Add ICC profile support

src/UglyToad.PdfPig.Tests/Graphics/Colors/ICCBasedColorSpaceDetailsTests.cs

@@ -0,0 +1,245 @@
+namespace UglyToad.PdfPig.Tests.Graphics.Colors
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Diagnostics.CodeAnalysis;
+    using UglyToad.PdfPig.Graphics.Colors;
+    using UglyToad.PdfPig.Graphics.Colors.Icc;
+    using UglyToad.PdfPig.Graphics.Core;
+    using Xunit;
+
+    public class ICCBasedColorSpaceDetailsTests
+    {
+        private sealed class StubTransform : IIccTransform
+        {
+            private readonly (double r, double g, double b) fixedOut;
+
+            public StubTransform(int components, (double r, double g, double b) fixedOut)
+            {
+                NumberOfComponents = components;
+                this.fixedOut = fixedOut;
+            }
+
+            public int NumberOfComponents { get; }
+
+            public (double r, double g, double b) ToRgb(ReadOnlySpan<double> values) => fixedOut;
+
+            public void Transform(ReadOnlySpan<byte> src, Span<byte> dstRgb)
+            {
+                int pixels = src.Length / NumberOfComponents;
+                for (int p = 0; p < pixels; p++)
+                {
+                    dstRgb[p * 3] = (byte)Math.Round(fixedOut.r * 255);
+                    dstRgb[p * 3 + 1] = (byte)Math.Round(fixedOut.g * 255);
+                    dstRgb[p * 3 + 2] = (byte)Math.Round(fixedOut.b * 255);
+                }
+            }
+        }
+
+        private sealed class StubProfile : IIccProfile
+        {
+            private readonly Dictionary<RenderingIntent, IIccTransform> transforms;
+
+            public StubProfile(int components, Dictionary<RenderingIntent, IIccTransform> transforms)
+            {
+                NumberOfComponents = components;
+                this.transforms = transforms;
+            }
+
+            public int NumberOfComponents { get; }
+
+            public bool TryGetTransform(RenderingIntent intent, [NotNullWhen(true)] out IIccTransform? transform)
+            {
+                if (transforms.TryGetValue(intent, out var t))
+                {
+                    transform = t;
+                    return true;
+                }
+                transform = null;
+                return false;
+            }
+        }
+
+        private sealed class StubService : IIccProfileService
+        {
+            private readonly IIccProfile? profile;
+
+            public StubService(IIccProfile? profile) { this.profile = profile; }
+
+            public bool TryGetProfile(Memory<byte> profileBytes, int numberOfColorComponents,
+                [NotNullWhen(true)] out IIccProfile? profile)
+            {
+                profile = this.profile;
+                return profile is not null;
+            }
+        }
+
+        [Fact]
+        public void WithoutService_FallsBackToAlternateColorSpace()
+        {
+            var details = new ICCBasedColorSpaceDetails(
+                numberOfColorComponents: 3,
+                alternateColorSpaceDetails: DeviceRgbColorSpaceDetails.Instance,
+                range: null,
+                metadata: null,
+                profile: new byte[] { 1, 2, 3 },
+                iccProfileService: null);
+
+            Assert.Equal(ColorSpace.DeviceRGB, details.BaseType);
+            Assert.Equal(3, details.BaseNumberOfColorComponents);
+            Assert.Null(details.IccProfile);
+            Assert.Null(details.GetTransform(RenderingIntent.RelativeColorimetric));
+
+            var (r, g, b) = details.GetColor(0.5, 0.5, 0.5).ToRGBValues();
