Undo margins when checking whether window is splittable

1 files changed, 13 insertions, 2 deletions

diff --git a/.emacs b/.emacs
index c07980a..c6e5595 100644
--- a/.emacs
+++ b/.emacs
@@ -128,7 +128,7 @@
 (defvar-local my/centered-width 'fill-column)
 (defvar-local my/centered-set-right-margin nil)
 
-(defun my/centered--undo-margins (&optional _size window-to-split)
+(defun my/centered--before-split (&optional _size window-to-split)
   (let ((windows (if (frame-root-window-p window-to-split)
                      (window-list)
                    (list window-to-split))))
@@ -136,7 +136,18 @@
       (when (buffer-local-value 'my/centered-mode (window-buffer w))
         (set-window-margins w nil nil)))))
 
-(advice-add 'split-window-right :before 'my/centered--undo-margins)
+(defun my/centered--around-splittable (splittable window &optional horizontal)
+  (if (and horizontal
+           (buffer-local-value 'my/centered-mode (window-buffer window)))
+    (let ((margins (window-margins window)))
+      (set-window-margins window nil nil)
+      (prog1
+          (funcall splittable window horizontal)
+        (apply 'set-window-margins window margins)))
+    (funcall splittable window horizontal)))
+
+(advice-add 'split-window-right :before 'my/centered--before-split)
+(advice-add 'window-splittable-p :around 'my/centered--around-splittable)
 
 (define-minor-mode my/centered-mode
   "Update margins to keep content centered."