Added preference setting to solve persistence as optional toggle.

docs/tutorial.md

@@ -220,6 +220,11 @@ You can choose the images following case.
 If this option is enabled, Screencast Keys will be enabled automatically when
 blender will startup up.
 
+### Persist Preferences
+If this option is enabled, Screencast Keys will store its preferences
+in a local file and will restore them when reloaded.
+The preferences are stored in blender's user configuration directory: `config/screencast_keys/preferences.json`
+
 ### UI
 
 #### Sidebar

src/screencast_keys/__init__.py

@@ -153,28 +153,17 @@ def register():
     context = bpy.context
     user_prefs = context.preferences
     prefs = user_prefs.addons[__package__].preferences
+    preferences.load_persisted_preferences(prefs)
     # Only default panel location is available in < 2.80
     if utils.compatibility.check_version(2, 80, 0) < 0:
         prefs.panel_space_type = 'VIEW_3D'
         prefs.panel_category = "Screencast Key"
         prefs.show_ui_in_sidebar = True
         prefs.show_ui_in_overlay = False
+    preferences.ensure_display_event_text_aliases(prefs)
     preferences.SK_Preferences.ui_in_sidebar_update_fn(prefs, context)
     preferences.SK_Preferences.ui_in_overlay_update_fn(prefs, context)
 
-    # Fix: https://github.com/nutti/Screencast-Keys/issues/195
-    # TODO: This workaround is hacky. We need to apply a better solution.
-    if len(prefs.display_event_text_aliases_props) == 0:
-        for event in list(ops.EventType):
-            item = prefs.display_event_text_aliases_props.add()
-            item.event_id = event.name
-            if event in ops.SK_OT_ScreencastKeys.MODIFIER_EVENT_TYPES:
-                item.default_text = common.fix_modifier_display_text(
-                    ops.EventType.names[event.name]
-                )
-            else:
-                item.default_text = ops.EventType.names[event.name]
-
     try:
         common.reload_custom_mouse_image(prefs, context)
     # pylint: disable=W0702
@@ -187,7 +176,11 @@ def unregister():
     user_prefs = context.preferences
     prefs = user_prefs.addons[__package__].preferences
     preferences.remove_custom_mouse_image(prefs, context)
-    prefs.display_event_text_aliases_props.clear()
+    if prefs.persist_preferences:
+        preferences.save_persisted_preferences(prefs)
+    else:
+        preferences.remove_persisted_preferences_file()
+        prefs.display_event_text_aliases_props.clear()
 
     bpy.app.handlers.load_post.remove(load_post_handler)
     unregister_shortcut_key()

src/screencast_keys/blender_manifest.toml

@@ -13,3 +13,6 @@ blender_version_min = "4.2.0"
 license = [
   "SPDX:GPL-3.0-or-later",
 ]
+
+[permissions]
+files = "Save settings to a file and restore/delete them according to preferences"

src/screencast_keys/preferences.py

@@ -19,6 +19,9 @@
 # <pep8 compliant>
 
 
+import json
+import os
+
 import bpy
 from bpy.props import (
     StringProperty,
@@ -32,6 +35,22 @@
 from .utils.bl_class_registry import BlClassRegistry
 from . import common
 from . import c_structure as cstruct    # extensions.blender.org: Delete line
+from . import ops 
+
+
+PERSISTED_PREFERENCE_EXCLUDES = {
+    "bl_idname",
+    "updater_branch_to_update",
+}
+
+PERSISTED_PREFERENCE_TYPES = {
+    'BOOLEAN',
+    'COLLECTION',
+    'ENUM',
+    'FLOAT',
+    'INT',
+    'STRING',
+}
 
 
 # extensions.blender.org: Delete block start
@@ -132,6 +151,151 @@ class DisplayEventTextAliasProperties(bpy.types.PropertyGroup):
     event_id: bpy.props.StringProperty(options={'HIDDEN'})
 
