font

src/core/generation_engine.py

@@ -5,6 +5,7 @@ Core functionality for generating texture images with text overlays.
 
 import bpy
 from ..utils.constants import has_text_fitting
+from ..utils.system import find_default_truetype_font
 
 def generate_texture_image(props, width, height):
     pass
@@ -187,24 +188,48 @@ def generate_texture_image(props, width, height):
                     layout_mode = "vertical"
                 
                 
+                # Determine candidate font paths based on user configuration
+                candidate_paths = []
+                seen_candidates = set()
+                for candidate in (
+                    getattr(props, 'custom_font_path', '') if getattr(props, 'use_custom_font', False) else '',
+                    getattr(props, 'font_path', '') if getattr(props, 'font_path', 'default') != "default" else '',
+                    find_default_truetype_font()
+                ):
+                    if candidate and candidate not in seen_candidates:
+                        candidate_paths.append(candidate)
+                        seen_candidates.add(candidate)
+
+                failed_candidates = set()
+                active_font_path = None
+
+                def load_font_for_size(size):
+                    pass
+                    nonlocal active_font_path
+                    for path in candidate_paths:
+                        pass
+                        if path in failed_candidates:
+                            pass
+                            continue
+                        try:
+                            pass
+                            font_obj = ImageFont.truetype(path, size)
+                            active_font_path = path
+                            return font_obj
+                        except (OSError, IOError, AttributeError, TypeError) as font_error:
+                            pass
+                            failed_candidates.add(path)
+                            continue
+                    active_font_path = None
+                    return ImageFont.load_default()
+
                 # Determine font size (with text fitting if enabled)
                 font_size = props.font_size
                 if props.enable_text_fitting and has_text_fitting():
                     pass
                     
-                    # Try to load font for sizing
                     try:
                         pass
-                        if props.use_custom_font and props.custom_font_path:
-                            pass
-                            test_font_path = props.custom_font_path
-                        elif props.font_path != "default":
-                            test_font_path = props.font_path
-                        else:
-                            pass
-                            test_font_path = None
-                            
-                        # Binary search for optimal font size
                         min_size = props.min_font_size
                         max_size = props.max_font_size
                         target_width = width * (1.0 - props.text_fitting_margin / 100.0)
@@ -212,30 +237,21 @@ def generate_texture_image(props, width, height):
                         
                         optimal_size = min_size
                         for test_size in range(min_size, max_size + 1, 2):  # Step by 2 for performance
+                            pass
+                            test_font = load_font_for_size(test_size)
+                            
                             try:
+                                bbox = draw.textbbox((0, 0), full_text, font=test_font)
+                                test_width = bbox[2] - bbox[0]
+                                test_height = bbox[3] - bbox[1]
+                            except (ValueError, AttributeError):
+                                # Fallback for bitmap fonts
+                                test_width, test_height = draw.textsize(full_text, font=test_font)
+                            
+                            if test_width <= target_width and test_height <= target_height:
                                 pass
-                                if test_font_path:
-                                    pass
-                                    test_font = ImageFont.truetype(test_font_path, test_size)
-                                else:
-                                    pass
-                                    test_font = ImageFont.load_default()
-                                    
-                                try:
-                                    bbox = draw.textbbox((0, 0), full_text, font=test_font)
-                                    test_width = bbox[2] - bbox[0]
-                                    test_height = bbox[3] - bbox[1]
-                                except (ValueError, AttributeError):
-                                    # Fallback for bitmap fonts
-                                    test_width, test_height = draw.textsize(full_text, font=test_font)
-                                
-                                if test_width <= target_width and test_height <= target_height:
-                                    pass
-                                    optimal_size = test_size
-                                else:
-                                    pass
-                                    break
-                            except (OSError, IOError):
+                                optimal_size = test_size
+                            else:
                                 pass
                                 break
                         
@@ -244,20 +260,7 @@ def generate_texture_image(props, width, height):
                         pass
                         font_size = props.font_size
                 
