/*

 * Copyright (c) 1988-91 by Patrick J. Naughton.

 *

 * Permission to use, copy, modify, and distribute this software and its

 * documentation for any purpose and without fee is hereby granted,

 * provided that the above copyright notice appear in all copies and that

 * both that copyright notice and this permission notice appear in

 * supporting documentation.

 *

 * This file is provided AS IS with no warranties of any kind.  The author

 * shall have no liability with respect to the infringement of copyrights,

 * trade secrets or any patents by this file or any part thereof.  In no

 * event will the author be liable for any lost revenue or profits or

 * other special, indirect and consequential damages.

 */

/*

 * Copyright 1994 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the

 * "Software"), to deal in the Software without restriction, including

 * without limitation the rights to use, copy, modify, merge, publish,

 * distribute, and/or sell copies of the Software, and to permit persons

 * to whom the Software is furnished to do so, provided that the above

 * copyright notice(s) and this permission notice appear in all copies of

 * the Software and that both the above copyright notice(s) and this

 * permission notice appear in supporting documentation.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT

 * OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR

 * HOLDERS INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL

 * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING

 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,

 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION

 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 *

 * Except as contained in this notice, the name of a copyright holder

 * shall not be used in advertising or otherwise to promote the sale, use

 * or other dealings in this Software without prior written authorization

 * of the copyright holder.

 */

#ifndef lint

static char sccsid[] = "@(#)hsbramp.c	35.3 08/09/18 XLOCK";

#endif

/*-

 * hsbramp.c - Create an HSB ramp.

 *

 * Copyright (c) 1991 by Patrick J. Naughton.

 *

 * See xlock.c for copying information.

 *

 * Revision History:

 * 29-Jul-90: renamed hsbramp.c from HSBmap.c

 *	      minor optimizations.

 * 01-Sep-88: Written.

 */

#include <sys/types.h>

#include <math.h>

void

hsb2rgb(H, S, B, r, g, b)

    double      H,

                S,

                B;

    u_char     *r,

               *g,

               *b;

{

    int         i;

    double      f;

    double      bb;

    u_char      p;

    u_char      q;

    u_char      t;

    H -= floor(H);		/* remove anything over 1 */

    H *= 6.0;

    i = floor(H);		/* 0..5 */

    f = H - (float) i;		/* f = fractional part of H */

    bb = 255.0 * B;

    p = (u_char) (bb * (1.0 - S));

    q = (u_char) (bb * (1.0 - (S * f)));

    t = (u_char) (bb * (1.0 - (S * (1.0 - f))));

    switch (i) {

    case 0:

	*r = (u_char) bb;

	*g = t;

	*b = p;

	break;

    case 1:

	*r = q;

	*g = (u_char) bb;

	*b = p;

	break;

    case 2:

	*r = p;

	*g = (u_char) bb;

	*b = t;

	break;

    case 3:

	*r = p;

	*g = q;

	*b = (u_char) bb;

	break;

    case 4:

	*r = t;

	*g = p;

	*b = (u_char) bb;

	break;

    case 5:

	*r = (u_char) bb;

	*g = p;

	*b = q;

	break;

    }

}

/*

 * Input is two points in HSB color space and a count

 * of how many discreet rgb space values the caller wants.

 *

 * Output is that many rgb triples which describe a linear

 * interpolate ramp between the two input colors.

 */

void

hsbramp(h1, s1, b1, h2, s2, b2, count, red, green, blue)

    double      h1,

                s1,

                b1,

                h2,

                s2,

                b2;

    int         count;

    u_char     *red,

               *green,

               *blue;

{

    double      dh;

    double      ds;

    double      db;

    dh = (h2 - h1) / count;

    ds = (s2 - s1) / count;

    db = (b2 - b1) / count;

    while (count--) {

	hsb2rgb(h1, s1, b1, red++, green++, blue++);

	h1 += dh;

	s1 += ds;

	b1 += db;

    }

}