Add Byte4

src/ImageSharp/Colors/Color.cs

@@ -10,7 +10,7 @@ namespace ImageSharp
     using System.Numerics;
 
     /// <summary>
-    /// Packed vector type containing four 8-bit unsigned normalized values ranging from 0 to 255.
+    /// Packed pixel type containing four 8-bit unsigned normalized values ranging from 0 to 255.
     /// The color components are stored in red, green, blue, and alpha order.
     /// </summary>
     /// <remarks>
@@ -19,9 +19,24 @@ namespace ImageSharp
     /// </remarks>
     public partial struct Color : IPackedPixel<uint>, IEquatable<Color>
     {
+        /// <summary>
+        /// The shift count for the red component
+        /// </summary>
         private const int RedShift = 0;
+
+        /// <summary>
+        /// The shift count for the green component
+        /// </summary>
         private const int GreenShift = 8;
+
+        /// <summary>
+        /// The shift count for the blue component
+        /// </summary>
         private const int BlueShift = 16;
+
+        /// <summary>
+        /// The shift count for the alpha component
+        /// </summary>
         private const int AlphaShift = 24;
 
         /// <summary>

src/ImageSharp/Colors/PackedPixel/Byte4.cs

@@ -0,0 +1,178 @@
+// <copyright file="Byte4.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 four 8-bit unsigned integer values, ranging from 0 to 255.
+    /// </summary>
+    public struct Byte4 : IPackedPixel<uint>, IEquatable<Byte4>, IPackedVector
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Byte4"/> struct. 
+        /// </summary>
+        /// <param name="vector">
+        /// A vector containing the initial values for the components of the Byte4 structure.
+        /// </param>
+        public Byte4(Vector4 vector)
+        {
+            this.PackedValue = Pack(ref vector);
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Byte4"/> struct. 
+        /// </summary>
+        /// <param name="x">The x-component</param>
+        /// <param name="y">The y-component</param>
+        /// <param name="z">The z-component</param>
+        /// <param name="w">The w-component</param>
+        public Byte4(float x, float y, float z, float w)
+        {
+            Vector4 vector = new Vector4(x, y, z, w);
+            this.PackedValue = Pack(ref vector);
+        }
+
+        /// <inheritdoc />
+        public uint PackedValue { get; set; }
+
+        /// <summary>
+        /// Compares two <see cref="Byte4"/> objects for equality.
+        /// </summary>
+        /// <param name="left">The <see cref="Byte4"/> on the left side of the operand.</param>
+        /// <param name="right">The <see cref="Byte4"/> 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 ==(Byte4 left, Byte4 right)
+        {
+            return left.PackedValue == right.PackedValue;
+        }
+
+        /// <summary>
+        /// Compares two <see cref="Byte4"/> objects for equality.
+        /// </summary>
+        /// <param name="left">The <see cref="Byte4"/> on the left side of the operand.</param>
+        /// <param name="right">The <see cref="Byte4"/> 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 !=(Byte4 left, Byte4 right)
+        {
+            return left.PackedValue != right.PackedValue;
+        }
+
+        /// <summary>
+        /// Sets the packed representation from a Vector4.
+        /// </summary>
+        /// <param name="vector">The vector to create the packed representation from.</param>
+        public void PackFromVector4(Vector4 vector)
+        {
+            this.PackedValue = Pack(ref vector);
+        }
+
+        /// <summary>
+        /// Expands the packed representation into a Vector4.
+        /// </summary>
+        /// <returns>The expanded vector.</returns>
+        public Vector4 ToVector4()
+        {
+            return new Vector4(
+                this.PackedValue & 0xFF,
+                (this.PackedValue >> 0x8) & 0xFF,
+                (this.PackedValue >> 0x10) & 0xFF,
+                (this.PackedValue >> 0x18) & 0xFF);
+        }
+
+        /// <inheritdoc />
+        public void PackFromBytes(byte x, byte y, byte z, byte w)
+        {
+            this.PackFromVector4(new Vector4(x, y, z, w) / 255F);
+        }
+
+        /// <inheritdoc />
+        public void ToBytes(byte[] bytes, int startIndex, ComponentOrder componentOrder)
+        {
+            Vector4 vector = this.ToVector4() * 255F;
+
+            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 Byte4) && this.Equals((Byte4)obj);
+        }
+
+        /// <inheritdoc />
+        public bool Equals(Byte4 other)
+        {
+            return this == other;
+        }
+
+        /// <inheritdoc />
+        public override int GetHashCode()
+        {
+            return this.PackedValue.GetHashCode();
+        }
+
+        /// <summary>
+        /// Returns a string representation of the current instance.
+        /// </summary>
+        /// <returns>String that represents the object.</returns>
+        public override string ToString()
+        {
+            return this.PackedValue.ToString("x8");
+        }
+
+        /// <summary>
+        /// Packs a vector into a uint.
+        /// </summary>
+        /// <param name="vector">The vector containing the values to pack.</param>
+        /// <returns>The <see cref="uint"/> containing the packed values.</returns>
+        private static uint Pack(ref Vector4 vector)
+        {
+            const float Max = 255F;
+            const float Min = 0F;
+
+            // Clamp the value between min and max values
+            uint byte4 = (uint)Math.Round(vector.X.Clamp(Min, Max)) & 0xFF;
+            uint byte3 = ((uint)Math.Round(vector.Y.Clamp(Min, Max)) & 0xFF) << 0x8;
+            uint byte2 = ((uint)Math.Round(vector.Z.Clamp(Min, Max)) & 0xFF) << 0x10;
+            uint byte1 = ((uint)Math.Round(vector.W.Clamp(Min, Max)) & 0xFF) << 0x18;
+
+            return byte4 | byte3 | byte2 | byte1;
+        }
+    }
+}

