From 08d3749a636f9cd51f70ba1eed043be8e6c2eca9 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Tue, 5 Oct 2021 16:57:55 -0700
Subject: feat(term): added ligature support. some combining character help

---
 sys/cmd/term/term.c | 47 ++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 36 insertions(+), 11 deletions(-)

(limited to 'sys/cmd/term/term.c')

diff --git a/sys/cmd/term/term.c b/sys/cmd/term/term.c
index f7687b9..77ed5c2 100644
--- a/sys/cmd/term/term.c
+++ b/sys/cmd/term/term.c
@@ -627,7 +627,7 @@ ttyread(void)
 		written = twrite(buf, buflen, 0);
 		buflen -= written;
 		/* keep any incomplete UTF-8 byte sequence for the next call */
-		if (buflen > 0)
+		if(buflen > 0)
 			memmove(buf, buf + written, buflen);
 		return ret;
 	}
@@ -989,7 +989,7 @@ tsetchar(rune u, Letter *attr, int x, int y)
 	};
 
 	/*
-	 * The table is proudly stolen from rxvt.
+	 * table is proudly stolen from rxvt.
 	 */
 	if (term.trantbl[term.charset] == CSgfx0 &&
 	   BETWEEN(u, 0x41, 0x7e) && vt100_0[u - 0x41])
@@ -2082,6 +2082,7 @@ tputc(rune u)
 	char c[UTFmax];
 	int  control;
 	int  width, len;
+    rune nu;
 	Letter *gp;
 
 	control = ISCONTROL(u);
@@ -2090,10 +2091,30 @@ tputc(rune u)
 		width = len = 1;
 	} else {
 		len = utf8·runetobyte(c, &u);
-		if (!control && (width = wcwidth(u)) == -1)
+		if(!control && (width = wcwidth(u)) == -1)
 			width = 1;
 	}
 
+    /* combining characters */
+    if(!width) {
+        if(term.c.x > 0)
+            gp = &term.line[term.c.y][term.c.x-1];
+        else if(term.c.y > 0)
+            gp = &term.line[term.c.y-1][term.col-1];
+        else
+            return;
+
+        printf("%d + %d\n", gp->u, u);
+
+        if(!hb_unicode_compose(hb_unicode_funcs_get_default(),gp->u, u, &nu)) {
+            assert(false);
+            return;
+        }
+
+        gp->u = nu;
+        return;
+    }
+
 	if (IS_SET(Tprint))
 		tprinter(c, len);
 
@@ -2103,7 +2124,7 @@ tputc(rune u)
 	 * receives a ESC, a SUB, a ST or any other C1 control
 	 * character.
 	 */
-	if (term.esc & Xstr) {
+	if(term.esc & Xstr) {
 		if (u == '\a' || u == 030 || u == 032 || u == 033 ||
 		   ISCONTROLC1(u)) {
 			term.esc &= ~(Xstart|Xstr|Xdcs);
@@ -2154,7 +2175,7 @@ check_control_code:
 	 * because they can be embedded inside a control sequence, and
 	 * they must not cause conflicts with sequences.
 	 */
-	if (control) {
+	if(control) {
 		tcontrolcode(u);
 		/*
 		 * control codes are not shown ever
@@ -2162,7 +2183,7 @@ check_control_code:
 		if (!term.esc)
 			term.lastc = 0;
 		return;
-	} else if (term.esc & Xstart) {
+	} else if(term.esc & Xstart) {
 		if (term.esc & Xcsi) {
 			csiescseq.buf[csiescseq.len++] = u;
 			if (BETWEEN(u, 0x40, 0x7E)
@@ -2191,6 +2212,7 @@ check_control_code:
 		 */
 		return;
 	}
+
 	if (selected(term.c.x, term.c.y))
 		selclear();
 
@@ -2212,7 +2234,7 @@ check_control_code:
 	tsetchar(u, &term.c.attr, term.c.x, term.c.y);
 	term.lastc = u;
 
-	if (width == 2) {
+	if(width == 2) {
 		gp->mode |= Gwrap;
 		if (term.c.x+1 < term.col) {
 			gp[1].u = '\0';
@@ -2234,16 +2256,16 @@ twrite(char *buf, int buflen, int show_ctrl)
 	int n;
 
 	for (n = 0; n < buflen; n += charsize) {
-		if (IS_SET(Tutf8) && !IS_SET(Tsixel)) {
+		if(IS_SET(Tutf8) && !IS_SET(Tsixel)) {
 			/* process a complete utf8 char */
 			charsize = utf8·bytetorune(&u, buf + n);
-			if (charsize == 0)
+			if(charsize == 0)
 				break;
 		} else {
 			u = buf[n] & 0xFF;
 			charsize = 1;
 		}
-		if (show_ctrl && ISCONTROL(u)) {
+		if(show_ctrl && ISCONTROL(u)) {
 			if (u & 0x80) {
 				u &= 0x7f;
 				tputc('^');
@@ -2377,7 +2399,10 @@ draw(void)
 		cx--;
 
 	drawregion(0, 0, term.col, term.row);
-	xdrawcursor(cx, term.c.y, term.line[term.c.y][cx], term.ocx, term.ocy, term.line[term.ocy][term.ocx]);
+	xdrawcursor(cx, term.c.y, term.line[term.c.y][cx],
+            term.ocx, term.ocy, term.line[term.ocy][term.ocx],
+            term.line[term.ocy], term.col
+    );
 	term.ocx = cx;
 	term.ocy = term.c.y;
 	xfinishdraw();
-- 
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