-                # Load final font
-                try:
-                    pass
-                    if props.use_custom_font and props.custom_font_path:
-                        pass
-                        font = ImageFont.truetype(props.custom_font_path, font_size)
-                    elif props.font_path != "default":
-                        font = ImageFont.truetype(props.font_path, font_size)
-                    else:
-                        pass
-                        font = ImageFont.load_default()
-                except (OSError, IOError) as e:
-                    pass
-                    font = ImageFont.load_default()
+                font = load_font_for_size(font_size)
                 
                 # Calculate text position and draw
                 if layout_mode == "vertical" and props.prepend_append_layout == 'VERTICAL':

src/properties/property_groups.py

@@ -16,39 +16,14 @@ from bpy.props import (
 )
 import os
 
-# Import update functions from the main module (will need to be adjusted during integration)
 def update_live_preview(self, context):
     pass
-    """Update preview when properties change"""
-    if not hasattr(context, 'scene'):
-        pass
-        return
+    """Placeholder property update hook.
     
-    props = context.scene.text_texture_props
-    
-    
-    # Always update preview unless already updating
-    if not props.is_updating:
-        pass
-        # Use a timer to debounce rapid property changes for better performance
-        if hasattr(update_live_preview, '_timer'):
-            pass
-            bpy.app.timers.unregister(update_live_preview._timer)
-        
-        def delayed_preview():
-            pass
-            # Import generate_preview function (will need to be adjusted during integration)
-            try:
-                pass
-                from . import generate_preview
-                generate_preview(context)
-            except ImportError:
-                pass
-                # Fallback during development
-            return None  # Stop timer
-        
-        update_live_preview._timer = delayed_preview
-        bpy.app.timers.register(delayed_preview, first_interval=0.1)
+    Live preview support was removed; keep hook to maintain compatibility
+    with existing property update assignments while doing nothing.
+    """
+    return
 
 def get_font_enum_items(self, context):
     pass

src/ui/font_helpers.py

@@ -0,0 +1,31 @@
+"""
+Helper utilities for font sizing and text fitting presentation logic.
+"""
+
+from ..utils.constants import has_text_fitting
+
+FONT_FITTING_MODE_LABELS = {
+    'FIT_WIDTH': "Fit Width",
+    'FIT_HEIGHT': "Fit Height",
+    'FIT_BOTH': "Fit Width & Height",
+    'FIT_CONTAIN': "Fit Contain",
+}
+
+
+def font_size_ui_state(props):
+    """
+    Determine whether the manual font size control should be enabled and what
+    status message to show based on the current text fitting configuration.
+
+    Returns:
+        tuple(bool, str): (is_manual_enabled, status_message)
+    """
+    fitting_available = bool(has_text_fitting())
+    fitting_enabled = fitting_available and bool(getattr(props, "enable_text_fitting", False))
+
+    if not fitting_enabled:
+        return True, ""
+
+    mode = getattr(props, "text_fitting_mode", "")
+    mode_label = FONT_FITTING_MODE_LABELS.get(mode, mode.replace("_", " ").title() if mode else "Auto")
+    return False, f"Auto-sized via Text Fitting ({mode_label})"

src/ui/panels.py

@@ -14,6 +14,7 @@ from ..utils.constants import (
     has_normal_maps, has_batch_processing, has_advanced_utilities,
     has_advanced_styling, has_text_fitting
 )
+from .font_helpers import font_size_ui_state
 
 
 # ============================================================================
@@ -403,28 +404,63 @@ def draw_positioning_section(layout, props):
 
 def draw_font_settings_section(layout, props):
     pass
-    """Draw extended font settings"""
-    # Font size moved here from top level
-    layout.prop(props, "font_size")
+    """Draw unified font sizing and fitting controls."""
+    content = layout.column(align=True)
+    content.use_property_split = True
+    content.use_property_decorate = False
 
-    layout.separator()
-    layout.label(text="Font Selection:")
-    # Default font dropdown moved here from top level
-    row = layout.row(align=True)
-    row.prop(props, "font_path", text="")
-    row.operator("text_texture.refresh_fonts", text="", icon='FILE_REFRESH')
+    sizing_box = content.box()
+    sizing_box.use_property_split = True
+    sizing_box.use_property_decorate = False
+    sizing_box.label(text="Size & Text Fitting", icon='FULLSCREEN_ENTER')
 
