start adding kerning table as a break from compact font format

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

@@ -27,5 +27,7 @@
         /// Where a character code isn't found it should map to index 0.
         /// </summary>
         public CMapTable CMapTable { get; set; }
+
+        public KerningTable KerningTable { get; set; }
     }
 }

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

@@ -102,7 +102,7 @@
 
                 if (!tables.TryGetValue(TrueTypeHeaderTable.Glyf, out var glyphHeaderTable))
                 {
-                    throw new InvalidOperationException("The glpyh table is required for non-PostScript fonts.");
+                    throw new InvalidOperationException("The glyph table is required for non-PostScript fonts.");
                 }
 
                 // glyf
@@ -137,6 +137,10 @@
             // os2
 
             // kern
+            if (tables.TryGetValue(TrueTypeHeaderTable.Kern, out var kernHeaderTable))
+            {
+                tableRegister.KerningTable = KerningTable.Load(data, kernHeaderTable);
+            }
         }
     }
 }

src/UglyToad.PdfPig/Fonts/TrueType/Tables/Kerning/KernCoverage.cs

@@ -0,0 +1,26 @@
+namespace UglyToad.PdfPig.Fonts.TrueType.Tables.Kerning
+{
+    using System;
+
+    [Flags]
+    internal enum KernCoverage
+    {
+        /// <summary>
+        /// The table is horizontal kerning data.
+        /// </summary>
+        Horizontal = 1,
+        /// <summary>
+        /// The table has minimum values rather than kerning values.
+        /// </summary>
+        Minimum = 1 << 1,
+        /// <summary>
+        /// Kerning is perpendicular to the flow of text.
+        /// If text is horizontal kerning will be in the up/down direction.
+        /// </summary>
+        CrossStream = 1 << 2,
+        /// <summary>
+        /// The value in this sub table should replace the currently accumulated value.
+        /// </summary>
+        Override = 1 << 3
+    }
+}

src/UglyToad.PdfPig/Fonts/TrueType/Tables/KerningTable.cs

@@ -0,0 +1,28 @@
+namespace UglyToad.PdfPig.Fonts.TrueType.Tables
+{
+    using Kerning;
+
+    internal class KerningTable
+    {
+        public static KerningTable Load(TrueTypeDataBytes data, TrueTypeHeaderTable headerTable)
+        {
+            data.Seek(headerTable.Offset);
+
+            var version = data.ReadUnsignedShort();
+
+            var numberOfSubtables = data.ReadUnsignedShort();
+
+            for (var i = 0; i < numberOfSubtables; i++)
+            {
+                var subtableVersion = data.ReadUnsignedShort();
+                var subtableLength = data.ReadUnsignedShort();
+                var coverage = data.ReadUnsignedShort();
+
+                var kernCoverage = (KernCoverage) coverage;
+                var format = ((coverage & 255) >> 8);
+            }
+
+            return new KerningTable();
+        }
+    }
+}

src/UglyToad.PdfPig/ICosUpdateInfo.cs

@@ -1,7 +0,0 @@
-namespace UglyToad.PdfPig
-{
-    internal interface ICosUpdateInfo
-    {
-        bool NeedsToBeUpdated { get; set; }
-    }
-}