Rounding rules for horizontal scaling widths are more complicated.

There is a first rounding to basic units on the input side.
After that, rounding rules differ between requests and macros.
Requests round to the nearest possible character position.
Macros round to the next character position to the left.

Implement that by changing the return value of term_hspan()
to basic units and leaving the second scaling and rounding stage
to the formatters instead of doing it in the terminal handler.

Improves for example argtable2(3).

6 files changed, 44 insertions, 50 deletions

diff --git a/man_term.c b/man_term.c
index 8272456c..93b664a9 100644
--- a/man_term.c
+++ b/man_term.c
@@ -1,4 +1,4 @@
-/*	$Id: man_term.c,v 1.174 2015/04/04 11:44:43 schwarze Exp $ */
+/*	$Id: man_term.c,v 1.175 2015/04/04 17:47:18 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2015 Ingo Schwarze <schwarze@openbsd.org>
@@ -427,7 +427,7 @@ pre_in(DECL_ARGS)
 	if ( ! a2roffsu(++cp, &su, SCALE_EN))
 		return(0);
 
-	v = term_hspan(p, &su);
+	v = (term_hspan(p, &su) + 11) / 24;
 
 	if (less < 0)
 		p->offset -= p->offset > v ? v : p->offset;
@@ -512,7 +512,7 @@ pre_HP(DECL_ARGS)
 
 	if ((nn = n->parent->head->child) != NULL &&
 	    a2roffsu(nn->string, &su, SCALE_EN)) {
-		len = term_hspan(p, &su);
+		len = term_hspan(p, &su) / 24;
 		if (len < 0 && (size_t)(-len) > mt->offset)
 			len = -mt->offset;
 		else if (len > SHRT_MAX)
@@ -597,7 +597,7 @@ pre_IP(DECL_ARGS)
 	if ((nn = n->parent->head->child) != NULL &&
 	    (nn = nn->next) != NULL &&
 	    a2roffsu(nn->string, &su, SCALE_EN)) {
-		len = term_hspan(p, &su);
+		len = term_hspan(p, &su) / 24;
 		if (len < 0 && (size_t)(-len) > mt->offset)
 			len = -mt->offset;
 		else if (len > SHRT_MAX)
@@ -679,7 +679,7 @@ pre_TP(DECL_ARGS)
 	if ((nn = n->parent->head->child) != NULL &&
 	    nn->string != NULL && ! (MAN_LINE & nn->flags) &&
 	    a2roffsu(nn->string, &su, SCALE_EN)) {
-		len = term_hspan(p, &su);
+		len = term_hspan(p, &su) / 24;
 		if (len < 0 && (size_t)(-len) > mt->offset)
 			len = -mt->offset;
 		else if (len > SHRT_MAX)
@@ -868,7 +868,7 @@ pre_RS(DECL_ARGS)
 	n = n->parent->head;
 	n->aux = SHRT_MAX + 1;
 	if (n->child != NULL && a2roffsu(n->child->string, &su, SCALE_EN))
-		n->aux = term_hspan(p, &su);
+		n->aux = term_hspan(p, &su) / 24;
 	if (n->aux < 0 && (size_t)(-n->aux) > mt->offset)
 		n->aux = -mt->offset;
 	else if (n->aux > SHRT_MAX)
diff --git a/mdoc_term.c b/mdoc_term.c
index 44b03b5c..cd27731a 100644
--- a/mdoc_term.c
+++ b/mdoc_term.c
@@ -1,4 +1,4 @@
-/*	$Id: mdoc_term.c,v 1.316 2015/04/02 23:48:20 schwarze Exp $ */
+/*	$Id: mdoc_term.c,v 1.317 2015/04/04 17:47:18 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010, 2012-2015 Ingo Schwarze <schwarze@openbsd.org>
@@ -533,7 +533,7 @@ a2width(const struct termp *p, const char *v)
 		SCALE_HS_INIT(&su, term_strlen(p, v));
 		su.scale /= term_strlen(p, "0");
 	}
-	return(term_hspan(p, &su));
+	return(term_hspan(p, &su) / 24);
 }
 