+            Assert.Equal(0.5, r);
+            Assert.Equal(0.5, g);
+            Assert.Equal(0.5, b);
+        }
+
+        [Fact]
+        public void WithService_BaseTypeIsDeviceRgbAndComponentsIsThree()
+        {
+            var profile = new StubProfile(4, new Dictionary<RenderingIntent, IIccTransform>
+            {
+                [RenderingIntent.RelativeColorimetric] = new StubTransform(4, (0, 0, 0)),
+            });
+
+            var details = new ICCBasedColorSpaceDetails(
+                numberOfColorComponents: 4,
+                alternateColorSpaceDetails: DeviceCmykColorSpaceDetails.Instance,
+                range: null,
+                metadata: null,
+                profile: new byte[] { 0x01 },
+                iccProfileService: new StubService(profile));
+
+            Assert.Equal(ColorSpace.DeviceRGB, details.BaseType);
+            Assert.Equal(3, details.BaseNumberOfColorComponents);
+            Assert.NotNull(details.IccProfile);
+            Assert.NotNull(details.GetTransform(RenderingIntent.RelativeColorimetric));
+        }
+
+        [Fact]
+        public void WithService_GetColorWithoutIntent_UsesRelativeColorimetric()
+        {
+            var profile = new StubProfile(4, new Dictionary<RenderingIntent, IIccTransform>
+            {
+                [RenderingIntent.RelativeColorimetric] = new StubTransform(4, (0.25, 0.5, 0.75)),
+                [RenderingIntent.Perceptual] = new StubTransform(4, (0.10, 0.10, 0.10)),
+            });
+
+            var details = new ICCBasedColorSpaceDetails(4, DeviceCmykColorSpaceDetails.Instance,
+                null, null, new byte[] { 0xAB }, new StubService(profile));
+
+            var (r, g, b) = details.GetColor(0.1, 0.2, 0.3, 0.4).ToRGBValues();
+            Assert.Equal(0.25, r);
+            Assert.Equal(0.50, g);
+            Assert.Equal(0.75, b);
+        }
+
+        [Fact]
+        public void WithService_GetColorWithIntent_RoutesThroughThatIntent()
+        {
+            var profile = new StubProfile(4, new Dictionary<RenderingIntent, IIccTransform>
+            {
+                [RenderingIntent.RelativeColorimetric] = new StubTransform(4, (0.25, 0.5, 0.75)),
+                [RenderingIntent.Perceptual] = new StubTransform(4, (0.10, 0.10, 0.10)),
+            });
+
+            var details = new ICCBasedColorSpaceDetails(4, DeviceCmykColorSpaceDetails.Instance,
+                null, null, new byte[] { 0xAB }, new StubService(profile));
+
+            var (r, g, b) = details.GetColor(new double[] { 0.1, 0.2, 0.3, 0.4 },
+                RenderingIntent.Perceptual).ToRGBValues();
+
+            Assert.Equal(0.10, r);
+            Assert.Equal(0.10, g);
+            Assert.Equal(0.10, b);
+        }
+
+        [Fact]
+        public void WithService_TransformIntentOverloadProducesIntentSpecificBuffer()
+        {
+            var profile = new StubProfile(4, new Dictionary<RenderingIntent, IIccTransform>
+            {
+                [RenderingIntent.RelativeColorimetric] = new StubTransform(4, (1.0, 0.0, 0.0)),
+                [RenderingIntent.Saturation] = new StubTransform(4, (0.0, 1.0, 0.0)),
+            });
+
+            var details = new ICCBasedColorSpaceDetails(4, DeviceCmykColorSpaceDetails.Instance,
+                null, null, new byte[] { 0xCD }, new StubService(profile));
+
+            Span<byte> input = stackalloc byte[8] { 10, 20, 30, 40, 50, 60, 70, 80 };
+
+            // Default intent (RelativeColorimetric) → red.
+            var def = details.Transform(input);
