implement the tbl(7) "center" layout option

1 files changed, 19 insertions, 3 deletions

diff --git a/tbl_term.c b/tbl_term.c
index e9497dd2..9b6aea36 100644
--- a/tbl_term.c
+++ b/tbl_term.c
@@ -1,4 +1,4 @@
-/*	$Id: tbl_term.c,v 1.33 2015/01/27 05:21:45 schwarze Exp $ */
+/*	$Id: tbl_term.c,v 1.34 2015/01/28 04:19:35 schwarze Exp $ */
 /*
  * Copyright (c) 2009, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2011, 2012, 2014, 2015 Ingo Schwarze <schwarze@openbsd.org>
@@ -63,8 +63,9 @@ term_tbl(struct termp *tp, const struct tbl_span *sp)
 	const struct tbl_head	*hp;
 	const struct tbl_cell	*cp;
 	const struct tbl_dat	*dp;
+	static size_t		 offset;
+	size_t			 rmargin, maxrmargin, tsz;
 	int			 horiz, spans, vert;
-	size_t			 rmargin, maxrmargin;
 
 	rmargin = tp->rmargin;
 	maxrmargin = tp->maxrmargin;
@@ -90,6 +91,21 @@ term_tbl(struct termp *tp, const struct tbl_span *sp)
 
 		tblcalc(&tp->tbl, sp, rmargin - tp->offset);
 
+		/* Center the table as a whole. */
+
+		offset = tp->offset;
+		if (sp->opts->opts & TBL_OPT_CENTRE) {
+			tsz = sp->opts->opts & (TBL_OPT_BOX | TBL_OPT_DBOX)
+			    ? 2 : !!sp->opts->lvert + !!sp->opts->rvert;
+			for (hp = sp->head; hp != NULL; hp = hp->next)
+				tsz += tp->tbl.cols[hp->ident].width + 3;
+			tsz -= 3;
+			if (offset + tsz > rmargin)
+				tsz -= 1;
+			tp->offset = (offset + rmargin > tsz) ?
+			    (offset + rmargin - tsz) / 2 : 0;
+		}
+
 		/* Horizontal frame at the start of boxed tables. */
 
 		if (sp->opts->opts & TBL_OPT_DBOX)
@@ -189,12 +205,12 @@ term_tbl(struct termp *tp, const struct tbl_span *sp)
 		assert(tp->tbl.cols);
 		free(tp->tbl.cols);
 		tp->tbl.cols = NULL;
+		tp->offset = offset;
 	}
 
 	tp->flags &= ~TERMP_NONOSPACE;
 	tp->rmargin = rmargin;
 	tp->maxrmargin = maxrmargin;
-
 }
 
 /*