Merge pull request #331 from kasperdaff/various-image-fixes

Various image related fixes and ICCBased (limited), CalGray and CalRGB color spaces support

src/UglyToad.PdfPig.Tests/Images/Files/iccbased-decoded.bin

@@ -0,0 +1 @@
+h･m

src/UglyToad.PdfPig.Tests/Images/ImageHelpers.cs

@@ -2,15 +2,28 @@
 {
     using System;
     using System.IO;
+    using System.IO.Compression;
     using UglyToad.PdfPig.Images.Png;
 
     public static class ImageHelpers
     {
         private static readonly string FilesFolder = Path.GetFullPath(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "..", "..", "..", "Images", "Files"));
 
-        public static byte[] LoadFileBytes(string filename)
+        public static byte[] LoadFileBytes(string filename, bool isCompressed = false)
         {
-            return File.ReadAllBytes(Path.Combine(FilesFolder, filename));
+            var filePath = Path.Combine(FilesFolder, filename);
+            var memoryStream = new MemoryStream();
+            if (isCompressed)
+            {
+                using (var deflateStream = new DeflateStream(File.OpenRead(filePath), CompressionMode.Decompress))
+                {
+                    deflateStream.CopyTo(memoryStream);
+                }
+
+                return memoryStream.ToArray();
+            }
+
+            return File.ReadAllBytes(filePath);
         }
 
         public static bool ImagesAreEqual(byte[] first, byte[] second)

src/UglyToad.PdfPig.Tests/Images/PngFromPdfImageFactoryTests.cs

@@ -1,5 +1,6 @@
 namespace UglyToad.PdfPig.Tests.Images
 {
+    using System.Collections.Generic;
     using System.Linq;
     using UglyToad.PdfPig.Graphics.Colors;
     using UglyToad.PdfPig.Images.Png;
@@ -150,7 +151,7 @@
             var decodedBytes = ImageHelpers.LoadFileBytes("ccittfax-decoded.bin");
             var image = new TestPdfImage
             {
-                ColorSpaceDetails = IndexedColorSpaceDetails.StencilBlackIs1,
+                ColorSpaceDetails = IndexedColorSpaceDetails.Stencil(DeviceGrayColorSpaceDetails.Instance, new[] { 1m, 0 }),
                 DecodedBytes = decodedBytes,
                 WidthInSamples = 1800,
                 HeightInSamples = 3113,
@@ -161,6 +162,103 @@
             Assert.True(ImageHelpers.ImagesAreEqual(LoadImage("ccittfax.png"), bytes));
         }
 
+        [Fact]
+        public void CanGeneratePngFromICCBasedImageData()
+        {
+            var decodedBytes = ImageHelpers.LoadFileBytes("iccbased-decoded.bin");
+            var image = new TestPdfImage
+            {
+                ColorSpaceDetails = new ICCBasedColorSpaceDetails(
+                    numberOfColorComponents: 3,
+                    alternateColorSpaceDetails: DeviceRgbColorSpaceDetails.Instance,
+                    range: new List<decimal> { 0, 1, 0, 1, 0, 1 },
+                    metadata: null),
+                DecodedBytes = decodedBytes,
+                WidthInSamples = 1,
+                HeightInSamples = 1,
+                BitsPerComponent = 8
+            };
+
+            Assert.True(PngFromPdfImageFactory.TryGenerate(image, out var bytes));
+            Assert.True(ImageHelpers.ImagesAreEqual(LoadImage("iccbased.png"), bytes));
+        }
+
+        [Fact]
+        public void AlternateColorSpaceDetailsIsCurrentlyUsedInPdfPigWhenGeneratingPngsFromICCBasedImageData()
+        {
+            var decodedBytes = ImageHelpers.LoadFileBytes("iccbased-decoded.bin");
+            var iccBasedImage = new TestPdfImage
+            {
+                ColorSpaceDetails = new ICCBasedColorSpaceDetails(
+                    numberOfColorComponents: 3,
+                    alternateColorSpaceDetails: DeviceRgbColorSpaceDetails.Instance,
+                    range: new List<decimal> { 0, 1, 0, 1, 0, 1 },
+                    metadata: null),
+                DecodedBytes = decodedBytes,
+                WidthInSamples = 1,
+                HeightInSamples = 1,
+                BitsPerComponent = 8
+            };
+
+            var deviceRGBImage = new TestPdfImage
+            {
+                ColorSpaceDetails = DeviceRgbColorSpaceDetails.Instance,
+                DecodedBytes = decodedBytes,
+                WidthInSamples = 1,
+                HeightInSamples = 1,
+                BitsPerComponent = 8
+            };
+
+            Assert.True(PngFromPdfImageFactory.TryGenerate(iccBasedImage, out var iccPngBytes));
+            Assert.True(PngFromPdfImageFactory.TryGenerate(deviceRGBImage, out var deviceRgbBytes));
+            Assert.Equal(iccPngBytes, deviceRgbBytes);
+
+        }
+
+        [Fact]
+        public void CanGeneratePngFromCalRGBImageData()
+        {
+            var decodedBytes = ImageHelpers.LoadFileBytes("calrgb-decoded.bin");
+            var image = new TestPdfImage
+            {
+                ColorSpaceDetails = new CalRGBColorSpaceDetails(
+                    whitePoint: new List<decimal> { 0.95043m, 1, 1.09m },
+                    blackPoint: null,
+                    gamma: new List<decimal> { 2.2m, 2.2m, 2.2m },
+                    matrix: new List<decimal> {
+                        0.41239m, 0.21264m, 0.01933m,
+                        0.35758m, 0.71517m, 0.11919m,
+                        0.18045m, 0.07218m, 0.9504m }),
+                DecodedBytes = decodedBytes,
+                WidthInSamples = 153,
+                HeightInSamples = 83,
+                BitsPerComponent = 8
+            };
+
+            Assert.True(PngFromPdfImageFactory.TryGenerate(image, out var bytes));
+            Assert.True(ImageHelpers.ImagesAreEqual(LoadImage("calrgb.png"), bytes));
+        }
+
+        [Fact]
+        public void CanGeneratePngFromCalGrayImageData()
+        {
+            var decodedBytes = ImageHelpers.LoadFileBytes("calgray-decoded.bin", isCompressed: true);
+            var image = new TestPdfImage
+            {
+                ColorSpaceDetails = new CalGrayColorSpaceDetails(
+                    whitePoint: new List<decimal> { 0.9505000114m, 1, 1.0889999866m },
+                    blackPoint: null,
+                    gamma: 2.2000000477m),
+                DecodedBytes = decodedBytes,
+                WidthInSamples = 2480,
+                HeightInSamples = 1748,
+                BitsPerComponent = 8,
+            };
+
+            Assert.True(PngFromPdfImageFactory.TryGenerate(image, out var bytes));
+            Assert.True(ImageHelpers.ImagesAreEqual(LoadImage("calgray.png"), bytes));
+        }
+
         private static byte[] LoadImage(string name)
         {
             return ImageHelpers.LoadFileBytes(name);

src/UglyToad.PdfPig.Tests/PublicApiScannerTests.cs

@@ -105,9 +105,12 @@
                 "UglyToad.PdfPig.Graphics.Colors.IColor",
                 "UglyToad.PdfPig.Graphics.Colors.RGBColor",
                 "UglyToad.PdfPig.Graphics.Colors.ColorSpaceDetails",
+                "UglyToad.PdfPig.Graphics.Colors.CalGrayColorSpaceDetails",
+                "UglyToad.PdfPig.Graphics.Colors.CalRGBColorSpaceDetails",
                 "UglyToad.PdfPig.Graphics.Colors.DeviceGrayColorSpaceDetails",
                 "UglyToad.PdfPig.Graphics.Colors.DeviceRgbColorSpaceDetails",
                 "UglyToad.PdfPig.Graphics.Colors.DeviceCmykColorSpaceDetails",
+                "UglyToad.PdfPig.Graphics.Colors.ICCBasedColorSpaceDetails",
                 "UglyToad.PdfPig.Graphics.Colors.IndexedColorSpaceDetails",
                 "UglyToad.PdfPig.Graphics.Colors.SeparationColorSpaceDetails",
                 "UglyToad.PdfPig.Graphics.Colors.UnsupportedColorSpaceDetails",

src/UglyToad.PdfPig.Tests/TestPdfImage.cs

@@ -6,6 +6,7 @@
     using UglyToad.PdfPig.Graphics.Colors;
     using UglyToad.PdfPig.Graphics.Core;
     using UglyToad.PdfPig.Images.Png;
+    using UglyToad.PdfPig.Tokens;
 
     public class TestPdfImage : IPdfImage
     {
@@ -31,6 +32,8 @@
 
         public bool IsInlineImage { get; set; }
 
+        public DictionaryToken ImageDictionary { get; set; }
+
         public ColorSpaceDetails ColorSpaceDetails { get; set; }
 
