bug#4234: allow xterm to detect the background color

bug#4234: allow xterm to detect the background color

[Dan Nicolaescu]

emacs/emacsclient -nw  running in an xterm set the frame background mode
to 'light.   
Not all users use the default white background, so they get the wrong
face colors. 
Newer xterms can tell what the background color is
(see http://permalink.gmane.org/gmane.emacs.devel/111270)

This patch implements reads the background color from xterm (iff it
supports the feature) and sets the background mode accordingly.

--- xterm.el.~1.62.~	2009-01-08 14:24:21.000000000 -0800
+++ xterm.el	2009-08-22 10:12:38.000000000 -0700
@@ -462,8 +462,6 @@
       (set-keymap-parent input-decode-map map)))
 
     (xterm-register-default-colors)
-    ;; This recomputes all the default faces given the colors we've just set up.
-    (tty-set-up-initial-frame-faces)
     
     ;; Try to turn on the modifyOtherKeys feature on modern xterms.
     ;; When it is turned on many more key bindings work: things like
@@ -472,7 +470,8 @@
     ;; modifyOtherKeys. At this time only xterm does.
     (let ((coding-system-for-read 'binary)
 	  (chr nil)
-	  (str nil))
+	  (str nil)
+	  version)
       ;; Pending input can be mistakenly returned by the calls to
       ;; read-event below.  Discard it.
       (discard-input)
@@ -494,8 +493,23 @@
 	    ;; NUMBER2 is the xterm version number, look for something
 	    ;; greater than 216, the version when modifyOtherKeys was
 	    ;; introduced.
-	    (when (>= (string-to-number
-		       (substring str (match-beginning 1) (match-end 1))) 216)
+	    (setq version (string-to-number
+			   (substring str (match-beginning 1) (match-end 1))))
+	    ;; xterm version 242 supports reporting the background
+	    ;; color, maybe earlier versions do too...
+	    (when (>= version 242)
+	      (send-string-to-terminal "\e]11;?\e\\")
+	      (when (equal (read-event nil nil 2) ?\e)
+		(when (equal (read-event nil nil 2) ?\])
+		  (setq str "")
+		  (while (not (equal (setq chr (read-event nil nil 2)) ?\\))
+		    (setq str (concat str (string chr))))
+		  (when (string-match "11;rgb:\\([a-f0-9]+\\)/\\([a-f0-9]+\\)/\\([a-f0-9]+\\)" str)
+		    (xterm-set-background-mode
+		     (string-to-number (match-string 1 str) 16)
+		     (string-to-number (match-string 2 str) 16)
+		     (string-to-number (match-string 3 str) 16))))))
+	    (when (>= version 216)
 	      ;; Make sure that the modifyOtherKeys state is restored when
 	      ;; suspending, resuming and exiting.
 	      (add-hook 'suspend-hook 'xterm-turn-off-modify-other-keys)
@@ -508,6 +522,9 @@
 		    xterm-modify-other-keys-terminal-list)
 	      (xterm-turn-on-modify-other-keys))))))
 
+    ;; This recomputes all the default faces given the colors we've just set up.
+    (tty-set-up-initial-frame-faces)
+
     (run-hooks 'terminal-init-xterm-hook))
 
 ;; Set up colors, for those versions of xterm that support it.
@@ -649,5 +666,11 @@ versions of xterm."
 	  (delq terminal xterm-modify-other-keys-terminal-list))
     (send-string-to-terminal "\e[>4m" terminal)))
 
+(defun xterm-set-background-mode (redc greenc bluec)
+  ;; Use the heuristic in `frame-set-background-mode' to decide if a
+  ;; frame is dark.
+  (when (< (+ redc greenc bluec) (* .6 (+ 65535 65535 65535)))
+    (set-terminal-parameter nil 'background-mode 'dark)))
+
 ;; arch-tag: 12e7ebdd-1e6c-4b25-b0f9-35ace25e855a
 ;;; xterm.el ends here

bug#4234: allow xterm to detect the background color

[Andreas Schwab]

Dan Nicolaescu <dann@ics.uci.edu> writes:

> @@ -494,8 +493,23 @@
>  	    ;; NUMBER2 is the xterm version number, look for something
>  	    ;; greater than 216, the version when modifyOtherKeys was
>  	    ;; introduced.

You should move the comment down to where this version number is actually
tested.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

bug#4234: marked as done (allow xterm to detect the background color)

[Emacs bug Tracking System]

[-- Attachment #1: Type: text/plain, Size: 869 bytes --]

Your message dated Sun, 20 Dec 2009 08:00:07 -0800 (PST)
with message-id <200912201600.nBKG073w021776@godzilla.ics.uci.edu>
and subject line Re: bug#4234: allow xterm to detect the background color
has caused the Emacs bug report #4234,
regarding allow xterm to detect the background color
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact bug-gnu-emacs@gnu.org
immediately.)


