add support for alternative colorspace in separation colorspaces #89

src/UglyToad.PdfPig.Tests/Graphics/TestOperationContext.cs

@@ -1,11 +1,14 @@
 namespace UglyToad.PdfPig.Tests.Graphics
 {
     using System.Collections.Generic;
+    using Content;
     using PdfPig.Geometry;
     using PdfPig.Graphics;
     using PdfPig.IO;
     using PdfPig.Tokens;
     using PdfPig.Core;
+    using PdfPig.Fonts;
+    using Tokens;
 
     internal class TestOperationContext : IOperationContext
     {
@@ -29,7 +32,7 @@
         {
             StateStack.Push(new CurrentGraphicsState());
             CurrentPath = new PdfPath();
-            ColorSpaceContext = new ColorSpaceContext(GetCurrentState);
+            ColorSpaceContext = new ColorSpaceContext(GetCurrentState, new ResourceStore(new TestPdfTokenScanner(), new TestFontFactory()));
         }
 
         public CurrentGraphicsState GetCurrentState()
@@ -89,5 +92,13 @@
         public void EndInlineImage(IReadOnlyList<byte> bytes)
         {
         }
+
+        private class TestFontFactory : IFontFactory
+        {
+            public IFont Get(DictionaryToken dictionary, bool isLenientParsing)
+            {
+                return null;
+            }
+        }
     }
 }

src/UglyToad.PdfPig/Content/IResourceStore.cs

@@ -1,6 +1,7 @@
 namespace UglyToad.PdfPig.Content
 {
     using Fonts;
+    using Graphics.Colors;
     using Tokens;
 
     internal interface IResourceStore
@@ -21,6 +22,6 @@
 
         IFont GetFontDirectly(IndirectReferenceToken fontReferenceToken, bool isLenientParsing);
 
-        bool TryGetNamedColorSpace(NameToken name, out IToken namedColorSpace);
+        bool TryGetNamedColorSpace(NameToken name, out ResourceColorSpace namedColorSpace);
     }
 }

src/UglyToad.PdfPig/Content/ResourceStore.cs

@@ -4,6 +4,7 @@
     using System.Collections.Generic;
     using Exceptions;
     using Fonts;
+    using Graphics.Colors;
     using Parser.Parts;
     using Tokenization.Scanner;
     using Tokens;
@@ -19,7 +20,7 @@
 
         private readonly Dictionary<NameToken, DictionaryToken> extendedGraphicsStates = new Dictionary<NameToken, DictionaryToken>();
 
-        private readonly Dictionary<NameToken, NameToken> colorSpaceNames = new Dictionary<NameToken, NameToken>();
+        private readonly Dictionary<NameToken, ResourceColorSpace> namedColorSpaces = new Dictionary<NameToken, ResourceColorSpace>();
 
         public ResourceStore(IPdfTokenScanner scanner, IFontFactory fontFactory)
         {
@@ -72,7 +73,7 @@
 
                     if (DirectObjectFinder.TryGet(nameColorSpacePair.Value, scanner, out NameToken colorSpaceName))
                     {
-                        colorSpaceNames[name] = colorSpaceName;
+                        namedColorSpaces[name] = new ResourceColorSpace(colorSpaceName);
                     }
                     else if (DirectObjectFinder.TryGet(nameColorSpacePair.Value, scanner, out ArrayToken colorSpaceArray))
                     {
@@ -88,7 +89,7 @@
                             throw new PdfDocumentFormatException($"Invalid ColorSpace array encountered in page resource dictionary: {colorSpaceArray}.");
                         }
 
-                        colorSpaceNames[name] = arrayNamedColorSpace;
+                        namedColorSpaces[name] = new ResourceColorSpace(arrayNamedColorSpace, colorSpaceArray);
                     }
                     else
                     {
@@ -158,16 +159,16 @@
             return font;
         }
 
-        public bool TryGetNamedColorSpace(NameToken name, out IToken namedToken)
+        public bool TryGetNamedColorSpace(NameToken name, out ResourceColorSpace namedToken)
         {
-            namedToken = null;
+            namedToken = default(ResourceColorSpace);
 
             if (name == null)
             {
                 throw new ArgumentNullException(nameof(name));
             }
 
-            if (!colorSpaceNames.TryGetValue(name, out var colorSpaceName))
+            if (!namedColorSpaces.TryGetValue(name, out var colorSpaceName))
             {
                 return false;
             }

src/UglyToad.PdfPig/Export/ITextExporter.cs

@@ -8,10 +8,10 @@ namespace UglyToad.PdfPig.Export
     public interface ITextExporter
     {
         /// <summary>
-        /// Get the text representation.
+        /// Get the text representation of a page in a desired format.
         /// </summary>
-        /// <param name="page"></param>
+        /// <param name="page">The page to convert to the format.</param>
-        /// <returns></returns>
+        /// <returns>The <see langword="string"/> containing the page contents represented in a compatible format.</returns>
         string Get(Page page);
     }
 }

src/UglyToad.PdfPig/Graphics/ColorSpaceContext.cs

@@ -2,27 +2,35 @@
 {
     using System;
     using Colors;
+    using Content;
     using Tokens;
 
     internal class ColorSpaceContext : IColorSpaceContext
     {
         private readonly Func<CurrentGraphicsState> currentStateFunc;
+        private readonly IResourceStore resourceStore;
 
         public ColorSpace CurrentStrokingColorSpace { get; private set; } = ColorSpace.DeviceGray;
 
         public ColorSpace CurrentNonStrokingColorSpace { get; private set; } = ColorSpace.DeviceGray;
 
