Add initial support to process CFF fonts contained inside a TrueType font

src/UglyToad.PdfPig.Fonts/TrueType/Parser/TrueTypeFontParser.cs

@@ -3,6 +3,7 @@
     using System;
     using System.Collections.Generic;
     using Tables;
+    using UglyToad.PdfPig.Fonts.CompactFontFormat;
 
     /// <summary>
     /// Parses TrueType fonts.
@@ -59,7 +60,36 @@
 
         private static TrueTypeFont ParseTables(float version, IReadOnlyDictionary<string, TrueTypeHeaderTable> tables, TrueTypeDataBytes data)
         {
-            var isPostScript = tables.ContainsKey(TrueTypeHeaderTable.Cff);
+            bool isPostScript = false;
+            CompactFontFormatFontCollection? cffFontCollection = null;
+
+            if (tables.TryGetValue(TrueTypeHeaderTable.Cff, out var cffTable))
+            {
+                isPostScript = true;
+                try
+                {
+                    /*
+                     * The presence of a CFF (Compact Font Format) table in a TrueType font creates a hybrid situation where the font
+                     * container uses TrueType structure but contains PostScript-based glyph descriptions. According to the OpenType
+                     * specification, when a TrueType font contains a CFF table instead of a traditional glyf table, it indicates
+                     * "an OpenType font with PostScript outlines". This creates what's known as an OpenType CFF font, which uses
+                     * PostScript Type 2 charstrings for glyph descriptions rather than TrueType quadratic curves.
+                     *
+                     * This is to fix P2P-33713919.pdf
+                     * See https://github.com/BobLd/PdfPig.Rendering.Skia/issues/46
+                     * TODO - Add test coverage and need to review if the logic belongs here
+                     */
+
+                    data.Seek(cffTable.Offset);
+                    var buffer = data.ReadByteArray((int)cffTable.Length);
+                    cffFontCollection = CompactFontFormatParser.Parse(new CompactFontFormatData(buffer));
+                }
+                catch (Exception e)
+                {
+                    System.Diagnostics.Debug.WriteLine(e);
+                    // Ignore
+                }
+            }
 
             var builder = new TableRegister.Builder();
 
@@ -102,7 +132,7 @@
             {
                 builder.Os2Table = TableParser.Parse<Os2Table>(os2Table, data, builder);
             }
-            
+
             if (!isPostScript)
             {
                 if (!tables.TryGetValue(TrueTypeHeaderTable.Loca, out var indexToLocationHeaderTable))
@@ -125,7 +155,7 @@
 
             OptionallyParseTables(tables, data, builder);
 
-            return new TrueTypeFont(version, tables, builder.Build());
+            return new TrueTypeFont(version, tables, builder.Build(), cffFontCollection);
         }
 
         internal static NameTable GetNameTable(TrueTypeDataBytes data)
@@ -134,7 +164,7 @@
             {
                 throw new ArgumentNullException(nameof(data));
             }
-            
+
             // Read these data points to move to the correct data location.
             data.Read32Fixed();
             int numberOfTables = data.ReadUnsignedShort();

src/UglyToad.PdfPig.Fonts/TrueType/TrueTypeFont.cs

@@ -5,6 +5,7 @@
     using Core;
     using Parser;
     using Tables.CMapSubTables;
+    using UglyToad.PdfPig.Fonts.CompactFontFormat;
 
     /// <summary>
     /// A TrueType font.
@@ -54,37 +55,53 @@
         /// </summary>
         public int NumberOfTables { get; }
 
+        // TODO - It would be better to use 'PdfCidCompactFontFormatFont' but the class is not accessible from here.
+        private readonly CompactFontFormatFontCollection? cffFontCollection;
+
         /// <summary>
         /// Create a new <see cref="TrueTypeFont"/>.
         /// </summary>
-        internal TrueTypeFont(float version, IReadOnlyDictionary<string, TrueTypeHeaderTable> tableHeaders, TableRegister tableRegister)
+        internal TrueTypeFont(float version, IReadOnlyDictionary<string, TrueTypeHeaderTable> tableHeaders, TableRegister tableRegister, CompactFontFormatFontCollection? cffFontCollection)
         {
             Version = version;
             TableHeaders = tableHeaders ?? throw new ArgumentNullException(nameof(tableHeaders));
             TableRegister = tableRegister ?? throw new ArgumentNullException(nameof(tableRegister));
             NumberOfTables = tableHeaders.Count;
 
