Add final polish improvements to plugin

- Add comprehensive docstring for __init__ method
- Initialize _temp_surface in __init__ instead of lazy initialization
- Extract font constants (FONT_FAMILY, FONT_SIZE_NORMAL, FONT_SIZE_SMALL, FONT_SIZE_LARGE)
- Replace all hardcoded font strings with constants
- All methods now have docstrings (100% coverage)

Benefits:
- Better initialization clarity
- Centralized font configuration
- Complete documentation coverage
- More maintainable code

MyTimeline.py

@@ -88,6 +88,12 @@ TOOLTIP_MAX_WIDTH = 500
 LABEL_BACKGROUND_PADDING = 8
 LABEL_BACKGROUND_RADIUS = 5
 
+# Font Constants
+FONT_FAMILY = "Sans"
+FONT_SIZE_NORMAL = 11
+FONT_SIZE_SMALL = 9
+FONT_SIZE_LARGE = 24
+
 # Visual Effect Constants
 MARKER_HOVER_SIZE_MULTIPLIER = 1.3
 MARKER_SELECTED_SIZE_MULTIPLIER = 1.2
@@ -272,6 +278,15 @@ class MyTimelineView(NavigationView):
     """
 
     def __init__(self, pdata, dbstate, uistate, nav_group=0):
+        """
+        Initialize the MyTimeline view.
+        
+        Args:
+            pdata: Plugin data object.
+            dbstate: Database state object.
+            uistate: UI state object.
+            nav_group: Navigation group identifier.
+        """
         NavigationView.__init__(
             self, _("MyTimeline"), pdata, dbstate, uistate, FamilyBookmarks, nav_group
         )
@@ -307,6 +322,9 @@ class MyTimelineView(NavigationView):
         self._cached_date_range: Optional[int] = None
         self._cached_min_date: Optional[int] = None
         self._cached_max_date: Optional[int] = None
+        
+        # Initialize temporary surface for text measurement (used in find_event_at_position)
+        self._temp_surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, 1, 1)
 
         # Connect to database changes
         self.dbstate.connect("database-changed", self.change_db)
@@ -1074,10 +1092,8 @@ class MyTimelineView(NavigationView):
         timeline_y_start = TIMELINE_MARGIN_TOP
         timeline_y_end = height - TIMELINE_MARGIN_BOTTOM
         
-        # Get adjusted events using cache (create temporary context if needed)
+        # Get adjusted events using cache (create temporary context for text measurement)
         # For click detection, we need a context for text measurement
-        if not hasattr(self, '_temp_surface') or self._temp_surface is None:
-            self._temp_surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, 1, 1)
         temp_context = cairo.Context(self._temp_surface)
         
         adjusted_events = self._get_adjusted_events(temp_context, timeline_y_start, timeline_y_end)
@@ -1271,8 +1287,8 @@ class MyTimelineView(NavigationView):
             height: Widget height.
         """
         context.set_source_rgb(0.6, 0.6, 0.6)
-        context.select_font_face("Sans", cairo.FONT_SLANT_NORMAL, cairo.FONT_WEIGHT_NORMAL)
+        context.select_font_face(FONT_FAMILY, cairo.FONT_SLANT_NORMAL, cairo.FONT_WEIGHT_NORMAL)
-        context.set_font_size(24)
+        context.set_font_size(FONT_SIZE_LARGE)
         text = _("No events found")
         (x_bearing, y_bearing, text_width, text_height, x_advance, y_advance) = context.text_extents(text)
         context.move_to((width - text_width) / 2, height / 2)
@@ -1583,7 +1599,7 @@ class MyTimelineView(NavigationView):
         layout = PangoCairo.create_layout(context)
         
         # Use modern font
-        font_desc = Pango.font_description_from_string("Sans 11")
+        font_desc = Pango.font_description_from_string(f"{FONT_FAMILY} {FONT_SIZE_NORMAL}")
         if is_hovered:
             font_desc.set_weight(Pango.Weight.BOLD)
         layout.set_font_description(font_desc)
@@ -1698,7 +1714,7 @@ class MyTimelineView(NavigationView):
         # Draw year label
         layout = PangoCairo.create_layout(context)
         layout.set_font_description(
-            Pango.font_description_from_string("Sans 9")
+            Pango.font_description_from_string(f"{FONT_FAMILY} {FONT_SIZE_SMALL}")
         )
         layout.set_text(str(year), -1)