-- 
4234: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=4234
Emacs Bug Tracking System
Contact bug-gnu-emacs@gnu.org with problems

[-- Attachment #2: Type: message/rfc822, Size: 5837 bytes --]

From: Dan Nicolaescu <dann@ics.uci.edu>
To: bug-gnu-emacs <bug-gnu-emacs@gnu.org>
Subject: allow xterm to detect the background color
Date: Sat, 22 Aug 2009 10:15:12 -0700 (PDT)
Message-ID: <200908221715.n7MHFCVA002498@godzilla.ics.uci.edu>


emacs/emacsclient -nw  running in an xterm set the frame background mode
to 'light.   
Not all users use the default white background, so they get the wrong
face colors. 
Newer xterms can tell what the background color is
(see http://permalink.gmane.org/gmane.emacs.devel/111270)

This patch implements reads the background color from xterm (iff it
supports the feature) and sets the background mode accordingly.

--- xterm.el.~1.62.~	2009-01-08 14:24:21.000000000 -0800
+++ xterm.el	2009-08-22 10:12:38.000000000 -0700
@@ -462,8 +462,6 @@
       (set-keymap-parent input-decode-map map)))
 
     (xterm-register-default-colors)
-    ;; This recomputes all the default faces given the colors we've just set up.
-    (tty-set-up-initial-frame-faces)
     
     ;; Try to turn on the modifyOtherKeys feature on modern xterms.
     ;; When it is turned on many more key bindings work: things like
@@ -472,7 +470,8 @@
     ;; modifyOtherKeys. At this time only xterm does.
     (let ((coding-system-for-read 'binary)
 	  (chr nil)
-	  (str nil))
+	  (str nil)
+	  version)
       ;; Pending input can be mistakenly returned by the calls to
       ;; read-event below.  Discard it.
       (discard-input)
@@ -494,8 +493,23 @@
 	    ;; NUMBER2 is the xterm version number, look for something
 	    ;; greater than 216, the version when modifyOtherKeys was
 	    ;; introduced.
-	    (when (>= (string-to-number
-		       (substring str (match-beginning 1) (match-end 1))) 216)
+	    (setq version (string-to-number
+			   (substring str (match-beginning 1) (match-end 1))))
+	    ;; xterm version 242 supports reporting the background
+	    ;; color, maybe earlier versions do too...
+	    (when (>= version 242)
+	      (send-string-to-terminal "\e]11;?\e\\")
+	      (when (equal (read-event nil nil 2) ?\e)
+		(when (equal (read-event nil nil 2) ?\])
+		  (setq str "")
+		  (while (not (equal (setq chr (read-event nil nil 2)) ?\\))
+		    (setq str (concat str (string chr))))
+		  (when (string-match "11;rgb:\\([a-f0-9]+\\)/\\([a-f0-9]+\\)/\\([a-f0-9]+\\)" str)
+		    (xterm-set-background-mode
+		     (string-to-number (match-string 1 str) 16)
+		     (string-to-number (match-string 2 str) 16)
+		     (string-to-number (match-string 3 str) 16))))))
+	    (when (>= version 216)
 	      ;; Make sure that the modifyOtherKeys state is restored when
 	      ;; suspending, resuming and exiting.
 	      (add-hook 'suspend-hook 'xterm-turn-off-modify-other-keys)
@@ -508,6 +522,9 @@
 		    xterm-modify-other-keys-terminal-list)
 	      (xterm-turn-on-modify-other-keys))))))
 
+    ;; This recomputes all the default faces given the colors we've just set up.
+    (tty-set-up-initial-frame-faces)
+
     (run-hooks 'terminal-init-xterm-hook))
 
 ;; Set up colors, for those versions of xterm that support it.
@@ -649,5 +666,11 @@ versions of xterm."
 	  (delq terminal xterm-modify-other-keys-terminal-list))
     (send-string-to-terminal "\e[>4m" terminal)))
 
+(defun xterm-set-background-mode (redc greenc bluec)
+  ;; Use the heuristic in `frame-set-background-mode' to decide if a
+  ;; frame is dark.
+  (when (< (+ redc greenc bluec) (* .6 (+ 65535 65535 65535)))
+    (set-terminal-parameter nil 'background-mode 'dark)))
+
 ;; arch-tag: 12e7ebdd-1e6c-4b25-b0f9-35ace25e855a
 ;;; xterm.el ends here



[-- Attachment #3: Type: message/rfc822, Size: 2660 bytes --]

From: Dan Nicolaescu <dann@ics.uci.edu>
To: 4234-done@emacsbugs.donarmstrong.com
Subject: Re: bug#4234: allow xterm to detect the background color
Date: Sun, 20 Dec 2009 08:00:07 -0800 (PST)
Message-ID: <200912201600.nBKG073w021776@godzilla.ics.uci.edu>

Patch is in.