         public IReadOnlyList<byte> DecodedBytes { get; set; }

src/UglyToad.PdfPig.Tests/Util/Matrix3x3Tests.cs

@@ -0,0 +1,121 @@
+namespace UglyToad.PdfPig.Tests.Util
+{
+    using Xunit;
+    using PdfPig.Util;
+
+    public class Matrix3x3Tests
+    {
+        [Fact]
+        public void CanCreate()
+        {
+            var matrix = new Matrix3x3(
+               1, 2, 3,
+               4, 5, 6,
+               7, 8, 9);
+
+            Assert.Equal(new double[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 }, matrix);
+        }
+
+        [Fact]
+        public void ExposesIdentityMatrix()
+        {
+            var matrix = new Matrix3x3(
+                1, 0, 0,
+                0, 1, 0,
+                0, 0, 1
+            );
+
+            Assert.Equal(matrix, Matrix3x3.Identity);
+        }
+
+        [Fact]
+        public void CanMultiplyWithFactor()
+        {
+            var matrix = new Matrix3x3(
+                1, 2, 3,
+                4, 5, 6,
+                7, 8, 9);
+
+            var result = matrix.Multiply(3);
+
+            Assert.Equal(new double[] { 3, 6, 9, 12, 15, 18, 21, 24, 27 }, result);
+        }
+
+        [Fact]
+        public void CanMultiplyWithVector()
+        {
+            var matrix = new Matrix3x3(
+                1, 2, 3,
+                4, 5, 6,
+                7, 8, 9);
+
+            var vector = (1, 2, 3);
+
+            var product = matrix.Multiply(vector);
+
+            Assert.Equal((14, 32, 50), product);
+            // Result can be verified here:
+            // https://www.wolframalpha.com/input/?i=%7B%7B1%2C2%2C+3%7D%2C%7B4%2C5%2C6%7D%2C%7B7%2C8%2C9%7D%7D.%7B1%2C2%2C3%7D
+        }
+
+        [Fact]
+        public void CanMultiplyWithMatrix()
+        {
+            var matrix = new Matrix3x3(
+               1, 2, 3,
+               4, 5, 6,
+               7, 8, 9);
+
+            var product = matrix.Multiply(matrix);
+
+            var expected = new Matrix3x3(
+                30, 36, 42,
+                66, 81, 96,
+                102, 126, 150);
+
+            Assert.Equal(expected, product);
+            // Result can be verified here:
+            // https://www.wolframalpha.com/input/?i=%7B%7B1%2C2%2C3%7D%2C%7B4%2C5%2C6%7D%2C%7B7%2C8%2C9%7D%7D.%7B%7B1%2C2%2C3%7D%2C%7B4%2C5%2C6%7D%2C%7B7%2C8%2C9%7D%7D
+
+        }
+
+        [Fact]
+        public void CanTranspose()
+        {
+            var matrix = new Matrix3x3(
+                1, 2, 3,
+                4, 5, 6,
+                7, 8, 9);
+
+            var transposed = matrix.Transpose();
+
+            Assert.Equal(new double[] { 1, 4, 7, 2, 5, 8, 3, 6, 9 }, transposed);
+        }
+
+        [Fact]
+        public void InverseReturnsMatrixIfPossible()
+        {
+            var matrix = new Matrix3x3(
+                1, 2, 3,
+                0, 1, 4,
+                5, 6, 0);
+
+            var inverse = matrix.Inverse();
+
+            Assert.Equal(new double[] { -24, 18, 5, 20, -15, -4, -5, 4, 1 }, inverse);
+            Assert.Equal(Matrix3x3.Identity, matrix.Multiply(inverse));
+        }
+
+        [Fact]
+        public void InverseReturnsNullIfNotPossible()
+        {
+            var matrix = new Matrix3x3(
+                1, 2, 3,
+                4, 5, 6,
+                7, 8, 9);
+
+            var inverse = matrix.Inverse();
+            Assert.Null(inverse);
+        }
+    }
+}

src/UglyToad.PdfPig.Tokens/DictionaryToken.cs

@@ -102,6 +102,16 @@
         /// <returns>A new <see cref="DictionaryToken"/> with the entry created or modified.</returns>
         public DictionaryToken With(string key, IToken value)
         {
+            if (key == null)
+            {
+                throw new ArgumentNullException(nameof(key));
+            }
+
+            if (value == null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
             var result = new Dictionary<string, IToken>(Data.Count + 1);
 
             foreach (var keyValuePair in Data)
@@ -114,6 +124,35 @@
             return new DictionaryToken(result);
         }
 
+        /// <summary>
+        /// Creates a copy of this dictionary with the entry with the specified key removed (if it exists).
+        /// </summary>
+        /// <param name="key">The key of the entry to remove.</param>
+        /// <returns>A new <see cref="DictionaryToken"/> with the entry removed.</returns>
+        public DictionaryToken Without(NameToken key) => Without(key.Data);
+
+        /// <summary>
+        /// Creates a copy of this dictionary with the entry with the specified key removed (if it exists).
+        /// </summary>
+        /// <param name="key">The key of the entry to remove.</param>
+        /// <returns>A new <see cref="DictionaryToken"/> with the entry removed.</returns>
+        public DictionaryToken Without(string key)
+        {
+            if (key == null)
+            {
+                throw new ArgumentNullException(nameof(key));
+            }
+
+            var result = new Dictionary<string, IToken>(Data.ContainsKey(key) ? Data.Count - 1 : Data.Count);
+
+            foreach (var keyValuePair in Data.Where(x => !x.Key.Equals(key)))
+            {
+                result[keyValuePair.Key] = keyValuePair.Value;
+            }
+
+            return new DictionaryToken(result);
+        }
+
         /// <summary>
         /// Create a new <see cref="DictionaryToken"/>.
         /// </summary>

src/UglyToad.PdfPig/Content/IPdfImage.cs

@@ -3,7 +3,8 @@
     using System.Collections.Generic;
     using Core;
     using Graphics.Colors;
-    using Graphics.Core;
+    using Graphics.Core;
+    using UglyToad.PdfPig.Tokens;
     using XObjects;
 
     /// <summary>
@@ -84,6 +85,11 @@
         /// </summary>
         bool IsInlineImage { get; }
 
+        /// <summary>
+        /// The full dictionary for this image object.
+        /// </summary>
+        DictionaryToken ImageDictionary { get; }
+
         /// <summary>
         /// Full details for the <see cref="ColorSpace"/> with any associated data.
         /// </summary>

src/UglyToad.PdfPig/Content/InlineImage.cs

@@ -8,8 +8,9 @@
     using Graphics.Colors;
     using Graphics.Core;
     using Tokens;
-    using Images.Png;
+    using Images.Png;
-
+    using UglyToad.PdfPig.Util.JetBrains.Annotations;
+
     /// <inheritdoc />
     /// <summary>
     /// A small image that is completely defined directly inline within a <see cref="T:UglyToad.PdfPig.Content.Page" />'s content stream.
@@ -42,6 +43,10 @@
         /// <inheritdoc />
         public bool IsInlineImage { get; } = true;
 
+        /// <inheritdoc />
+        [NotNull]
+        public DictionaryToken ImageDictionary { get; }
+
         /// <inheritdoc />
         public RenderingIntent RenderingIntent { get; }
 
@@ -76,6 +81,7 @@
             IsImageMask = isImageMask;
             RenderingIntent = renderingIntent;
             Interpolate = interpolate;
+            ImageDictionary = streamDictionary;
 
             RawBytes = bytes;
             ColorSpaceDetails = colorSpaceDetails;

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

@@ -0,0 +1,111 @@
+namespace UglyToad.PdfPig.Graphics.Colors
+{
+    using System;
+    using UglyToad.PdfPig.Util;
+
+    /// <summary>
+    /// Transformer for CIEBased color spaces.
+    ///
+    /// In addition to the PDF spec itself, the transformation implementation is based on the descriptions in:
+    /// https://en.wikipedia.org/wiki/SRGB#The_forward_transformation_(CIE_XYZ_to_sRGB) and
+    /// http://www.brucelindbloom.com/index.html?Eqn_XYZ_to_RGB.html
+    /// </summary>
+    internal class CIEBasedColorSpaceTransformer
+    {
+        private readonly RGBWorkingSpace destinationWorkingSpace;
+        private readonly Matrix3x3 transformationMatrix;
+        private readonly ChromaticAdaptation chromaticAdaptation;
+
+        // These properties control how the color is translated from ABC to XYZ:
+        public Func<(double A, double B, double C), (double A, double B, double C)> DecoderABC { get; set; } = color => color;
+        public Func<(double L, double M, double N), (double L, double M, double N)> DecoderLMN { get; set; } = color => color;
+        public Matrix3x3 MatrixABC { get; set; } = Matrix3x3.Identity;
+        public Matrix3x3 MatrixLMN { get; set; } = Matrix3x3.Identity;
+
+        public CIEBasedColorSpaceTransformer((double X, double Y, double Z) sourceReferenceWhite, RGBWorkingSpace destinationWorkingSpace)
+        {
+            this.destinationWorkingSpace = destinationWorkingSpace;
+
+            // Create an adapter capable of adapting from one reference white to another
+            chromaticAdaptation = new ChromaticAdaptation(sourceReferenceWhite, destinationWorkingSpace.ReferenceWhite);
+
+            // Construct the transformation matrix capable of transforming from XYZ of the source color space
+            // to RGB of the destination color space
+            var xr = destinationWorkingSpace.RedPrimary.x;
+            var yr = destinationWorkingSpace.RedPrimary.y;
+
+            var xg = destinationWorkingSpace.GreenPrimary.x;
+            var yg = destinationWorkingSpace.GreenPrimary.y;
+
+            var xb = destinationWorkingSpace.BluePrimary.x;
+            var yb = destinationWorkingSpace.BluePrimary.y;
+
+            var Xr = xr / yr;
+            var Yr = 1;
+            var Zr = (1 - xr - yr) / yr;
+
+            var Xg = xg / yg;
+            var Yg = 1;
+            var Zg = (1 - xg - yg) / yg;
+
+            var Xb = xb / yb;
+            var Yb = 1;
+            var Zb = (1 - xb - yb) / yb;
+
+            var mXYZ = new Matrix3x3(
+                Xr, Xg, Xb,
+                Yr, Yg, Yb,
+                Zr, Zg, Zb).Inverse();
+
+            var S = mXYZ.Multiply(destinationWorkingSpace.ReferenceWhite);
+
+            var Sr = S.Item1;
+            var Sg = S.Item2;
+            var Sb = S.Item3;
+
+            var M = new Matrix3x3(
+                Sr * Xr, Sg * Xg, Sb * Xb,
+                Sr * Yr, Sg * Yg, Sb * Yb,
+                Sr * Zr, Sg * Zg, Sb * Zb);
+
+            transformationMatrix = M.Inverse();
+        }
+
+        /// <summary>
+        /// Transforms the supplied ABC color to the RGB color of the <see cref="RGBWorkingSpace"/>
+        /// that was supplied to this <see cref="CIEBasedColorSpaceTransformer"/> as the destination
+        /// workspace.
+        /// A, B and C represent red, green and blue calibrated color values in the range 0 to 1. 
+        /// </summary>
+        public (double R, double G, double B) TransformToRGB((double A, double B, double C) color)
+        {
+            var xyz = TransformToXYZ(color);
+
+            var adaptedColor = chromaticAdaptation.Transform(xyz);
+            var rgb = transformationMatrix.Multiply(adaptedColor);
+
+            var gammaCorrectedR = destinationWorkingSpace.GammaCorrection(rgb.Item1);
+            var gammaCorrectedG = destinationWorkingSpace.GammaCorrection(rgb.Item2);
+            var gammaCorrectedB = destinationWorkingSpace.GammaCorrection(rgb.Item3);
+
+            return (Clamp(gammaCorrectedR), Clamp(gammaCorrectedG), Clamp(gammaCorrectedB));
+        }
+
+        private (double X, double Y, double Z) TransformToXYZ((double A, double B, double C) color)
+        {
+            var decodedABC = DecoderABC(color);
+            var lmn = MatrixABC.Multiply(decodedABC);
+
+            var decodedLMN = DecoderLMN(lmn);
+            var xyz = MatrixLMN.Multiply(decodedLMN);
+
+            return xyz;
+        }
+
+        private static double Clamp(double value)
+        {
+            // Force value into range [0..1]
+            return value < 0 ? 0 : value > 1 ? 1 : value;
+        }
+    }
+}