 /*
diff --git a/term.c b/term.c
index 6476b0e7..68f3ea04 100644
--- a/term.c
+++ b/term.c
@@ -1,4 +1,4 @@
-/*	$Id: term.c,v 1.246 2015/04/02 23:48:20 schwarze Exp $ */
+/*	$Id: term.c,v 1.247 2015/04/04 17:47:18 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2015 Ingo Schwarze <schwarze@openbsd.org>
@@ -619,8 +619,7 @@ void
 term_setwidth(struct termp *p, const char *wstr)
 {
 	struct roffsu	 su;
-	size_t		 width;
-	int		 iop;
+	int		 iop, width;
 
 	iop = 0;
 	width = 0;
@@ -831,11 +830,12 @@ term_vspan(const struct termp *p, const struct roffsu *su)
 	return(ri < 66 ? ri : 1);
 }
 
+/*
+ * Convert a scaling width to basic units, rounding down.
+ */
 int
 term_hspan(const struct termp *p, const struct roffsu *su)
 {
-	double		 v;
 
-	v = (*p->hspan)(p, su);
-	return(v > 0.0 ? v + 0.0005 : v - 0.0005);
+	return((*p->hspan)(p, su));
 }
diff --git a/term.h b/term.h
index ab34717b..bda7f7da 100644
--- a/term.h
+++ b/term.h
@@ -1,4 +1,4 @@
-/*	$Id: term.h,v 1.112 2015/04/02 23:48:20 schwarze Exp $ */
+/*	$Id: term.h,v 1.113 2015/04/04 17:47:18 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2011-2015 Ingo Schwarze <schwarze@openbsd.org>
@@ -95,9 +95,9 @@ struct	termp {
 	void		(*end)(struct termp *);
 	void		(*endline)(struct termp *);
 	void		(*advance)(struct termp *, size_t);
-	void		(*setwidth)(struct termp *, int, size_t);
+	void		(*setwidth)(struct termp *, int, int);
 	size_t		(*width)(const struct termp *, int);
-	double		(*hspan)(const struct termp *,
+	int		(*hspan)(const struct termp *,
 				const struct roffsu *);
 	const void	 *argf;		/* arg for headf/footf */
 	struct termp_ps	 *ps;
diff --git a/term_ascii.c b/term_ascii.c
index f217b9a4..7abbb91f 100644
--- a/term_ascii.c
+++ b/term_ascii.c
@@ -1,4 +1,4 @@
-/*	$Id: term_ascii.c,v 1.44 2015/03/27 21:33:20 schwarze Exp $ */
+/*	$Id: term_ascii.c,v 1.45 2015/04/04 17:47:18 schwarze Exp $ */
 /*
  * Copyright (c) 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2014, 2015 Ingo Schwarze <schwarze@openbsd.org>
@@ -40,7 +40,7 @@
 
 static	struct termp	 *ascii_init(enum termenc, const struct mchars *,
 				const struct manoutput *);
-static	double		  ascii_hspan(const struct termp *,
+static	int		  ascii_hspan(const struct termp *,
 				const struct roffsu *);
 static	size_t		  ascii_width(const struct termp *, int);
 static	void		  ascii_advance(struct termp *, size_t);
@@ -48,7 +48,7 @@ static	void		  ascii_begin(struct termp *);
 static	void		  ascii_end(struct termp *);
 static	void		  ascii_endline(struct termp *);
 static	void		  ascii_letter(struct termp *, int);
-static	void		  ascii_setwidth(struct termp *, int, size_t);
+static	void		  ascii_setwidth(struct termp *, int, int);
 
 #if HAVE_WCHAR
 static	void		  locale_advance(struct termp *, size_t);
@@ -137,15 +137,16 @@ locale_alloc(const struct mchars *mchars, const struct manoutput *outopts)
 }
 
 static void
-ascii_setwidth(struct termp *p, int iop, size_t width)
+ascii_setwidth(struct termp *p, int iop, int width)
 {
 
+	width /= 24;
 	p->rmargin = p->defrmargin;
 	if (iop > 0)
 		p->defrmargin += width;
 	else if (iop == 0)
-		p->defrmargin = width ? width : p->lastrmargin;
-	else if (p->defrmargin > width)
+		p->defrmargin = width ? (size_t)width : p->lastrmargin;
+	else if (p->defrmargin > (size_t)width)
 		p->defrmargin -= width;
 	else
 		p->defrmargin = 0;
@@ -218,52 +219,45 @@ ascii_advance(struct termp *p, size_t len)
 		putchar(' ');
 }
 
-static double
+static int
 ascii_hspan(const struct termp *p, const struct roffsu *su)
 {
 	double		 r;
 
