From 97b5962ab1ce08f50001f2bbcd87685e8dcce222 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Fri, 6 Aug 2021 03:13:05 +0000
Subject: [PATCH] Correctly draw wide characters that are partially obscured.

---
 tty.c | 31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/tty.c b/tty.c
index 425d3420..cb179250 100644
--- a/tty.c
+++ b/tty.c
@@ -1349,7 +1349,7 @@ tty_draw_line(struct tty *tty, struct screen *s, u_int px, u_int py, u_int nx,
 	struct grid_line	*gl;
 	struct client		*c = tty->client;
 	u_int			 i, j, ux, sx, width;
-	int			 flags, cleared = 0, wrapped = 0;
+	int			 flags, cleared = 0, wrapped = 0, hidden;
 	char			 buf[512];
 	size_t			 len;
 	u_int			 cellsize;
@@ -1449,17 +1449,24 @@ tty_draw_line(struct tty *tty, struct screen *s, u_int px, u_int py, u_int nx,
 			screen_select_cell(s, &last, gcp);
 		else
 			memcpy(&last, gcp, sizeof last);
-		if (!tty_check_overlay(tty, atx + ux, aty)) {
-			if (~gcp->flags & GRID_FLAG_PADDING)
-				ux += gcp->data.width;
-		} else if (ux + gcp->data.width > nx) {
-			tty_attributes(tty, &last, defaults, palette);
-			tty_cursor(tty, atx + ux, aty);
-			for (j = 0; j < gcp->data.width; j++) {
-				if (ux + j > nx)
-					break;
-				tty_putc(tty, ' ');
-				ux++;
+
+		hidden = 0;
+		for (j = 0; j < gcp->data.width; j++) {
+			if (!tty_check_overlay(tty, atx + ux + j, aty)) {
+				hidden = 1;
+				break;
+			}
+		}
+		if (hidden || ux + gcp->data.width > nx) {
+			if (~gcp->flags & GRID_FLAG_PADDING) {
+				tty_attributes(tty, &last, defaults, palette);
+				tty_cursor(tty, atx + ux, aty);
+				for (j = 0; j < gcp->data.width; j++) {
+					if (ux + j > nx)
+						break;
+					tty_putc(tty, ' ');
+					ux++;
+				}
 			}
 		} else if (gcp->attr & GRID_ATTR_CHARSET) {
 			tty_attributes(tty, &last, defaults, palette);