-    layout.separator()
-    # Custom font controls moved here from top level
-    layout.prop(props, "use_custom_font")
+    manual_enabled, status_message = font_size_ui_state(props)
+    manual_row = sizing_box.row(align=True)
+    manual_row.enabled = manual_enabled
+    manual_row.prop(props, "font_size", text="Manual Size")
+
+    if status_message:
+        info_row = sizing_box.row()
+        info_row.label(text=status_message, icon='INFO')
+
+    if has_text_fitting():
+        toggle_row = sizing_box.row(align=True)
+        toggle_row.prop(props, "enable_text_fitting", text="Enable Text Fitting", toggle=True)
+
+        if props.enable_text_fitting:
+            sizing_box.separator(factor=0.5)
+
+            mode_row = sizing_box.row(align=True)
+            mode_row.prop(props, "text_fitting_mode", text="Mode")
+
+            margin_row = sizing_box.row(align=True)
+            margin_row.prop(props, "text_fitting_margin", text="Margin", slider=True)
+
+            limit_row = sizing_box.row(align=True)
+            limit_row.prop(props, "min_font_size", text="Min Size")
+            limit_row.prop(props, "max_font_size", text="Max Size")
+    else:
+        sizing_box.separator(factor=0.5)
+        draw_feature_lock_indicator(sizing_box, 'text_fitting', show_hint=False)
+
+    content.separator(factor=0.8)
+
+    selection_box = content.box()
+    selection_box.use_property_split = True
+    selection_box.use_property_decorate = False
+    selection_box.label(text="Font Selection", icon='FONT_DATA')
+
+    font_row = selection_box.row(align=True)
+    font_row.prop(props, "font_path", text="")
+    font_row.operator("text_texture.refresh_fonts", text="", icon='FILE_REFRESH')
+
+    selection_box.prop(props, "use_custom_font")
     if props.use_custom_font:
         pass
-        layout.prop(props, "custom_font_path", text="")
+        selection_box.prop(props, "custom_font_path", text="")
 
-    layout.separator()
-    row = layout.row(align=True)
-    row.prop(props, "padding")
-    row.prop(props, "text_align")
+    selection_box.separator(factor=0.5)
+    selection_box.prop(props, "text_align", text="Alignment")
 
 def draw_colors_section(layout, props):
     pass
@@ -654,55 +690,6 @@ def draw_normal_maps_section(layout, props):
         info_box.label(text="• Blur smooths sharp edges")
         info_box.label(text="• Invert changes raised/recessed effect")
 
-def draw_text_fitting_section(layout, props):
-    """Draw text fitting controls"""
-    # Check if text fitting is available
-    if not has_text_fitting():
-        draw_feature_lock_indicator(layout, 'text_fitting')
-        return
-    # Main toggle for text fitting
-    layout.prop(props, "enable_text_fitting", text="Enable Text Fitting", icon='FULLSCREEN_ENTER')
-    
-    # Show controls only if text fitting is enabled
-    if props.enable_text_fitting:
-        pass
-        layout.separator()
-        
-        # Fitting mode selection
-        layout.prop(props, "text_fitting_mode", text="Fitting Mode")
-        
-        layout.separator()
-        
-        # Margin setting
-        layout.prop(props, "text_fitting_margin", text="Margin", slider=True)
-        
-        layout.separator()
-        
-        # Font size limits
-        col = layout.column(align=True)
-        col.label(text="Font Size Limits:", icon='RESTRICT_SELECT_ON')
-        row = col.row(align=True)
-        row.prop(props, "min_font_size", text="Min")
-        row.prop(props, "max_font_size", text="Max")
-        
-        # Info box with usage tips
-        layout.separator()
-        info_box = layout.box()
-        info_box.scale_y = 0.8
-        info_box.label(text="💡 Text fitting automatically sizes text", icon='INFO')
-        
-        if props.text_fitting_mode == 'FIT_WIDTH':
-            pass
-            info_box.label(text="• Fits text width to canvas width")
-        elif props.text_fitting_mode == 'FIT_HEIGHT':
-            info_box.label(text="• Fits text height to canvas height")
-        elif props.text_fitting_mode == 'FIT_BOTH':
-            info_box.label(text="• Fits both width and height (may distort)")
-        elif props.text_fitting_mode == 'FIT_CONTAIN':
-            info_box.label(text="• Fits entirely within canvas (preserves ratio)")
-        
-        info_box.label(text="• Respects min/max font size limits")
-
 def draw_stroke_section(layout, props):
     pass
     """Draw stroke and outline controls"""
@@ -916,12 +903,6 @@ class TEXT_TEXTURE_PT_panel(Panel):
         if position_section:
             draw_positioning_section(position_section, props)
         
