Get the background mode from the terminal for xterm, and set

faces accordingly.
* term/xterm.el (xterm-set-background-mode): New function.
(terminal-init-xterm): Use it in case xterm supports background
color queries.  Recompute faces after getting the background
color.

diff --git a/etc/NEWS b/etc/NEWS
index c41a437ea2f0607d2dd96dc2d5ce45362d9e43a3..f351fe9e16ef849162f6b96420295e363e8aae6a 100644 (file)
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -339,6 +339,11 @@ That means, they change `default-directory' to the new users value,
 and let commands run under that user permissions.  It works even when
 `default-directory' is already remote.
 
+*** When running in a new enough xterm (newer than version 242), emacs
+asks xterm what the background color is and it sets up faces
+accordingly for a dark background if needed (the current default is to
+consider the background light).
+
 \f
 * New Modes and Packages in Emacs 23.2
 

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 2d2d938639a70136d3785ff88037115add637130..1630f37ba4d363022301e468fcf19a774df84cf6 100644 (file)
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,12 @@
+2009-12-07  Dan Nicolaescu  <dann@ics.uci.edu>
+
+       Get the background mode from the terminal for xterm, and set
+       faces accordingly.
+       * term/xterm.el (xterm-set-background-mode): New function.
+       (terminal-init-xterm): Use it in case xterm supports background
+       color queries.  Recompute faces after getting the background
+       color.
+
 2009-12-07  Ulrich Mueller  <ulm@gentoo.org>
 
        * emacs-lisp/bytecomp.el (byte-compile-insert-header): Put the version

diff --git a/lisp/term/xterm.el b/lisp/term/xterm.el
index 0fcccc3508d061ab54f339d68d1aa66e0445d9c1..bef43776daefa18402dce9eefc76419323697b60 100644 (file)
--- a/lisp/term/xterm.el
+++ b/lisp/term/xterm.el
@@ -462,9 +462,7 @@
       (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
     ;; C-. C-, etc.
@@ -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)
@@ -491,11 +490,26 @@
          (while (not (equal (setq chr (read-event nil nil 2)) ?c))
            (setq str (concat str (string chr))))
          (when (string-match ">0;\\([0-9]+\\);0" str)
+           (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))))))
            ;; 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)
+           (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