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

@@ -0,0 +1,66 @@
+namespace UglyToad.PdfPig.Graphics.Colors
+{
+    using UglyToad.PdfPig.Util;
+
+    /// <summary>
+    /// Encapsulates the algorithm for chromatic adaptation described here:
+    /// http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html
+    /// </summary>
+    internal class ChromaticAdaptation
+    {
+        public enum Method { XYZScaling, Bradford, VonKries };
+
+        private readonly Matrix3x3 adaptationMatrix;
+
+        public ChromaticAdaptation(
+            (double Xws, double Yws, double Zws) sourceReferenceWhite,
+            (double Xwd, double Ywd, double Zwd) destinationReferenceWhite,
+            Method method = Method.Bradford)
+        {
+            var coneReponseDomain = GetConeResponseDomain(method);
+            var inverseConeResponseDomain = coneReponseDomain.Inverse();
+            var (ρS, γS, βS) = coneReponseDomain.Multiply(sourceReferenceWhite);
+
+            var (ρD, γD, βD) = coneReponseDomain.Multiply(destinationReferenceWhite);
+
+            var scale = new Matrix3x3(
+                ρD / ρS, 0, 0,
+                0, γD / γS, 0,
+                0, 0, βD / βS);
+
+            adaptationMatrix = inverseConeResponseDomain.Multiply(scale).Multiply(coneReponseDomain);
+        }
+
+        public (double X, double Y, double Z) Transform((double X, double Y, double Z) sourceColor)
+        {
+            return adaptationMatrix.Multiply(sourceColor);
+        }
+
+        private static Matrix3x3 GetConeResponseDomain(Method method)
+        {
+            switch (method)
+            {
+                case Method.XYZScaling:
+                    return new Matrix3x3(
+                        1.0000000, 0.0000000, 0.0000000,
+                        0.0000000, 1.0000000, 0.0000000,
+                        0.0000000, 0.0000000, 1.0000000);
+
+                case Method.Bradford:
+                    return new Matrix3x3(
+                        0.8951000, 0.2664000, -0.1614000,
+                       -0.7502000, 1.7135000, 0.0367000,
+                        0.0389000, -0.0685000, 1.0296000);
+
+                case Method.VonKries:
+                    return new Matrix3x3(
+                        0.4002400, 0.7076000, -0.0808100,
+                       -0.2263000, 1.1653200, 0.0457000,
+                        0.0000000, 0.0000000, 0.9182200);
+
+                default:
+                    return GetConeResponseDomain(Method.Bradford);
+            }
+        }
+    }
+}

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

@@ -1,10 +1,14 @@
 namespace UglyToad.PdfPig.Graphics.Colors
 {
-    using System;
-    using System.Collections.Generic;
     using PdfPig.Core;
-    using Tokens;
+    using System;
-
+    using System.Collections.Generic;
+    using System.Linq;
+    using Tokens;
+    using UglyToad.PdfPig.Content;
+    using UglyToad.PdfPig.Util;
+    using UglyToad.PdfPig.Util.JetBrains.Annotations;
+
     /// <summary>
     /// Contains more document-specific information about the <see cref="ColorSpace"/>.
     /// </summary>
@@ -85,23 +89,15 @@
     public class IndexedColorSpaceDetails : ColorSpaceDetails
     {
         /// <summary>
-        /// A color space useful for extracting stencil masks as black-and-white images.  
+        /// Creates a indexed color space useful for exracting stencil masks as black-and-white images,
-        /// Index 0 is black and index 1 is white.
+        /// i.e. with a color palette of two colors (black and white). If the decode parameter array is
-        /// </summary>
+        /// [0, 1] it indicates that black is at index 0 in the color palette, whereas [1, 0] indicates
-        internal static readonly IndexedColorSpaceDetails StencilBlackIs0
+        /// that the black color is at index 1.
-            = new IndexedColorSpaceDetails(DeviceGrayColorSpaceDetails.Instance, 1, new byte[] { 0, 255 });
+        /// </summary>
-
+        internal static ColorSpaceDetails Stencil(ColorSpaceDetails colorSpaceDetails, decimal[] decode)
-        /// <summary>
-        /// A color space useful for extracting stencil masks as black-and-white images.  
-        /// Index 0 is white and index 1 is black.
-        /// </summary>
-        internal static readonly IndexedColorSpaceDetails StencilBlackIs1
-            = new IndexedColorSpaceDetails(DeviceGrayColorSpaceDetails.Instance, 1, new byte[] { 255, 0 });
-
-        internal static ColorSpaceDetails Stencil(decimal[] decode)
         {
-            return decode.Length >= 2 && decode[0] == 1 && decode[1] == 0 ?
+            var blackIsOne = decode.Length >= 2 && decode[0] == 1 && decode[1] == 0;
-                StencilBlackIs1 : StencilBlackIs0 /* default */; 
+            return new IndexedColorSpaceDetails(colorSpaceDetails, 1, blackIsOne ? new byte[] { 255, 0 } : new byte[] { 0, 255 });
         }
 
