Add HalfVector2

src/ImageSharp/Colors/PackedPixel/HalfSingle.cs

@@ -93,7 +93,7 @@ namespace ImageSharp
         /// <inheritdoc />
         public void PackFromBytes(byte x, byte y, byte z, byte w)
         {
-            this.PackFromVector4(new Vector4(x, y, z, w) / 255F);
+            this.PackFromVector4(new Vector4(x, y, z, w) / MaxBytes);
         }
 
         /// <inheritdoc />

src/ImageSharp/Colors/PackedPixel/HalfVector2.cs

@@ -0,0 +1,187 @@
+// <copyright file="HalfVector2.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 pixel type containing two 16-bit floating-point values.
+    /// </summary>
+    public struct HalfVector2 : IPackedPixel<uint>, IEquatable<HalfVector2>
+    {
+        /// <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="HalfVector2"/> struct.
+        /// </summary>
+        /// <param name="x">The x-component.</param>
+        /// <param name="y">The y-component.</param>
+        public HalfVector2(float x, float y)
+        {
+            this.PackedValue = Pack(x, y);
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="HalfVector2"/> struct.
+        /// </summary>
+        /// <param name="vector">A vector containing the initial values for the components.</param>
+        public HalfVector2(Vector2 vector)
+        {
+            this.PackedValue = Pack(vector.X, vector.Y);
+        }
+
+        /// <inheritdoc />
+        public uint PackedValue { get; set; }
+
+        /// <summary>
+        /// Compares two <see cref="HalfVector2"/> objects for equality.
+        /// </summary>
+        /// <param name="left">
+        /// The <see cref="HalfVector2"/> on the left side of the operand.
+        /// </param>
+        /// <param name="right">
+        /// The <see cref="HalfVector2"/> 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 ==(HalfVector2 left, HalfVector2 right)
+        {
+            return left.Equals(right);
+        }
+
+        /// <summary>
+        /// Compares two <see cref="HalfVector2"/> objects for equality.
+        /// </summary>
+        /// <param name="left">
+        /// The <see cref="HalfVector2"/> on the left side of the operand.
+        /// </param>
+        /// <param name="right">
+        /// The <see cref="HalfVector2"/> 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 !=(HalfVector2 left, HalfVector2 right)
+        {
+            return !left.Equals(right);
+        }
+
+        /// <summary>
+        /// Expands the packed representation into a <see cref="Vector2"/>.
+        /// </summary>
+        /// <returns>The <see cref="Vector2"/>.</returns>
+        public Vector2 ToVector2()
+        {
+            Vector2 vector;
+            vector.X = HalfTypeHelper.Unpack((ushort)this.PackedValue);
+            vector.Y = HalfTypeHelper.Unpack((ushort)(this.PackedValue >> 0x10));
+            return vector;
+        }
+
+        /// <inheritdoc />
+        public void PackFromVector4(Vector4 vector)
+        {
+            this.PackedValue = Pack(vector.X, vector.Y);
+        }
+
+        /// <inheritdoc />
+        public Vector4 ToVector4()
+        {
+            Vector2 vector = this.ToVector2();
+            return new Vector4(vector.X, vector.Y, 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 string ToString()
+        {
+            return this.ToVector2().ToString();
+        }
+
+        /// <inheritdoc />
+        public override int GetHashCode()
+        {
+            return this.PackedValue.GetHashCode();
+        }
+
+        /// <inheritdoc />
+        public override bool Equals(object obj)
+        {
+            return (obj is HalfVector2) && this.Equals((HalfVector2)obj);
+        }
+
+        /// <inheritdoc />
+        public bool Equals(HalfVector2 other)
+        {
+            return this.PackedValue.Equals(other.PackedValue);
+        }
+
+        /// <summary>
+        /// Packs the <see cref="float"/> components into a <see cref="uint"/>.
+        /// </summary>
+        /// <param name="x">The x-component</param>
+        /// <param name="y">The y-component</param>
+        /// <returns>The <see cref="uint"/> containing the packed values.</returns>
+        private static uint Pack(float x, float y)
+        {
+            uint num2 = HalfTypeHelper.Pack(x);
+            uint num = (uint)(HalfTypeHelper.Pack(y) << 0x10);
+            return num2 | num;
+        }
+    }
+}

tests/ImageSharp.Tests/Colors/PackedPixelTests.cs

@@ -285,6 +285,43 @@ namespace ImageSharp.Tests.Colors
             Assert.Equal(bgra, new byte[] { 0, 0, 128, 255 });
         }
 
+        [Fact]
+        public void HalfVector2()
+        {
+            // Test PackedValue
+            Assert.Equal(0u, new HalfVector2(Vector2.Zero).PackedValue);
+            Assert.Equal(1006648320u, new HalfVector2(Vector2.One).PackedValue);
+            Assert.Equal(3033345638u, new HalfVector2(0.1f, -0.3f).PackedValue);
+
+            // Test ToVector2
+            Assert.True(Equal(Vector2.Zero, new HalfVector2(Vector2.Zero).ToVector2()));
+            Assert.True(Equal(Vector2.One, new HalfVector2(Vector2.One).ToVector2()));
+            Assert.True(Equal(Vector2.UnitX, new HalfVector2(Vector2.UnitX).ToVector2()));
+            Assert.True(Equal(Vector2.UnitY, new HalfVector2(Vector2.UnitY).ToVector2()));
+
+            // Test ordering
+            float x = .5F;
+            float y = .25F;
+            Assert.True(Equal(new Vector4(x, y, 0, 1), new HalfVector2(x, y).ToVector4()));
+
+            byte[] rgb = new byte[3];
+            byte[] rgba = new byte[4];
+            byte[] bgr = new byte[3];
+            byte[] bgra = new byte[4];
+
+            new HalfVector2(x, y).ToBytes(rgb, 0, ComponentOrder.XYZ);
+            Assert.Equal(rgb, new byte[] { 128, 64, 0 });
+
+            new HalfVector2(x, y).ToBytes(rgba, 0, ComponentOrder.XYZW);
+            Assert.Equal(rgba, new byte[] { 128, 64, 0, 255 });
+
+            new HalfVector2(x, y).ToBytes(bgr, 0, ComponentOrder.ZYX);
+            Assert.Equal(bgr, new byte[] { 0, 64, 128 });
+
+            new HalfVector2(x, y).ToBytes(bgra, 0, ComponentOrder.ZYXW);
+            Assert.Equal(bgra, new byte[] { 0, 64, 128, 255 });
+        }
+
         // Comparison helpers with small tolerance to allow for floating point rounding during computations.
         public static bool Equal(float a, float b)
         {