Sublime NEO layout fix

This is a gtk plugin that fixes a problem with the fourth layer of the NEO 2 keyboard layout with sublime. Sublime ignores the layer 4 mapped keys like Left, Right, Backspace, Enter, ... that can be accessed via MOD4 + S,F,W,V, ...

Usage

Start sublime by prior setting the GTK_MODULES environment variable, so that this module is loaded.

GTK_MODULES=gtkneofix-gtk-module:$GTK_MODULES sublime_text

If you follow the optional installation steps from below, this automatically happens every time sublime_text is started, without the need to set GTK_MODULES first.

Debugging: If something does not work as expected, start sublime with -w. See output and ask.

Installation

Needed tools, libraries and compilers (If I forgot something, please issue a ticket):

    sudo apt-get install autoconf build-essential libgtk2.0-dev git libtool automake

Then execute these commands

    git clone https://github.com/Phaiax/gtkneofix.git
    cd gtkneofix
    autoreconf -i
    ./configure
    make
    sudo make install
    # revert
    sudo make uninstall

Optionally

    # cd gtkneofix
    #   If you already have your own bin/ in $PATH, copy or link ./bin/sublime_text into that.
    #       (your own bin/ must come before /usr/bin in $PATH)
    #   Otherwise:
    mkdir ~/bin
    echo "\n# https://github.com/Phaiax/gtkneofix\nPATH=\$HOME/bin:\$PATH" >> ~/.bashrc
    source ~/.bashrc # applies new path on this shell only. Logout and login to apply everywhere.
    cp ./bin/sublime_text ~/bin
    cp ./bin/sublime_text ~/bin/subl
    # or: sudo cp ./bin/sublime_text /usr/bin/subl

    # Update desktop / menu icon (redo after every sublime update)
    sudo cp /usr/share/applications/sublime_text.desktop /usr/share/applications/sublime_text.desktop.backup.`date +%s`
    sudo sed -i "s/Exec=\\//Exec=env GTK_MODULES=gtkneofix-gtk-module:\\\$GTK_MODULES \\//g" /usr/share/applications/sublime_text.desktop

make install only creates these files (the final directory may differ between distributions)

└── usr
    └── lib
        └── x86_64-linux-gnu
            └── gtk-2.0
                └── modules
                    ├── libgtkneofix-gtk-module.a
                    ├── libgtkneofix-gtk-module.la
                    └── libgtkneofix-gtk-module.so

Note: Even if the configure script allows to set --with-gtk=3, it may not work for GTK3 apps. (Sublime uses GTK2)

Dev Notes

It took some effort for me to find this method of fixing the problem, since I knew nothing about how keys were handled and nothing about GTK :D

The Problem

Sublime interprets the hardware_keycode and not the keyval as it should.

The Solution

Hook a key event handler and change the hardware_keycode of the incomming event to the hardware_keycode of the 'real' key if the corresponding layer 4 key was pressed.

Dear sublime

please just test for the event->keyval and not event->hardware_keycode.

Testing

gtktestapp can be used to test the keys: ./gtktestapp --gtk-module $PWD/.libs/libgtkneofix-gtk-module.so

Sublime can also be started with the --gtk-module argument, but this opens the .so file in the editor. sublime_text --gtk-module $PWD/.libs/libgtkneofix-gtk-module.so -w

Interesting pieces of code

gtk_main_do_events
    gtk_propagate_event ??

gdkevents.c
    gdk_event_handler_set // GTK does: gdk_event_handler_set(gtk_main_do_events)
                          // @ gtkmain.c:680 do_pre_parse_initialization():
                          // ...   gdk_event_handler_set ((GdkEventFunc)gtk_main_do_event, NULL, NULL);
                          // danach ist _gdk_event_func = gtk_main_do_event

gdkeventloop-quarz.c:672 gdk_event_dispatch calls _gdk_event_func
                                            with the event from _gdk_event_unqueue()
gdkevents-x11.c:2328 _gdk_events_queue() get events from X11 and append them to queue
               :1015,1141,661 translation from x events to gdk events,
                              calls gdk_keymap_translate_keyboard_state()

gtkdialog.c
    gtk_dialog_close // possibility to create own events and propagate them through the usual event handling

gtkwidget.c:4890
    gtk_widget_event_internal(): emits event auf widget
        emittet erst signal EVENT, dann das dem event entsprechende signal, dann das signal EVENT_AFTER
        das entsprechende signal wird nach event->type ausgesucht, zb event->type==GDK_KEY_PRESS
    gtk_widget_event(): calls gtk_widget_event_internal()
gtkwindow.c:5179
    gtk_window_propagate_key_event(): Propagate a key press or release event to the focus widget and
                                      up the focus container chain until a widget handles @event.
    gtk_window_key_press_event(): calls * gtk_window_activate_key
                                        * gtk_window_propagate_key_event
                                        * key_press_event
    fktptr window->key_press_event = gtk_window_key_press_event
gtkwidget.c:1381 // signal_new key-pressed
    signal key-press-event calls widget->key_press_event