif(image)
struct xvimage *image;

INPUT

image
    xvimage structure of the character image to be dithered by error diffusion.

OUTPUT

image
    holds the result of the dithered image.

Return Value:
    1 on success, 0 on failure.

MODIFICATIONS
Marcelo Teran, Mark Young

DESCRIPTION
lverrdif performs a dithering operation using four-direction error diffusion. This dither produces images that are easy on the eyes up close. They also have good greyscale from far away, except when the image has slowly varying intensity. In that case, some peculiar patterns may appear. image is a pointer to a Khoros image structure containing the character image to be dithered. image is also used to hold the result of the dithered image. This is done to save space, but you must be careful not to overwrite important data.

lverrdif returns a value of one upon success and a zero on failure.

SEE ALSO
verrdif(1), intro(3), vipl(3), verror(3), vutils(3)

RESTRICTIONS
verrdif operates only on BYTE data storage type images.

AUTHOR
Scott Wilson

COPYRIGHT
Copyright 1991, University of New Mexico. All rights reserved.