Add FreeType loader for TTF/OTF rendering

FontManagement/FontManager.cs

@@ -3,6 +3,7 @@
 using System.Globalization;
 using System.IO;
 using FontStashSharp;
+using FontStashSharp.Interfaces;
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Content;
 using Microsoft.Xna.Framework.Graphics;
@@ -61,7 +62,7 @@ public static void Initialize()
     /// <summary>
     /// Creates a new FontSystem with current text shaping settings.
     /// </summary>
-    private static FontSystem CreateFontSystem()
+    private static FontSystem CreateFontSystem(IFontLoader fontLoader = null)
     {
         var settings = new FontSystemSettings
         {
@@ -71,7 +72,8 @@ private static FontSystem CreateFontSystem()
             TextureWidth = fontRenderingSettings.TextureWidth,
             TextureHeight = fontRenderingSettings.TextureHeight,
             GlyphRenderResult = fontRenderingSettings.GlyphRenderResult,
-            UseEmToPixelsScale = true
+            UseEmToPixelsScale = true,
+            FontLoader = fontLoader,
         };
 
         if (textShapingSettings.Enabled)
@@ -84,7 +86,7 @@ private static FontSystem CreateFontSystem()
             settings.ShapedTextCacheSize = textShapingSettings.CacheSize;
         }
 
-        return new FontSystem(settings);
+        return new FontSystem(settings) { DefaultCharacter = '?' };
     }
 
     public static Vector2 MeasureString(string text, int fontIndex)
@@ -265,12 +267,16 @@ private static void CreateFontIndexesFromIni(IniFile iniFile, ContentManager con
             string fontPath = iniFile.GetStringValue(section, "Path", "");
             int size = iniFile.GetIntValue(section, "Size", 16);
             string fontTypeStr = iniFile.GetStringValue(section, "Type", nameof(FontType.SpriteFont));
+            string fontLoaderStr = iniFile.GetStringValue(section, "Loader", nameof(TTFFontLoader.StbTrueType));
             int fallback = iniFile.GetIntValue(section, "Fallback", -1);
 
             if (!Enum.TryParse<FontType>(fontTypeStr, true, out var fontType))
                 throw new Exception($"Invalid font type for {section}: {fontTypeStr}");
 
-            fontConfigs.Add(new FontConfig(fontPath, size, fontType, fallback));
+            if (!Enum.TryParse<TTFFontLoader>(fontLoaderStr, true, out var fontLoader))
+                throw new Exception($"Invalid font loader for {section}: {fontLoaderStr}");
+
+            fontConfigs.Add(new FontConfig(fontPath, size, fontType, fontLoader, fallback));
         }
 
         for (int i = 0; i < fontCount; i++)
@@ -299,7 +305,17 @@ private static void CreateFontIndexesFromIni(IniFile iniFile, ContentManager con
     /// </summary>
     private static void CreateTrueTypeFontIndex(int fontIndex, FontConfig config, List<FontConfig> allConfigs, string searchPath)
     {
-        FontSystem fontSystem = CreateFontSystem();
+        IFontLoader fontLoader = config.FontLoader switch
+        {
+            // Note: FontStashSharp automatically uses StbTrueType with parameters specified in FontSystemSettings, so we return null here to use the default loader.
+            TTFFontLoader.StbTrueType => null,
+            TTFFontLoader.FreeType => new FreeTypeFontLoader(FreeTypeRenderMode.Normal),
+            TTFFontLoader.FreeTypeMono => new FreeTypeFontLoader(FreeTypeRenderMode.Mono),
+            TTFFontLoader.Forme => throw new NotImplementedException("Forme font loader is not implemented yet"),
+            _ => throw new Exception($"Unsupported font loader for Font{fontIndex}: {config.FontLoader}")
+        };
+
+        FontSystem fontSystem = CreateFontSystem(fontLoader);
         fontSystem.DefaultCharacter = '?';
         fontSystems.Add(fontSystem);
 
@@ -395,13 +411,15 @@ private readonly struct FontConfig
         public string Path { get; }
         public int Size { get; }
         public FontType FontType { get; }
+        public TTFFontLoader FontLoader { get; }
         public int Fallback { get; }
 
-        public FontConfig(string path, int size, FontType fontType, int fallback)
+        public FontConfig(string path, int size, FontType fontType, TTFFontLoader fontLoader, int fallback)
         {
             Path = path;
             Size = size;
             FontType = fontType;
+            FontLoader = fontLoader;
             Fallback = fallback;
         }
     }

FontManagement/FreeTypeFontLoader.cs

@@ -0,0 +1,22 @@
+using FontStashSharp.Interfaces;
+
+namespace Rampastring.XNAUI.FontManagement;
+
+/// <summary>
+/// FreeType-based font loader that correctly handles embedded bitmap fonts in TTF files.
+/// Replaces FontStashSharp.Rasterizers.FreeType which has broken struct layouts on Windows x64
+/// (FreeTypeSharp maps C 'long' to IntPtr instead of int, causing struct field misalignment).
+/// </summary>
+public sealed class FreeTypeFontLoader : IFontLoader
+{
+    public FreeTypeRenderMode RenderMode { get; } = FreeTypeRenderMode.Normal;
+
+    public FreeTypeFontLoader() { }
+
+    public FreeTypeFontLoader(FreeTypeRenderMode renderMode)
+    {
+        RenderMode = renderMode;
+    }
+
+    public IFontSource Load(byte[] data) => new FreeTypeFontSource(data) { RenderMode = RenderMode };
+}