I think I figured that setxkbmap nightmare out

README.md

@@ -17,6 +17,5 @@ work.
 - [ ] load xmodmap files from the config path
 - [x] show a list that can be extended with a `[+]` button
 - [ ] The list shows `[keycode, current key for that keycode -> target]`
-- [ ] generate a xmodmap.*.whatever file out of that (like for example https://github.com/sezanzeb/colemakDE/blob/master/xmodmap.colemak.de)
-- [ ] load that file (`setxkbmap funnystuff; xmodmap xmodmap.asdf.whatever`, `setxkbmap funnystuff -device <id>`).
-- [ ] Does it need to be loaded on every startup or every time the device connects? If so, add udev rules
+- [ ] generate a file for /usr/share/X11/xkb/symbols/ for each preset, (symlink to home .config/?)
+- [ ] load that file with `setxkbmap preset1234 -device 13` (on startup?, udev on mouse connect?)

bin/key-mapper-gtk

@@ -32,7 +32,8 @@ gi.require_version('GLib', '2.0')
 from gi.repository import Gtk
 
 from keymapper.data import get_data_path
-from keymapper.presets import find_devices, get_presets, get_mappings, \
+from keymapper.X import find_devices
+from keymapper.presets import get_presets, get_mappings, \
     find_newest_preset, create_preset
 from keymapper.logger import logger, update_verbosity, log_info
 
@@ -129,7 +130,7 @@ class Window:
     def on_select_device(self, device):
         """List all presets, create one if none exist yet."""
         if isinstance(device, Gtk.ComboBoxText):
-            preset = device.get_active_text()
+            device = device.get_active_text()
 
         device = device.get_active_text()
         presets = get_presets(device)

keymapper/X.py

@@ -0,0 +1,71 @@
+#!/usr/bin/python3
+# -*- coding: utf-8 -*-
+# key-mapper - GUI for device specific keyboard mappings
+# Copyright (C) 2020 sezanzeb <proxima@hip70890b.de>
+#
+# This file is part of key-mapper.
+#
+# key-mapper is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# key-mapper is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with key-mapper.  If not, see <https://www.gnu.org/licenses/>.
+
+
+"""Stuff that interacts with the X Server"""
+
+
+import re
+import subprocess
+
+
+# mapping of keycode to character, e.g. 38 to the 'A' key of the keyboard.
+# This depends on the configured keyboard layout.
+# example: 38: "a A a A ae AE ae"
+key_mapping = {}
+
+
+def load_keymapping():
+    """Load the current active mapping of keycodes"""
+    # to get ASCII codes: xmodmap -pk
+    output = subprocess.check_output(['xmodmap', '-p']).decode()
+    for line in output.split('\n'):
+        search = re.search(r'(\d+) = (.+)', line)
+        if search is not None:
+            key_mapping[search[0]] = search[1]
+
+
+def get_xinput_list(type):
+    """Run xinput and get the result as list.
+
+    Parameters
+    ----------
+    type : string
+        Ine of 'id' or 'name'
+    """
+    output = subprocess.check_output(['xinput', 'list', f'--{type}-only'])
+    return [line for line in output.decode().split('\n') if line != '']
+
+
+def find_devices():
+    """Get a list of (id, name) for each input device."""
+    # `xinput list`
+    ids = get_xinput_list('id')
+    names = get_xinput_list('name')
+
+    # names contains duplicates and "Virtual"-somethings, filter those
+    known_names = []
+    # TODO remember all IDS? try each one of them for setxkbmap until success?
+    result = []
+    for (id, name) in zip(ids, names):
+        if name not in known_names and not name.startswith('Virtual'):
+            known_names.append(name)
+            result.append((id, name))
+    return result

keymapper/presets.py

@@ -41,22 +41,6 @@ def get_xinput_list(type):
     return [line for line in output.decode().split('\n') if line != '']
 
 
-def find_devices():
-    """Get a list of (id, name) for each input device."""
-    # `xinput list`
-    ids = get_xinput_list('id')
-    names = get_xinput_list('name')
-
-    # names contains duplicates and "Virtual"-somethings, filter those
-    known_names = []
-    result = []
-    for (id, name) in zip(ids, names):
-        if name not in known_names and not name.startswith('Virtual'):
-            known_names.append(name)
-            result.append((id, name))
-    return result
-
-
 def get_presets(device):
     """Get all configured presets for the device, sorted by modification date.