From: Gerd Möllmann <gerd.moellmann@gmail.com>
Date: Sun, 9 Mar 2025 09:04:41 +0000 (+0100)
Subject: Fix drawing to the bottom-right corner of terminals
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=d33b30ccce17c90eab8a881021ebce4cecb3815d;p=emacs.git

Fix drawing to the bottom-right corner of terminals

* src/term.c (tty_write_glyphs_1): Renamed from tty_write_glyphs. Don't
check if writing the bottom-right corner.
(tty_write_glyphs): New function handling case of writing to the
bottom-right corner, and otherwise calling tty_write_glyphs_1.

(cherry picked from commit 6fb68f4310d808827b83da053fbc112b316b7757)
---

diff --git a/src/term.c b/src/term.c
index 6990978ecfb..bc7a9c78f0d 100644
--- a/src/term.c
+++ b/src/term.c
@@ -750,19 +750,13 @@ encode_terminal_code (struct glyph *src, int src_len,
 /* An implementation of write_glyphs for termcap frames. */
 
 static void
-tty_write_glyphs (struct frame *f, struct glyph *string, int len)
+tty_write_glyphs_1 (struct frame *f, struct glyph *string, int len)
 {
   struct tty_display_info *tty = FRAME_TTY (f);
   tty_turn_off_insert (tty);
   tty_hide_cursor (tty);
 
-  /* Don't dare write in last column of bottom line, if Auto-Wrap,
-     since that would scroll the whole frame on some terminals.  */
-  if (AutoWrap (tty)
-      && curY (tty) + 1 == FRAME_TOTAL_LINES (f)
-      && (curX (tty) + len) == FRAME_COLS (f))
-    len --;
-  if (len <= 0)
+  if (len == 0)
     return;
 
   cmplus (tty, len);
@@ -968,6 +962,30 @@ tty_insert_glyphs (struct frame *f, struct glyph *start, int len)
   cmcheckmagic (tty);
 }
 
+static void
+tty_write_glyphs (struct frame *f, struct glyph *string, int len)
+{
+  struct tty_display_info *tty = FRAME_TTY (f);
+  /* Don't dare write in last column of bottom line, if Auto-Wrap,
+     since that would scroll the whole frame on some terminals.  */
+  if (AutoWrap (tty)
+      && curY (tty) + 1 == FRAME_TOTAL_LINES (f)
+      && curX (tty) + len == FRAME_COLS (f)
+      && curX (tty) < FRAME_COLS (f) - 1
+      && len > 0)
+    {
+      /* Write glyphs except the first. */
+      int old_x = curX (tty), old_y = curY (tty);
+      tty_write_glyphs_1 (f, string + 1, len - 1);
+
+      /* Insert the first glyph, shifting the rest right.  */
+      cmgoto (tty, old_y, old_x);
+      tty_insert_glyphs (f, string, 1);
+    }
+  else
+    tty_write_glyphs_1 (f, string, len);
+}
+
 /* An implementation of delete_glyphs for termcap frames. */
 
 static void