Properly handle ZapfDingbats font for Type1FontSimple and Type1Standard14Font and add tests

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

@@ -0,0 +1,55 @@
+namespace UglyToad.PdfPig.Tests.Integration
+{
+    using System.Linq;
+
+    public class ZapfDingbatsTests
+    {
+        [Fact]
+        public void Type1Standard14Font1()
+        {
+            using (var document = PdfDocument.Open(IntegrationHelpers.GetDocumentPath("TIKA-469-0")))
+            {
+                var page = document.GetPage(2);
+                Assert.Contains("●", page.Letters.Select(l => l.Value));
+            }
+        }
+
+        [Fact]
+        public void Type1Standard14Font2()
+        {
+            // This document does not actually contain circular references
+            using (var document = PdfDocument.Open(IntegrationHelpers.GetDocumentPath("MOZILLA-LINK-5251-1")))
+            {
+                var page = document.GetPage(1);
+                Assert.Contains("✁", page.Letters.Select(l => l.Value));
+                Assert.Contains("✂", page.Letters.Select(l => l.Value));
+                Assert.Contains("✄", page.Letters.Select(l => l.Value));
+                Assert.Contains("☎", page.Letters.Select(l => l.Value));
+                Assert.Contains("✆", page.Letters.Select(l => l.Value));
+                Assert.Contains("✇", page.Letters.Select(l => l.Value));
+            }
+        }
+
+        [Fact]
+        public void Type1FontSimple1()
+        {
+            // This document does not actually contain circular references
+            using (var document = PdfDocument.Open(IntegrationHelpers.GetDocumentPath("MOZILLA-2775-1")))
+            {
+                var page = document.GetPage(11);
+                Assert.Contains("●", page.Letters.Select(l => l.Value));
+            }
+        }
+
+        [Fact]
+        public void Type1FontSimple2()
+        {
+            // This document does not actually contain circular references
+            using (var document = PdfDocument.Open(IntegrationHelpers.GetDocumentPath("PDFBOX-492-4.jar-8")))
+            {
+                var page = document.GetPage(1);
+                Assert.Contains("\u25a0", page.Letters.Select(l => l.Value));
+            }
+        }
+    }
+}

src/UglyToad.PdfPig/PdfFonts/Simple/TrueTypeSimpleFont.cs

@@ -62,6 +62,9 @@
 
             Details = descriptor?.ToDetails(Name?.Data)
                       ?? FontDetails.GetDefault(Name?.Data);
+
+            // Assumption is ZapfDingbats is not possible here. We need to change the behaviour if not the case
+            System.Diagnostics.Debug.Assert(!(encoding is ZapfDingbatsEncoding || Details.Name.Contains("ZapfDingbats")));
         }
 
         public int ReadCharacterCode(IInputBytes bytes, out int codeLength)

src/UglyToad.PdfPig/PdfFonts/Simple/TrueTypeStandard14FallbackSimpleFont.cs

@@ -42,6 +42,9 @@
                 fontMetrics.Weight == "Bold",
                 fontMetrics.Weight == "Bold" ? 700 : FontDetails.DefaultWeight,
                 fontMetrics.ItalicAngle != 0);
+
+            // Assumption is ZapfDingbats is not possible here. We need to change the behaviour if not the case
+            System.Diagnostics.Debug.Assert(!(encoding is ZapfDingbatsEncoding || Details.Name.Contains("ZapfDingbats")));
         }
 
         public int ReadCharacterCode(IInputBytes bytes, out int codeLength)

src/UglyToad.PdfPig/PdfFonts/Simple/Type1FontSimple.cs

@@ -37,6 +37,8 @@
 
         private readonly TransformationMatrix fontMatrix;
 