+            Assert.Equal(255, def[0]); Assert.Equal(0, def[1]); Assert.Equal(0, def[2]);
+
+            // Explicit Saturation → green.
+            var sat = details.Transform(input, RenderingIntent.Saturation);
+            Assert.Equal(0, sat[0]); Assert.Equal(255, sat[1]); Assert.Equal(0, sat[2]);
+        }
+
+        [Fact]
+        public void IndexedWithIccBase_TransformWithIntent_RoutesThroughThatIntent()
+        {
+            // /Indexed [/ICCBased ...] palette image with 2 entries:
+            //   index 0 -> CMYK (0.1, 0.2, 0.3, 0.4)
+            //   index 1 -> CMYK (0.5, 0.6, 0.7, 0.8)
+            // ICC profile stub maps any input to a fixed RGB per intent.
+            var profile = new StubProfile(4, new Dictionary<RenderingIntent, IIccTransform>
+            {
+                [RenderingIntent.RelativeColorimetric] = new StubTransform(4, (1.0, 0.0, 0.0)), // red
+                [RenderingIntent.Saturation] = new StubTransform(4, (0.0, 1.0, 0.0)), // green
+            });
+
+            var iccBase = new ICCBasedColorSpaceDetails(4, DeviceCmykColorSpaceDetails.Instance,
+                null, null, new byte[] { 0x01 }, new StubService(profile));
+
+            // 2-entry CMYK palette (8 bytes).
+            byte[] colorTable =
+            [
+                (byte)(0.1 * 255), (byte)(0.2 * 255), (byte)(0.3 * 255), (byte)(0.4 * 255),
+                (byte)(0.5 * 255), (byte)(0.6 * 255), (byte)(0.7 * 255), (byte)(0.8 * 255),
+            ];
+            var indexed = new IndexedColorSpaceDetails(iccBase, hiVal: 1, colorTable: colorTable);
+
+            // Image bytes: 3 pixels of index 0, 1, 0.
+            Span<byte> input = stackalloc byte[3] { 0, 1, 0 };
+
+            // Default intent -> red.
+            var def = indexed.Transform(input.ToArray());
+            Assert.Equal(9, def.Length); // 3 pixels * 3 bytes RGB
+            Assert.Equal(255, def[0]); Assert.Equal(0, def[1]); Assert.Equal(0, def[2]);
+
+            // Saturation intent -> green. THIS is the case my first refactor missed:
+            // ColorSpaceDetailsByteConverter -> Indexed.Transform -> BaseColorSpace.Transform
+            // used to drop the intent at the Indexed boundary.
+            var sat = ((ColorSpaceDetails)indexed).Transform(input.ToArray(), RenderingIntent.Saturation);
+            Assert.Equal(9, sat.Length);
+            Assert.Equal(0, sat[0]); Assert.Equal(255, sat[1]); Assert.Equal(0, sat[2]);
+        }
+
+        [Fact]
+        public void WithService_GetTransformFallsBackToRelativeColorimetricForUnsupportedIntent()
+        {
+            // Profile only supports RelativeColorimetric; ask for Perceptual.
+            var profile = new StubProfile(3, new Dictionary<RenderingIntent, IIccTransform>
+            {
+                [RenderingIntent.RelativeColorimetric] = new StubTransform(3, (0.4, 0.5, 0.6)),
+            });
+
+            var details = new ICCBasedColorSpaceDetails(3, DeviceRgbColorSpaceDetails.Instance,
+                null, null, new byte[] { 0x99 }, new StubService(profile));
+
+            // Direct GetTransform: returns null for unsupported intent.
+            Assert.Null(details.GetTransform(RenderingIntent.Perceptual));
+
+            // GetColor with unsupported intent: falls back to RelativeColorimetric internally.
+            var (r, g, b) = details.GetColor(new double[] { 0.1, 0.2, 0.3 },
+                RenderingIntent.Perceptual).ToRGBValues();
+            Assert.Equal(0.4, r);
+            Assert.Equal(0.5, g);
+            Assert.Equal(0.6, b);
+        }
+    }
+}

