From: Tim Ruffing <crypto@timruffing.de>
Date: Thu, 11 Nov 2021 06:14:57 +0000 (+0100)
Subject: Support Tc terminfo flag for 24-bit color support in terminal
X-Git-Tag: emacs-29.0.90~3668^2~58
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=f30f53115928fd65d066944d53d07742b0807670;p=emacs.git

Support Tc terminfo flag for 24-bit color support in terminal

* src/term.c (init_tty): Use the Tc flag (bug#44950).

Copyright-paperwork-exempt: yes
---

diff --git a/etc/NEWS b/etc/NEWS
index e32446997b9..e0b1c35d81f 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -46,6 +46,11 @@ time.
 
 * Changes in Emacs 29.1
 
+** Terminal Emacs
+
+---
+*** Emacs will now use 24-bit colors on terminal that support "Tc".
+
 ** Emoji
 
 +++
diff --git a/src/term.c b/src/term.c
index 6f0b827cfc8..d86ae12ba84 100644
--- a/src/term.c
+++ b/src/term.c
@@ -4152,10 +4152,12 @@ use the Bourne shell command 'TERM=...; export TERM' (C-shell:\n\
 	       could return 32767.  */
 	    tty->TN_max_colors = 16777216;
 	  }
-	/* Fall back to xterm+direct (semicolon version) if requested
-	   by the COLORTERM environment variable.  */
-	else if ((bg = getenv("COLORTERM")) != NULL
-		 && strcasecmp(bg, "truecolor") == 0)
+	/* Fall back to xterm+direct (semicolon version) if Tc is set
+	   (de-facto standard introduced by tmux) or if	requested by
+	   the COLORTERM environment variable.  */
+	else if (tigetflag("Tc")
+		 || ((bg = getenv("COLORTERM")) != NULL
+		     && strcasecmp(bg, "truecolor") == 0))
 	  {
 	    tty->TS_set_foreground = "\033[%?%p1%{8}%<%t3%p1%d%e38;2;%p1%{65536}%/%d;%p1%{256}%/%{255}%&%d;%p1%{255}%&%d%;m";
 	    tty->TS_set_background = "\033[%?%p1%{8}%<%t4%p1%d%e48;2;%p1%{65536}%/%d;%p1%{256}%/%{255}%&%d;%p1%{255}%&%d%;m";