Change the focus of windows within vim and i3 with the same keystroke

asked 2013-12-12 23:05:01 +0000

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I wrote some bits of glue to change the focus between windows in i3 and vim using the same keystroke (SuperL+ArrowKeys or hjkl). It consists of a C bit (It used to be written in python, but the new version of libxdo broke it in my setup), a plug-in for vim, and configurations for the vim and i3 mappings.

To use it you would need libxdo (part of xdotools).

The C bit (i put in ~/bin/i3_vim_focus):

/* File: i3_vim_focus.c
 *
 * Compile with:
 * gcc -lX11 -lxdo -o i3_vim_focus i3_vim_focus.c $(pkg-config --libs --cflags i3ipc-glib-1.0)
 *
 */

#include <stdio.h>

#include <strings.h>
#include <string.h>

#include <xdo.h>

#include <glib/gprintf.h>
#include <i3ipc-glib/i3ipc-glib.h>

int main(int argc, char *argv[]) {

    char cmd[20];

    unsigned char *name;
    int name_len;
    int name_type;
    Window window_ret;

    i3ipcConnection *conn;
    gchar *reply;

    if(argc < 2){
        printf("Missing argument\n");
        return 1;
    }

    xdo_t *xdo = xdo_new(NULL);
    xdo_get_active_window(xdo, &window_ret);
    xdo_get_window_name(xdo, window_ret, &name, &name_len, &name_type);

    if(strstr(name, "VIM")) 
    {
        strcpy(cmd, "Escape+g+w+");


        strcat(cmd, (argv[1][0] == 'l')? "h" :
                    (argv[1][0] == 'd')? "j" :
                    (argv[1][0] == 'u')? "k" :
                                         "l" );

        xdo_send_keysequence_window(xdo, window_ret, cmd, 0);
    }
    else
    {
        conn = i3ipc_connection_new(NULL, NULL);
        strcpy(cmd, "focus ");
        strcat(cmd, argv[1]);
        reply = i3ipc_connection_message(conn, I3IPC_MESSAGE_TYPE_COMMAND, cmd, NULL);
        g_free(reply);
        g_object_unref(conn);
    }

    XFree(name);
    return  0;
}

The vim-plugin (I put in ~/.vim/plugin/focus.vim):

func! Focus(comando,vim_comando)
  let oldw = winnr()
  silent exe 'wincmd ' . a:vim_comando
  let neww = winnr()
  if oldw == neww
    silent exe '!i3-msg -q focus ' . a:comando
    if !has("gui_running")
        redraw!
    endif
  endif
endfunction

The i3 configuration (~/.i3/config, I use Mod4 as $mod):

# change focus
bindsym $mod+h exec "i3_vim_focus left"
bindsym $mod+j exec "i3_vim_focus down"
bindsym $mod+k exec "i3_vim_focus up"
bindsym $mod+l exec "i3_vim_focus right"

# alternatively, you can use the cursor keys:
bindsym $mod+Left  exec "i3_vim_focus left"
bindsym $mod+Down  exec "i3_vim_focus down"
bindsym $mod+Up    exec "i3_vim_focus up"
bindsym $mod+Right exec "i3_vim_focus right"

The vim bindings (~/.vimrc):

" Focus!
map gwl :call Focus('right','l')<CR>
map gwh :call Focus('left','h')<CR>
map gwk :call Focus('up','k')<CR>
map gwj :call Focus('down','j')<CR>