From 91b97a0f6a2f85316e9d8a6a468f06b8fd097ad3 Mon Sep 17 00:00:00 2001
From: arakiken <arakiken@users.sf.net>
Date: Sat, 29 Jul 2023 17:35:00 +0900
Subject: [PATCH] * ui_screen.c: convert_char_index_to_x() never returns minus
 value.

---
 ChangeLog             | 4 ++++
 uitoolkit/ui_screen.c | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 9d2418ad..fd5df3de 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2023-07-29  Araki Ken  <arakiken@users.sf.net>
+
+	* ui_screen.c: convert_char_index_to_x() never returns minus value.
+
 2023-06-11  Araki Ken  <arakiken@users.sf.net>
 
 	* configure.in, README, README.ja: Additional information of
diff --git a/uitoolkit/ui_screen.c b/uitoolkit/ui_screen.c
index 40b351cf..0984586a 100644
--- a/uitoolkit/ui_screen.c
+++ b/uitoolkit/ui_screen.c
@@ -164,6 +164,11 @@ static int convert_char_index_to_x(
         x -= ui_calculate_vtchar_width(ui_get_font(screen->font_man, vt_char_font(ch)), ch, NULL);
       }
     }
+
+    if (x < 0) {
+      /* XXX This causes screen corruption, but avoids segfault in fb, wayland and sdl2. */
+      x = 0;
+    }
   } else {
     /*
      * excluding the last char width.