feat(themes): apply theme typography font-size overrides on every activation path

HellionChat/FontManager.cs

@@ -6,6 +6,7 @@ using Dalamud.Interface.GameFonts;
 using Dalamud.Interface.ManagedFontAtlas;
 using Dalamud.Interface.Utility;
 using Dalamud.Plugin;
+using HellionChat.Themes;
 
 namespace HellionChat;
 
@@ -39,6 +40,12 @@ public sealed class FontManager : IDisposable
     internal IFontHandle? RegularFont;
     internal IFontHandle? ItalicFont;
 
+    // Wired post-build (B4b-3); a Func keeps FontManager off the theme layer.
+    private Func<ThemeTypography?>? _typographySource;
+
+    // Lets RebuildDelegateFontsIfChanged skip rebuilds when the size is unchanged.
+    private (float Global, float Symbols) _lastBuiltFingerprint;
+
     // True once every required atlas-owned handle reports Available. Components
     // gate their first-frame draw on this — without it the layout math would
     // run against placeholder font metrics and snap when the real atlas
@@ -104,6 +111,9 @@ public sealed class FontManager : IDisposable
             if (Plugin.Config.ItalicEnabled)
                 ItalicFont = BuildItalicFontHandle(atlas);
         }
+
+        // Source is still null here, so this is the config-only baseline.
+        _lastBuiltFingerprint = EffectiveFontFingerprint();
     }
 
     // Called from the settings save path when one of the font-related
@@ -125,6 +135,37 @@ public sealed class FontManager : IDisposable
 
         ItalicFont?.Dispose();
         ItalicFont = Plugin.Config.ItalicEnabled ? BuildItalicFontHandle(atlas) : null;
+
+        _lastBuiltFingerprint = EffectiveFontFingerprint();
+    }
+
+    public void SetTypographySource(Func<ThemeTypography?> source) => _typographySource = source;
+
+    internal float ResolveGlobalFontPt() =>
+        FontSizeResolver.ResolveGlobalPt(
+            _typographySource?.Invoke(),
+            Plugin.Config.UseHellionFont,
+            Plugin.Config.FontSizeV2,
+            Plugin.Config.GlobalFontV2.SizePt
+        );
+
+    internal float ResolveSymbolsFontPt() =>
+        FontSizeResolver.ResolveSymbolsPt(
+            _typographySource?.Invoke(),
+            Plugin.Config.SymbolsFontSizeV2
+        );
+
+    internal (float Global, float Symbols) EffectiveFontFingerprint() =>
+        (ResolveGlobalFontPt(), ResolveSymbolsFontPt());
+
+    // Rebuilds only when the effective size changed (live fingerprint, TOCTOU-free).
+    // The atlas rebuild must run on the framework/draw thread — callers ensure that.
+    internal void RebuildDelegateFontsIfChanged()
+    {
+        if (EffectiveFontFingerprint() != _lastBuiltFingerprint)
+        {
+            RebuildDelegateFonts();
+        }
     }
 
     // Instance method so Ranges / JpRange are reachable without parameter
@@ -133,12 +174,7 @@ public sealed class FontManager : IDisposable
         atlas.NewDelegateFontHandle(e =>
             e.OnPreBuild(tk =>
             {
-                // UseHellionFont swaps the source font but keeps the size
-                // selector tied to FontSizeV2 (the bundled font ships as
-                // a single weight).
-                var basePt = Plugin.Config.UseHellionFont
-                    ? Plugin.Config.FontSizeV2
-                    : Plugin.Config.GlobalFontV2.SizePt;
+                var basePt = ResolveGlobalFontPt();
                 var config = new SafeFontConfig { SizePt = basePt, GlyphRanges = Ranges };
                 // Missing embedded resource falls back to the configured
                 // system font instead of taking the whole UiBuilder down.
@@ -164,7 +200,7 @@ public sealed class FontManager : IDisposable
                     "noto-cjk-fallback"
                 );
 
-                config.SizePt = Plugin.Config.SymbolsFontSizeV2;
+                config.SizePt = ResolveSymbolsFontPt();
                 tk.AddGameSymbol(config);
 
                 tk.Font = config.MergeFont;
@@ -201,7 +237,7 @@ public sealed class FontManager : IDisposable
                     "noto-cjk-fallback"
                 );
 
-                config.SizePt = Plugin.Config.SymbolsFontSizeV2;
+                config.SizePt = ResolveSymbolsFontPt();
                 tk.AddGameSymbol(config);
 
                 tk.Font = config.MergeFont;

HellionChat/FontSizeResolver.cs

@@ -0,0 +1,18 @@
+using HellionChat.Themes;
+
+namespace HellionChat;
+
+// Pure size resolution, split out of FontManager so it is unit-testable without
+// building the font atlas. A typography override wins; null falls back to config.
+internal static class FontSizeResolver
+{
+    internal static float ResolveGlobalPt(
+        ThemeTypography? typography,
+        bool useHellionFont,
+        float fontSizeV2,
+        float globalSizePt
+    ) => typography?.OverrideGlobalFontSizePt ?? (useHellionFont ? fontSizeV2 : globalSizePt);
+
+    internal static float ResolveSymbolsPt(ThemeTypography? typography, float symbolsSizePt) =>
+        typography?.OverrideSymbolsFontSizePt ?? symbolsSizePt;
+}

HellionChat/Infrastructure/Hosting/InitHostedServices.cs

@@ -16,16 +16,26 @@ namespace HellionChat.Infrastructure.Hosting;
 // at Build, which runs the service ctor (IPC subscribe etc.) right then
 // instead of lazily on first GetRequiredService.
 
