terminal-focus-reporting.el
Minor mode for terminal focus reporting.
This plugin restores focus-in-hook, focus-out-hook functionality.
Now Emacs can, for example, save when the terminal loses a focus, even if it's inside the tmux.
You don't need this plugin for latest Emacs. Since Emacs 27 it now requests and recognizes focus-change notifications from TTYs. You would rather need to hook the after focus change:
(add-function :after after-focus-change-function (lambda () (save-some-buffers t)))Usage
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Install it from Melpa
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Add code to the Emacs config file:
(unless (display-graphic-p)
(terminal-focus-reporting-mode))How it works
Emacs and terminal communicate by sending and receiving special string sequences.
For example, if the program (emacs) sends to the terminal the text <Esc>[?1004h,
terminal enables "focus reporting" feature and sends special sequences to the program
when focus lost or restored.
This can be tested directly in the terminal executing this command:
$ echo -e "\e[?1004h" && read
and if we let terminal lose a focus and then restore it, we will see these commands sent back by the terminal:
^[[O^[[I
This plugin is able to enable and disable terminal focus reporting and can read special
commands from the terminal and execute needed hooks (focus-in, focus-out) when the terminal
fires focus lost or focus restored events respectively.