From e50fe12e566ea624061245012f903388818209c5 Mon Sep 17 00:00:00 2001
From: Pierre Neidhardt <mail@ambrevar.xyz>
Date: Wed, 27 May 2020 12:15:27 +0200
Subject: [PATCH] EXWM: Add toggle for automatic screen change configuration.

---
 .emacs.d/lisp/init-exwm.el | 82 +++++++++++++++++++++++++-------------
 1 file changed, 55 insertions(+), 27 deletions(-)

diff --git a/.emacs.d/lisp/init-exwm.el b/.emacs.d/lisp/init-exwm.el
index 081f327a..e457ba84 100644
--- a/.emacs.d/lisp/init-exwm.el
+++ b/.emacs.d/lisp/init-exwm.el
@@ -212,39 +212,67 @@
 ;; https://github.com/ch11ng/exwm/issues/287
 (add-to-list 'exwm-manage-configurations '((string= exwm-title "Kingdom Come: Deliverance") managed t))
 
+;; Gens
+(add-to-list 'exwm-manage-configurations '((string= exwm-class-name "Gens") floating nil))
+
+(defvar ambrevar/exwm-change-screen-turn-off-primary nil
+  "Turn off primary display when cable is plugged.")
 ;; Function to automatically toggle between internal/external screens.
 (defun ambrevar/exwm-change-screen-hook ()
-  (let ((xrandr-output-regexp "\n\\([^ ]+\\) connected ")
-        (xrandr-monitor-regexp "\n .* \\([^ \n]+\\)")
-        default-output)
-    (with-temp-buffer
-      (call-process "xrandr" nil t nil)
-      (goto-char (point-min))
-      (re-search-forward xrandr-output-regexp nil 'noerror)
-      (setq default-output (match-string 1))
-      (forward-line)
-      (if (not (re-search-forward xrandr-output-regexp nil 'noerror))
-          (progn
-            (call-process "xrandr" nil nil nil "--output" default-output "--auto" "--primary")
-            (with-temp-buffer
-              ;; Turn off all monitors that are not DEFAULT-OUTPUT.
-              ;; See "--auto" in xrandr(1) and https://github.com/ch11ng/exwm/issues/529.
-              (call-process "xrandr" nil t nil "--listactivemonitors")
-              (goto-char (point-min))
-              (while (not (eobp))
-                (when (and (re-search-forward xrandr-monitor-regexp nil 'noerror)
-                           (not (string= (match-string 1) default-output)))
-                  (call-process "xrandr" nil nil nil "--output" (match-string 1) "--auto")))))
-        (call-process
-         "xrandr" nil nil nil
-         "--output" (match-string 1) "--primary" "--auto"
-         "--output" default-output "--off")
-        (setq exwm-randr-workspace-monitor-plist (list 0 (match-string 1)))))))
+  (let* ((xrandr-output-regexp "\n\\([^ ]+\\) connected ")
+         (xrandr-monitor-regexp "\n .* \\([^ \n]+\\)")
+         (find-first-output (lambda ()
+                              (call-process "xrandr" nil t nil)
+                              (goto-char (point-min))
+                              (re-search-forward xrandr-output-regexp nil 'noerror)
+                              (match-string 1)))
+         (default-output (with-temp-buffer
+                           (funcall find-first-output)))
+         (second-output (with-temp-buffer
+                          (funcall find-first-output)
+                          (forward-line)
+                          (when (re-search-forward xrandr-output-regexp nil 'noerror)
+                            (match-string 1)))))
+    (if (not second-output)
+        (progn
+          (call-process "xrandr" nil nil nil "--output" default-output "--auto" "--primary")
+          (with-temp-buffer
+            ;; Turn off all monitors that are not DEFAULT-OUTPUT.
+            ;; See "--auto" in xrandr(1) and https://github.com/ch11ng/exwm/issues/529.
+            (call-process "xrandr" nil t nil "--listactivemonitors")
+            (goto-char (point-min))
+            (while (not (eobp))
+              (when (and (re-search-forward xrandr-monitor-regexp nil 'noerror)
+                         (not (string= (match-string 1) default-output)))
+                (call-process "xrandr" nil nil nil "--output" (match-string 1) "--auto")))))
+      (apply #'call-process
+             "xrandr" nil nil nil
+             "--output" second-output
+             "--auto"
+             (append
+              (if ambrevar/exwm-change-screen-turn-off-primary '("--primary") '())
+              (when ambrevar/exwm-change-screen-turn-off-primary
+                (list "--output" default-output "--off"))))
+      (setq exwm-randr-workspace-monitor-plist (list 0 second-output)))))
 
 (require 'exwm-randr)
-(add-hook 'exwm-randr-screen-change-hook 'ambrevar/exwm-change-screen-hook)
 (exwm-randr-enable)
 
+(defun ambrevar/exwm-change-screen-toggle (&optional setting)
+  "Toggle automatic multiscreen configuration.
+Turn off if you want to set the display settings manually.
+WIth SETTING to :ENABLE or :DISABLE, set"
+  (interactive)
+  (if (member 'ambrevar/exwm-change-screen-hook exwm-randr-screen-change-hook)
+      (progn
+        (remove-hook 'exwm-randr-screen-change-hook 'ambrevar/exwm-change-screen-hook)
+        (message "Manual multiscreen handling."))
+    (add-hook 'exwm-randr-screen-change-hook 'ambrevar/exwm-change-screen-hook)
+    (message "Automatic multiscreen handling.")))
+(add-hook 'exwm-randr-screen-change-hook 'ambrevar/exwm-change-screen-hook)
+;; TODO: Turn the toggle into a global minor mode.
+;; Even better: Use autorandr_launcher (https://github.com/phillipberndt/autorandr/issues/210).
+
 (setq exwm-edit-bind-default-keys nil)
 (when (require 'exwm-edit nil 'noerror)
   (require 'patch-exwm-edit))