Decode ICC profile into metadata

src/ImageSharp/Formats/Heif/Heif4CharCode.cs

@@ -248,4 +248,14 @@ public enum Heif4CharCode : uint
     /// </summary>
     free = 0x66726565U,
 
+    /// <summary>
+    /// ICC Color Profile.
+    /// </summary>
+    rICC = 0x72494343U,
+
+    /// <summary>
+    /// ICC Color Profile.
+    /// </summary>
+    prof = 0x70726F66U,
+
 }

src/ImageSharp/Formats/Heif/Heif4CharCode.tt

@@ -54,6 +54,8 @@
         "pict", "Picture handler type",
         "uuid", "Unique Identifier",
         "free", "Free space",
+        "rICC", "ICC Color Profile",
+        "prof", "ICC Color Profile",
     };
 #>
 

src/ImageSharp/Formats/Heif/HeifDecoderCore.cs

@@ -7,6 +7,7 @@ using System.Text;
 using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.Metadata;
+using SixLabors.ImageSharp.Metadata.Profiles.Icc;
 using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Formats.Heif;
@@ -442,8 +443,17 @@ internal sealed class HeifDecoderCore : IImageDecoderInternals
                     properties.Add(new KeyValuePair<Heif4CharCode, object>(Heif4CharCode.pixi, new int[] { channelCount, bitsPerPixel }));
 
                     break;
-                case Heif4CharCode.altt:
                 case Heif4CharCode.colr:
+                    Heif4CharCode profileType = (Heif4CharCode)BinaryPrimitives.ReadUInt32BigEndian(buffer);
+                    if (profileType is Heif4CharCode.rICC or Heif4CharCode.prof)
+                    {
+                        byte[] iccData = new byte[itemLength - 4];
+                        buffer[4..].CopyTo(iccData);
+                        this.metadata.IccProfile = new IccProfile(iccData);
+                    }
+
+                    break;
+                case Heif4CharCode.altt:
                 case Heif4CharCode.imir:
                 case Heif4CharCode.irot:
                 case Heif4CharCode.iscl: