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1.1 root 1: #include <stdio.h>
2: #include "pic.h"
3: #include "y.tab.h"
4:
5: struct obj *arcgen(type) /* handles circular and (eventually) elliptical arcs */
6: {
7: static int prevw = HT/10;
8: static int prevh = HT/5;
9: static int prevrad = HT/2;
10: static int dtox[2][4] ={ 1, -1, -1, 1, 1, 1, -1, -1 };
11: static int dtoy[2][4] ={ 1, 1, -1, -1, -1, 1, 1, -1 };
12: static int dctrx[2][4] ={ 0, -1, 0, 1, 0, 1, 0, -1 };
13: static int dctry[2][4] ={ 1, 0, -1, 0, -1, 0, 1, 0 };
14: static int nexthv[2][4] ={ U_DIR, L_DIR, D_DIR, R_DIR, D_DIR, R_DIR, U_DIR, L_DIR };
15: double sqrt(), atan2(), sin(), cos();
16: float dx2, dy2, ht, phi, r, d;
17: int i, head, to, at, cw, invis;
18: struct obj *p, *ppos;
19: coord fromx, fromy, tox, toy;
20:
21: prevrad = getvar("arcrad");
22: prevh = getvar("arrowht");
23: prevw = getvar("arrowwid");
24: fromx = curx;
25: fromy = cury;
26: head = to = at = cw = invis = 0;
27: for (i = 0; i < nattr; i++) {
28: switch (attr[i].a_type) {
29: case LJUST: case RJUST: case CENTER: case SPREAD: case FILL: case ABOVE: case BELOW:
30: savetext(attr[i].a_type, attr[i].a_val);
31: break;
32: case HEAD:
33: head += attr[i].a_val;
34: break;
35: case INVIS:
36: invis = INVIS;
37: break;
38: case HEIGHT: /* length of arrowhead */
39: prevh = attr[i].a_val;
40: break;
41: case WIDTH: /* width of arrowhead */
42: prevw = attr[i].a_val;
43: break;
44: case RADIUS:
45: prevrad = attr[i].a_val;
46: break;
47: case DIAMETER:
48: prevrad = attr[i].a_val / 2;
49: break;
50: case CW:
51: cw = 1;
52: break;
53: case FROM: /* start point of arc */
54: ppos = (struct obj *) attr[i].a_val;
55: fromx = ppos->o_x;
56: fromy = ppos->o_y;
57: break;
58: case TO: /* end point of arc */
59: ppos = (struct obj *) attr[i].a_val;
60: tox = ppos->o_x;
61: toy = ppos->o_y;
62: to++;
63: break;
64: case AT: /* center of arc */
65: ppos = (struct obj *) attr[i].a_val;
66: curx = ppos->o_x;
67: cury = ppos->o_y;
68: at = 1;
69: break;
70: case UP:
71: hvmode = U_DIR;
72: break;
73: case DOWN:
74: hvmode = D_DIR;
75: break;
76: case RIGHT:
77: hvmode = R_DIR;
78: break;
79: case LEFT:
80: hvmode = L_DIR;
81: break;
82: }
83: }
84: if (!at && !to) { /* the defaults are mostly OK */
85: curx = fromx + prevrad * dctrx[cw][hvmode];
86: cury = fromy + prevrad * dctry[cw][hvmode];
87: tox = fromx + prevrad * dtox[cw][hvmode];
88: toy = fromy + prevrad * dtoy[cw][hvmode];
89: hvmode = nexthv[cw][hvmode];
90: }
91: else if (!at) {
92: dx2 = (float)(tox - fromx) / 2;
93: dy2 = (float)(toy - fromy) / 2;
94: phi = atan2(dy2, dx2) + (cw ? -PI2 : PI2);
95: for (r=prevrad; (d = r*r - (dx2*dx2+dy2*dy2)) <= 0.0; r *= 2)
96: ; /* this kludge gets around too-small radii */
97: ht = sqrt(d);
98: curx = fromx + dx2 + ht * cos(phi) + 0.5;
99: cury = fromy + dy2 + ht * sin(phi) + 0.5;
100: dprintf("dx2,dy2=%g,%g, phi=%g, r,ht=%g,%g\n",
101: dx2, dy2, phi, r, ht);
102: }
103: else if (at && !to) { /* do we have all the cases??? */
104: tox = fromx + prevrad * dtox[cw][hvmode];
105: toy = fromy + prevrad * dtoy[cw][hvmode];
106: hvmode = nexthv[cw][hvmode];
107: }
108: if (cw) { /* interchange roles of from-to and heads */
109: coord temp;
110: temp = fromx; fromx = tox; tox = temp;
111: temp = fromy; fromy = toy; toy = temp;
112: if (head == HEAD1)
113: head = HEAD2;
114: else if (head == HEAD2)
115: head = HEAD1;
116: }
117: p = makenode(type, 6);
118: /* these are wrong in general */
119: extreme(fromx, fromy);
120: extreme(tox, toy);
121: p->o_val[0] = fromx;
122: p->o_val[1] = fromy;
123: p->o_val[2] = tox;
124: p->o_val[3] = toy;
125: if (cw) {
126: curx = fromx;
127: cury = fromy;
128: } else {
129: curx = tox;
130: cury = toy;
131: }
132: p->o_val[4] = prevw;
133: p->o_val[5] = prevh;
134: p->o_attr = head | (cw ? CW_ARC : 0) | invis;
135: dprintf("arc at %d %d from %d %d to %d %d head %d %d\n",
136: p->o_x, p->o_y,
137: p->o_val[0], p->o_val[1], p->o_val[2], p->o_val[3], p->o_val[4], p->o_val[5]);
138: return(p);
139: }
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