handle checked state of radio buttons and checkboxes

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

@@ -2,6 +2,7 @@
 {
     using System;
     using System.Linq;
+    using AcroForms.Fields;
     using Xunit;
 
     public class AcroFormsBasicFieldsTests
@@ -53,5 +54,38 @@
                 Assert.Equal(18, fields.Count);
             }
         }
+
+        [Fact]
+        public void GetsRadioButtonState()
+        {
+            using (var document = PdfDocument.Open(GetFilename(), ParsingOptions.LenientParsingOff))
+            {
+                var form = document.GetForm();
+                var radioButtons = form.Fields.OfType<AcroRadioButtonsField>().ToList();
+
+                Assert.Equal(2, radioButtons.Count);
+
+                // ReSharper disable once PossibleInvalidOperationException
+                var ordered = radioButtons.OrderBy(x => x.Children.Min(y => y.Bounds.Value.Left)).ToList();
+
+                var left = ordered[0];
+
+                Assert.Equal(2, left.Children.Count);
+                foreach (var acroFieldBase in left.Children)
+                {
+                    var button = Assert.IsType<AcroRadioButtonField>(acroFieldBase);
+                    Assert.False(button.IsSelected);
+                }
+
+                var right = ordered[1];
+                Assert.Equal(2, right.Children.Count);
+
+                var buttonOn = Assert.IsType<AcroRadioButtonField>(right.Children[0]);
+                Assert.True(buttonOn.IsSelected);
+
+                var buttonOff = Assert.IsType<AcroRadioButtonField>(right.Children[1]);
+                Assert.False(buttonOff.IsSelected);
+            }
+        }
     }
 }

src/UglyToad.PdfPig/AcroForms/AcroForm.cs

@@ -16,6 +16,8 @@
     /// </remarks>
     internal class AcroForm
     {
+        private readonly IReadOnlyDictionary<IndirectReference, AcroFieldBase> fieldsWithReferences;
+
         /// <summary>
         /// The raw PDF dictionary which is the root form object.
         /// </summary>
@@ -33,20 +35,21 @@
         public bool NeedAppearances { get; }
 
         /// <summary>
-        /// All root fields in this form with their corresponding references.
+        /// All root fields in this form.
         /// </summary>
-        public IReadOnlyDictionary<IndirectReference, AcroFieldBase> Fields { get; }
+        public IReadOnlyList<AcroFieldBase> Fields { get; }
 
         /// <summary>
         /// Create a new <see cref="AcroForm"/>.
         /// </summary>
         public AcroForm(DictionaryToken dictionary, SignatureFlags signatureFlags, bool needAppearances,
-            IReadOnlyDictionary<IndirectReference, AcroFieldBase> fields)
+            IReadOnlyDictionary<IndirectReference, AcroFieldBase> fieldsWithReferences)
         {
             Dictionary = dictionary ?? throw new ArgumentNullException(nameof(dictionary));
             SignatureFlags = signatureFlags;
             NeedAppearances = needAppearances;
-            Fields = fields ?? throw new ArgumentNullException(nameof(fields));
+            this.fieldsWithReferences = fieldsWithReferences ?? throw new ArgumentNullException(nameof(fieldsWithReferences));
+            Fields = fieldsWithReferences.Values.ToList();
         }
 
         /// <summary>
@@ -61,14 +64,14 @@
 
             foreach (var field in Fields)
             {
-                if (field.Value.PageNumber == pageNumber)
+                if (field.PageNumber == pageNumber)
                 {
-                    yield return field.Value;
+                    yield return field;
                 }
-                else if (field.Value is AcroNonTerminalField parent
+                else if (field is AcroNonTerminalField parent
                 && parent.Children.Any(x => x.PageNumber == pageNumber))
                 {
-                    yield return field.Value;
+                    yield return field;
                 }
             }
         }

src/UglyToad.PdfPig/AcroForms/AcroFormFactory.cs

@@ -112,7 +112,9 @@
         private AcroFieldBase GetAcroField(DictionaryToken fieldDictionary, Catalog catalog,
             IReadOnlyList<DictionaryToken> parentDictionaries)
         {
-            fieldDictionary = CreateInheritedDictionary(fieldDictionary, parentDictionaries);
+            var (combinedFieldDictionary, inheritsValue) = CreateInheritedDictionary(fieldDictionary, parentDictionaries);
+
+            fieldDictionary = combinedFieldDictionary;
 
             fieldDictionary.TryGet(NameToken.Ft, tokenScanner, out NameToken fieldType);
             fieldDictionary.TryGet(NameToken.Ff, tokenScanner, out NumericToken fieldFlagsToken);
@@ -194,9 +196,13 @@
                     }
                     else
                     {
+                        var (isChecked, valueToken) = GetCheckedState(fieldDictionary, inheritsValue);
+
                         var field = new AcroRadioButtonField(fieldDictionary, fieldType, buttonFlags, information,
                             pageNumber,
-                            bounds);
+                            bounds,
+                            valueToken,
+                            isChecked);
                         