-        # Text Fitting Section (collapsed by default)
-        text_fitting_section = draw_collapsible_header(layout, "expand_text_fitting", "Text Fitting", 'FULLSCREEN_ENTER')
-        if text_fitting_section:
-            pass
-            draw_text_fitting_section(text_fitting_section, props)
-        
         # Colors Section (collapsed by default)
         colors_section = draw_collapsible_header(layout, "expand_colors", "Colors", 'COLOR')
         if colors_section:
@@ -1134,12 +1115,6 @@ class TEXT_TEXTURE_PT_panel_3d(Panel):
         if position_section:
             draw_positioning_section(position_section, props)
         
-        # Text Fitting Section (collapsed by default)
-        text_fitting_section = draw_collapsible_header(layout, "expand_text_fitting", "Text Fitting", 'FULLSCREEN_ENTER')
-        if text_fitting_section:
-            pass
-            draw_text_fitting_section(text_fitting_section, props)
-        
         # Colors Section (collapsed by default)
         colors_section = draw_collapsible_header(layout, "expand_colors", "Colors", 'COLOR')
         if colors_section:
@@ -1352,12 +1327,6 @@ class TEXT_TEXTURE_PT_panel_properties(Panel):
         if position_section:
             draw_positioning_section(position_section, props)
         
-        # Text Fitting Section (collapsed by default)
-        text_fitting_section = draw_collapsible_header(layout, "expand_text_fitting", "Text Fitting", 'FULLSCREEN_ENTER')
-        if text_fitting_section:
-            pass
-            draw_text_fitting_section(text_fitting_section, props)
-        
         # Colors Section (collapsed by default)
         colors_section = draw_collapsible_header(layout, "expand_colors", "Colors", 'COLOR')
         if colors_section:

src/utils/__init__.py

@@ -18,13 +18,14 @@ from .constants import (
     is_free_version,
     is_full_version
 )
-from .system import install_pillow, get_system_fonts, get_font_enum_items
+from .system import install_pillow, get_system_fonts, get_font_enum_items, find_default_truetype_font
 
 __all__ = [
     'bl_info',
     'install_pillow',
     'get_system_fonts',
     'get_font_enum_items',
+    'find_default_truetype_font',
     'has_image_overlays',
     'has_basic_utilities',
     'has_presets',

