#20 support retrieval of named system fonts for truetype on windows

src/UglyToad.PdfPig/Fonts/Parser/Handlers/TrueTypeFontHandler.cs

@@ -1,6 +1,7 @@
 namespace UglyToad.PdfPig.Fonts.Parser.Handlers
 {
     using System;
+    using SystemFonts;
     using Cmap;
     using Encodings;
     using Exceptions;
@@ -18,18 +19,20 @@
     internal class TrueTypeFontHandler : IFontHandler
     {
         private readonly ILog log;
+        private readonly IPdfTokenScanner pdfScanner;
         private readonly IFilterProvider filterProvider;
         private readonly CMapCache cMapCache;
         private readonly FontDescriptorFactory fontDescriptorFactory;
         private readonly TrueTypeFontParser trueTypeFontParser;
         private readonly IEncodingReader encodingReader;
-        private readonly IPdfTokenScanner pdfScanner;
+        private readonly ISystemFontFinder systemFontFinder;
 
         public TrueTypeFontHandler(ILog log, IPdfTokenScanner pdfScanner, IFilterProvider filterProvider, 
             CMapCache cMapCache,
             FontDescriptorFactory fontDescriptorFactory,
             TrueTypeFontParser trueTypeFontParser,
-            IEncodingReader encodingReader)
+            IEncodingReader encodingReader,
+            ISystemFontFinder systemFontFinder)
         {
             this.log = log;
             this.filterProvider = filterProvider;
@@ -37,6 +40,7 @@
             this.fontDescriptorFactory = fontDescriptorFactory;
             this.trueTypeFontParser = trueTypeFontParser;
             this.encodingReader = encodingReader;
+            this.systemFontFinder = systemFontFinder;
             this.pdfScanner = pdfScanner;
         }
 
@@ -73,8 +77,16 @@
 
         private TrueTypeFontProgram ParseTrueTypeFont(FontDescriptor descriptor)
         {
-            if (descriptor?.FontFile == null)
+            if (descriptor.FontFile == null)
             {
+                try
+                {
+                    return systemFontFinder.GetTrueTypeFont(descriptor.FontName.Data);
+                }
+                catch (Exception ex)
+                {
+                    log.Error($"Failed finding system font by name: {descriptor.FontName}.", ex);
+                }
                 // TODO: check if this font is present on the host OS. See: FileSystemFontProvider.java
                 return null;
             }

src/UglyToad.PdfPig/Fonts/SystemFonts/ISystemFontFinder.cs

@@ -0,0 +1,9 @@
+using UglyToad.PdfPig.Fonts.TrueType;
+
+namespace UglyToad.PdfPig.Fonts.SystemFonts
+{
+    internal interface ISystemFontFinder
+    {
+        TrueTypeFontProgram GetTrueTypeFont(string name);
+    }
+}

src/UglyToad.PdfPig/Fonts/SystemFonts/SystemFontFinder.cs

@@ -9,12 +9,12 @@
     using TrueType;
     using TrueType.Parser;
 
-    internal class SystemFontFinder
+    internal class SystemFontFinder : ISystemFontFinder
     {
         private readonly TrueTypeFontParser trueTypeFontParser;
         private readonly Lazy<IReadOnlyList<SystemFontRecord>> availableFonts;
-
-        private readonly Dictionary<string, IFont> cache = new Dictionary<string, IFont>();
+        
+        private readonly Dictionary<string, TrueTypeFontProgram> cache = new Dictionary<string, TrueTypeFontProgram>(StringComparer.OrdinalIgnoreCase);
 
         public SystemFontFinder(TrueTypeFontParser trueTypeFontParser)
         {
@@ -42,6 +42,11 @@
 
         public TrueTypeFontProgram GetTrueTypeFont(string name)
         {
+            if (cache.TryGetValue(name, out var result))
+            {
+                return result;
+            }
+
             foreach (var record in availableFonts.Value)
             {
                 if (record.Type == SystemFontType.TrueType)
@@ -50,13 +55,21 @@
                     {
                         var input = new StreamInputBytes(fileStream);
                         var trueType = trueTypeFontParser.Parse(new TrueTypeDataBytes(input));
-                        //TODO: cache.
+                        var psName = trueType.TableRegister.NameTable?.GetPostscriptName() ?? trueType.Name;
+
+                        if (!cache.ContainsKey(psName))
+                        {
+                            cache[psName] = trueType;
+                        }
+
+                        if (string.Equals(psName, name, StringComparison.OrdinalIgnoreCase))
+                        {
+                            return trueType;
+                        }
                     }
                 }
-                else if (record.Type == SystemFontType.OpenType)
-                {
-                    throw new NotImplementedException($"TODO: OpenType fonts. Found system font: {record.Path}.");
-                }
+
+                // TODO: OTF
             }
 
             return null;

src/UglyToad.PdfPig/Parser/PdfDocumentFactory.cs

@@ -12,6 +12,7 @@
     using Fonts.Parser;
     using Fonts.Parser.Handlers;
     using Fonts.Parser.Parts;
+    using Fonts.SystemFonts;
     using Fonts.TrueType.Parser;
     using Fonts.Type1.Parser;
     using Graphics;
@@ -107,7 +108,7 @@
             var fontFactory = new FontFactory(log, new Type0FontHandler(cidFontFactory,
                 cMapCache, 
                 filterProvider, pdfScanner),
-                new TrueTypeFontHandler(log, pdfScanner, filterProvider, cMapCache, fontDescriptorFactory, trueTypeFontParser, encodingReader),
+                new TrueTypeFontHandler(log, pdfScanner, filterProvider, cMapCache, fontDescriptorFactory, trueTypeFontParser, encodingReader, new SystemFontFinder(new TrueTypeFontParser())),
                 new Type1FontHandler(pdfScanner, cMapCache, filterProvider, fontDescriptorFactory, encodingReader, 
                     new Type1FontParser(new Type1EncryptedPortionParser()),
                     new CompactFontFormatParser(new CompactFontFormatIndividualFontParser(compactFontFormatIndexReader, new CompactFontFormatTopLevelDictionaryReader(),