/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI" /* SVr4.0 1.4 */
/*LINTLIBRARY*/
#include <stdlib.h>
#include <plot.h>
#include <math.h>
#include "con.h"
static int quad_l(short, short, short, short);
static int del = 20;
static void
step(int d)
{
del = d;
}
void
arc(short x, short y, short x0, short y0, short x1, short y1)
{
double pc;
short flg, m, xc, yc, xs, ys, qs, qf, qt, qtctr = 0;
short m0, m1;
float dx, dy, r;
char use;
dx = x - x0;
dy = y - y0;
r = (dx * dx) + (dy * dy);
pc = r;
pc = sqrt(pc);
flg = (short)(pc / 4);
if (flg == 0)
step(1);
else if (flg < del)
step(flg);
xc = xs = x0;
yc = ys = y0;
move(xs, ys);
if ((x0 == x1) && (y0 == y1))
flg = 0;
else flg = 1;
qs = quad_l(x, y, x0, y0);
qf = quad_l(x, y, x1, y1);
if ((abs(x - x1)) < (abs(y - y1))) {
use = 'x';
if ((qs == 2) || (qs == 3))
m = -1;
else m = 1;
} else {
use = 'y';
if (qs > 2)
m = -1;
else m = 1;
}
if (qs == qf) {
m0 = (y0 - y) / (x0 - x);
m1 = (y1 - y) / (x1 - x);
if (m0 >= m1)
qt = 4;
else qt = 0;
} else if ((qt = qf - qs) < 0)
qt += 4;
/* LINTED */
while (1) {
switch (use) {
case 'x':
if ((qs == 2) || (qs == 3))
yc -= del;
else yc += del;
dy = yc - y;
pc = r - dy * dy;
xc = (short)(m * sqrt(pc) + x);
if (((x < xs) && (x >= xc)) ||
((x > xs) && (x <= xc)) ||
((y < ys) && (y >= yc)) ||
((y > ys) && (y <= yc))) {
if (++qtctr > qt)
return;
if (++qs > 4)
qs = 1;
if ((qs == 2) || (qs == 3))
m = -1;
else m = 1;
flg = 1;
}
cont(xc, yc);
xs = xc;
ys = yc;
if ((qs == qf) && (flg == 1))
switch (qf) {
case 3:
case 4:
if (xs >= x1)
return;
continue;
case 1:
case 2:
if (xs <= x1)
return;
}
continue;
case 'y':
if (qs > 2)
xc += del;
else xc -= del;
dx = xc - x;
pc = r - dx * dx;
yc = (short)(m * sqrt(pc) + y);
if (((x < xs) && (x >= xc)) ||
((x > xs) && (x <= xc)) ||
((y < ys) && (y >= yc)) ||
((y > ys) && (y <= yc))) {
if (++qtctr > qt)
return;
if (++qs > 4)
qs = 1;
if (qs > 2)
m = -1;
else m = 1;
flg = 1;
}
cont(xc, yc);
xs = xc;
ys = yc;
if ((qs == qf) && (flg == 1))
switch (qs) {
case 1:
case 4:
if (ys >= y1)
return;
continue;
case 2:
case 3:
if (ys <= y1)
return;
}
}
}
}
/*
* these is a local function not to be confused with the
* system wide quad
*/
static int
quad_l(short x, short y, short xp, short yp)
{
if (x < xp)
if (y <= yp)
return (1);
else return (4);
else if (x > xp)
if (y < yp)
return (2);
else return (3);
else if (y < yp)
return (2);
else return (4);
}