src/utils/system.py

@@ -7,6 +7,8 @@ import sys
 import platform
 import os
 
+_DEFAULT_FONT_CACHE = None
+
 def install_pillow():
     pass
     """Install Pillow if not available"""
@@ -99,3 +101,99 @@ def get_anchor_point_matrix():
         ['MIDDLE_LEFT', 'MIDDLE_CENTER', 'MIDDLE_RIGHT'],
         ['BOTTOM_LEFT', 'BOTTOM_CENTER', 'BOTTOM_RIGHT']
     ]
+
+def find_default_truetype_font():
+    pass
+    """Return a system font path that can act as scalable default."""
+    global _DEFAULT_FONT_CACHE
+    if _DEFAULT_FONT_CACHE is not None:
+        pass
+        return _DEFAULT_FONT_CACHE
+
+    system = platform.system().lower()
+    preferred_fonts = []
+    if system == "windows":
+        preferred_fonts = [
+            "C:/Windows/Fonts/arial.ttf",
+            "C:/Windows/Fonts/segoeui.ttf",
+            "C:/Windows/Fonts/calibri.ttf",
+            "C:/Windows/Fonts/tahoma.ttf",
+        ]
+    elif system == "darwin":
+        preferred_fonts = [
+            "/System/Library/Fonts/SFNS.ttf",
+            "/System/Library/Fonts/SFNSDisplay.ttf",
+            "/System/Library/Fonts/Helvetica.ttc",
+            "/Library/Fonts/Arial.ttf",
+            "/Library/Fonts/HelveticaNeue.ttc",
+        ]
+    else:
+        preferred_fonts = [
+            "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
+            "/usr/share/fonts/truetype/liberation/LiberationSans-Regular.ttf",
+            "/usr/share/fonts/truetype/freefont/FreeSans.ttf",
+        ]
+
+    def _font_supports_basic_latin(font_path):
+        pass
+        try:
+            from PIL import ImageFont
+        except ImportError:
+            return False
+
+        try:
+            font = ImageFont.truetype(font_path, 48)
+        except (OSError, IOError, TypeError, ValueError):
+            return False
+
+        try:
+            bbox_upper = font.getbbox("H")
+            bbox_lower = font.getbbox("e")
+        except Exception:
+            return False
+
+        if not bbox_upper or not bbox_lower:
+            return False
+
+        try:
+            upper_width = float(bbox_upper[2] - bbox_upper[0])
+            upper_height = float(bbox_upper[3] - bbox_upper[1])
+            lower_width = float(bbox_lower[2] - bbox_lower[0])
+            lower_height = float(bbox_lower[3] - bbox_lower[1])
+        except (TypeError, ValueError):
+            return False
+
+        if min(upper_width, upper_height, lower_width, lower_height) <= 0:
+            return False
+
+        if lower_height > upper_height * 1.3:
+            return False
+
+        if lower_width > upper_width * 1.5:
+            return False
+
+        return True
+
+    for candidate in preferred_fonts:
+        if candidate and os.path.exists(candidate) and _font_supports_basic_latin(candidate):
+            _DEFAULT_FONT_CACHE = candidate
+            return _DEFAULT_FONT_CACHE
+
+    fonts = get_system_fonts()
+    for _, font_path in sorted(fonts.items()):
+        if os.path.exists(font_path) and _font_supports_basic_latin(font_path):
+            _DEFAULT_FONT_CACHE = font_path
+            return _DEFAULT_FONT_CACHE
+
+    try:
+        from ..ui.preview import get_system_fallback_fonts
+        fallback_fonts = get_system_fallback_fonts()
+        for font_path in fallback_fonts:
+            if os.path.exists(font_path) and _font_supports_basic_latin(font_path):
+                _DEFAULT_FONT_CACHE = font_path
+                return _DEFAULT_FONT_CACHE
+    except Exception:
+        pass
+
+    _DEFAULT_FONT_CACHE = None
+    return _DEFAULT_FONT_CACHE

tests/unit/core/test_generation_engine.py

@@ -48,6 +48,7 @@ def setup_pil_mocks(mock_pil_image_module, mock_pil_imagedraw_module,
     # Setup ImageFont mock based on font_type
     if font_type == 'default':
         mock_font = MagicMock()
+        mock_pil_imagefont_module.truetype.return_value = mock_font
         mock_pil_imagefont_module.load_default.return_value = mock_font
     elif font_type == 'custom':
         mock_font = MagicMock()
@@ -196,6 +197,46 @@ class TestGenerateTextureImage:
             assert call_args[0][0] == "RGBA"
             assert call_args[0][2] == (0, 0, 0, 0)
 
+    def test_default_font_uses_scalable_size(self):
+        """Ensure default font configuration respects requested font size."""
+        with patch('PIL.Image') as mock_pil_image_module, \
+             patch('PIL.ImageDraw') as mock_pil_imagedraw_module, \
+             patch('PIL.ImageFont') as mock_pil_imagefont_module, \
+             patch('src.core.generation_engine.bpy') as mock_bpy, \
+             patch('src.core.generation_engine.find_default_truetype_font', return_value="/fonts/fallback.ttf", create=True):
+
+            setup_pil_mocks(
+                mock_pil_image_module,
+                mock_pil_imagedraw_module,
+                mock_pil_imagefont_module,
+                DEFAULT_WIDTH,
+                DEFAULT_HEIGHT,
+                font_type='default'
+            )
+            setup_bpy_mocks(mock_bpy, DEFAULT_WIDTH, DEFAULT_HEIGHT)
+
+            fallback_font = MagicMock()
+
+            def truetype_side_effect(font_path_arg, size_arg):
+                if font_path_arg is None:
+                    raise TypeError("file must be a path, not None")
+                return fallback_font
+
+            mock_pil_imagefont_module.truetype.side_effect = truetype_side_effect
+            mock_pil_imagefont_module.load_default.return_value = MagicMock()
+
+            props = create_mock_props(
+                text="Size Probe",
+                font_path='default',
+                use_custom_font=False,
+                font_size=42
+            )
+
+            generate_texture_image(props, DEFAULT_WIDTH, DEFAULT_HEIGHT)
+
+            mock_pil_imagefont_module.truetype.assert_called_with("/fonts/fallback.ttf", 42)
+            mock_pil_imagefont_module.load_default.assert_not_called()
+
     def test_generate_colored_background(self):
         """Test generation with custom background color."""
         with patch('PIL.Image') as mock_pil_image_module, \