 
+def persisted_preferences_filepath(create=False):
+    config_dir = bpy.utils.user_resource(
+        'CONFIG', path="screencast_keys", create=create)
+    if not config_dir:
+        return ""
+
+    return os.path.join(config_dir, "preferences.json")
+
+
+def _rna_properties(data):
+    for prop in data.bl_rna.properties:
+        if prop.identifier == "rna_type":
+            continue
+        if prop.identifier in PERSISTED_PREFERENCE_EXCLUDES:
+            continue
+        if prop.type not in PERSISTED_PREFERENCE_TYPES:
+            continue
+        if prop.is_readonly and prop.type != 'COLLECTION':
+            continue
+        yield prop
+
+
+def _serialize_property(data, prop):
+    value = getattr(data, prop.identifier)
+    if prop.type == 'COLLECTION':
+        return [_serialize_preferences(item) for item in value]
+    if getattr(prop, "array_length", 0) > 0:
+        return list(value)
+
+    return value
+
+
+def _serialize_preferences(data):
+    preferences = {}
+    for prop in _rna_properties(data):
+        try:
+            preferences[prop.identifier] = _serialize_property(data, prop)
+        except TypeError:
+            continue
+
+    return preferences
+
+
+def _apply_preferences(data, preferences):
+    properties = {
+        prop.identifier: prop
+        for prop in _rna_properties(data)
+    }
+    for identifier, value in preferences.items():
+        if identifier not in properties:
+            continue
+
+        prop = properties[identifier]
+        if prop.type == 'COLLECTION':
+            if not isinstance(value, list):
+                continue
+            collection = getattr(data, identifier)
+            collection.clear()
+            for item_data in value:
+                if not isinstance(item_data, dict):
+                    continue
+                item = collection.add()
+                _apply_preferences(item, item_data)
+        else:
+            try:
+                data[identifier] = value
+            except (AttributeError, KeyError, TypeError, ValueError):
+                try:
+                    setattr(data, identifier, value)
+                except (TypeError, ValueError):
+                    continue
+
+
+def ensure_display_event_text_aliases(prefs):
+
+
+    event_aliases = {
+        item.event_id: item
+        for item in prefs.display_event_text_aliases_props
+    }
+    for event in list(ops.EventType):
+        if event in ops.SK_OT_ScreencastKeys.MODIFIER_EVENT_TYPES:
+            default_text = common.fix_modifier_display_text(
+                ops.EventType.names[event.name]
+            )
+        else:
+            default_text = ops.EventType.names[event.name]
+
+        if event.name in event_aliases:
+            event_aliases[event.name].default_text = default_text
+        else:
+            item = prefs.display_event_text_aliases_props.add()
+            item.event_id = event.name
+            item.default_text = default_text
+
+
+def load_persisted_preferences(prefs):
+    filepath = persisted_preferences_filepath()
+    if not filepath or not os.path.exists(filepath):
+        return
+
+    try:
+        with open(filepath, "r", encoding="utf-8") as file:
+            data = json.load(file)
+    except (OSError, json.JSONDecodeError):
+        return
+
+    if not data.get("persist_preferences", False):
+        return
+
+    _apply_preferences(prefs, data.get("preferences", {}))
+    prefs.persist_preferences = True
+
+
+def save_persisted_preferences(prefs):
+    filepath = persisted_preferences_filepath(create=True)
+    if not filepath:
+        return
+
+    data = {
+        "version": "1.0.0",
+        "persist_preferences": True,
+        "preferences": _serialize_preferences(prefs),
+    }
+
+    try:
+        tmp_filepath = "{}.tmp".format(filepath)
+        with open(tmp_filepath, "w", encoding="utf-8") as file:
+            json.dump(data, file, ensure_ascii=False, indent=2)
+        os.replace(tmp_filepath, filepath)
+    except (OSError, TypeError):
+        return
+
+
+def remove_persisted_preferences_file():
+    filepath = persisted_preferences_filepath()
+    if not filepath:
+        return
+
+    try:
+        os.remove(filepath)
+    except OSError:
+        return
+
+
 # pylint: disable=W0613
 def remove_custom_mouse_image(self, _):
     def remove_image(image_name):
@@ -525,6 +689,13 @@ def ui_in_overlay_update_fn(self, _):
         update=ui_in_overlay_update_fn,
     )
 
+    persist_preferences: bpy.props.BoolProperty(
+        name="Persist Preferences",
+        description="Store add-on preferences in Blender user configuration "
+                    "and restore them when this add-on is enabled again",
+        default=False,
+    )
+
     display_event_text_aliases_props: bpy.props.CollectionProperty(
         type=DisplayEventTextAliasProperties
     )
@@ -547,6 +718,7 @@ def draw(self, _):
             layout.separator()
 
             layout.prop(self, "enable_on_startup")
+            layout.prop(self, "persist_preferences")
 
             column = layout.column()
             split = column.split()