```   1: /*
2:  * Copyright (c) 1980 Regents of the University of California.
4:  * specifies the terms and conditions for redistribution.
5:  */
6:
7: #ifndef lint
8: static char sccsid[] = "@(#)arc.c	5.1 (Berkeley) 5/7/85";
9: #endif not lint
10:
11: #include "hp2648.h"
12:
13: arc(xcent,ycent,xbeg,ybeg,xend,yend)
14: int xcent,ycent,xbeg,ybeg,xend,yend;
15: {
16:     double costheta,sintheta,x,y,xn,r;
17:     double x1,y1,x2,y2;
18:     int xi,yi,crosspflag,crossp;
19:
20:     r = (xcent-xbeg)*(xcent-xbeg)+(ycent-ybeg)*(ycent-ybeg);
21:     r = pow(r,0.5);
22:     if(r<1){
23:         point(xcent,ycent);
24:         return;
25:     }
26:     sintheta = 1.0/r;
27:     costheta = pow(1-sintheta*sintheta,0.5);
28:     xi = x = xbeg-xcent;
29:     yi = y = ybeg-ycent;
30:     x1 = xcent;
31:     y1 = ycent;
32:     x2 = xend;
33:     y2 = yend;
34:     crosspflag = 0;
35:     do {
36:         crossp = cross_product(x1,y1,x2,y2,x,y);
37:         if(crossp >0 && crosspflag == 0) crosspflag = 1;
38:         point(xcent+xi,ycent+yi);
39:         xn = x;
40:         xi = x = x*costheta + y*sintheta;
41:         yi = y = y*costheta - xn*sintheta;
42:     } while( crosspflag == 0 || crossp >0);
43: }
44:
45: cross_product(x1,y1,x2,y2,x3,y3)
46: double x1,x2,x3,y1,y2,y3;
47: {
48:     double z,a,b;
49:     a = (y3-y2)*(x2-x1);
50:     b = (x3-x2)*(y2-y1);
51:     z = a-b;
52:     if(z<0) return(-1);
53:     if(z>0) return(1);
54:     return(0);
55: }
```

#### Defined functions

arc defined in line 13; never used
cross_product defined in line 45; used 1 times
• in line 36

#### Defined variables

sccsid defined in line 8; never used
 Last modified: 1985-05-07 Generated: 2016-12-26 Generated by src2html V0.67 page hit count: 705