map missing character codes directly #44

previously if no matching unicode was found for a character code we would return a null letter. instead we now map from the character code directly to a character. this seems to work for most documents, except where there are ligatures, e.g. fi or ff, but is still better than not returning anything.

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

@@ -24,7 +24,7 @@
 
                 var page2 = document.GetPage(2);
 
-                Assert.Contains("isθc={θc1,θc2,...,θcn},", page2.Text);
+                Assert.Contains("is~θc={θc1,θc2,...,θcn},", page2.Text);
             }
         }
 

src/UglyToad.PdfPig/Graphics/ContentStreamProcessor.cs

@@ -137,6 +137,8 @@
                 if (!foundUnicode || unicode == null)
                 {
                     log.Warn($"We could not find the corresponding character with code {code} in font {font.Name}.");
+                    // Try casting directly to string as in PDFBox 1.8.
+                    unicode = new string((char)code, 1);
                 }
 
                 var wordSpacing = 0m;