-        public ColorSpaceContext(Func<CurrentGraphicsState> currentStateFunc)
+        public NameToken AdvancedStrokingColorSpace { get; private set; }
+
+        public NameToken AdvancedNonStrokingColorSpace { get; private set; }
+
+        public ColorSpaceContext(Func<CurrentGraphicsState> currentStateFunc, IResourceStore resourceStore)
         {
             this.currentStateFunc = currentStateFunc ?? throw new ArgumentNullException(nameof(currentStateFunc));
+            this.resourceStore = resourceStore ?? throw new ArgumentNullException(nameof(resourceStore));
         }
 
         public void SetStrokingColorspace(NameToken colorspace)
         {
-            if (colorspace.TryMapToColorSpace(out var colorspaceActual))
+            void DefaultColorSpace(ColorSpace? colorSpaceActual = null)
             {
-                CurrentStrokingColorSpace = colorspaceActual;
+                if (colorSpaceActual.HasValue)
-                switch (colorspaceActual)
+                {
+                    switch (colorSpaceActual)
                     {
                         case ColorSpace.DeviceGray:
                             currentStateFunc().CurrentStrokingColor = GrayColor.Black;
@@ -45,12 +53,40 @@
                 }
             }
 
-        public void SetNonStrokingColorspace(NameToken colorspace)
+            AdvancedStrokingColorSpace = null;
-        {
+
             if (colorspace.TryMapToColorSpace(out var colorspaceActual))
             {
-                CurrentNonStrokingColorSpace = colorspaceActual;
+                CurrentStrokingColorSpace = colorspaceActual;
-                switch (colorspaceActual)
+            }
+            else if (resourceStore.TryGetNamedColorSpace(colorspace, out var namedColorSpace))
+            {
+                if (namedColorSpace.Name == NameToken.Separation && namedColorSpace.Data is ArrayToken separationArray
+                                                                 && separationArray.Length == 4
+                                                                 && separationArray[2] is NameToken alternativeColorSpaceName
+                                                                 && alternativeColorSpaceName.TryMapToColorSpace(out colorspaceActual))
+                {
+                    AdvancedStrokingColorSpace = namedColorSpace.Name;
+                    CurrentStrokingColorSpace = colorspaceActual;
+                }
+                else
+                {
+                    DefaultColorSpace();
+                }
+            }
+            else
+            {
+                DefaultColorSpace();
+            }
+        }
+
+        public void SetNonStrokingColorspace(NameToken colorspace)
+        {
+            void DefaultColorSpace(ColorSpace? colorSpaceActual = null)
+            {
+                if (colorSpaceActual.HasValue)
+                {
+                    switch (colorSpaceActual)
                     {
                         case ColorSpace.DeviceGray:
                             currentStateFunc().CurrentNonStrokingColor = GrayColor.Black;
@@ -73,6 +109,33 @@
                 }
             }
 
+            AdvancedNonStrokingColorSpace = null;
+
+            if (colorspace.TryMapToColorSpace(out var colorspaceActual))
+            {
+                CurrentNonStrokingColorSpace = colorspaceActual;
+            }
+            else if (resourceStore.TryGetNamedColorSpace(colorspace, out var namedColorSpace))
+            {
+                if (namedColorSpace.Name == NameToken.Separation && namedColorSpace.Data is ArrayToken separationArray
+                                                                 && separationArray.Length == 4
+                                                                 && separationArray[2] is NameToken alternativeColorSpaceName
+                                                                 && alternativeColorSpaceName.TryMapToColorSpace(out var colorSpaceActual))
+                {
+                    AdvancedNonStrokingColorSpace = namedColorSpace.Name;
+                    CurrentNonStrokingColorSpace = colorSpaceActual;
+                }
+                else
+                {
+                    DefaultColorSpace();
+                }
+            }
+            else
+            {
+                DefaultColorSpace();
+            }
+        }
+
         public void SetStrokingColorGray(decimal gray)
         {
             CurrentStrokingColorSpace = ColorSpace.DeviceGray;

src/UglyToad.PdfPig/Graphics/Colors/ResourceStateColorSpace.cs

@@ -0,0 +1,22 @@
+namespace UglyToad.PdfPig.Graphics.Colors
+{
+    using Tokens;
+
+    /// <summary>
+    /// A color space definition from a resource dictionary.
+    /// </summary>
+    internal struct ResourceColorSpace
+    {
+        public NameToken Name { get; }
+
+        public IToken Data { get; }
+
+        public ResourceColorSpace(NameToken name, IToken data)
+        {
+            Name = name;
+            Data = data;
+        }
+
+        public ResourceColorSpace(NameToken name) : this(name, null) { }
+    }
+}

