Use StringToken.GetBytes() in ShowPositionedText() to fix #668 and add test

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

@@ -0,0 +1,32 @@
+namespace UglyToad.PdfPig.Tests.Integration
+{
+    using PdfPig.Core;
+    using PdfPig.Geometry;
+    using System.Linq;
+    using Xunit;
+
+    public class EncodingsTests
+    {
+        [Fact]
+        public void Issue688()
+        {
+            string path = IntegrationHelpers.GetDocumentPath("Indexed-DeviceRGB-JPXDecode-0-.0.0.255.0.-Font-F1_1_missing_char_255-1.pdf");
+            using (var document = PdfDocument.Open(path))
+            {
+                var page = document.GetPage(1);
+                var letters = page.Letters;
+                Assert.NotEmpty(letters);
+
+                var rect = new PdfRectangle(207, 158, 229, 168.5);
+
+                var missingChars = letters.Where(l => rect.Contains(l.GlyphRectangle)).ToArray();
+
+                Assert.NotEmpty(missingChars);
+                Assert.True(missingChars.Length == 2);
+
+                Assert.Equal("先", missingChars[0].Value);
+                Assert.Equal("祖", missingChars[1].Value);
+            }
+        }
+    }
+}

src/UglyToad.PdfPig/Graphics/BaseStreamProcessor.cs

@@ -388,7 +388,7 @@
                     }
                     else
                     {
-                        bytes = OtherEncodings.StringAsLatin1Bytes(((StringToken)token).Data);
+                        bytes = ((StringToken)token).GetBytes();
                     }
 
                     ShowText(new ByteArrayInputBytes(bytes));