From 4e333e4605a3ac27a920f1079021f02f2167940b Mon Sep 17 00:00:00 2001
From: Elie Le Vaillant <eolien55@disroot.org>
Date: Sat, 14 Sep 2024 15:23:40 +0000
Subject: [PATCH] pdf&ps: Add support for line control

This includes line thickness, line cap and line
join. This was added to ps using \X'set' commands.

A new drawing primitive, mirroring groff's, was
introduced: \D't'. It allows directly setting line
width using units. \D't 1i' has expected results
(a line width of an inch), whereas

.nr a 1i
.dv set linewidth \na

does not, because the argument of linewidth is in
thousandths of ems. It's also arguably more
cumbersome.
---
 pdf.c  |  9 +++++++--
 post.c |  3 +++
 post.h |  1 +
 ps.c   | 32 ++++++++++++++++++++++++++++++++
 4 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/pdf.c b/pdf.c
index d881266..e34414f 100644
--- a/pdf.c
+++ b/pdf.c
@@ -879,8 +879,8 @@ void drawend(int close, int fill)
 	fill = !fill ? 2 : fill;
 	if (l_page != page_n || l_size != o_s || l_wid != pdf_linewid ||
 			l_cap != pdf_linecap || l_join != pdf_linejoin) {
-		int lwid = pdf_linewid * o_s;
-		sbuf_printf(pg, "%d.%03d w\n", lwid / 1000, lwid % 1000);
+		int lwid = pdf_linewid;
+		sbuf_printf(pg, "%d.%02d w\n", lwid / 100, lwid % 100);
 		sbuf_printf(pg, "%d J %d j\n", pdf_linecap, pdf_linejoin);
 		l_page = page_n;
 		l_size = o_s;
@@ -979,6 +979,11 @@ void draws(int h1, int v1, int h2, int v2)
 	outrel(h1, v1);
 }
 
+void drawt(int w)
+{
+	pdf_linewid = w * 7200 / dev_res;
+}
+
 void docheader(char *title, int pagewidth, int pageheight, int linewidth)
 {
 	if (title)
diff --git a/post.c b/post.c
index fb52a65..11bce12 100644
--- a/post.c
+++ b/post.c
@@ -232,6 +232,9 @@ static void postdraw(void)
 	int c = next();
 	drawbeg();
 	switch (tolower(c)) {
+	case 't':
+		drawt(nextnum());
+		break;
 	case 'l':
 		h1 = nextnum();
 		v1 = nextnum();
diff --git a/post.h b/post.h
index 0f30569..67e5740 100644
--- a/post.h
+++ b/post.h
@@ -77,6 +77,7 @@ void drawc(int c);
 void drawe(int h, int v);
 void drawa(int h1, int v1, int h2, int v2);
 void draws(int h1, int v1, int h2, int v2);
+void drawt(int w);
 
 void docheader(char *title, int pagewidth, int pageheight, int linewidth);
 void doctrailer(int pages);
diff --git a/ps.c b/ps.c
index 33336f8..30e2c6a 100644
--- a/ps.c
+++ b/ps.c
@@ -8,6 +8,7 @@
 static char ps_title[256];	/* document title */
 static char ps_author[256];	/* document author */
 static int ps_height;		/* document height in basic units */
+static int page_n = 0;		/* number of pages */
 static int o_f, o_s, o_m;	/* font and size */
 static int o_h, o_v;		/* current user position */
 static int p_f, p_s, p_m;	/* output postscript font */
@@ -16,6 +17,10 @@ static int o_qv, o_qh, o_qend;	/* queued character position */
 static int o_rh, o_rv, o_rdeg;	/* previous rotation position and degree */
 static int o_gname;		/* use glyphshow for all glyphs */
 
+static int ps_linewid;		/* line width in basic units */
+static int ps_linecap = 1;	/* line cap style: 0 (butt), 1 (round), 2 (projecting square) */
+static int ps_linejoin = 1;	/* line join style: 0 (miter), 1 (round), 2 (bevel) */
+
 static char o_fonts[FNLEN * NFONTS] = " ";
 
 static void outvf(char *s, va_list ap)
@@ -200,10 +205,24 @@ void drawmend(char *s)
 	outf("%s grestore\n", s);
 }
 
+static int l_page, l_size, l_wid, l_cap, l_join;	/* drawing line properties */
+
 void drawbeg(void)
 {
 	o_flush();
 	out_fontup(o_f);
+	if (l_page != page_n || l_size != o_s || l_wid != ps_linewid ||
+			l_cap != ps_linecap || l_join != ps_linejoin) {
+		outf("%d setlinewidth ", ps_linewid);
+		outf("%d setlinecap ", ps_linecap);
+		outf("%d setlinejoin\n", ps_linejoin);
+		o_flush();
+		l_page = page_n;
+		l_size = o_s;
+		l_wid = ps_linewid;
+		l_cap = ps_linecap;
+		l_join = ps_linejoin;
+	}
 	if (draw_path)
 		return;
 	outf("newpath ");
@@ -258,6 +277,11 @@ void draws(int h1, int v1, int h2, int v2)
 	outrel(h1, v1);
 }
 
+void drawt(int w)
+{
+	ps_linewid = w;
+}
+
 void outeps(char *eps, int hwid, int vwid)
 {
 	char buf[1 << 12];
@@ -371,10 +395,17 @@ void outinfo(char *kwd, char *val)
 
 void outset(char *var, char *val)
 {
+	if (!strcmp("linewidth", var))
+		ps_linewid = atoi(val);
+	if (!strcmp("linecap", var))
+		ps_linecap = atoi(val);
+	if (!strcmp("linejoin", var))
+		ps_linejoin = atoi(val);
 }
 
 void docpagebeg(int n)
 {
+	page_n = n;
 	out("%%%%Page: %d %d\n", n, n);
 	out("/saveobj save def\n");
 	out("mark\n");
@@ -506,6 +537,7 @@ static char *prolog =
 /* pagewidth and pageheight are in tenths of a millimetre */
 void docheader(char *title, int pagewidth, int pageheight, int linewidth)
 {
+	ps_linewid = linewidth * dev_res / 7200;
 	ps_height = pageheight * dev_res / 254;
 	out("%%!PS-Adobe-2.0\n");
 	out("%%%%Version: 1.0\n");