                         result = field;
                     }
@@ -210,16 +216,6 @@
                 }
                 else
                 {
-                    var isChecked = false;
-                    if (!fieldDictionary.TryGetOptionalTokenDirect(NameToken.V, tokenScanner, out NameToken valueToken))
-                    {
-                        valueToken = NameToken.Off;
-                    }
-                    else
-                    {
-                        isChecked = !string.Equals(valueToken.Data, NameToken.Off, StringComparison.OrdinalIgnoreCase);
-                    }
-
                     if (children.Count > 0)
                     {
                         result = new AcroCheckboxesField(fieldDictionary, fieldType, buttonFlags, information,
@@ -227,6 +223,7 @@
                     }
                     else
                     {
+                        var (isChecked, valueToken) = GetCheckedState(fieldDictionary, inheritsValue);
                         var field = new AcroCheckboxField(fieldDictionary, fieldType, buttonFlags, information,
                             valueToken,
                             isChecked,
@@ -440,14 +437,39 @@
                 pageNumber,
                 bounds);
         }
+
+        private (bool isChecked, NameToken stateName) GetCheckedState(DictionaryToken fieldDictionary, bool inheritsValue)
+        {
+            var isChecked = false;
+            if (!fieldDictionary.TryGetOptionalTokenDirect(NameToken.V, tokenScanner, out NameToken valueToken))
+            {
+                valueToken = NameToken.Off;
+            }
+            else if (inheritsValue && fieldDictionary.TryGet(NameToken.As, tokenScanner, out NameToken appearanceStateName))
+            {
+                // The parent field's V entry holds a name object corresponding to the 
+                // appearance state of whichever child field is currently in the on state.
+                isChecked = appearanceStateName.Equals(valueToken);
+                valueToken = appearanceStateName;
+            }
+            else
+            {
+                isChecked = !string.Equals(valueToken.Data, NameToken.Off, StringComparison.OrdinalIgnoreCase);
+            }
+
+            return (isChecked, valueToken);
+        }
         
-        private static DictionaryToken CreateInheritedDictionary(DictionaryToken fieldDictionary, IReadOnlyList<DictionaryToken> parents)
+        private static (DictionaryToken dictionary, bool inheritsValue) CreateInheritedDictionary(DictionaryToken fieldDictionary, 
+            IReadOnlyList<DictionaryToken> parents)
         {
             if (parents.Count == 0)
             {
-                return fieldDictionary;
+                return (fieldDictionary, false);
             }
 
+            var inheritsValue = false;
+
             var inheritedDictionary = new Dictionary<NameToken, IToken>();
             foreach (var parent in parents)
             {
@@ -457,16 +479,26 @@
                     if (InheritableFields.Contains(key))
                     {
                         inheritedDictionary[key] = kvp.Value;
+
+                        if (NameToken.V.Equals(key))
+                        {
+                            inheritsValue = true;
+                        }
                     }
                 }
             }
 
             foreach (var kvp in fieldDictionary.Data)
             {
-                inheritedDictionary[NameToken.Create(kvp.Key)] = kvp.Value;
+                var key = NameToken.Create(kvp.Key);
+                inheritedDictionary[key] = kvp.Value;
+                if (NameToken.V.Equals(key))
+                {
+                    inheritsValue = false;
+                }
             }
 
-            return new DictionaryToken(inheritedDictionary);
+            return (new DictionaryToken(inheritedDictionary), inheritsValue);
         }
 
         private static bool IsChoiceSelected(IReadOnlyList<string> selectedOptionNames, IReadOnlyList<int> selectedOptionIndices, int index, string name)

src/UglyToad.PdfPig/AcroForms/Fields/AcroRadioButtonField.cs

@@ -14,6 +14,16 @@
         /// </summary>
         public AcroButtonFieldFlags Flags { get; }
 
+        /// <summary>
+        /// The current value of this radio button.
+        /// </summary>
+        public NameToken CurrentValue { get; }
+
+        /// <summary>
+        /// Whether the radio button is currently on/active.
+        /// </summary>
+        public bool IsSelected { get; }
+        
         /// <inheritdoc />
         /// <summary>
         /// Create a new <see cref="AcroRadioButtonField"/>.
@@ -21,10 +31,14 @@
         public AcroRadioButtonField(DictionaryToken dictionary, string fieldType, AcroButtonFieldFlags fieldFlags,
             AcroFieldCommonInformation information,
             int? pageNumber,
-            PdfRectangle? bounds) :
+            PdfRectangle? bounds,
+            NameToken currentValue,
+            bool isSelected) :
             base(dictionary, fieldType, (uint)fieldFlags, AcroFieldType.RadioButton, information, pageNumber, bounds)
         {
             Flags = fieldFlags;
+            CurrentValue = currentValue;
+            IsSelected = isSelected;
         }
     }
 }