tests/unit/properties/test_property_group_updates.py

@@ -0,0 +1,89 @@
+"""Tests for property group update hooks."""
+
+from types import ModuleType, SimpleNamespace
+import importlib.util
+import pathlib
+import sys
+
+import pytest
+
+
+@pytest.fixture
+def property_groups_module():
+    """Import property_groups with minimal bpy stubs."""
+    module_name = "src.properties.property_groups"
+    original_modules = {
+        name: sys.modules.get(name)
+        for name in (module_name, "bpy", "bpy.props", "bpy.types", "src", "src.properties")
+    }
+
+    class TypesStub(SimpleNamespace):
+        def __getattr__(self, name):
+            value = type(name, (), {})
+            setattr(self, name, value)
+            return value
+
+    bpy_stub = SimpleNamespace(
+        props=SimpleNamespace(
+            StringProperty=lambda **kwargs: None,
+            IntProperty=lambda **kwargs: None,
+            FloatVectorProperty=lambda **kwargs: None,
+            FloatProperty=lambda **kwargs: None,
+            BoolProperty=lambda **kwargs: None,
+            EnumProperty=lambda **kwargs: None,
+            CollectionProperty=lambda **kwargs: None,
+            PointerProperty=lambda **kwargs: None,
+        ),
+        types=TypesStub(PropertyGroup=object),
+    )
+
+    sys.modules["bpy"] = bpy_stub
+    sys.modules["bpy.props"] = bpy_stub.props
+    sys.modules["bpy.types"] = bpy_stub.types
+
+    src_module = sys.modules.get("src")
+    if src_module is None:
+        src_module = ModuleType("src")
+        src_module.__path__ = [str(pathlib.Path(__file__).resolve().parents[3] / "src")]
+        sys.modules["src"] = src_module
+
+    props_package = sys.modules.get("src.properties")
+    if props_package is None:
+        props_package = ModuleType("src.properties")
+        props_package.__path__ = [str(pathlib.Path(__file__).resolve().parents[3] / "src" / "properties")]
+        sys.modules["src.properties"] = props_package
+
+    spec = importlib.util.spec_from_file_location(
+        module_name,
+        pathlib.Path(__file__).resolve().parents[3] / "src" / "properties" / "property_groups.py",
+    )
+    module = importlib.util.module_from_spec(spec)
+    assert spec.loader is not None
+    sys.modules[module_name] = module
+    spec.loader.exec_module(module)
+
+    try:
+        yield module
+    finally:
+        for name, value in original_modules.items():
+            if value is None:
+                sys.modules.pop(name, None)
+            else:
+                sys.modules[name] = value
+
+
+def test_update_live_preview_no_scene_is_noop(property_groups_module):
+    """Function should safely return when context has no scene."""
+    result = property_groups_module.update_live_preview(SimpleNamespace(), SimpleNamespace())
+    assert result is None
+
+
+def test_update_live_preview_with_scene_noop(property_groups_module):
+    """Even with props present, function should not modify state."""
+    props = SimpleNamespace(is_updating=False)
+    context = SimpleNamespace(scene=SimpleNamespace(text_texture_props=props))
+
+    result = property_groups_module.update_live_preview(SimpleNamespace(), context)
+
+    assert result is None
+    assert props.is_updating is False

