From b72fec0a52a921b747d3f09b8792c05e574d0998 Mon Sep 17 00:00:00 2001
From: Ben Harris <bjh21@bjh21.me.uk>
Date: Mon, 31 Mar 2025 10:04:18 +0100
Subject: [PATCH] Display some IM pre-edit state when painting the terminal

This is approximately how it should work: term_set_preedit_text stashes
data in the terminal structure and then do_paint() renders it in place
of what's in the terminal buffer.  Currently this only works for a
single narrow character, and it copies the existing attributes under the
cursor, but this might actually be enough for the UK keyboard layout in
GNOME.
---
 terminal/terminal.c | 14 +++++++++-----
 terminal/terminal.h |  3 +++
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/terminal/terminal.c b/terminal/terminal.c
index d945494b..d8f5f5e9 100644
--- a/terminal/terminal.c
+++ b/terminal/terminal.c
@@ -6199,6 +6199,9 @@ static void do_paint(Terminal *term)
 
             if (i == our_curs_y && j == our_curs_x)
                 tattr |= cursor;
+                if (term->preedit_char != -1)
+                    tchar = term->preedit_char;
+            }
 
             /* FULL-TERMCHAR */
             newline[j].attr = tattr;
@@ -8115,19 +8118,20 @@ void term_notify_window_size_pixels(Terminal *term, int x, int y)
 void term_set_preedit_text(Terminal *term, char *preedit_text)
 {
     BinarySource src[1];
-    pos oldcurs = term->curs;
 
     if (preedit_text != NULL) {
         debug("Pre-edit:");
         BinarySource_BARE_INIT(src, preedit_text, strlen(preedit_text));
-        while (get_avail(src)) {
+        if (get_avail(src)) {
             unsigned int c = decode_utf8(src, NULL);
             debug(" U+%04X", c);
-            term_display_graphic_char(term, c);
-        }
+            term->preedit_char = c;
+        } else
+            term->preedit_char = -1;
         debug("\n");
-        term->curs = oldcurs;
     } else {
         debug("Pre-edit finished\n");
+        term->preedit_char = -1;
     }
+    seen_disp_event(term);
 }
diff --git a/terminal/terminal.h b/terminal/terminal.h
index df6ba4cc..b9159eb6 100644
--- a/terminal/terminal.h
+++ b/terminal/terminal.h
@@ -442,6 +442,9 @@ struct terminal_tag {
      */
     struct term_userpass_state *userpass_state;
     bool userpass_utf8_override;
+
+    /* Input method state. */
+    int preedit_char;                  /* -1 for none */
 };
 
 static inline bool in_utf(Terminal *term)