+        private readonly bool isZapfDingbats;
+
         public NameToken Name { get; }
 
         public bool IsVertical { get; } = false;
@@ -80,6 +82,7 @@
             Name = name;
             Details = fontDescriptor?.ToDetails(name?.Data)
                       ?? FontDetails.GetDefault(name?.Data);
+            isZapfDingbats = encoding is ZapfDingbatsEncoding || Details.Name.Contains("ZapfDingbats");
         }
 
         public int ReadCharacterCode(IInputBytes bytes, out int codeLength)
@@ -124,6 +127,14 @@
 
             try
             {
+                if (isZapfDingbats)
+                {
+                    value = GlyphList.ZapfDingbats.NameToUnicode(name);
+                    if (value is not null)
+                    {
+                        return true;
+                    }
+                }
                 value = GlyphList.AdobeGlyphList.NameToUnicode(name);
             }
             catch

src/UglyToad.PdfPig/PdfFonts/Simple/Type1Standard14Font.cs

@@ -18,6 +18,7 @@ namespace UglyToad.PdfPig.PdfFonts.Simple
     {
         private readonly AdobeFontMetrics standardFontMetrics;
         private readonly Encoding encoding;
+        private readonly bool isZapfDingbats;
 
         public NameToken Name { get; }
 
@@ -39,6 +40,7 @@ namespace UglyToad.PdfPig.PdfFonts.Simple
                 standardFontMetrics.Weight == "Bold",
                 standardFontMetrics.Weight == "Bold" ? 700 : FontDetails.DefaultWeight,
                 standardFontMetrics.ItalicAngle != 0);
+            isZapfDingbats = encoding is ZapfDingbatsEncoding || Details.Name.Contains("ZapfDingbats");
         }
 
         public int ReadCharacterCode(IInputBytes bytes, out int codeLength)
@@ -49,39 +51,35 @@ namespace UglyToad.PdfPig.PdfFonts.Simple
 
         public bool TryGetUnicode(int characterCode, [NotNullWhen(true)] out string? value)
         {
+            value = null;
+
             var name = encoding.GetName(characterCode);
+
             if (string.Equals(name, GlyphList.NotDefined, StringComparison.OrdinalIgnoreCase))
             {
-                value = null;
                 return false;
             }
 
-            if (encoding is ZapfDingbatsEncoding)
+            try
             {
-                var listed = GlyphList.ZapfDingbats.NameToUnicode(name);
+                if (isZapfDingbats)
+                {
+                    value = GlyphList.ZapfDingbats.NameToUnicode(name);
 
-                value = listed;
+                    if (value is not null)
+                    {
+                        return true;
+                    }
+                }
 
-                return true;
+                value = GlyphList.AdobeGlyphList.NameToUnicode(name);
+            }
+            catch
+            {
+                return false;
             }
 
-            if (encoding is StandardEncoding || encoding is SymbolEncoding)
+            return value is not null;
-            {
-                var listed = GlyphList.AdobeGlyphList.NameToUnicode(name);
-
-                value = listed;
-
-                return true;
-            }
-            else
-            {
-                Debug.WriteLine($"Warning: Type1Standard14Font with unexpected encoding: '{encoding.EncodingName}' Expected: 'ZapfDingbatsEncoding','SymbolEncoding' or 'StandardEncoding' . Font: '{standardFontMetrics.FontName}'");
-                var listed = GlyphList.AdobeGlyphList.NameToUnicode(name);
-
-                value = listed;
-
-                return true;
-            }
         }
 
         public CharacterBoundingBox GetBoundingBox(int characterCode)

src/UglyToad.PdfPig/PdfFonts/Simple/Type3Font.cs

@@ -42,6 +42,9 @@
             this.widths = widths;
             this.toUnicodeCMap = new ToUnicodeCMap(toUnicodeCMap);
             Details = FontDetails.GetDefault(name?.Data);
+
+            // Assumption is ZapfDingbats is not possible here. We need to change the behaviour if not the case
+            System.Diagnostics.Debug.Assert(!(encoding is ZapfDingbatsEncoding || Details.Name.Contains("ZapfDingbats")));
         }
 
         public int ReadCharacterCode(IInputBytes bytes, out int codeLength)