         /// <summary>
@@ -185,6 +181,248 @@
             AlternateColorSpaceDetails = alternateColorSpaceDetails;
             TintFunction = tintFunction;
         }
+    }
+
+    /// <summary>
+    /// CIE (Commission Internationale de l'Éclairage) colorspace.
+    /// Specifies color related to human visual perception with the aim of producing consistent color on different output devices.
+    /// CalGray - A CIE A color space with a single transformation.
+    /// A represents the gray component of a calibrated gray space. The component must be in the range 0.0 to 1.0.
+    /// </summary>
+    public class CalGrayColorSpaceDetails : ColorSpaceDetails
+    {
+        private readonly CIEBasedColorSpaceTransformer colorSpaceTransformer;
+        /// <summary>
+        /// An array of three numbers [XW  YW  ZW] specifying the tristimulus value, in the CIE 1931 XYZ space of the
+        /// diffuse white point. The numbers XW and ZW shall be positive, and YW shall be equal to 1.0.
+        /// </summary>
+        public IReadOnlyList<decimal> WhitePoint { get; }
+
+        /// <summary>
+        /// An array of three numbers [XB  YB  ZB] specifying the tristimulus value, in the CIE 1931 XYZ space of the
+        /// diffuse black point. All three numbers must be non-negative. Default value: [0.0  0.0  0.0].
+        /// </summary>
+        public IReadOnlyList<decimal> BlackPoint { get; }
+
+        /// <summary>
+        /// A number defining defining the gamma for the gray (A) component. Gamma must be positive and is generally
+        /// greater than or equal to 1. Default value: 1.
+        /// </summary>
+        public decimal Gamma { get; }
+
+        /// <summary>
+        /// Create a new <see cref="CalGrayColorSpaceDetails"/>.
+        /// </summary>
+        public CalGrayColorSpaceDetails([NotNull] IReadOnlyList<decimal> whitePoint, [CanBeNull] IReadOnlyList<decimal> blackPoint, decimal? gamma)
+            : base(ColorSpace.CalGray)
+        {
+            WhitePoint = whitePoint ?? throw new ArgumentNullException(nameof(whitePoint));
+            if (WhitePoint.Count != 3)
+            {
+                throw new ArgumentOutOfRangeException(nameof(whitePoint), whitePoint, $"Must consist of exactly three numbers, but was passed {whitePoint.Count}.");
+            }
+
+            BlackPoint = blackPoint ?? new[] { 0m, 0, 0 }.ToList();
+            if (BlackPoint.Count != 3)
+            {
+                throw new ArgumentOutOfRangeException(nameof(blackPoint), blackPoint, $"Must consist of exactly three numbers, but was passed {blackPoint.Count}.");
+            }
+
+            Gamma = gamma ?? 1m;
+
+            colorSpaceTransformer =
+                new CIEBasedColorSpaceTransformer(((double)WhitePoint[0], (double)WhitePoint[1], (double)WhitePoint[2]), RGBWorkingSpace.sRGB)
+                {
+                    DecoderABC = color => (
+                    Math.Pow(color.A, (double)Gamma),
+                    Math.Pow(color.B, (double)Gamma),
+                    Math.Pow(color.C, (double)Gamma)),
+
+                    MatrixABC = new Matrix3x3(
+                    (double)WhitePoint[0], 0, 0,
+                    0, (double)WhitePoint[1], 0,
+                    0, 0, (double)WhitePoint[2])
+                };
+        }
+
+        /// <summary>
+        /// Transforms the supplied A color to grayscale RGB (sRGB) using the propties of this
+        /// <see cref="CalGrayColorSpaceDetails"/> in the transformation process.
+        /// A represents the gray component of a calibrated gray space. The component must be in the range 0.0 to 1.0. 
+        /// </summary>
+        internal RGBColor TransformToRGB(decimal colorA)
+        {
+            var colorRgb = colorSpaceTransformer.TransformToRGB(((double)colorA, (double)colorA, (double)colorA));
+            return new RGBColor((decimal)colorRgb.R, (decimal)colorRgb.G, (decimal)colorRgb.B);
+        }
+    }
+
+    /// <summary>
+    /// CIE (Commission Internationale de l'Éclairage) colorspace.
+    /// Specifies color related to human visual perception with the aim of producing consistent color on different output devices.
+    /// CalRGB - A CIE ABC color space with a single transformation.
+    /// A, B and C represent red, green and blue color values in the range 0.0 to 1.0. 
+    /// </summary>
+    public class CalRGBColorSpaceDetails : ColorSpaceDetails
+    {
+        private readonly CIEBasedColorSpaceTransformer colorSpaceTransformer;
+
+        /// <summary>
+        /// An array of three numbers [XW  YW  ZW] specifying the tristimulus value, in the CIE 1931 XYZ space of the
+        /// diffuse white point. The numbers XW and ZW shall be positive, and YW shall be equal to 1.0.
+        /// </summary>
+        public IReadOnlyList<decimal> WhitePoint { get; }
+
+        /// <summary>
+        /// An array of three numbers [XB  YB  ZB] specifying the tristimulus value, in the CIE 1931 XYZ space of the
+        /// diffuse black point. All three numbers must be non-negative. Default value: [0.0  0.0  0.0].
+        /// </summary>
+        public IReadOnlyList<decimal> BlackPoint { get; }
+
+        /// <summary>
+        /// An array of three numbers [GR  GG  GB] specifying the gamma for the red, green and blue (A, B, C) components
+        /// of the color space. Default value: [1.0  1.0  1.0].
+        /// </summary>
+        public IReadOnlyList<decimal> Gamma { get; }
+
+        /// <summary>
+        /// An array of nine numbers [XA  YA  ZA  XB  YB  ZB  XC  YC  ZC] specifying the linear interpretation of the
+        /// decoded A, B, C components of the color space with respect to the final XYZ representation. Default value:
+        /// [1  0  0  0  1  0  0  0  1].
+        /// </summary>
+        public IReadOnlyList<decimal> Matrix { get; }
+
+        /// <summary>
+        /// Create a new <see cref="CalRGBColorSpaceDetails"/>.
+        /// </summary>
+        public CalRGBColorSpaceDetails([NotNull] IReadOnlyList<decimal> whitePoint, [CanBeNull] IReadOnlyList<decimal> blackPoint, [CanBeNull] IReadOnlyList<decimal> gamma, [CanBeNull] IReadOnlyList<decimal> matrix)
+            : base(ColorSpace.CalRGB)
+        {
+            WhitePoint = whitePoint ?? throw new ArgumentNullException(nameof(whitePoint));
+            if (WhitePoint.Count != 3)
+            {
+                throw new ArgumentOutOfRangeException(nameof(whitePoint), whitePoint, $"Must consist of exactly three numbers, but was passed {whitePoint.Count}.");
+            }
+
+            BlackPoint = blackPoint ?? new[] { 0m, 0, 0 }.ToList();
+            if (BlackPoint.Count != 3)
+            {
+                throw new ArgumentOutOfRangeException(nameof(blackPoint), blackPoint, $"Must consist of exactly three numbers, but was passed {blackPoint.Count}.");
+            }
+
+            Gamma = gamma ?? new[] { 1m, 1, 1 }.ToList();
+            if (Gamma.Count != 3)
+            {
+                throw new ArgumentOutOfRangeException(nameof(gamma), gamma, $"Must consist of exactly three numbers, but was passed {gamma.Count}.");
+            }
+
+            Matrix = matrix ?? new[] { 1m, 0, 0, 0, 1, 0, 0, 0, 1 }.ToList();
+            if (Matrix.Count != 9)
+            {
+                throw new ArgumentOutOfRangeException(nameof(matrix), matrix, $"Must consist of exactly nine numbers, but was passed {matrix.Count}.");
+            }
+           
+            colorSpaceTransformer =
+                new CIEBasedColorSpaceTransformer(((double)WhitePoint[0], (double)WhitePoint[1], (double)WhitePoint[2]), RGBWorkingSpace.sRGB)
+                {
+                    DecoderABC = color => (
+                    Math.Pow(color.A, (double)Gamma[0]),
+                    Math.Pow(color.B, (double)Gamma[1]),
+                    Math.Pow(color.C, (double)Gamma[2])),
+
+                    MatrixABC = new Matrix3x3(
+                    (double)Matrix[0], (double)Matrix[3], (double)Matrix[6],
+                    (double)Matrix[1], (double)Matrix[4], (double)Matrix[7],
+                    (double)Matrix[2], (double)Matrix[5], (double)Matrix[8])
+                };
+        }
+
+        /// <summary>
+        /// Transforms the supplied ABC color to RGB (sRGB) using the propties of this <see cref="CalRGBColorSpaceDetails"/>
+        /// in the transformation process.
+        /// A, B and C represent red, green and blue calibrated color values in the range 0.0 to 1.0. 
+        /// </summary>
+        internal RGBColor TransformToRGB((decimal A, decimal B, decimal C) colorAbc)
+        {
+            var colorRgb = colorSpaceTransformer.TransformToRGB(((double)colorAbc.A, (double)colorAbc.B, (double)colorAbc.C));
+            return new RGBColor((decimal)colorRgb.R, (decimal) colorRgb.G, (decimal) colorRgb.B);
+        }
+    }
+
+    /// <summary>
+    /// The ICCBased color space is one of the CIE-based color spaces supported in PDFs. These color spaces
+    /// enable a page description to specify color values in a way that is related to human visual perception.
+    /// The goal is for the same color specification to produce consistent results on different output devices,
+    /// within the limitations of each device.
+    ///
+    /// Currently support for this color space is limited in PdfPig. Calculations will only be based on
+    /// the color space of <see cref="AlternateColorSpaceDetails"/>.
+    /// </summary>
+    public class ICCBasedColorSpaceDetails : ColorSpaceDetails
+    {
+        /// <summary>
+        /// The number of color components in the color space described by the ICC profile data.
+        /// This numbers shall match the number of components actually in the ICC profile.
+        /// Valid values are 1, 3 and 4.
+        /// </summary>
+        public int NumberOfColorComponents { get; }
+
+        /// <summary>
+        /// An alternate color space that can be used in case the one specified in the stream data is not
+        /// supported. Non-conforming readers may use this color space. The alternate color space may be any
+        /// valid color space (except a Pattern color space). If this property isn't explicitly set during
+        /// construction, it will assume one of the color spaces, DeviceGray, DeviceRGB or DeviceCMYK depending
+        /// on whether the value of <see cref="NumberOfColorComponents"/> is 1, 3 or respectively.
+        ///
+        /// Conversion of the source color values should not be performed when using the alternate color space.
+        /// Color values within the range of the ICCBased color space might not be within the range of the
+        /// alternate color space. In this case, the nearest values within the range of the alternate space
+        /// must be substituted.
+        /// </summary>
+        [NotNull]
+        public ColorSpaceDetails AlternateColorSpaceDetails { get; }
+
+        /// <summary>
+        /// A list of 2 x <see cref="NumberOfColorComponents"/> numbers [min0 max0  min1 max1  ...] that
+        /// specifies the minimum and maximum valid values of the corresponding color components. These
+        /// values must match the information in the ICC profile. Default value: [0.0 1.0  0.0 1.0  ...].
+        /// </summary>
+        [NotNull]
+        public IReadOnlyList<decimal> Range { get; }
+
+        /// <summary>
+        /// An optional metadata stream that contains metadata for the color space.
+        /// </summary>
+        [CanBeNull]
+        public XmpMetadata Metadata { get; }
+
+        /// <summary>
+        /// Create a new <see cref="ICCBasedColorSpaceDetails"/>.
+        /// </summary>
+        internal ICCBasedColorSpaceDetails(int numberOfColorComponents, [CanBeNull] ColorSpaceDetails alternateColorSpaceDetails,
+            [CanBeNull] IReadOnlyList<decimal> range, [CanBeNull] XmpMetadata metadata)
+            : base(ColorSpace.ICCBased)
+        {
+            if (numberOfColorComponents != 1 && numberOfColorComponents != 3 && numberOfColorComponents != 4)
+            {
+                throw new ArgumentOutOfRangeException(nameof(numberOfColorComponents), "must be 1, 3 or 4");
+            }
+
+            NumberOfColorComponents = numberOfColorComponents;
+            AlternateColorSpaceDetails = alternateColorSpaceDetails ??
+                (NumberOfColorComponents == 1 ? (ColorSpaceDetails) DeviceGrayColorSpaceDetails.Instance :
+                NumberOfColorComponents == 3 ? (ColorSpaceDetails) DeviceRgbColorSpaceDetails.Instance : (ColorSpaceDetails) DeviceCmykColorSpaceDetails.Instance);
+
+            BaseType = AlternateColorSpaceDetails.BaseType;
+            Range = range ??
+                Enumerable.Range(0, numberOfColorComponents).Select(x => new[] { 0.0m, 1.0m }).SelectMany(x => x).ToList();
+            if (Range.Count != 2 * numberOfColorComponents)
+            {
+                throw new ArgumentOutOfRangeException(nameof(range), range,
+                    $"Must consist of exactly {2 * numberOfColorComponents } (2 x NumberOfColorComponents), but was passed {range.Count }");
+            }
+            Metadata = metadata;
+        }
     }
 
     /// <summary>

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

@@ -0,0 +1,178 @@
+namespace UglyToad.PdfPig.Graphics.Colors
+{
+    using System;
+
+    // The RGB working space specifications below were obtained from: http://www.brucelindbloom.com/index.html?WorkingSpaceInfo.html
+    internal class RGBWorkingSpace
+    {
+        public static readonly XYZReferenceWhite ReferenceWhites = new XYZReferenceWhite();
+      
+        public static readonly RGBWorkingSpace AdobeRGB1998 = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(2.2),
+            ReferenceWhite = ReferenceWhites.D65,
+            RedPrimary = (0.6400, 0.3300, 0.297361),
+            GreenPrimary = (0.2100, 0.7100, 0.627355),
+            BluePrimary = (0.1500, 0.0600, 0.075285),
+        };
+
+        public static readonly RGBWorkingSpace AppleRGB = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(1.8),
+            ReferenceWhite = ReferenceWhites.D65,
+            RedPrimary = (0.6250, 0.3400, 0.244634),
+            GreenPrimary = (0.2800, 0.5950, 0.672034),
+            BluePrimary = (0.1550, 0.0700, 0.083332)
+        };
+
+        public static readonly RGBWorkingSpace BestRGB = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(2.2),
+            ReferenceWhite = ReferenceWhites.D50,
+            RedPrimary = (0.7347, 0.2653, 0.228457),
+            GreenPrimary = (0.2150, 0.7750, 0.737352),
+            BluePrimary = (0.1300, 0.0350, 0.034191)
+        };
+
+        public static readonly RGBWorkingSpace BetaRGB = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(2.2),
+            ReferenceWhite = ReferenceWhites.D50,
+            RedPrimary = (0.6888, 0.3112, 0.303273),
+            GreenPrimary = (0.1986, 0.7551, 0.663786),
+            BluePrimary = (0.1265, 0.0352, 0.032941)
+        };
+
+        public static readonly RGBWorkingSpace BruceRGB = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(2.2),
+            ReferenceWhite = ReferenceWhites.D65,
+            RedPrimary = (0.6400, 0.3300, 0.240995),
+            GreenPrimary = (0.2800, 0.6500, 0.683554),
+            BluePrimary = (0.1500, 0.0600, 0.075452)
+        };
+
+        public static readonly RGBWorkingSpace CIE_RGB = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(2.2),
+            ReferenceWhite = ReferenceWhites.E,
+            RedPrimary = (0.7350, 0.2650, 0.176204),
+            GreenPrimary = (0.2740, 0.7170, 0.812985),
+            BluePrimary = (0.1670, 0.0090, 0.010811)
+        };
+
+        public static readonly RGBWorkingSpace ColorMatchRGB = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(1.8),
+            ReferenceWhite = ReferenceWhites.D50,
+            RedPrimary = (0.6300, 0.3400, 0.274884),
+            GreenPrimary = (0.2950, 0.6050, 0.658132),
+            BluePrimary = (0.1500, 0.0750, 0.066985)
+        };
+
+        public static readonly RGBWorkingSpace DonRGB4 = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(2.2),
+            ReferenceWhite = ReferenceWhites.D50,
+            RedPrimary = (0.6960, 0.3000, 0.278350),
+            GreenPrimary = (0.2150, 0.7650, 0.687970),
+            BluePrimary = (0.1300, 0.0350, 0.033680)
+        };
+
+        public static readonly RGBWorkingSpace EktaSpacePS5 = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(2.2),
+            ReferenceWhite = ReferenceWhites.D50,
+            RedPrimary = (0.6950, 0.3050, 0.260629),
+            GreenPrimary = (0.2600, 0.7000, 0.734946),
+            BluePrimary = (0.1100, 0.0050, 0.004425)
+        };
+
+        public static readonly RGBWorkingSpace NTSC_RGB = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(2.2),
+            ReferenceWhite = ReferenceWhites.C,
+            RedPrimary = (0.6700, 0.3300, 0.298839),
+            GreenPrimary = (0.2100, 0.7100, 0.586811),
+            BluePrimary = (0.1400, 0.0800, 0.114350)
+        };
+
+        public static readonly RGBWorkingSpace PAL_SECAM_RGB = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(2.2),
+            ReferenceWhite = ReferenceWhites.D65,
+            RedPrimary = (0.6400, 0.3300, 0.222021),
+            GreenPrimary = (0.2900, 0.6000, 0.706645),
+            BluePrimary = (0.1500, 0.0600, 0.071334)
+        };
+
+        public static readonly RGBWorkingSpace ProPhotoRGB = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(1.8),
+            ReferenceWhite = ReferenceWhites.D50,
+            RedPrimary = (0.7347, 0.2653, 0.288040),
+            GreenPrimary = (0.1596, 0.8404, 0.711874),
+            BluePrimary = (0.0366, 0.0001, 0.000086)
+        };
+
+        public static readonly RGBWorkingSpace SMPTE_C_RGB = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(2.2),
+            ReferenceWhite = ReferenceWhites.D65,
+            RedPrimary = (0.6300, 0.3400, 0.212395),
+            GreenPrimary = (0.3100, 0.5950, 0.701049),
+            BluePrimary = (0.1550, 0.0700, 0.086556)
+        };
+
+        public static readonly RGBWorkingSpace sRGB = new RGBWorkingSpace
+        {
+            // sRGB gamma correction obtained from: http://www.brucelindbloom.com/index.html?Eqn_XYZ_to_RGB.html
+            GammaCorrection = val => val <= 0.0031308 ? 12.92 * val : (1.055 * Math.Pow(val, (1 / 2.4)) - 0.055),
+            ReferenceWhite = ReferenceWhites.D65,
+            RedPrimary = (0.6400, 0.3300, 0.212656),
+            GreenPrimary = (0.3000, 0.6000, 0.715158),
+            BluePrimary = (0.1500, 0.0600, 0.072186),
+        };
+
+        public static readonly RGBWorkingSpace WideGamutRGB = new RGBWorkingSpace
+        {
+            GammaCorrection = CreateGammaFunc(2.2),
+            ReferenceWhite = ReferenceWhites.D50,
+            RedPrimary = (0.7350, 0.2650, 0.258187),
+            GreenPrimary = (0.1150, 0.8260, 0.724938),
+            BluePrimary = (0.1570, 0.0180, 0.016875)
+        };
+
+        public Func<double, double> GammaCorrection { get; private set; } 
+        public (double X, double Y, double Z) ReferenceWhite { get; private set; }
+        public (double x, double y, double Y) RedPrimary { get; private set; }
+        public (double x, double y, double Y) BluePrimary { get; private set; }
+        public (double x, double y, double Y) GreenPrimary { get; private set; }
+
+        private static Func<double, double> CreateGammaFunc(double gamma)
+        {
+            return val =>
+            {
+                var result = Math.Pow(val, 1 / gamma);
+                return double.IsNaN(result) ? 0 : result;
+            };
+        }
+
+        // The reference white values below were obtained from: http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html
+        internal class XYZReferenceWhite
+        {
+            internal XYZReferenceWhite() {}
+            public readonly (double X, double Y, double Z) A = (1.09850, 1.00000, 0.35585);
+            public readonly (double X, double Y, double Z) B = (0.99072, 1.00000, 0.85223);
+            public readonly (double X, double Y, double Z) C = (0.98074, 1.00000,	1.18232);
+            public readonly (double X, double Y, double Z) D50 = (0.96422, 1.00000, 0.82521);
+            public readonly (double X, double Y, double Z) D55 = (0.95682, 1.00000, 0.92149);
+            public readonly (double X, double Y, double Z) D65 = (0.95047, 1.00000, 1.08883);
+            public readonly (double X, double Y, double Z) D75 = (0.94972, 1.00000, 1.22638);
+            public readonly (double X, double Y, double Z) E = (1.00000, 1.00000, 1.00000);
+            public readonly (double X, double Y, double Z) F2 = (0.99186, 1.00000, 0.67393);
+            public readonly (double X, double Y, double Z) F7 = (0.95041, 1.00000, 1.08747);
+            public readonly (double X, double Y, double Z) F11 = (1.00962, 1.00000, 0.64350);
+        }
+    }
+}

src/UglyToad.PdfPig/Images/ColorSpaceDetailsByteConverter.cs

@@ -5,8 +5,8 @@
     using System.Linq;
     using Content;
     using Core;
-    using Graphics.Colors;
+    using Graphics.Colors;
-
+
     /// <summary>
     /// Utility for working with the bytes in <see cref="IPdfImage"/>s and converting according to their <see cref="ColorSpaceDetails"/>.s
     /// </summary>
@@ -28,48 +28,92 @@
             if (details == null)
             {
                 return decoded.ToArray();
+            }
+
+            if (bitsPerComponent != 8)
+            {
+                // Unpack components such that they occupy one byte each
+                decoded = UnpackComponents(decoded, bitsPerComponent);
+            }
+
+            // Remove padding bytes when the stride width differs from the image width
+            var bytesPerPixel = details is IndexedColorSpaceDetails ? 1 : GetBytesPerPixel(details);
+            var strideWidth = decoded.Count / imageHeight / bytesPerPixel;
+            if (strideWidth != imageWidth)
+            {
+                decoded = RemoveStridePadding(decoded.ToArray(), strideWidth, imageWidth, imageHeight, bytesPerPixel);
             }
 
