ref: cbe4b116989c0bfec49b9ae7a1d9a85ead6648ae
dir: /sys/src/cmd/eqn/fromto.c/
# include "e.h"
void fromto(int p1, int p2, int p3)
{
double b, h1, b1, t;
int subps;
yyval = salloc();
lfont[yyval] = rfont[yyval] = 0;
h1 = eht[yyval] = eht[p1];
b1 = ebase[p1];
b = 0;
subps = ps;
ps += deltaps;
nrwid(p1, ps, p1);
printf(".nr %d \\n(%d\n", yyval, p1);
if (p2 > 0) {
nrwid(p2, subps, p2);
printf(".if \\n(%d>\\n(%d .nr %d \\n(%d\n", p2, yyval, yyval, p2);
eht[yyval] += eht[p2];
b = eht[p2];
}
if (p3 > 0) {
nrwid(p3, subps, p3);
printf(".if \\n(%d>\\n(%d .nr %d \\n(%d\n", p3, yyval, yyval, p3);
eht[yyval] += eht[p3];
}
printf(".ds %d ", yyval); /* bottom of middle box */
if (p2 > 0) {
t = eht[p2]-ebase[p2]+b1;
printf("\\v'%gm'\\h'\\n(%du-\\n(%du/2u'%s\\*(%d%s",
REL(t,ps), yyval, p2, DPS(ps,subps), p2, DPS(subps,ps));
printf("\\h'-\\n(%du-\\n(%du/2u'\\v'%gm'\\\n",
yyval, p2, REL(-t,ps));
}
printf("\\h'\\n(%du-\\n(%du/2u'\\*(%d\\h'\\n(%du-\\n(%du/2u'\\\n",
yyval, p1, p1, yyval, p1);
if (p3 >0) {
t = h1-b1+ebase[p3];
printf("\\v'%gm'\\h'-\\n(%du-\\n(%du/2u'%s\\*(%d%s\\h'\\n(%du-\\n(%du/2u'\\v'%gm'\\\n",
REL(-t,ps), yyval, p3, DPS(ps,subps), p3, DPS(subps,ps), yyval, p3, REL(t,ps));
}
printf("\n");
ebase[yyval] = b + b1;
dprintf(".\tS%d <- %d from %d to %d; h=%g b=%g\n",
yyval, p1, p2, p3, eht[yyval], ebase[yyval]);
sfree(p1);
if (p2 > 0)
sfree(p2);
if (p3 > 0)
sfree(p3);
}