Add NormalizedByte2

src/ImageSharp/Colors/PackedPixel/NormalizedByte2.cs

@@ -0,0 +1,187 @@
+// <copyright file="NormalizedByte2.cs" company="James Jackson-South">
+// Copyright (c) James Jackson-South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageSharp
+{
+    using System;
+    using System.Numerics;
+
+    /// <summary>
+    /// Packed packed pixel type containing two 8-bit signed normalized values, ranging from −1 to 1.
+    /// </summary>
+    public struct NormalizedByte2 : IPackedPixel<ushort>, IEquatable<NormalizedByte2>
+    {
+        /// <summary>
+        /// The maximum byte value.
+        /// </summary>
+        private static readonly Vector4 MaxBytes = new Vector4(255);
+
+        /// <summary>
+        /// The half vector value.
+        /// </summary>
+        private static readonly Vector4 Half = new Vector4(0.5F);
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="NormalizedByte2"/> struct.
+        /// </summary>
+        /// <param name="vector">The vector containing the component values.</param>
+        public NormalizedByte2(Vector2 vector)
+        {
+            this.PackedValue = Pack(vector.X, vector.Y);
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="NormalizedByte2"/> struct.
+        /// </summary>
+        /// <param name="x">The x-component.</param>
+        /// <param name="y">The y-component.</param>
+        public NormalizedByte2(float x, float y)
+        {
+            this.PackedValue = Pack(x, y);
+        }
+
+        /// <inheritdoc />
+        public ushort PackedValue { get; set; }
+
+        /// <summary>
+        /// Compares two <see cref="NormalizedByte2"/> objects for equality.
+        /// </summary>
+        /// <param name="left">
+        /// The <see cref="NormalizedByte2"/> on the left side of the operand.
+        /// </param>
+        /// <param name="right">
+        /// The <see cref="NormalizedByte2"/> on the right side of the operand.
+        /// </param>
+        /// <returns>
+        /// True if the <paramref name="left"/> parameter is equal to the <paramref name="right"/> parameter; otherwise, false.
+        /// </returns>
+        public static bool operator ==(NormalizedByte2 left, NormalizedByte2 right)
+        {
+            return left.PackedValue == right.PackedValue;
+        }
+
+        /// <summary>
+        /// Compares two <see cref="NormalizedByte2"/> objects for equality.
+        /// </summary>
+        /// <param name="left">
+        /// The <see cref="NormalizedByte2"/> on the left side of the operand.
+        /// </param>
+        /// <param name="right">
+        /// The <see cref="NormalizedByte2"/> on the right side of the operand.
+        /// </param>
+        /// <returns>
+        /// True if the <paramref name="left"/> parameter is not equal to the <paramref name="right"/> parameter; otherwise, false.
+        /// </returns>
+        public static bool operator !=(NormalizedByte2 left, NormalizedByte2 right)
+        {
+            return left.PackedValue != right.PackedValue;
+        }
+
+        /// <summary>
+        /// Expands the packed representation into a <see cref="Vector2"/>.
+        /// The vector components are typically expanded in least to greatest significance order.
+        /// </summary>
+        /// <returns>The <see cref="Vector2"/>.</returns>
+        public Vector2 ToVector2()
+        {
+            return new Vector2(
+                ((sbyte)((this.PackedValue >> 0) & 0xFF)) / 127F,
+                ((sbyte)((this.PackedValue >> 8) & 0xFF)) / 127F);
+        }
+
+        /// <inheritdoc />
+        public void PackFromVector4(Vector4 vector)
+        {
+            this.PackedValue = Pack(vector.X, vector.Y);
+        }
+
+        /// <inheritdoc />
+        public Vector4 ToVector4()
+        {
+            return new Vector4(this.ToVector2(), 0F, 1F);
+        }
+
+        /// <inheritdoc />
+        public void PackFromBytes(byte x, byte y, byte z, byte w)
+        {
+            this.PackFromVector4(new Vector4(x, y, z, w) / MaxBytes);
+        }
+
+        /// <inheritdoc />
+        public void ToBytes(byte[] bytes, int startIndex, ComponentOrder componentOrder)
+        {
+            Vector4 vector = this.ToVector4();
+            vector *= MaxBytes;
+            vector += Half;
+            vector = Vector4.Clamp(vector, Vector4.Zero, MaxBytes);
+
+            switch (componentOrder)
+            {
+                case ComponentOrder.ZYX:
+                    bytes[startIndex] = (byte)vector.Z;
+                    bytes[startIndex + 1] = (byte)vector.Y;
+                    bytes[startIndex + 2] = (byte)vector.X;
+                    break;
+                case ComponentOrder.ZYXW:
+                    bytes[startIndex] = (byte)vector.Z;
+                    bytes[startIndex + 1] = (byte)vector.Y;
+                    bytes[startIndex + 2] = (byte)vector.X;
+                    bytes[startIndex + 3] = (byte)vector.W;
+                    break;
+                case ComponentOrder.XYZ:
+                    bytes[startIndex] = (byte)vector.X;
+                    bytes[startIndex + 1] = (byte)vector.Y;
+                    bytes[startIndex + 2] = (byte)vector.Z;
+                    break;
+                case ComponentOrder.XYZW:
+                    bytes[startIndex] = (byte)vector.X;
+                    bytes[startIndex + 1] = (byte)vector.Y;
+                    bytes[startIndex + 2] = (byte)vector.Z;
+                    bytes[startIndex + 3] = (byte)vector.W;
+                    break;
+                default:
+                    throw new NotSupportedException();
+            }
+        }
+
+        /// <inheritdoc />
+        public override bool Equals(object obj)
+        {
+            return (obj is NormalizedByte2) && this.Equals((NormalizedByte2)obj);
+        }
+
+        /// <inheritdoc />
+        public bool Equals(NormalizedByte2 other)
+        {
+            return this.PackedValue == other.PackedValue;
+        }
+
+        /// <inheritdoc />
+        public override int GetHashCode()
+        {
+            return this.PackedValue.GetHashCode();
+        }
+
+        /// <inheritdoc />
+        public override string ToString()
+        {
+            return this.PackedValue.ToString("X");
+        }
+
+        /// <summary>
+        /// Packs the <see cref="float"/> components into a <see cref="ushort"/>.
+        /// </summary>
+        /// <param name="x">The x-component</param>
+        /// <param name="y">The y-component</param>
+        /// <returns>The <see cref="ushort"/> containing the packed values.</returns>
+        private static ushort Pack(float x, float y)
+        {
+            int byte2 = (((ushort)Math.Round(x.Clamp(-1F, 1F) * 127F)) & 0xFF) << 0;
+            int byte1 = (((ushort)Math.Round(y.Clamp(-1F, 1F) * 127F)) & 0xFF) << 8;
+
+            return (ushort)(byte2 | byte1);
+        }
+    }
+}

