Resolve image data (implementation from @kasperdaff)

src/UglyToad.PdfPig/PdfExtensions.cs

@@ -1,87 +1,130 @@
-namespace UglyToad.PdfPig
+namespace UglyToad.PdfPig
 {
-    using System;
+    using System;
     using System.Diagnostics.CodeAnalysis;
-    using Core;
+    using Core;
-    using Filters;
+    using Filters;
     using Parser.Parts;
-    using Tokenization.Scanner;
+    using Tokenization.Scanner;
-    using Tokens;
+    using Tokens;
-
-    /// <summary>
-    /// Extensions for PDF types.
-    /// </summary>
-    public static class PdfExtensions
-    {
-        /// <summary>
-        /// Try and get the entry with a given name and type or look-up the object if it's an indirect reference.
-        /// </summary>
-        public static bool TryGet<T>(this DictionaryToken dictionary, NameToken name, IPdfTokenScanner tokenScanner, [NotNullWhen(true)] out T? token) 
-            where T : class, IToken
-        {
-            token = default;
-            if (!dictionary.TryGet(name, out var t) || !(t is T typedToken))
-            {
-                if (t is IndirectReferenceToken reference)
-                {
-                    return DirectObjectFinder.TryGet(reference, tokenScanner, out token);
-                }
-
-                return false;
-            }
-
-            token = typedToken;
-            return true;
-        }
 
-        /// <summary>
+    /// <summary>
-        /// Get the entry with a given name and type or look-up the object if it's an indirect reference.
+    /// Extensions for PDF types.
-        /// </summary>
+    /// </summary>
-        public static T Get<T>(this DictionaryToken dictionary, NameToken name, IPdfTokenScanner scanner) where T : class, IToken
+    public static class PdfExtensions
-        {
+    {
-            if (!dictionary.TryGet(name, out var token) || !(token is T typedToken))
+        /// <summary>
-            {
+        /// Try and get the entry with a given name and type or look-up the object if it's an indirect reference.
-                if (!(token is IndirectReferenceToken indirectReference))
+        /// </summary>
-                {
+        public static bool TryGet<T>(this DictionaryToken dictionary, NameToken name, IPdfTokenScanner tokenScanner, [NotNullWhen(true)] out T? token)
-                    throw new PdfDocumentFormatException($"Dictionary does not contain token with name {name} of type {typeof(T).Name}.");
+            where T : class, IToken
-                }
+        {
-
+            token = default;
-                typedToken = DirectObjectFinder.Get<T>(indirectReference, scanner);
+            if (!dictionary.TryGet(name, out var t) || !(t is T typedToken))
-            }
+            {
-
+                if (t is IndirectReferenceToken reference)
-            return typedToken;
+                {
+                    return DirectObjectFinder.TryGet(reference, tokenScanner, out token);
+                }
+
+                return false;
+            }
+
+            token = typedToken;
+            return true;
         }
 