-internal sealed class ThemeRegistryInitHostedService(ThemeRegistry registry) : IHostedService
+internal sealed class ThemeRegistryInitHostedService(
+    ThemeRegistry registry,
+    FontManager fontManager
+) : IHostedService
 {
-    public Task StartAsync(CancellationToken cancellationToken)
+    public async Task StartAsync(CancellationToken cancellationToken)
     {
         // Materialise the lazy AllCustom enumerable so the slug lookup hits a
         // warm cache; otherwise the first Switch falls through to the built-in
         // default when Config.Theme points at a custom slug.
         foreach (var _ in registry.AllCustom()) { }
         registry.SwitchSilent(Plugin.Config.Theme);
-        return Task.CompletedTask;
+
+        // B4b-3: point font sizes at the active theme's typography, wire future
+        // theme switches to the atlas rebuild, and apply the boot theme's override.
+        fontManager.SetTypographySource(() => registry.Active.Typography);
+        registry.SetActiveChangedCallback(() => fontManager.RebuildDelegateFontsIfChanged());
+        await Plugin.Framework.RunOnFrameworkThread(() =>
+            fontManager.RebuildDelegateFontsIfChanged()
+        );
     }
 
     public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;

HellionChat/PluginHostFactory.cs

@@ -334,7 +334,8 @@ internal static class PluginHostFactory
         // does not need one — its ctor runs the init inline inside a single
         // SuppressAutoRebuild block on eager resolve.
         services.AddHostedService(sp => new ThemeRegistryInitHostedService(
-            sp.GetRequiredService<ThemeRegistry>()
+            sp.GetRequiredService<ThemeRegistry>(),
+            sp.GetRequiredService<FontManager>()
         ));
         services.AddHostedService(sp => new IpcManagerInitHostedService(
             sp.GetRequiredService<IpcManager>()

HellionChat/Themes/ThemeRegistry.cs

@@ -47,6 +47,12 @@ public sealed class ThemeRegistry
     public Theme? EditingThemeBuffer => _editingThemeBuffer;
     public event Action? OnEditingBufferChanged;
 
+    // Fired after _active changes (Switch / RefreshActiveIfStale); the init host
+    // wires it to the font-atlas rebuild. NOT fired by SwitchSilent (boot handles that).
+    private Action? _onActiveChanged;
+
+    internal void SetActiveChangedCallback(Action callback) => _onActiveChanged = callback;
+
     // Shared slug guard for any code path that turns a slug into a filename.
     // Both SaveEditingBuffer (F1) and ImportFromPath (M6) call this so the
     // path-traversal/invalid-char rules live in exactly one place.
@@ -190,27 +196,32 @@ public sealed class ThemeRegistry
             _active = builtin;
             _active.RecomputeAbgrCache();
             _activeCustomPath = null;
-            return;
         }
-
-        var customTheme = LoadCustomBySlug(slug, out var customPath);
-        if (customTheme is not null)
+        else
         {
-            _active = customTheme;
-            // Defensive — ensures any future theme source always gets a populated cache.
-            _active.RecomputeAbgrCache();
-            _activeCustomPath = customPath;
-            // Force a first-tick reload-check after the switch so the stamp
-            // baseline is established on the next RefreshActiveIfStale call.
-            _lastActiveStamp = DateTime.MinValue;
-            return;
+            var customTheme = LoadCustomBySlug(slug, out var customPath);
+            if (customTheme is not null)
+            {
+                _active = customTheme;
+                // Defensive — ensures any future theme source always gets a populated cache.
+                _active.RecomputeAbgrCache();
+                _activeCustomPath = customPath;
+                // Force a first-tick reload-check after the switch so the stamp
+                // baseline is established on the next RefreshActiveIfStale call.
+                _lastActiveStamp = DateTime.MinValue;
+            }
+            else
+            {
+                // Fallback: neither built-in nor custom matched. Drop to default
+                // and clear the active custom path so RefreshActiveIfStale stays idle.
+                _active = _builtIns[DefaultSlug];
+                _active.RecomputeAbgrCache();
+                _activeCustomPath = null;
+            }
         }
 
-        // Fallback: neither built-in nor custom matched. Drop to default
-        // and clear the active custom path so RefreshActiveIfStale stays idle.
-        _active = _builtIns[DefaultSlug];
-        _active.RecomputeAbgrCache();
-        _activeCustomPath = null;
+        // Notify listeners (the init host wires the font-atlas rebuild here).
+        _onActiveChanged?.Invoke();
     }
 
     // SwitchSilent is the plugin-load init path -- identical to Switch
@@ -426,6 +437,9 @@ public sealed class ThemeRegistry
                 {
                     reloaded.RecomputeAbgrCache();
                     _active = reloaded;
+                    // Same-slug save bypasses Switch's notify (it noop'd on same slug);
+                    // fire here so a typography change applies (no-op if size unchanged).
+                    _onActiveChanged?.Invoke();
                 }
             }
 
@@ -568,6 +582,7 @@ public sealed class ThemeRegistry
         // RecomputeAbgrCache happens inside RefreshCustomCache on cache miss.
         var reloaded = Get(_active.Slug);
         _active = reloaded;
+        _onActiveChanged?.Invoke();
     }
 
     // 0x80070020 = SHARING_VIOLATION, 0x80070021 = LOCK_VIOLATION.

HellionChat/Themes/ThemeTypography.cs

@@ -1,6 +1,7 @@
 namespace HellionChat.Themes;
 
 // Optional per-theme; reserved as an extension point for future theme slots.
+// Italic body-size override intentionally omitted (v1.9.0 Typography-Polish).
 public sealed record ThemeTypography(
     float? OverrideGlobalFontSizePt = null,
     float? OverrideSymbolsFontSizePt = null