-	/*
-	 * Approximate based on character width.
-	 * None of these will be actually correct given that an inch on
-	 * the screen depends on character size, terminal, etc., etc.
-	 */
 	switch (su->unit) {
 	case SCALE_BU:
-		r = su->scale * 10.0 / 240.0;
+		r = su->scale;
 		break;
 	case SCALE_CM:
-		r = su->scale * 10.0 / 2.54;
+		r = su->scale * 240.0 / 2.54;
 		break;
 	case SCALE_FS:
-		r = su->scale * 2730.666;
+		r = su->scale * 65536.0;
 		break;
 	case SCALE_IN:
-		r = su->scale * 10.0;
+		r = su->scale * 240.0;
 		break;
 	case SCALE_MM:
-		r = su->scale / 100.0;
+		r = su->scale * 0.24;
 		break;
+	case SCALE_VS:
+		/* FALLTHROUGH */
 	case SCALE_PC:
-		r = su->scale * 10.0 / 6.0;
+		r = su->scale * 40.0;
 		break;
 	case SCALE_PT:
-		r = su->scale * 10.0 / 72.0;
-		break;
-	case SCALE_VS:
-		r = su->scale * 2.0 - 1.0;
+		r = su->scale * 10.0 / 3.0;
 		break;
 	case SCALE_EN:
 		/* FALLTHROUGH */
 	case SCALE_EM:
-		r = su->scale;
+		r = su->scale * 24.0;
 		break;
 	default:
 		abort();
 		/* NOTREACHED */
 	}
-
-	return(r);
+	return(r > 0.0 ? r + 0.01 : r - 0.01);
 }
 
 const char *
diff --git a/term_ps.c b/term_ps.c
index 961de1b0..bd86d791 100644
--- a/term_ps.c
+++ b/term_ps.c
@@ -1,4 +1,4 @@
-/*	$Id: term_ps.c,v 1.73 2015/03/27 21:33:20 schwarze Exp $ */
+/*	$Id: term_ps.c,v 1.74 2015/04/04 17:47:18 schwarze Exp $ */
 /*
  * Copyright (c) 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2014, 2015 Ingo Schwarze <schwarze@openbsd.org>
@@ -87,7 +87,7 @@ struct	termp_ps {
 	size_t		  pdfobjsz;	/* size of pdfobjs */
 };
 
-static	double		  ps_hspan(const struct termp *,
+static	int		  ps_hspan(const struct termp *,
 				const struct roffsu *);
 static	size_t		  ps_width(const struct termp *, int);
 static	void		  ps_advance(struct termp *, size_t);
@@ -106,7 +106,7 @@ __attribute__((__format__ (__printf__, 2, 3)))
 static	void		  ps_printf(struct termp *, const char *, ...);
 static	void		  ps_putchar(struct termp *, char);
 static	void		  ps_setfont(struct termp *, enum termfont);
-static	void		  ps_setwidth(struct termp *, int, size_t);
+static	void		  ps_setwidth(struct termp *, int, int);
 static	struct termp	 *pspdf_alloc(const struct mchars *,
 				const struct manoutput *);
 static	void		  pdf_obj(struct termp *, size_t);
@@ -620,7 +620,7 @@ pspdf_alloc(const struct mchars *mchars, const struct manoutput *outopts)
 }
 
 static void
-ps_setwidth(struct termp *p, int iop, size_t width)
+ps_setwidth(struct termp *p, int iop, int width)
 {
 	size_t	 lastwidth;
 
@@ -628,8 +628,8 @@ ps_setwidth(struct termp *p, int iop, size_t width)
 	if (iop > 0)
 		p->ps->width += width;
 	else if (iop == 0)
-		p->ps->width = width ? width : p->ps->lastwidth;
-	else if (p->ps->width > width)
+		p->ps->width = width ? (size_t)width : p->ps->lastwidth;
+	else if (p->ps->width > (size_t)width)
 		p->ps->width -= width;
 	else
 		p->ps->width = 0;
@@ -1273,7 +1273,7 @@ ps_width(const struct termp *p, int c)
 	return((size_t)fonts[(int)TERMFONT_NONE].gly[c].wx);
 }
 
-static double
+static int
 ps_hspan(const struct termp *p, const struct roffsu *su)
 {
 	double		 r;
@@ -1325,7 +1325,7 @@ ps_hspan(const struct termp *p, const struct roffsu *su)
 		break;
 	}
 
-	return(r);
+	return(r * 24.0);
 }
 
 static void