-            switch (details)
+            // In case of indexed color space images, unwrap indices to actual pixel component values
+            if (details is IndexedColorSpaceDetails indexed)
             {
-                case IndexedColorSpaceDetails indexed:
+                decoded = UnwrapIndexedColorSpaceBytes(indexed, decoded);
-                    if (bitsPerComponent != 8)
+
-                    {
+                // Use the base color space in potential further decoding
-                        // To ease unwrapping further below the indices are unpacked to occupy a single byte each
+                details = indexed.BaseColorSpaceDetails;
-                        decoded = UnpackIndices(decoded, bitsPerComponent);
+            }
-
+
-                        // Remove padding bytes when the stride width differs from the image width
+            if (details is CalRGBColorSpaceDetails calRgb)
-                        var stride = (imageWidth * bitsPerComponent + 7) / 8;
+            {
-                        var strideWidth = stride * (8 / bitsPerComponent);
+                decoded = TransformToRGB(calRgb, decoded);
-                        if (strideWidth != imageWidth)
+            }
-                        {
+
-                            decoded = RemoveStridePadding(decoded.ToArray(), strideWidth, imageWidth, imageHeight);
+            if (details is CalGrayColorSpaceDetails calGray)
-                        }
+            {
-                    }
+                decoded = TransformToRgbGrayScale(calGray, decoded);
-
-                    return UnwrapIndexedColorSpaceBytes(indexed, decoded);
             }
 
             return decoded.ToArray();
         }
 
-        private static byte[] UnpackIndices(IReadOnlyList<byte> input, int bitsPerComponent)
+        private static int GetBytesPerPixel(ColorSpaceDetails details)
-        {
+        {
-                IEnumerable<byte> Unpack(byte b)
+            switch (details)
+            {
+                case DeviceGrayColorSpaceDetails deviceGray:
+                    return 1;
+
+                case CalGrayColorSpaceDetails calGray:
+                    return 1;
+
+                case DeviceRgbColorSpaceDetails deviceRgb:
+                    return 3;
+
+                case CalRGBColorSpaceDetails calRgb:
+                    return 3;
+
+                case DeviceCmykColorSpaceDetails deviceCmyk:
+                    return 4;
+
+                case IndexedColorSpaceDetails indexed:
+                    return GetBytesPerPixel(indexed.BaseColorSpaceDetails);
+
+                case ICCBasedColorSpaceDetails iccBased:
+                    // Currently PdfPig only supports the 'Alternate' color space of ICCBasedColorSpaceDetails
+                    return GetBytesPerPixel(iccBased.AlternateColorSpaceDetails);
+
+                default:
+                    return 1;
+            }
+        }
+
+        private static byte[] UnpackComponents(IReadOnlyList<byte> input, int bitsPerComponent)
+        {
+            IEnumerable<byte> Unpack(byte b)
+            {
+                // Enumerate bits in bitsPerComponent-sized chunks from MSB to LSB, masking on the appropriate bits
+                for (int i = 8 - bitsPerComponent; i >= 0; i -= bitsPerComponent)
                 {
-                    // Enumerate bits in bitsPerComponent-sized chunks from MSB to LSB, masking on the appropriate bits
+                    yield return (byte)((b >> i) & ((int)Math.Pow(2, bitsPerComponent) - 1));
-                    for (int i = 8 - bitsPerComponent; i >= 0; i -= bitsPerComponent)
-                    {
-                        yield return (byte)((b >> i) & ((int)Math.Pow(2, bitsPerComponent) - 1));
-                    }
                 }
-               
+            }
-                return input.SelectMany(b => Unpack(b)).ToArray();
+
+            return input.SelectMany(b => Unpack(b)).ToArray();
         }
 
-        private static byte[] RemoveStridePadding(byte[] input, int strideWidth, int imageWidth, int imageHeight)
+        private static byte[] RemoveStridePadding(byte[] input, int strideWidth, int imageWidth, int imageHeight, int multiplier)
         {
-            var result = new byte[imageWidth * imageHeight];
+            var result = new byte[imageWidth * imageHeight * multiplier];
             for (int y = 0; y < imageHeight; y++)
             {
                 int sourceIndex = y * strideWidth;
@@ -80,13 +124,42 @@
             return result;
         }
 
+        private static IReadOnlyList<byte> TransformToRgbGrayScale(CalGrayColorSpaceDetails calGray, IReadOnlyList<byte> decoded)
+        {
+            var transformed = new List<byte>();
+            for (var i = 0; i < decoded.Count; i++)
+            {
+                var component = decoded[i] / 255m;
+                var rgbPixel = calGray.TransformToRGB(component);
+                // We only need one component here 
+                transformed.Add(ConvertToByte(rgbPixel.R));
+            }
+
+            return transformed;
+        }
+
+        private static IReadOnlyList<byte> TransformToRGB(CalRGBColorSpaceDetails calRgb, IReadOnlyList<byte> decoded)
+        {
+            var transformed = new List<byte>();
+            for (var i = 0; i < decoded.Count; i += 3)
+            {
+                var rgbPixel = calRgb.TransformToRGB((decoded[i] / 255m, decoded[i + 1] / 255m, decoded[i + 2] / 255m));
+                transformed.Add(ConvertToByte(rgbPixel.R));
+                transformed.Add(ConvertToByte(rgbPixel.G));
+                transformed.Add(ConvertToByte(rgbPixel.B));
+            }
+
+            return transformed;
+        }
+
         private static byte[] UnwrapIndexedColorSpaceBytes(IndexedColorSpaceDetails indexed, IReadOnlyList<byte> input)
         {
             var multiplier = 1;
             Func<byte, IEnumerable<byte>> transformer = null;
-            switch (indexed.BaseColorSpaceDetails.Type)
+            switch (indexed.BaseType)
             {
                 case ColorSpace.DeviceRGB:
+                case ColorSpace.CalRGB:
                     transformer = x =>
                     {
                         var r = new byte[3];
@@ -114,6 +187,7 @@
                     multiplier = 4;
                     break;
                 case ColorSpace.DeviceGray:
+                case ColorSpace.CalGray:
                     transformer = x => new[] { indexed.ColorTable[x] };
                     multiplier = 1;
                     break;
@@ -136,5 +210,11 @@
 
             return input.ToArray();
         }
+
+        private static byte ConvertToByte(decimal componentValue)
+        {
+            var rounded = Math.Round(componentValue * 255, MidpointRounding.AwayFromZero);
+            return (byte)rounded;
+        }
     }
 }

src/UglyToad.PdfPig/Images/Png/PngFromPdfImageFactory.cs

@@ -2,6 +2,7 @@
 {
     using Content;
     using Graphics.Colors;
+    using UglyToad.PdfPig.Core;
 
     internal static class PngFromPdfImageFactory
     {
@@ -15,7 +16,8 @@
 
             var isColorSpaceSupported =
                 actualColorSpace == ColorSpace.DeviceGray || actualColorSpace == ColorSpace.DeviceRGB
-                || actualColorSpace == ColorSpace.DeviceCMYK;
+                || actualColorSpace == ColorSpace.DeviceCMYK || actualColorSpace == ColorSpace.CalGray 
+                || actualColorSpace == ColorSpace.CalRGB;
 
             if (!isColorSpaceSupported || !image.TryGetBytes(out var bytesPure))
             {
@@ -27,12 +29,27 @@
                 bytesPure = ColorSpaceDetailsByteConverter.Convert(image.ColorSpaceDetails, bytesPure,
                     image.BitsPerComponent, image.WidthInSamples, image.HeightInSamples);
 
-                var numberOfComponents = actualColorSpace == ColorSpace.DeviceCMYK ? 4 : actualColorSpace == ColorSpace.DeviceRGB ? 3 : 1;
+                var numberOfComponents =
+                    actualColorSpace == ColorSpace.DeviceCMYK ? 4 :
+                    actualColorSpace == ColorSpace.DeviceRGB ? 3 :
+                    actualColorSpace == ColorSpace.CalRGB ? 3 : 1;
+
                 var is3Byte = numberOfComponents == 3;
 
                 var builder = PngBuilder.Create(image.WidthInSamples, image.HeightInSamples, false);
 