tests/ImageSharp.Tests/Colors/PackedPixelTests.cs

@@ -368,6 +368,48 @@ namespace ImageSharp.Tests.Colors
             Assert.Equal(bgra, new byte[] { 191, 128, 64, 255 });
         }
 
+        [Fact]
+        public void NormalizedByte2()
+        {
+            // Test PackedValue
+            Assert.Equal(0x0, new NormalizedByte2(Vector2.Zero).PackedValue);
+            Assert.Equal(0x7F7F, new NormalizedByte2(Vector2.One).PackedValue);
+            Assert.Equal(0x8181, new NormalizedByte2(-Vector2.One).PackedValue);
+
+            // Test ToVector2
+            Assert.True(Equal(Vector2.One, new NormalizedByte2(Vector2.One).ToVector2()));
+            Assert.True(Equal(Vector2.Zero, new NormalizedByte2(Vector2.Zero).ToVector2()));
+            Assert.True(Equal(-Vector2.One, new NormalizedByte2(-Vector2.One).ToVector2()));
+            Assert.True(Equal(Vector2.One, new NormalizedByte2(Vector2.One * 1234.0f).ToVector2()));
+            Assert.True(Equal(-Vector2.One, new NormalizedByte2(Vector2.One * -1234.0f).ToVector2()));
+
+            // Test ToVector2
+            Assert.True(Equal(new Vector4(1, 1, 0, 1), new NormalizedByte2(Vector2.One).ToVector4()));
+            Assert.True(Equal(new Vector4(0, 0, 0, 1), new NormalizedByte2(Vector2.Zero).ToVector4()));
+
+            // Test Ordering
+            float x = 0.1f;
+            float y = -0.3f;
+            Assert.Equal(0xda0d, new NormalizedByte2(x, y).PackedValue);
+
+            byte[] rgb = new byte[3];
+            byte[] rgba = new byte[4];
+            byte[] bgr = new byte[3];
+            byte[] bgra = new byte[4];
+
+            new NormalizedByte2(x, y).ToBytes(rgb, 0, ComponentOrder.XYZ);
+            Assert.Equal(rgb, new byte[] { 26, 0, 0 });
+
+            new NormalizedByte2(x, y).ToBytes(rgba, 0, ComponentOrder.XYZW);
+            Assert.Equal(rgba, new byte[] { 26, 0, 0, 255 });
+
+            new NormalizedByte2(x, y).ToBytes(bgr, 0, ComponentOrder.ZYX);
+            Assert.Equal(bgr, new byte[] { 0, 0, 26 });
+
+            new NormalizedByte2(x, y).ToBytes(bgra, 0, ComponentOrder.ZYXW);
+            Assert.Equal(bgra, new byte[] { 0, 0, 26, 255 });
+        }
+
         // Comparison helpers with small tolerance to allow for floating point rounding during computations.
         public static bool Equal(float a, float b)
         {

tests/ImageSharp.Tests/Formats/GeneralFormatTests.cs

@@ -59,6 +59,7 @@ namespace ImageSharp.Tests
                 // Image<HalfSingle, ushort> image = file.CreateImage().To<HalfSingle, ushort>();
                 // Image<HalfVector2, uint> image = file.CreateImage().To<HalfVector2, uint>();
                 // Image<HalfVector4, ulong> image = file.CreateImage().To<HalfVector4, ulong>();
+                // Image<NormalizedByte2, ushort> image = file.CreateImage().To<NormalizedByte2, ushort>();
 
                 using (FileStream output = File.OpenWrite($"{path}/{file.FileName}"))
                 {