FloatImg/lib/fimg-2gray.c

/*
 *		fimg-2gray.c
 */

#include  <stdio.h>
#include  <stdlib.h>
#include  <unistd.h>
#include  "string.h"

#include  "../floatimg.h"

extern int verbosity;		/* must be declared around main() */

/* --------------------------------------------------------------------- */
/*
 *	floating imgs MUST be allocated before calling this func.
 */
int fimg_mk_gray_from(FloatImg *src, FloatImg*dst, int k)
{
float		kr, kg, kb, kdiv;
int		nbb, foo;

kr = kg = kb = 1.0;		/* canonic random values */
kdiv = kr + kg + kb;

/* we must check the validity of our parameters */
if (FIMG_TYPE_RGB != src->type) {
	fprintf(stderr, "%s : bad src type %d on %p\n", __func__, 
				src->type, src);
	return -8;
	}

if (FIMG_TYPE_GRAY != dst->type) {
	fprintf(stderr, "%s : bad dst type %d on %p\n", __func__, 
				dst->type, dst);
	/*
	 * may be we can convert dst picture on the fly ?
	 */
	return -9;
	}

/* entering the main processing loop */
nbb = src->width * src->height;

for (foo=0; foo<nbb; foo++) {
	dst->R[foo] = ( (src->R[foo] * kr) +
			(src->G[foo] * kg) +
			(src->B[foo] * kb) ) /
				kdiv;
	}

return 0;
}
/* --------------------------------------------------------------------- */