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

@@ -194,7 +194,9 @@ public void CanGeneratePngFromICCBasedImageData()
                     numberOfColorComponents: 3,
                     alternateColorSpaceDetails: DeviceRgbColorSpaceDetails.Instance,
                     range: new List<double> { 0, 1, 0, 1, 0, 1 },
-                    metadata: null),
+                    metadata: null,
+                    profile: Memory<byte>.Empty,
+                    iccProfileService: null),
                 DecodedBytes = decodedBytes,
                 WidthInSamples = 1,
                 HeightInSamples = 1,
@@ -215,7 +217,9 @@ public void AlternateColorSpaceDetailsIsCurrentlyUsedInPdfPigWhenGeneratingPngsF
                     numberOfColorComponents: 3,
                     alternateColorSpaceDetails: DeviceRgbColorSpaceDetails.Instance,
                     range: new List<double> { 0, 1, 0, 1, 0, 1 },
-                    metadata: null),
+                    metadata: null,
+                    profile: Memory<byte>.Empty,
+                    iccProfileService: null),
                 DecodedBytes = decodedBytes,
                 WidthInSamples = 1,
                 HeightInSamples = 1,

src/UglyToad.PdfPig.Tests/PublicApiScannerTests.cs

@@ -172,6 +172,11 @@ public void OnlyExposedApiIsPublic()
                 "UglyToad.PdfPig.Graphics.Colors.DeviceCmykColorSpaceDetails",
                 "UglyToad.PdfPig.Graphics.Colors.DeviceNColorSpaceDetails",
                 "UglyToad.PdfPig.Graphics.Colors.ICCBasedColorSpaceDetails",
+                "UglyToad.PdfPig.Graphics.Colors.Icc.IIccProfile",
+                "UglyToad.PdfPig.Graphics.Colors.Icc.IIccProfileService",
+                "UglyToad.PdfPig.Graphics.Colors.Icc.IIccTransform",
+                "UglyToad.PdfPig.Graphics.Colors.Icc.OutputIntent",
+                "UglyToad.PdfPig.Graphics.Colors.Icc.IccProfileReference",
                 "UglyToad.PdfPig.Graphics.Colors.IndexedColorSpaceDetails",
                 "UglyToad.PdfPig.Graphics.Colors.LabColorSpaceDetails",
                 "UglyToad.PdfPig.Graphics.Colors.PatternColorSpaceDetails",

src/UglyToad.PdfPig/Content/IResourceStore.cs

@@ -5,6 +5,7 @@
     using Graphics.Colors;
     using PdfFonts;
     using Tokens;
+    using UglyToad.PdfPig.Graphics.Colors.Icc;
 
     /// <summary>
     /// Resource store.
@@ -52,6 +53,15 @@ public interface IResourceStore
         /// </summary>
         ColorSpaceDetails GetColorSpaceDetails(NameToken? name, DictionaryToken? dictionary);
 
+        /// <summary>
+        /// Get the colour space details for a device colour space selected directly (for example by the
+        /// <c>g</c> / <c>rg</c> / <c>k</c> operators), applying the <c>DefaultGray</c> / <c>DefaultRGB</c> /
+        /// <c>DefaultCMYK</c> substitution from the current resource dictionary when present (PDF 2.0,
+        /// 8.6.5.6 "Default colour spaces"). Returns the device colour space itself when no matching
+        /// default colour space is defined.
+        /// </summary>
+        ColorSpaceDetails GetDeviceColorSpaceDetails(ColorSpace deviceColorSpace);
+
         /// <summary>
         /// Get the marked content properties dictionary corresponding to the name.
         /// </summary>
@@ -66,5 +76,25 @@ public interface IResourceStore
         /// Get the shading corresponding to the name.
         /// </summary>
         Shading GetShading(NameToken name);
+
+        /// <summary>
+        /// The configured ICC profile service (from <see cref="ParsingOptions.IccProfileService"/>),
+        /// or <c>null</c> when ICC-based color spaces should fall back to their alternate color space.
+        /// </summary>
+        IIccProfileService? IccProfileService { get; }
+
+        /// <summary>
+        /// The document catalog's output intent ICC profile (document scope), resolved from the catalog's
+        /// <c>/OutputIntents</c> array (<c>/DestOutputProfile</c>), or <c>null</c> when the document declares
+        /// no usable output intent (or no <see cref="IccProfileService"/> is configured / output-intent
+        /// colour management is disabled). Used to colour-manage the device colour spaces (DeviceCMYK /
+        /// DeviceRGB / DeviceGray) per PDF/X semantics.
+        /// <para>
+        /// A page may override it with its own page-level <c>/OutputIntents</c> (PDF 2.0, Table 31); that
+        /// override is page-scoped and is resolved per page onto the graphics state
+        /// (<c>CurrentGraphicsState.OutputIntent</c>), with this document-level value as the fallback.
+        /// </para>
+        /// </summary>
+        OutputIntent? OutputIntent { get; }
     }
 }