From 68be92331b62825d684f0d06a837b5440b65a205 Mon Sep 17 00:00:00 2001
From: Ynse Hoornenborg <github@ynse.nl>
Date: Sat, 13 Jul 2024 09:23:29 +0200
Subject: [PATCH] PlaneCount calculation inside ObuColorConfig

---
 .../Heif/Av1/OpenBitstreamUnit/ObuColorConfig.cs | 16 +++++++++++++---
 .../Heif/Av1/OpenBitstreamUnit/ObuReader.cs      |  1 -
 .../Heif/Av1/OpenBitstreamUnit/ObuWriter.cs      |  1 -
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuColorConfig.cs b/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuColorConfig.cs
index 3c7349b199..7e169f43fd 100644
--- a/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuColorConfig.cs
+++ b/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuColorConfig.cs
@@ -5,18 +5,28 @@ namespace SixLabors.ImageSharp.Formats.Heif.Av1.OpenBitstreamUnit;
 
 internal class ObuColorConfig
 {
+    private bool isMonochrome;
+
     public bool IsColorDescriptionPresent { get; set; }
 
     /// <summary>
-    /// Gets or sets the number of color channels in this image.
+    /// Gets the number of color channels in this image. Can have the value 1 or 3.
     /// </summary>
-    public int PlaneCount { get; set; }
+    public int PlaneCount { get; private set; }
 
     /// <summary>
     /// Gets or sets a value indicating whether the image has a single greyscale plane, will have
     /// <see cref="Av1Constants.MaxPlanes"/> color planes otherwise.
     /// </summary>
-    public bool IsMonochrome { get; set; }
+    public bool IsMonochrome
+    {
+        get => this.isMonochrome;
+        set
+        {
+            this.PlaneCount = value ? 1 : Av1Constants.MaxPlanes;
+            this.isMonochrome = value;
+        }
+    }
 
     public ObuColorPrimaries ColorPrimaries { get; set; }
 
diff --git a/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuReader.cs b/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuReader.cs
index fc3b19d319..01e1a50c0f 100644
--- a/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuReader.cs
+++ b/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuReader.cs
@@ -465,7 +465,6 @@ internal class ObuReader
             colorConfig.IsMonochrome = reader.ReadBoolean();
         }
 
-        colorConfig.PlaneCount = colorConfig.IsMonochrome ? 1 : Av1Constants.MaxPlanes;
         colorConfig.IsColorDescriptionPresent = reader.ReadBoolean();
         colorConfig.ColorPrimaries = ObuColorPrimaries.Unspecified;
         colorConfig.TransferCharacteristics = ObuTransferCharacteristics.Unspecified;
diff --git a/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuWriter.cs b/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuWriter.cs
index 1b704309d1..4a154da0e7 100644
--- a/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuWriter.cs
+++ b/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuWriter.cs
@@ -112,7 +112,6 @@ internal class ObuWriter
             writer.WriteBoolean(colorConfig.IsMonochrome);
         }
 
-        colorConfig.PlaneCount = colorConfig.IsMonochrome ? 1 : Av1Constants.MaxPlanes;
         writer.WriteBoolean(false); // colorConfig.IsColorDescriptionPresent
         if (colorConfig.IsMonochrome)
         {