start adding support for reading and applying XObjects

src/UglyToad.PdfPig.Tests/Integration/PigProductionHandbookTests.cs

@@ -24,6 +24,18 @@
             }
         }
 
+        [Fact]
+        public void CanReadPage9()
+        {
+            using (var document = PdfDocument.Open(GetFilename()))
+            {
+                var page = document.GetPage(9);
+
+                // TODO: This page requires a CFF font parser for Type 1 fonts, see 5.5.1
+                Assert.Contains("BreedsNative breeds of pig can be found throughout the country. They are a small body size compared to other exotic and crosses pig types. There name varies from region to region, for example", page.Text);
+            }
+        }
+
         [Fact]
         public void HasCorrectNumberOfPages()
         {

src/UglyToad.PdfPig/Content/ResourceContainer.cs

@@ -30,6 +30,21 @@
                 
                 LoadFontDictionary(fontDictionary, isLenientParsing);
             }
+
+            if (resourceDictionary.TryGet(NameToken.Xobject, out var xobjectBase))
+            {
+                var xobjectDictionary = DirectObjectFinder.Get<DictionaryToken>(xobjectBase, scanner);
+
+                foreach (var pair in xobjectDictionary.Data)
+                {
+                    if (!(pair.Value is IndirectReferenceToken reference))
+                    {
+                        throw new InvalidOperationException($"Expected the XObject dictionary value for key /{pair.Key} to be an indirect reference, instead got: {pair.Value}.");
+                    }
+
+                    currentResourceState[NameToken.Create(pair.Key)] = reference.Data;
+                }
+            }
         }
 
         private void LoadFontDictionary(DictionaryToken fontDictionary, bool isLenientParsing)

src/UglyToad.PdfPig/Graphics/Operations/InvokeNamedXObject.cs

@@ -0,0 +1,28 @@
+namespace UglyToad.PdfPig.Graphics.Operations
+{
+    using Content;
+    using Tokenization.Tokens;
+
+    internal class InvokeNamedXObject : IGraphicsStateOperation
+    {
+        public const string Symbol = "Do";
+
+        public string Operator => Symbol;
+
+        public NameToken Name { get; }
+
+        public InvokeNamedXObject(NameToken name)
+        {
+            Name = name;
+        }
+
+        public void Run(IOperationContext operationContext, IResourceStore resourceStore)
+        {
+        }
+
+        public override string ToString()
+        {
+            return $"{Name} {Symbol}";
+        }
+    }
+}

src/UglyToad.PdfPig/Graphics/ReflectionGraphicsStateOperationFactory.cs

@@ -163,7 +163,11 @@ namespace UglyToad.PdfPig.Graphics
                 {
                     if (operands[offset] is NameToken name)
                     {
-                        arguments.Add(name.Data);
+                        arguments.Add(name);
+                    }
+                    else if (operands[offset] is StringToken s)
+                    {
+                        arguments.Add(NameToken.Create(s.Data));
                     }
                     else
                     {