Add auto hide tabs feature to tabs layer

Ideally it would be great to implement tabs switch with C-tab (or C-}) that
shows the tabs as long as C is pressed. However Emacs does not support key
release events so this function uses a timer as a workaround.

To me Emacs looks better when tabs are hidden, and also packages like
pdf-continuous-scroll-mode break when tabs are shown.

Author: dalanicolai

CHANGELOG.develop

@@ -329,6 +329,8 @@ sane way, here is the complete list of changed key bindings
   - Move major specific error key bindings to ~SPC m E~ prefix
     (thanks to Sylvain Benner)
   - Changed ~SPC e e~ to ~SPC e b~ for =flycheck-buffer=
+***** Tabs
+- Add auto hide tabs feature (thanks to Daniel Nicolai)
 ***** Vagrant
 - Key bindings:
   - Vagrant key bindings prefix is now ~SPC a V~.
@@ -390,6 +392,7 @@ sane way, here is the complete list of changed key bindings
 - prolog (thanks to Newres Al Haider)
 - reasonml (thanks to fredyr and Dave Aitken)
 - solidity (thanks to Brooklyn Zelenka and Seong Yong-ju)
+- tabs (thanks to Deepu Puthrote)
 - protobuf (thanks to Amol Mandhane)
 - restructuredtext (thanks to Wei-Wei Guo and Kalle Lindqvist)
 - semantic-web (thanks to Andreas Textor)

layers/+emacs/tabs/README.org

@@ -14,6 +14,7 @@ This layer adds support for tabs. Implementation is done using [[https://github.
 
 ** Features:
 - Sets up tabs using Centaur tabs as backend
+- Optionally auto hide tabs after delay
 
 * Install
 To use this configuration layer, add it to your =~/.spacemacs=. You will need to
@@ -24,6 +25,15 @@ file.
 You can set hooks for buffers in which it isn't desired to have tabs by
 customizing =centaur-tabs-hide-tabs-hooks=
 
+Alternatively you can set ~spacemacs-tabs-auto-hide~ to ~t~ to auto hide tabs after some
+delay ~spacemacs-tabs-auto-hide-delay~ via the :variables keyword in your dotfile:
+#+begin_src emacs-lisp
+     (tabs :variables
+           spacemacs-tabs-auto-hide t
+           spacemacs-tabs-auto-hide-delay 3)
+#+end_src
+
+
 * Key bindings
 
 | Key binding | Description                                           |

layers/+emacs/tabs/funcs.el

@@ -0,0 +1,60 @@
+(defcustom spacemacs-tabs-auto-hide nil
+  "If non-nil hide tabs automatically after TABS-AUTO-HIDE-DELAY seconds."
+  :type '(boolean)
+  :group 'centaur-tabs)
+
+(defcustom spacemacs-tabs-auto-hide-delay 2
+  "Tabs auto hide delay in seconds."
+  :type '(float)
+  :group 'centaur-tabs)
+
+(defun spacemacs//tabs-timer-initialize (secs)
+  (setq spacemacs-tabs-timer (run-with-timer secs nil (lambda () (centaur-tabs-local-mode 1)))))
+
+(defun spacemacs//tabs-timer-hide ()
+  (spacemacs//tabs-timer-initialize spacemacs-tabs-auto-hide-delay))
+
+(when spacemacs-tabs-auto-hide
+  (add-hook 'window-setup-hook 'spacemacs//tabs-timer-hide)
+  (add-hook 'find-file-hook 'spacemacs//tabs-timer-hide)
+  (add-hook 'change-major-mode-hook 'spacemacs//tabs-timer-hide))
+
+(defun spacemacs//tabs-switch-and-hide (arg)
+  (cancel-timer spacemacs-tabs-timer)
+  (centaur-tabs-local-mode 1)
+  ;; (if arg
+  ;;     (centaur-tabs-backward)
+  ;;   (centaur-tabs-forward))
+  (pcase arg
+    ('backward (centaur-tabs-backward))
+    ('forward (centaur-tabs-forward))
+    ('backward-group (centaur-tabs-backward-group))
+    ('forward-group (centaur-tabs-forward-group)))
+  (centaur-tabs-local-mode 0)
+  (spacemacs//tabs-timer-hide))
+
+(defun spacemacs//centaur-tabs-forward-and-hide ()
+  (spacemacs//tabs-switch-and-hide 'forward))
+
+(defun spacemacs//centaur-tabs-backward-and-hide ()
+  (spacemacs//tabs-switch-and-hide 'backward))
+
+(defun spacemacs/tabs-forward ()
+  (interactive)
+  (if spacemacs-tabs-auto-hide
+      (spacemacs//centaur-tabs-forward-and-hide)
+    (centaur-tabs-forward)))
+
+(defun spacemacs/tabs-backward ()
+  (interactive)
+  (if spacemacs-tabs-auto-hide
+      (spacemacs//centaur-tabs-backward-and-hide)
+    (centaur-tabs-backward)))
+
+(defun spacemacs/tabs-forward-group-and-hide ()
+  (interactive)
+  (spacemacs//tabs-switch-and-hide 'forward-group))
+
+(defun spacemacs/tabs-backward-group-and-hide ()
+  (interactive)
+  (spacemacs//tabs-switch-and-hide 'backward-group))

layers/+emacs/tabs/packages.el

@@ -32,8 +32,8 @@
       (centaur-tabs-group-buffer-groups))
     (centaur-tabs-mode t)
     :bind
-    ("C-{" . centaur-tabs-backward)
-    ("C-}" . centaur-tabs-forward)
+    ("C-{" . spacemacs/tabs-backward)
+    ("C-}" . spacemacs/tabs-forward)
     ("C-M-{" . centaur-tabs-move-current-tab-to-left)
     ("C-M-}" . centaur-tabs-move-current-tab-to-right)
     ("C-c t s" . centaur-tabs-counsel-switch-group)