-            if (TableRegister.CMapTable != null)
+            /*
+             * The presence of a CFF (Compact Font Format) table in a TrueType font creates a hybrid situation where the font
+             * container uses TrueType structure but contains PostScript-based glyph descriptions. According to the OpenType
+             * specification, when a TrueType font contains a CFF table instead of a traditional glyf table, it indicates
+             * "an OpenType font with PostScript outlines". This creates what's known as an OpenType CFF font, which uses
+             * PostScript Type 2 charstrings for glyph descriptions rather than TrueType quadratic curves.
+             *
+             * This is to fix P2P-33713919.pdf
+             * See https://github.com/BobLd/PdfPig.Rendering.Skia/issues/46
+             * TODO - Add test coverage and need to review if the logic belongs here
+             */
+            this.cffFontCollection = cffFontCollection;
+
+            if (TableRegister.CMapTable is not null)
             {
                 const int encodingSymbol = 0;
                 const int encodingUnicode = 1;
                 const int encodingMacRoman = 0;
 
                 foreach (var subTable in TableRegister.CMapTable.SubTables)
                 {
-                    if (WindowsSymbolCMap == null
+                    if (WindowsSymbolCMap is null
                         && subTable.PlatformId == TrueTypeCMapPlatform.Windows
                         && subTable.EncodingId == encodingSymbol)
                     {
                         WindowsSymbolCMap = subTable;
                     }
-                    else if (WindowsUnicodeCMap == null
+                    else if (WindowsUnicodeCMap is null
                              && subTable.PlatformId == TrueTypeCMapPlatform.Windows
                              && subTable.EncodingId == encodingUnicode)
                     {
                         WindowsUnicodeCMap = subTable;
                     }
-                    else if (MacRomanCMap == null
+                    else if (MacRomanCMap is null
                              && subTable.PlatformId == TrueTypeCMapPlatform.Macintosh
                              && subTable.EncodingId == encodingMacRoman)
                     {
@@ -107,8 +124,36 @@
         {
             boundingBox = default(PdfRectangle);
 
-            if (TableRegister.GlyphTable == null)
+            if (TableRegister.GlyphTable is null)
             {
+                if (cffFontCollection is not null)
+                {
+                    /*
+                     * The presence of a CFF (Compact Font Format) table in a TrueType font creates a hybrid situation where the font
+                     * container uses TrueType structure but contains PostScript-based glyph descriptions. According to the OpenType
+                     * specification, when a TrueType font contains a CFF table instead of a traditional glyf table, it indicates
+                     * "an OpenType font with PostScript outlines". This creates what's known as an OpenType CFF font, which uses
+                     * PostScript Type 2 charstrings for glyph descriptions rather than TrueType quadratic curves.
+                     *
+                     * This is to fix P2P-33713919.pdf
+                     * See https://github.com/BobLd/PdfPig.Rendering.Skia/issues/46
+                     * TODO - Add test coverage and need to review if the logic belongs here
+                     */
+
+                    var name = cffFontCollection.FirstFont.GetCharacterName(characterCode, true); // TODO cid?
+                    if (string.IsNullOrEmpty(name))
+                    {
+                        return false;
+                    }
+
+                    var bbox = cffFontCollection.FirstFont.GetCharacterBoundingBox(name);
+                    if (bbox.HasValue)
+                    {
+                        boundingBox = bbox.Value;
+                        return true;
+                    }
+                }
+
                 return false;
             }
 
@@ -143,8 +188,30 @@
         {
             path = null;
 
-            if (TableRegister.GlyphTable == null)
+            if (TableRegister.GlyphTable is null)
             {
+                if (cffFontCollection is not null)
+                {
+                    /*
+                     * The presence of a CFF (Compact Font Format) table in a TrueType font creates a hybrid situation where the font
+                     * container uses TrueType structure but contains PostScript-based glyph descriptions. According to the OpenType
+                     * specification, when a TrueType font contains a CFF table instead of a traditional glyf table, it indicates
+                     * "an OpenType font with PostScript outlines". This creates what's known as an OpenType CFF font, which uses
+                     * PostScript Type 2 charstrings for glyph descriptions rather than TrueType quadratic curves.
+                     *
+                     * This is to fix P2P-33713919.pdf
+                     * See https://github.com/BobLd/PdfPig.Rendering.Skia/issues/46
+                     * TODO - Add test coverage and need to review if the logic belongs here
+                     */
+
+                    var name = cffFontCollection.FirstFont.GetCharacterName(characterCode, true);
+                    if (string.IsNullOrEmpty(name))
+                    {
+                        return false;
+                    }
+                    return cffFontCollection.FirstFont.TryGetPath(name, out path);
+                }
+
                 return false;
             }
 
@@ -188,7 +255,7 @@
         {
             width = 0;
 
-            if (TableRegister.HorizontalMetricsTable == null)
+            if (TableRegister.HorizontalMetricsTable is null)
             {
                 return false;
             }
@@ -210,7 +277,7 @@
                 return true;
             }
 
-            if (TableRegister.CMapTable == null)
+            if (TableRegister.CMapTable is null)
             {
                 return false;
             }