From d6d126d88d2e5b0ef0e9dc10fbc3afaa14f10524 Mon Sep 17 00:00:00 2001
From: Darth Affe <darthaffe@wyrez.org>
Date: Sun, 18 Aug 2024 12:44:42 +0200
Subject: [PATCH] Improved equality comparison for images and added methods to
 get raw data access on image-rows

---
 HPPH/Images/Image.cs    | 32 ++++++++++++--------------------
 HPPH/Images/ImageRow.cs |  5 ++++-
 2 files changed, 16 insertions(+), 21 deletions(-)

diff --git a/HPPH/Images/Image.cs b/HPPH/Images/Image.cs
index 1bbea09..8820d42 100644
--- a/HPPH/Images/Image.cs
+++ b/HPPH/Images/Image.cs
@@ -249,49 +249,41 @@ public sealed class Image<T> : IImage<T>, IEquatable<Image<T>>
     /// <inheritdoc />
     IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
 
-    //TODO DarthAffe 20.07.2024: All of those equals can be optimized
     /// <inheritdoc />
     public bool Equals(IImage? other)
     {
         if (other == null) return false;
         if (other.ColorFormat != ColorFormat) return false;
-        if (other.Width != Width) return false;
-        if (other.Height != Height) return false;
 
-        for (int y = 0; y < Height; y++)
-            for (int x = 0; x < Width; x++)
-                if (!this[x, y].Equals(other[x, y]))
-                    return false;
-
-        return true;
+        return Equals(other.AsRefImage<T>());
     }
 
     /// <inheritdoc />
     public bool Equals(IImage<T>? other)
     {
         if (other == null) return false;
-        if (other.Width != Width) return false;
-        if (other.Height != Height) return false;
 
-        for (int y = 0; y < Height; y++)
-            for (int x = 0; x < Width; x++)
-                if (!this[x, y].Equals(other[x, y]))
-                    return false;
-
-        return true;
+        return Equals(other.AsRefImage());
     }
 
     /// <inheritdoc />
     public bool Equals(Image<T>? other)
     {
         if (other == null) return false;
+
+        return Equals(other.AsRefImage());
+    }
+
+    public bool Equals(RefImage<T> other)
+    {
         if (other.Width != Width) return false;
         if (other.Height != Height) return false;
 
+        RefImage<T> thisRef = AsRefImage();
+
         for (int y = 0; y < Height; y++)
-            for (int x = 0; x < Width; x++)
-                if (!this[x, y].Equals(other[x, y]))
-                    return false;
+            if (!thisRef.Rows[y].AsByteSpan().SequenceEqual(other.Rows[y].AsByteSpan()))
+                return false;
 
         return true;
     }
diff --git a/HPPH/Images/ImageRow.cs b/HPPH/Images/ImageRow.cs
index 40235bb..2bc42da 100644
--- a/HPPH/Images/ImageRow.cs
+++ b/HPPH/Images/ImageRow.cs
@@ -47,6 +47,9 @@ public readonly ref struct ImageRow<T>
 
     #region Methods
 
+    public ReadOnlySpan<T> AsSpan() => MemoryMarshal.Cast<byte, T>(AsByteSpan());
+    public ReadOnlySpan<byte> AsByteSpan() => _buffer.Slice(_start, SizeInBytes);
+
     public void CopyTo(Span<T> destination) => CopyTo(MemoryMarshal.AsBytes(destination));
 
     public void CopyTo(Span<byte> destination)
@@ -54,7 +57,7 @@ public readonly ref struct ImageRow<T>
         if (destination == null) throw new ArgumentNullException(nameof(destination));
         if (destination.Length < SizeInBytes) throw new ArgumentException("The destination is too small to fit this image.", nameof(destination));
 
-        _buffer.Slice(_start, SizeInBytes).CopyTo(destination);
+        AsByteSpan().CopyTo(destination);
     }
 
     public T[] ToArray()