tests/ImageSharp.Tests/Colors/PackedVectorTests.cs

@@ -200,6 +200,57 @@ namespace ImageSharp.Tests.Colors
             Assert.Equal(bgra, new byte[] { 131, 0, 24, 0 });
         }
 
+        [Fact]
+        public void Byte4()
+        {
+            // Test the limits.
+            Assert.Equal((uint)0x0, new Byte4(Vector4.Zero).PackedValue);
+            Assert.Equal(0xFFFFFFFF, new Byte4(Vector4.One * 255).PackedValue);
+
+            // Test ToVector4.
+            Assert.True(Equal(Vector4.One * 255, new Byte4(Vector4.One * 255).ToVector4()));
+            Assert.True(Equal(Vector4.Zero, new Byte4(Vector4.Zero).ToVector4()));
+            Assert.True(Equal(Vector4.UnitX * 255, new Byte4(Vector4.UnitX * 255).ToVector4()));
+            Assert.True(Equal(Vector4.UnitY * 255, new Byte4(Vector4.UnitY * 255).ToVector4()));
+            Assert.True(Equal(Vector4.UnitZ * 255, new Byte4(Vector4.UnitZ * 255).ToVector4()));
+            Assert.True(Equal(Vector4.UnitW * 255, new Byte4(Vector4.UnitW * 255).ToVector4()));
+
+            // Test clamping.
+            Assert.True(Equal(Vector4.Zero, new Byte4(Vector4.One * -1234.0f).ToVector4()));
+            Assert.True(Equal(Vector4.One * 255, new Byte4(Vector4.One * 1234.0f).ToVector4()));
+
+            // Test ordering
+            float x = 0x2d;
+            float y = 0x36;
+            float z = 0x7b;
+            float w = 0x1a;
+            Assert.Equal((uint)0x1a7b362d, new Byte4(x, y, z, w).PackedValue);
+
+            x = 127.5f;
+            y = -12.3f;
+            z = 0.5f;
+            w = -0.7f;
+            Assert.Equal((uint)128, new Byte4(x, y, z, w).PackedValue);
+
+            // Test ordering
+            byte[] rgb = new byte[3];
+            byte[] rgba = new byte[4];
+            byte[] bgr = new byte[3];
+            byte[] bgra = new byte[4];
+
+            new Byte4(x, y, z, w).ToBytes(rgb, 0, ComponentOrder.XYZ);
+            Assert.Equal(rgb, new byte[] { 128, 0, 0 });
+
+            new Byte4(x, y, z, w).ToBytes(rgba, 0, ComponentOrder.XYZW);
+            Assert.Equal(rgba, new byte[] { 128, 0, 0, 0 });
+
+            new Byte4(x, y, z, w).ToBytes(bgr, 0, ComponentOrder.ZYX);
+            Assert.Equal(bgr, new byte[] { 0, 0, 128 });
+
+            new Byte4(x, y, z, w).ToBytes(bgra, 0, ComponentOrder.ZYXW);
+            Assert.Equal(bgra, new byte[] { 0, 0, 128, 0 });
+        }
+
         // 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

@@ -55,6 +55,7 @@ namespace ImageSharp.Tests
                 // Image<Bgr565, ushort> image = file.CreateImage().To<Bgr565, ushort>();
                 // Image<Bgra4444, ushort> image = file.CreateImage().To<Bgra4444, ushort>();
                 // Image<Bgra5551, ushort> image = file.CreateImage().To<Bgra5551, ushort>();
+                // Image<Byte4, uint> image = file.CreateImage().To<Byte4, uint>();
 
                 using (FileStream output = File.OpenWrite($"{path}/{file.FileName}"))
                 {