-        /// <summary>
+        /// <summary>
-        /// Get the decoded data from this stream.
+        /// Get the entry with a given name and type or look-up the object if it's an indirect reference.
-        /// </summary>
+        /// </summary>
-        public static ReadOnlyMemory<byte> Decode(this StreamToken stream, IFilterProvider filterProvider)
+        public static T Get<T>(this DictionaryToken dictionary, NameToken name, IPdfTokenScanner scanner) where T : class, IToken
-        {
+        {
-            var filters = filterProvider.GetFilters(stream.StreamDictionary);
+            if (!dictionary.TryGet(name, out var token) || !(token is T typedToken))
-
+            {
-            var transform = stream.Data;
+                if (!(token is IndirectReferenceToken indirectReference))
-            for (var i = 0; i < filters.Count; i++)
+                {
-            {
+                    throw new PdfDocumentFormatException($"Dictionary does not contain token with name {name} of type {typeof(T).Name}.");
-                transform = filters[i].Decode(transform.Span, stream.StreamDictionary, i);
+                }
-            }
+
-
+                typedToken = DirectObjectFinder.Get<T>(indirectReference, scanner);
-            return transform;
+            }
+
+            return typedToken;
         }
-
+
-        /// <summary>
+        /// <summary>
-        /// Get the decoded data from this stream.
+        /// Get the decoded data from this stream.
-        /// </summary>
+        /// </summary>
-        public static ReadOnlyMemory<byte> Decode(this StreamToken stream, ILookupFilterProvider filterProvider, IPdfTokenScanner scanner)
+        public static ReadOnlyMemory<byte> Decode(this StreamToken stream, IFilterProvider filterProvider)
-        {
+        {
-            var filters = filterProvider.GetFilters(stream.StreamDictionary, scanner);
+            var filters = filterProvider.GetFilters(stream.StreamDictionary);
-
+
-            var transform = stream.Data;
+            var transform = stream.Data;
-            for (var i = 0; i < filters.Count; i++)
+            for (var i = 0; i < filters.Count; i++)
-            {
+            {
-                transform = filters[i].Decode(transform.Span, stream.StreamDictionary, i);
+                transform = filters[i].Decode(transform.Span, stream.StreamDictionary, i);
-            }
+            }
-
+
-            return transform;
+            return transform;
-        }
+        }
-    }
+
-}
+        /// <summary>
+        /// Get the decoded data from this stream.
+        /// </summary>
+        public static ReadOnlyMemory<byte> Decode(this StreamToken stream, ILookupFilterProvider filterProvider, IPdfTokenScanner scanner)
+        {
+            var filters = filterProvider.GetFilters(stream.StreamDictionary, scanner);
+
+            var transform = stream.Data;
+            for (var i = 0; i < filters.Count; i++)
+            {
+                transform = filters[i].Decode(transform.Span, stream.StreamDictionary, i);
+            }
+
+            return transform;
+        }
+
+        /// <summary>
+        /// Returns an equivalent token where any indirect references of child objects are
+        /// recursively traversed and resolved.
+        /// </summary>
+        internal static T Resolve<T>(this T token, IPdfTokenScanner scanner) where T : IToken
+        {
+            return (T)ResolveInternal(token, scanner);
+        }
+
+        private static IToken ResolveInternal(this IToken token, IPdfTokenScanner scanner)
+        {
+            if (token is StreamToken stream)
+            {
+                return new StreamToken(Resolve(stream.StreamDictionary, scanner), stream.Data);
+            }
+
+            if (token is DictionaryToken dict)
+            {
+                var resolvedItems = new Dictionary<NameToken, IToken>();
+                foreach (var kvp in dict.Data)
+                {
+                    var value = kvp.Value is IndirectReferenceToken reference ? scanner.Get(reference.Data).Data : kvp.Value;
+                    resolvedItems[NameToken.Create(kvp.Key)] = ResolveInternal(value, scanner);
+                }
+
+                return new DictionaryToken(resolvedItems);
+            }
+
+            if (token is ArrayToken arr)
+            {
+                var resolvedItems = new List<IToken>();
+                for (int i = 0; i < arr.Length; i++)
+                {
+                    var value = arr.Data[i] is IndirectReferenceToken reference ? scanner.Get(reference.Data).Data : arr.Data[i];
+                    resolvedItems.Add(ResolveInternal(value, scanner));
+                }
+                return new ArrayToken(resolvedItems);
+            }
+
+            var val = token is IndirectReferenceToken tokenReference ? scanner.Get(tokenReference.Data).Data : token;
+            return val;
+        }
+    }
+}

src/UglyToad.PdfPig/XObjects/XObjectFactory.cs

@@ -34,24 +34,18 @@
             if (xObject.Type != XObjectType.Image)
             {
                 throw new InvalidOperationException($"Cannot create an image from an XObject with type: {xObject.Type}.");
-            }
+            }
-
+
-            var dictionary = xObject.Stream.StreamDictionary;
+            var dictionary = xObject.Stream.StreamDictionary.Resolve(pdfScanner);
 
             var bounds = xObject.AppliedTransformation.Transform(new PdfRectangle(new PdfPoint(0, 0), new PdfPoint(1, 1)));
 
-            var width = dictionary.Get<NumericToken>(NameToken.Width, pdfScanner).Int;
+            var width = dictionary.GetInt(NameToken.Width);
-            var height = dictionary.Get<NumericToken>(NameToken.Height, pdfScanner).Int;
+            var height = dictionary.GetInt(NameToken.Height);
 
-            bool isImageMask = false;
+            var isImageMask = dictionary.TryGet(NameToken.ImageMask, out BooleanToken isMaskToken) && isMaskToken.Data;
-            if (dictionary.TryGet(NameToken.ImageMask, pdfScanner, out BooleanToken? isMaskToken))
-            {
-                dictionary = dictionary.With(NameToken.ImageMask, isMaskToken);
-                isImageMask = isMaskToken.Data;
-            }
 
-            var isJpxDecode = dictionary.TryGet(NameToken.Filter, pdfScanner, out NameToken filterName)
+            var isJpxDecode = dictionary.TryGet(NameToken.Filter, out NameToken filterName) && filterName.Equals(NameToken.JpxDecode);
-                && filterName.Equals(NameToken.JpxDecode);
 
             int bitsPerComponent;
             if (isImageMask)
@@ -63,7 +57,7 @@
                 if (isJpxDecode)
                 {
                     // Optional for JPX
-                    if (dictionary.TryGet(NameToken.BitsPerComponent, pdfScanner, out NumericToken? bitsPerComponentToken))
+                    if (dictionary.TryGet(NameToken.BitsPerComponent, out NumericToken? bitsPerComponentToken))
                     {
                         bitsPerComponent = bitsPerComponentToken.Int;
                         System.Diagnostics.Debug.Assert(bitsPerComponent == Jpeg2000Helper.GetJp2BitsPerComponent(xObject.Stream.Data.Span));
@@ -76,7 +70,7 @@
                 }
                 else
                 {
-                    if (!dictionary.TryGet(NameToken.BitsPerComponent, pdfScanner, out NumericToken? bitsPerComponentToken))
+                    if (!dictionary.TryGet(NameToken.BitsPerComponent, out NumericToken? bitsPerComponentToken))
                     {
                         throw new PdfDocumentFormatException($"No bits per component defined for image: {dictionary}.");
                     }
@@ -86,26 +80,14 @@
             }
 