-                var isCorrectlySized = bytesPure.Count == (image.WidthInSamples * image.HeightInSamples * numberOfComponents);
+                var requiredSize = (image.WidthInSamples * image.HeightInSamples * numberOfComponents);
+
+                var actualSize = bytesPure.Count;
+                var isCorrectlySized = bytesPure.Count == requiredSize ||
+                    // Spec, p. 37: "...error if the stream contains too much data, with the exception that
+                    // there may be an extra end-of-line marker..."
+                    (actualSize == requiredSize + 1 && bytesPure[actualSize - 1] == ReadHelper.AsciiLineFeed) ||
+                    (actualSize == requiredSize + 1 && bytesPure[actualSize - 1] == ReadHelper.AsciiCarriageReturn) ||
+                    // The combination of a CARRIAGE RETURN followed immediately by a LINE FEED is treated as one EOL marker.
+                    (actualSize == requiredSize + 2 &&
+                        bytesPure[actualSize - 2] == ReadHelper.AsciiCarriageReturn &&
+                        bytesPure[actualSize - 1] == ReadHelper.AsciiLineFeed);
 
                 if (!isCorrectlySized)
                 {

src/UglyToad.PdfPig/Util/ColorSpaceDetailsParser.cs

@@ -64,6 +64,7 @@
 
             return false;
         }
+
     }
 
     internal static class ColorSpaceDetailsParser
@@ -78,10 +79,18 @@
             if (imageDictionary.GetObjectOrDefault(NameToken.ImageMask, NameToken.Im) != null ||
                 filterProvider.GetFilters(imageDictionary, scanner).OfType<CcittFaxDecodeFilter>().Any())
             {
+                if (cannotRecurse)
+                {
+                    return UnsupportedColorSpaceDetails.Instance;
+                }
+
+                var colorSpaceDetails = GetColorSpaceDetails(colorSpace, imageDictionary.Without(NameToken.Filter).Without(NameToken.F), scanner, resourceStore, filterProvider, true);
+                
                 var decodeRaw = imageDictionary.GetObjectOrDefault(NameToken.Decode, NameToken.D) as ArrayToken
                     ?? new ArrayToken(EmptyArray<IToken>.Instance);
                 var decode = decodeRaw.Data.OfType<NumericToken>().Select(x => x.Data).ToArray();
-                return IndexedColorSpaceDetails.Stencil(decode);
+
+                return IndexedColorSpaceDetails.Stencil(colorSpaceDetails, decode);
             }
 
             if (!colorSpace.HasValue)
@@ -98,22 +107,159 @@
                 case ColorSpace.DeviceCMYK:
                     return DeviceCmykColorSpaceDetails.Instance;
                 case ColorSpace.CalGray:
-                    return UnsupportedColorSpaceDetails.Instance;
+                    {
+                        if (!TryGetColorSpaceArray(imageDictionary, resourceStore, scanner, out var colorSpaceArray)
+                                || colorSpaceArray.Length != 2)
+                        {
+                            return UnsupportedColorSpaceDetails.Instance;
+                        }
+
+                        var first = colorSpaceArray[0] as NameToken;
+
+                        if (first == null || !ColorSpaceMapper.TryMap(first, resourceStore, out var innerColorSpace)
+                            || innerColorSpace != ColorSpace.CalGray)
+                        {
+                            return UnsupportedColorSpaceDetails.Instance;
+                        }
+
+                        var second = colorSpaceArray[1];
+
+                        // WhitePoint is required
+                        if (!DirectObjectFinder.TryGet(second, scanner, out DictionaryToken dictionaryToken) ||
+                            !dictionaryToken.TryGet(NameToken.WhitePoint, scanner, out ArrayToken whitePointToken))
+                        {
+                            return UnsupportedColorSpaceDetails.Instance;
+                        }
+
+                        var whitePoint = whitePointToken.Data.OfType<NumericToken>().Select(x => x.Data).ToList();
+
+                        // BlackPoint is optional
+                        IReadOnlyList<decimal> blackPoint = null;
+                        if (dictionaryToken.TryGet(NameToken.BlackPoint, scanner, out ArrayToken blackPointToken))
+                        {
+                            blackPoint = blackPointToken.Data.OfType<NumericToken>().Select(x => x.Data).ToList();
+                        }
+
+                        // Gamma is optional
+                        decimal? gamma = null;
+                        if (dictionaryToken.TryGet(NameToken.Gamma, scanner, out NumericToken gammaToken))
+                        {
+                            gamma = gammaToken.Data;
+                        }
+
+                        return new CalGrayColorSpaceDetails(whitePoint, blackPoint, gamma);
+                    }
                 case ColorSpace.CalRGB:
-                    return UnsupportedColorSpaceDetails.Instance;
+                    {
+                        if (!TryGetColorSpaceArray(imageDictionary, resourceStore, scanner, out var colorSpaceArray)
+                            || colorSpaceArray.Length != 2)
+                        {
+                            return UnsupportedColorSpaceDetails.Instance;
+                        }
+
+                        var first = colorSpaceArray[0] as NameToken;
+
+                        if (first == null || !ColorSpaceMapper.TryMap(first, resourceStore, out var innerColorSpace)
+                            || innerColorSpace != ColorSpace.CalRGB)
+                        {
+                            return UnsupportedColorSpaceDetails.Instance;
+                        }
+
+                        var second = colorSpaceArray[1];
+
+                        // WhitePoint is required
+                        if (!DirectObjectFinder.TryGet(second, scanner, out DictionaryToken dictionaryToken) ||
+                            !dictionaryToken.TryGet(NameToken.WhitePoint, scanner, out ArrayToken whitePointToken))
+                        {
+                            return UnsupportedColorSpaceDetails.Instance;
+                        }
+
+                        var whitePoint = whitePointToken.Data.OfType<NumericToken>().Select(x => x.Data).ToList();
+
+                        // BlackPoint is optional
+                        IReadOnlyList<decimal> blackPoint = null;
+                        if (dictionaryToken.TryGet(NameToken.BlackPoint, scanner, out ArrayToken blackPointToken))
+                        {
+                            blackPoint = blackPointToken.Data.OfType<NumericToken>().Select(x => x.Data).ToList();
+                        }
+
+                        // Gamma is optional
+                        IReadOnlyList<decimal> gamma = null;
+                        if (dictionaryToken.TryGet(NameToken.Gamma, scanner, out ArrayToken gammaToken))
+                        {
+                            gamma = gammaToken.Data.OfType<NumericToken>().Select(x => x.Data).ToList();
+                        }
+
+                        // Matrix is optional
+                        IReadOnlyList<decimal> matrix = null;
+                        if (dictionaryToken.TryGet(NameToken.Matrix, scanner, out ArrayToken matrixToken))
+                        {
+                            matrix = matrixToken.Data.OfType<NumericToken>().Select(x => x.Data).ToList();
+                        }
+
+                        return new CalRGBColorSpaceDetails(whitePoint, blackPoint, gamma, matrix);
+                    }
                 case ColorSpace.Lab:
                     return UnsupportedColorSpaceDetails.Instance;
                 case ColorSpace.ICCBased:
-                    return UnsupportedColorSpaceDetails.Instance;
+                    {
+                        if (!TryGetColorSpaceArray(imageDictionary, resourceStore, scanner, out var colorSpaceArray)
+                            || colorSpaceArray.Length != 2)
+                        {
+                            return UnsupportedColorSpaceDetails.Instance;
+                        }
+
+                        var first = colorSpaceArray[0] as NameToken;
+
+                        if (first == null || !ColorSpaceMapper.TryMap(first, resourceStore, out var innerColorSpace)
+                            || innerColorSpace != ColorSpace.ICCBased)
+                        {
+                            return UnsupportedColorSpaceDetails.Instance;
+                        }
+
+                        var second = colorSpaceArray[1];
+
+                        // N is required
+                        if (!DirectObjectFinder.TryGet(second, scanner, out StreamToken streamToken) ||
+                            !streamToken.StreamDictionary.TryGet(NameToken.N, scanner, out NumericToken numeric))
+                        {
+                            return UnsupportedColorSpaceDetails.Instance;
+                        }
+
+                        // Alternate is optional
+                        ColorSpaceDetails alternateColorSpaceDetails = null;
+                        if (streamToken.StreamDictionary.TryGet(NameToken.Alternate, out NameToken alternateColorSpaceNameToken) &&
+                            ColorSpaceMapper.TryMap(alternateColorSpaceNameToken, resourceStore, out var alternateColorSpace))
+                        {
+                            alternateColorSpaceDetails =
+                                GetColorSpaceDetails(alternateColorSpace, imageDictionary, scanner, resourceStore, filterProvider, true);
+                        }
+
+                        // Range is optional
+                        IReadOnlyList<decimal> range = null;
+                        if (streamToken.StreamDictionary.TryGet(NameToken.Range, scanner, out ArrayToken arrayToken))
+                        {
+                            range = arrayToken.Data.OfType<NumericToken>().Select(x => x.Data).ToList();
+                        }
+
+                        // Metadata is optional
+                        XmpMetadata metadata = null;
+                        if (streamToken.StreamDictionary.TryGet(NameToken.Metadata, scanner, out StreamToken metadataStream))
+                        {
+                            metadata = new XmpMetadata(metadataStream, filterProvider, scanner);
+                        }
+
+                        return new ICCBasedColorSpaceDetails(numeric.Int, alternateColorSpaceDetails, range, metadata);
+                    }
                 case ColorSpace.Indexed:
                     {
                         if (cannotRecurse)
                         {
                             return UnsupportedColorSpaceDetails.Instance;
-                        }
+                        }
-
+
-                        if (!imageDictionary.TryGet(NameToken.ColorSpace, scanner, out ArrayToken colorSpaceArray)
+                        if (!TryGetColorSpaceArray(imageDictionary, resourceStore, scanner, out var colorSpaceArray)
-                        || colorSpaceArray.Length != 4)
+                            || colorSpaceArray.Length != 4)
                         {
                             // Error instead?
                             return UnsupportedColorSpaceDetails.Instance;
@@ -122,7 +268,7 @@
                         var first = colorSpaceArray[0] as NameToken;
 
