blob: ef995bbb35e0237a497ced61647d691de3c7f3fd [file] [log] [blame]
/* ti.c: classify line intersections */
# include "t.h"
/* determine local environment for intersections */
int
interv(int i, int c)
{
int ku, kl;
if (c >= ncol || c == 0) {
if (dboxflg) {
if (i == 0)
return(BOT);
if (i >= nlin)
return(TOP);
return(THRU);
}
if (c >= ncol)
return(0);
}
ku = i > 0 ? lefdata(i - 1, c) : 0;
if (i + 1 >= nlin && allh(i))
kl = 0;
else
kl = lefdata(allh(i) ? i + 1 : i, c);
if (ku == 2 && kl == 2)
return(THRU);
if (ku == 2)
return(TOP);
if (kl == BOT)
return(2);
return(0);
}
int
interh(int i, int c)
{
int kl, kr;
if (fullbot[i] == '=' || (dboxflg && (i == 0 || i >= nlin - 1))) {
if (c == ncol)
return(LEFT);
if (c == 0)
return(RIGHT);
return(THRU);
}
if (i >= nlin)
return(0);
kl = c > 0 ? thish (i, c - 1) : 0;
if (kl <= 1 && i > 0 && allh(up1(i)))
kl = c > 0 ? thish(up1(i), c - 1) : 0;
kr = thish(i, c);
if (kr <= 1 && i > 0 && allh(up1(i)))
kr = c > 0 ? thish(up1(i), c) : 0;
if (kl == '=' && kr == '=')
return(THRU);
if (kl == '=')
return(LEFT);
if (kr == '=')
return(RIGHT);
return(0);
}
int
up1(int i)
{
i--;
while (instead[i] && i > 0)
i--;
return(i);
}