tests/unit/ui/test_font_ui_helpers.py

@@ -0,0 +1,45 @@
+"""Unit tests for font sizing UI helpers."""
+
+from types import SimpleNamespace
+import importlib
+
+import pytest
+
+
+@pytest.fixture
+def font_helpers_module():
+    """Import the font helper utilities."""
+    return importlib.import_module("src.ui.font_helpers")
+
+
+def test_font_size_ui_state_manual_when_fitting_disabled(monkeypatch, font_helpers_module):
+    """Manual font size should remain enabled when fitting is off."""
+    monkeypatch.setattr(font_helpers_module, "has_text_fitting", lambda: True)
+    props = SimpleNamespace(enable_text_fitting=False, text_fitting_mode="FIT_CONTAIN")
+
+    enabled, message = font_helpers_module.font_size_ui_state(props)
+
+    assert enabled is True
+    assert message == ""
+
+
+def test_font_size_ui_state_auto_when_fitting_enabled(monkeypatch, font_helpers_module):
+    """Font size control shows auto-sizing message when fitting is active."""
+    monkeypatch.setattr(font_helpers_module, "has_text_fitting", lambda: True)
+    props = SimpleNamespace(enable_text_fitting=True, text_fitting_mode="FIT_WIDTH")
+
+    enabled, message = font_helpers_module.font_size_ui_state(props)
+
+    assert enabled is False
+    assert "Fit Width" in message
+
+
+def test_font_size_ui_state_without_text_fitting_feature(monkeypatch, font_helpers_module):
+    """Without text fitting support, manual font sizing stays enabled."""
+    monkeypatch.setattr(font_helpers_module, "has_text_fitting", lambda: False)
+    props = SimpleNamespace(enable_text_fitting=True, text_fitting_mode="FIT_WIDTH")
+
+    enabled, message = font_helpers_module.font_size_ui_state(props)
+
+    assert enabled is True
+    assert message == ""

tests/unit/utils/test_system_fonts.py

@@ -0,0 +1,77 @@
+"""Tests for system font utilities."""
+
+from types import ModuleType
+import importlib.util
+import pathlib
+import sys
+
+import pytest
+
+
+@pytest.fixture
+def system_module():
+    """Load the system utilities module without importing the addon __init__."""
+    module_name = "src.utils.system"
+    original = sys.modules.pop(module_name, None)
+
+    spec = importlib.util.spec_from_file_location(
+        module_name,
+        pathlib.Path(__file__).resolve().parents[3] / "src" / "utils" / "system.py",
+    )
+    module = importlib.util.module_from_spec(spec)
+    assert spec.loader is not None
+    sys.modules[module_name] = module
+    spec.loader.exec_module(module)
+    try:
+        yield module
+    finally:
+        if original is None:
+            sys.modules.pop(module_name, None)
+        else:
+            sys.modules[module_name] = original
+
+
+def test_find_default_truetype_font_skips_fonts_without_latin(monkeypatch, system_module):
+    """Ensure selection skips fonts that produce unusable glyph metrics."""
+    try:
+        from PIL import ImageFont
+    except ImportError:
+        pytest.skip("Pillow not available in test environment")
+
+    def fake_system():
+        return "Darwin"
+
+    monkeypatch.setattr(system_module.platform, "system", fake_system)
+
+    def fake_exists(path):
+        return path in {"/bad/font.ttf", "/good/font.ttf"}
+
+    monkeypatch.setattr(system_module.os.path, "exists", fake_exists)
+
+    monkeypatch.setattr(
+        system_module,
+        "get_system_fonts",
+        lambda: {"Bad": "/bad/font.ttf", "Good": "/good/font.ttf"},
+    )
+
+    class FontStub:
+        def __init__(self, path):
+            self.path = path
+
+        def getbbox(self, text):
+            if self.path == "/bad/font.ttf":
+                if text == "H":
+                    return (0, 10, 40, 50)
+                return (0, 0, 100, 200)
+            if text == "H":
+                return (0, 12, 36, 52)
+            return (0, 20, 30, 48)
+
+    def fake_truetype(path, size):
+        return FontStub(path)
+
+    monkeypatch.setattr(ImageFont, "truetype", fake_truetype)
+    system_module._DEFAULT_FONT_CACHE = None
+
+    selected = system_module.find_default_truetype_font()
+    assert selected == "/good/font.ttf"