                         if (first == null || !ColorSpaceMapper.TryMap(first, resourceStore, out var innerColorSpace)
-                        || innerColorSpace != ColorSpace.Indexed)
+                            || innerColorSpace != ColorSpace.Indexed)
                         {
                             return UnsupportedColorSpaceDetails.Instance;
                         }
@@ -206,8 +352,8 @@
                     return UnsupportedColorSpaceDetails.Instance;
                 case ColorSpace.Separation:
                     {
-                        if (!imageDictionary.TryGet(NameToken.ColorSpace, scanner, out ArrayToken colorSpaceArray)
+                        if (!TryGetColorSpaceArray(imageDictionary, resourceStore, scanner, out var colorSpaceArray)
-                            || colorSpaceArray.Length != 4)
+                             || colorSpaceArray.Length != 4)
                         {
                             // Error instead?
                             return UnsupportedColorSpaceDetails.Instance;
@@ -282,7 +428,23 @@
                     return UnsupportedColorSpaceDetails.Instance;
                 default:
                     return UnsupportedColorSpaceDetails.Instance;
-            }
+            }
-        }
+        }
+
+        private static bool TryGetColorSpaceArray(DictionaryToken imageDictionary, IResourceStore resourceStore,
+            IPdfTokenScanner scanner,
+            out ArrayToken colorSpaceArray)
+        {
+            var colorSpace = imageDictionary.GetObjectOrDefault(NameToken.ColorSpace, NameToken.Cs);
+
+            if (!DirectObjectFinder.TryGet(colorSpace, scanner, out colorSpaceArray)
+                && DirectObjectFinder.TryGet(colorSpace, scanner, out NameToken colorSpaceName) &&
+                resourceStore.TryGetNamedColorSpace(colorSpaceName, out var colorSpaceNamedToken))
+            {
+                colorSpaceArray = colorSpaceNamedToken.Data as ArrayToken;
+            }
+
+            return colorSpaceArray != null;
+        }
     }
 }

src/UglyToad.PdfPig/Util/Matrix3x3.cs

@@ -0,0 +1,206 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace UglyToad.PdfPig.Util
+{
+    internal class Matrix3x3 : IEnumerable<double>, IEquatable<Matrix3x3>
+    {
+        /// <summary>
+        /// The identity matrix. The result of multiplying a matrix with
+        /// the identity matrix is the matrix itself.
+        /// </summary>
+        public static readonly Matrix3x3 Identity = new Matrix3x3(
+            1, 0, 0,
+            0, 1, 0,
+            0, 0, 1);
+
+        private readonly double m11;
+        private readonly double m12;
+        private readonly double m13;
+
+        private readonly double m21;
+        private readonly double m22;
+        private readonly double m23;
+
+        private readonly double m31;
+        private readonly double m32;
+        private readonly double m33;
+
+        /// <summary>
+        /// Creates a 3x3 matrix with the following layout:
+        /// 
+        /// | m11  m12  m13 |
+        /// | m21  m22  m23 |
+        /// | m31  m32  m33 |
+        /// 
+        /// </summary>
+        public Matrix3x3(double m11, double m12, double m13, double m21, double m22, double m23, double m31, double m32, double m33)
+        {
+            this.m11 = m11;
+            this.m12 = m12;
+            this.m13 = m13;
+
+            this.m21 = m21;
+            this.m22 = m22;
+            this.m23 = m23;
+
+            this.m31 = m31;
+            this.m32 = m32;
+            this.m33 = m33;
+        }
+
+        public IEnumerator<double> GetEnumerator()
+        {
+            yield return m11;
+            yield return m12;
+            yield return m13;
+            yield return m21;
+            yield return m22;
+            yield return m23;
+            yield return m31;
+            yield return m32;
+            yield return m33;
+        }
+
+        /// <summary>
+        /// Returns a new matrix that is the inverse of this matrix (i.e. multiplying a matrix with
+        /// its inverse matrix yields the identity matrix).
+        ///
+        /// If an inverse matrix does not exist, null is returned.
+        /// </summary>
+        public Matrix3x3 Inverse()
+        {
+            var determinant = GetDeterminant();
+
+            // No inverse matrix exists when determinant is zero
+            if (determinant == 0)
+            {
+                return null;
+            }
+
+            var transposed = Transpose();
+            var minorm11 = (transposed.m22 * transposed.m33) - (transposed.m23 * transposed.m32);
+            var minorm12 = (transposed.m21 * transposed.m33) - (transposed.m23 * transposed.m31);
+            var minorm13 = (transposed.m21 * transposed.m32) - (transposed.m22 * transposed.m31);
+
+            var minorm21 = (transposed.m12 * transposed.m33) - (transposed.m13 * transposed.m32);
+            var minorm22 = (transposed.m11 * transposed.m33) - (transposed.m13 * transposed.m31);
+            var minorm23 = (transposed.m11 * transposed.m32) - (transposed.m12 * transposed.m31);
+
+            var minorm31 = (transposed.m12 * transposed.m23) - (transposed.m13 * transposed.m22);
+            var minorm32 = (transposed.m11 * transposed.m23) - (transposed.m13 * transposed.m21);
+            var minorm33 = (transposed.m11 * transposed.m22) - (transposed.m12 * transposed.m21);
+
+            var adjugate = new Matrix3x3(
+                minorm11, -minorm12, minorm13,
+                -minorm21, minorm22, -minorm23,
+                minorm31, -minorm32, minorm33);
+
+            return adjugate.Multiply(1 / determinant);
+        }
+
+        /// <summary>
+        /// Returns a new matrix with each element being a mulitple of the supplied factor.
+        /// </summary>
+        public Matrix3x3 Multiply(double factor)
+        {
+            return new Matrix3x3(
+                m11 * factor, m12 * factor, m13 * factor,
+                m21 * factor, m22 * factor, m23 * factor,
+                m31 * factor, m32 * factor, m33 * factor);
+        }
+
+        /// <summary>
+        /// Multiplies this matrix with the supplied 3-element vector
+        /// and returns a new 3-element vector as the result.
+        /// </summary>
+        public (double, double, double) Multiply((double, double, double) vector)
+        {
+            return (
+                m11 * vector.Item1 + m12 * vector.Item2 + m13 * vector.Item3,
+                m21 * vector.Item1 + m22 * vector.Item2 + m23 * vector.Item3,
+                m31 * vector.Item1 + m32 * vector.Item2 + m33 * vector.Item3);
+        }
+
+        /// <summary>
+        /// Returns a new matrix that is the 'dot product' of this matrix
+        /// and the supplied matrix.
+        /// </summary>
+        public Matrix3x3 Multiply(Matrix3x3 matrix)
+        {
+            return new Matrix3x3(
+                m11 * matrix.m11 + m12 * matrix.m21 + m13 * matrix.m31,
+                m11 * matrix.m12 + m12 * matrix.m22 + m13 * matrix.m32,
+                m11 * matrix.m13 + m12 * matrix.m23 + m13 * matrix.m33,
+                m21 * matrix.m11 + m22 * matrix.m21 + m23 * matrix.m31,
+                m21 * matrix.m12 + m22 * matrix.m22 + m23 * matrix.m32,
+                m21 * matrix.m13 + m22 * matrix.m23 + m23 * matrix.m33,
+                m31 * matrix.m11 + m32 * matrix.m21 + m33 * matrix.m31,
+                m31 * matrix.m12 + m32 * matrix.m22 + m33 * matrix.m32,
+                m31 * matrix.m13 + m32 * matrix.m23 + m33 * matrix.m33);
+        }
+
+        /// <summary>
+        /// Returns a new matrix that is the transpose of this matrix
+        /// (i.e. the tranpose of a matrix, is a matrix with its rows
+        /// and column interchanged)
+        /// </summary>
+        public Matrix3x3 Transpose()
+        {
+            return new Matrix3x3(
+                m11, m21, m31,
+                m12, m22, m32,
+                m13, m23, m33);
+        }
+
+        public override bool Equals(object obj)
+        {
+            var other = obj as Matrix3x3;
+            return Equals(other);
+        }
+
+        public bool Equals(Matrix3x3 other)
+        {
+            if (other == null)
+            { 
+                return false;
+            }
+
+            if (ReferenceEquals(this, other))
+            {
+                return true;
+            }
+
+            return
+                m11 == other.m11 &&
+                m12 == other.m12 &&
+                m13 == other.m13 &&
+                m21 == other.m21 &&
+                m22 == other.m22 &&
+                m23 == other.m23 &&
+                m31 == other.m31 &&
+                m32 == other.m32 &&
+                m33 == other.m33;
+        }
+
+        public override int GetHashCode()
+        {
+            return (m11, m12, m13, m21, m22, m23, m31, m32, m33).GetHashCode();
+        }
+
+        private double GetDeterminant()
+        {
+            var minorM11 = (m22 * m33) - (m23 * m32);
+            var minorM12 = (m21 * m33) - (m23 * m31);
+            var minorM13 = (m21 * m32) - (m22 * m31);
+
+            return m11 * minorM11 - m12 * minorM12 + m13 * minorM13;
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+    }
+}

src/UglyToad.PdfPig/XObjects/XObjectImage.cs

@@ -6,7 +6,6 @@
     using Core;
     using Graphics.Colors;
     using Graphics.Core;
-    using Images;
     using Images.Png;
     using Tokens;
     using Util.JetBrains.Annotations;
@@ -57,9 +56,7 @@
         /// <inheritdoc />
         public bool IsInlineImage { get; } = false;
 
-        /// <summary>
+        /// <inheritdoc />
-        /// The full dictionary for this Image XObject.
-        /// </summary>
         [NotNull]
         public DictionaryToken ImageDictionary { get; }