1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
23 /* All Rights Reserved */
24
25
26 /*
27 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
28 * Use is subject to license terms.
29 */
30
31 #pragma ident "%Z%%M% %I% %E% SMI" /* SVr4.0 1.4 */
32 /*LINTLIBRARY*/
33
34 #include <stdlib.h>
35 #include <plot.h>
36 #include <math.h>
37 #include "con.h"
38
39 static int quad_l(short, short, short, short);
40 static int del = 20;
41
42 static void
step(int d)43 step(int d)
44 {
45 del = d;
46 }
47
48 void
arc(short x,short y,short x0,short y0,short x1,short y1)49 arc(short x, short y, short x0, short y0, short x1, short y1)
50 {
51 double pc;
52 short flg, m, xc, yc, xs, ys, qs, qf, qt, qtctr = 0;
53 short m0, m1;
54 float dx, dy, r;
55 char use;
56 dx = x - x0;
57 dy = y - y0;
58 r = (dx * dx) + (dy * dy);
59 pc = r;
60 pc = sqrt(pc);
61 flg = (short)(pc / 4);
62 if (flg == 0)
63 step(1);
64 else if (flg < del)
65 step(flg);
66 xc = xs = x0;
67 yc = ys = y0;
68 move(xs, ys);
69 if ((x0 == x1) && (y0 == y1))
70 flg = 0;
71 else flg = 1;
72 qs = quad_l(x, y, x0, y0);
73 qf = quad_l(x, y, x1, y1);
74 if ((abs(x - x1)) < (abs(y - y1))) {
75 use = 'x';
76 if ((qs == 2) || (qs == 3))
77 m = -1;
78 else m = 1;
79 } else {
80 use = 'y';
81 if (qs > 2)
82 m = -1;
83 else m = 1;
84 }
85 if (qs == qf) {
86 m0 = (y0 - y) / (x0 - x);
87 m1 = (y1 - y) / (x1 - x);
88 if (m0 >= m1)
89 qt = 4;
90 else qt = 0;
91 } else if ((qt = qf - qs) < 0)
92 qt += 4;
93 /* LINTED */
94 while (1) {
95 switch (use) {
96 case 'x':
97 if ((qs == 2) || (qs == 3))
98 yc -= del;
99 else yc += del;
100 dy = yc - y;
101 pc = r - dy * dy;
102 xc = (short)(m * sqrt(pc) + x);
103 if (((x < xs) && (x >= xc)) ||
104 ((x > xs) && (x <= xc)) ||
105 ((y < ys) && (y >= yc)) ||
106 ((y > ys) && (y <= yc))) {
107 if (++qtctr > qt)
108 return;
109 if (++qs > 4)
110 qs = 1;
111 if ((qs == 2) || (qs == 3))
112 m = -1;
113 else m = 1;
114 flg = 1;
115 }
116 cont(xc, yc);
117 xs = xc;
118 ys = yc;
119 if ((qs == qf) && (flg == 1))
120 switch (qf) {
121 case 3:
122 case 4:
123 if (xs >= x1)
124 return;
125 continue;
126 case 1:
127 case 2:
128 if (xs <= x1)
129 return;
130 }
131 continue;
132 case 'y':
133 if (qs > 2)
134 xc += del;
135 else xc -= del;
136 dx = xc - x;
137 pc = r - dx * dx;
138 yc = (short)(m * sqrt(pc) + y);
139 if (((x < xs) && (x >= xc)) ||
140 ((x > xs) && (x <= xc)) ||
141 ((y < ys) && (y >= yc)) ||
142 ((y > ys) && (y <= yc))) {
143 if (++qtctr > qt)
144 return;
145 if (++qs > 4)
146 qs = 1;
147 if (qs > 2)
148 m = -1;
149 else m = 1;
150 flg = 1;
151 }
152 cont(xc, yc);
153 xs = xc;
154 ys = yc;
155 if ((qs == qf) && (flg == 1))
156 switch (qs) {
157 case 1:
158 case 4:
159 if (ys >= y1)
160 return;
161 continue;
162 case 2:
163 case 3:
164 if (ys <= y1)
165 return;
166 }
167 }
168 }
169 }
170
171 /*
172 * these is a local function not to be confused with the
173 * system wide quad
174 */
175 static int
quad_l(short x,short y,short xp,short yp)176 quad_l(short x, short y, short xp, short yp)
177 {
178 if (x < xp)
179 if (y <= yp)
180 return (1);
181 else return (4);
182 else if (x > xp)
183 if (y < yp)
184 return (2);
185 else return (3);
186 else if (y < yp)
187 return (2);
188 else return (4);
189 }
190