PixelConversion_ConvertToRgba32_AsPartOfCompositeOperation

tests/ImageSharp.Benchmarks/General/PixelConversion/PixelConversion_ConvertToRgba32_AsPartOfCompositeOperation.cs

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+using System.Runtime.CompilerServices;
+
+using BenchmarkDotNet.Attributes;
+
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Benchmarks.General.PixelConversion
+{
+    public class PixelConversion_ConvertToRgba32_AsPartOfCompositeOperation
+    {
+        struct ConversionRunner<T>
+            where T : struct, ITestPixel<T>
+        {
+            private T[] source;
+
+            private Rgba32[] dest;
+
+            public ConversionRunner(int count)
+            {
+                this.source = new T[count];
+                this.dest = new Rgba32[count];
+            }
+
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            public void RunRetvalConversion()
+            {
+                int count = this.source.Length;
+
+                ref T sourceBaseRef = ref this.source[0];
+                ref Rgba32 destBaseRef = ref this.dest[0];
+
+                Rgba32 temp;
+
+                for (int i = 0; i < count; i++)
+                {
+                    temp = Unsafe.Add(ref sourceBaseRef, i).ToRgba32();
+
+                    // manipulate pixel before saving to dest buffer:
+                    temp.A = 0;
+
+                    Unsafe.Add(ref destBaseRef, i) = temp;
+                }
+            }
+
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            public void RunCopyToConversion()
+            {
+                int count = this.source.Length;
+
+                ref T sourceBaseRef = ref this.source[0];
+                ref Rgba32 destBaseRef = ref this.dest[0];
+
+                Rgba32 temp = default;
+
+                for (int i = 0; i < count; i++)
+                {
+                    Unsafe.Add(ref sourceBaseRef, i).CopyToRgba32(ref temp);
+
+                    // manipulate pixel before saving to dest buffer:
+                    temp.A = 0;
+
+                    Unsafe.Add(ref destBaseRef, i) = temp;
+                }
+            }
+        }
+
+        private ConversionRunner<TestRgba> compatibleMemoryLayoutRunner;
+
+        private ConversionRunner<TestArgb> permutedRunner;
+
+        [Params(128)]
+        public int Count { get; set; }
+
+        [GlobalSetup]
+        public void Setup()
+        {
+            this.compatibleMemoryLayoutRunner = new ConversionRunner<TestRgba>(this.Count);
+            this.permutedRunner = new ConversionRunner<TestArgb>(this.Count);
+        }
+
+        [Benchmark(Baseline = true)]
+        public void CompatibleRetval()
+        {
+            this.compatibleMemoryLayoutRunner.RunRetvalConversion();
+        }
+
+        [Benchmark]
+        public void CompatibleCopyTo()
+        {
+            this.compatibleMemoryLayoutRunner.RunCopyToConversion();
+        }
+
+        [Benchmark]
+        public void PermutedRetval()
+        {
+            this.permutedRunner.RunRetvalConversion();
+        }
+
+        [Benchmark]
+        public void PermutedCopyTo()
+        {
+            this.permutedRunner.RunCopyToConversion();
+        }
+    }
+
+    // RESULTS:
+    //            Method | Count |       Mean |     Error |    StdDev | Scaled | ScaledSD |
+    // ----------------- |------ |-----------:|----------:|----------:|-------:|---------:|
+    //  CompatibleRetval |   128 |   210.1 ns | 0.8443 ns | 0.7484 ns |   1.00 |     0.00 |
+    //  CompatibleCopyTo |   128 |   140.1 ns | 0.4297 ns | 0.4019 ns |   0.67 |     0.00 |
+    //    PermutedRetval |   128 | 1,044.6 ns | 3.7901 ns | 3.3599 ns |   4.97 |     0.02 |
+    //    PermutedCopyTo |   128 |   140.3 ns | 0.6495 ns | 0.5757 ns |   0.67 |     0.00 |
+}