             var intent = xObject.DefaultRenderingIntent;
-            if (dictionary.TryGet(NameToken.Intent, pdfScanner, out NameToken renderingIntentToken))
+            if (dictionary.TryGet(NameToken.Intent, out NameToken renderingIntentToken))
             {
                 intent = renderingIntentToken.Data.ToRenderingIntent();
             }
 
-            var interpolate = dictionary.TryGet(NameToken.Interpolate, pdfScanner, out BooleanToken? interpolateToken)
+            var interpolate = dictionary.TryGet(NameToken.Interpolate, out BooleanToken? interpolateToken)
-                              && interpolateToken.Data;
+                              && interpolateToken.Data;
-
+
-            if (dictionary.TryGet(NameToken.Filter, out var filterToken) && filterToken is IndirectReferenceToken)
-            {
-                if (dictionary.TryGet(NameToken.Filter, pdfScanner, out ArrayToken? filterArray))
-                {
-                    dictionary = dictionary.With(NameToken.Filter, filterArray);
-                }
-                else if (dictionary.TryGet(NameToken.Filter, pdfScanner, out NameToken? filterNameToken))
-                {
-                    dictionary = dictionary.With(NameToken.Filter, filterNameToken);
-                }
-            }
-
             var supportsFilters = true;
             var filters = filterProvider.GetFilters(dictionary, pdfScanner);
             foreach (var filter in filters)
@@ -115,34 +97,15 @@
                     supportsFilters = false;
                     break;
                 }
-            }
-
-            var decodeParams = dictionary.GetObjectOrDefault(NameToken.DecodeParms, NameToken.Dp);
-            if (decodeParams is IndirectReferenceToken refToken)
-            {
-                dictionary = dictionary.With(NameToken.DecodeParms, pdfScanner.Get(refToken.Data).Data);
             }
 
-            var jbig2GlobalsParams = dictionary.GetObjectOrDefault(NameToken.Jbig2Globals);
-            if (jbig2GlobalsParams is IndirectReferenceToken jbig2RefToken)
-            {
-                dictionary = dictionary.With(NameToken.Jbig2Globals, pdfScanner.Get(jbig2RefToken.Data).Data);
-            }
-
-            var imParams = dictionary.GetObjectOrDefault(NameToken.Im);
-            if (imParams is IndirectReferenceToken imRefToken)
-            {
-                dictionary = dictionary.With(NameToken.Im, pdfScanner.Get(imRefToken.Data).Data);
-            }
-
             var streamToken = new StreamToken(dictionary, xObject.Stream.Data);
 
             var decodedBytes = supportsFilters ? new Lazy<ReadOnlyMemory<byte>>(() => streamToken.Decode(filterProvider, pdfScanner))
                 : null;
 
             var decode = Array.Empty<double>();
-
+            if (dictionary.TryGet(NameToken.Decode, out ArrayToken decodeArrayToken))
-            if (dictionary.TryGet(NameToken.Decode, pdfScanner, out ArrayToken? decodeArrayToken))
             {
                 decode = decodeArrayToken.Data.OfType<NumericToken>()
                     .Select(x => x.Double)
@@ -152,11 +115,11 @@
             ColorSpaceDetails? details = null;
             if (!isImageMask)
             {
-                if (dictionary.TryGet(NameToken.ColorSpace, pdfScanner, out NameToken? colorSpaceNameToken))
+                if (dictionary.TryGet(NameToken.ColorSpace, out NameToken? colorSpaceNameToken))
                 {
                     details = resourceStore.GetColorSpaceDetails(colorSpaceNameToken, dictionary);
                 }
-                else if (dictionary.TryGet(NameToken.ColorSpace, pdfScanner, out ArrayToken? colorSpaceArrayToken)
+                else if (dictionary.TryGet(NameToken.ColorSpace, out ArrayToken? colorSpaceArrayToken)
                     && colorSpaceArrayToken.Length > 0 && colorSpaceArrayToken.Data[0] is NameToken firstColorSpaceName)
                 {
                     details = resourceStore.GetColorSpaceDetails(firstColorSpaceName, dictionary);
@@ -164,7 +127,7 @@
                 else if (!isJpxDecode)
                 {
                     details = xObject.DefaultColorSpace;
-                }
+                }
             }
             else
             {
@@ -184,7 +147,7 @@
                 dictionary,
                 xObject.Stream.Data,
                 decodedBytes,
-                details);
+                details);
         }
     }
 }