/*-

 * HSBmap.c - Create an HSB ramp.

 *

 *

 * 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, sublicense,

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

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice (including the next

 * paragraph) shall be included in all copies or substantial portions of the

 * Software.

 *

 * 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.  IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

 * DEALINGS IN THE SOFTWARE.

 *

 * Author: Patrick J. Naughton

 * [email protected]

 */

#include <sys/types.h>

#include <math.h>

    double      H,

    u_char     *r,

{

    register int i;

    register double f,

                bb;

    register u_char p,

                q,

                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;

    }

}

void

    double      h1,

    int         start,

    u_char     *red,

{

    double      dh,

                ds,

                db;

    register u_char *r,

               *g,

               *b;

    register int i;

    r = red;

    g = green;

    b = blue;

    dh = (h2 - h1) / 255.0;

    ds = (s2 - s1) / 255.0;

    db = (b2 - b1) / 255.0;

    for (i = start; i <= end; i++) {

	hsb2rgb(h1, s1, b1, r++, g++, b++);

	h1 += dh;

	s1 += ds;

	b1 += db;

    }

}