src/UglyToad.PdfPig/Graphics/ContentStreamProcessor.cs

@@ -92,7 +92,7 @@
             this.filterProvider = filterProvider ?? throw new ArgumentNullException(nameof(filterProvider));
             this.log = log;
             graphicsStack.Push(new CurrentGraphicsState());
-            ColorSpaceContext = new ColorSpaceContext(GetCurrentState);
+            ColorSpaceContext = new ColorSpaceContext(GetCurrentState, resourceStore);
         }
 
         public PageContent Process(IReadOnlyList<IGraphicsStateOperation> operations)

src/UglyToad.PdfPig/Graphics/IColorSpaceContext.cs

@@ -18,6 +18,16 @@
         /// </summary>
         ColorSpace CurrentNonStrokingColorSpace { get; }
 
+        /// <summary>
+        /// The name of the advanced ColorSpace active for stroking operations, if any.
+        /// </summary>
+        NameToken AdvancedStrokingColorSpace { get; }
+
+        /// <summary>
+        /// The name of the advanced ColorSpace active for non-stroking operations, if any.
+        /// </summary>
+        NameToken AdvancedNonStrokingColorSpace { get; }
+        
         /// <summary>
         ///  Set the current color space to use for stroking operations.
         /// </summary>

src/UglyToad.PdfPig/Graphics/InlineImageBuilder.cs

@@ -42,17 +42,17 @@
                     return true;
                 }
 
-                if (!resourceStore.TryGetNamedColorSpace(name, out var colorSpaceNamedToken) || !(colorSpaceNamedToken is NameToken newName))
+                if (!resourceStore.TryGetNamedColorSpace(name, out var colorSpaceNamedToken))
                 {
                     return false;
                 }
 
-                if (newName.TryMapToColorSpace(out colorSpaceResult))
+                if (colorSpaceNamedToken.Name.TryMapToColorSpace(out colorSpaceResult))
                 {
                     return true;
                 }
 
-                if (TryExtendedColorSpaceNameMapping(newName, out colorSpaceResult))
+                if (TryExtendedColorSpaceNameMapping(colorSpaceNamedToken.Name, out colorSpaceResult))
                 {
                     return true;
                 }

src/UglyToad.PdfPig/Graphics/Operations/SetNonStrokeColorAdvanced.cs

@@ -54,7 +54,8 @@
         /// <inheritdoc />
         public void Run(IOperationContext operationContext)
         {
-            if (operationContext.ColorSpaceContext.CurrentNonStrokingColorSpace.GetFamily() != ColorSpaceFamily.Device)
+            if (operationContext.ColorSpaceContext.CurrentNonStrokingColorSpace.GetFamily() != ColorSpaceFamily.Device
+                || operationContext.ColorSpaceContext.AdvancedNonStrokingColorSpace != null)
             {
                 return;
             }

src/UglyToad.PdfPig/Graphics/Operations/SetStrokeColorAdvanced.cs

@@ -54,7 +54,8 @@
         /// <inheritdoc />
         public void Run(IOperationContext operationContext)
         {
-            if (operationContext.ColorSpaceContext.CurrentStrokingColorSpace.GetFamily() != ColorSpaceFamily.Device)
+            if (operationContext.ColorSpaceContext.CurrentStrokingColorSpace.GetFamily() != ColorSpaceFamily.Device
+                || operationContext.ColorSpaceContext.AdvancedStrokingColorSpace != null)
             {
                 return;
             }

src/UglyToad.PdfPig/Parser/PageFactory.cs

@@ -138,6 +138,7 @@
 
         private PageContent GetContent(IReadOnlyList<byte> contentBytes, CropBox cropBox, UserSpaceUnit userSpaceUnit, PageRotationDegrees rotation, bool isLenientParsing)
         {
+            var txt = OtherEncodings.BytesAsLatin1String(contentBytes);
             var operations = pageContentParser.Parse(new ByteArrayInputBytes(contentBytes));
 
             var context = new ContentStreamProcessor(cropBox.Bounds, resourceStore, userSpaceUnit, rotation, isLenientParsing, pdfScanner, 

src/UglyToad.PdfPig/XObjects/XObjectFactory.cs

@@ -122,12 +122,12 @@
                 return true;
             }
 
-            if (!resourceStore.TryGetNamedColorSpace(name, out var colorSpaceNamedToken) || !(colorSpaceNamedToken is NameToken newName))
+            if (!resourceStore.TryGetNamedColorSpace(name, out var colorSpaceNamedToken))
             {
                 return false;
             }
 
-            return newName.TryMapToColorSpace(out colorSpaceResult);
+            return colorSpaceNamedToken.Name.TryMapToColorSpace(out colorSpaceResult);
         }
     }
 }