Add Short4

src/ImageSharp/Colors/PackedPixel/Short2.cs

@@ -16,7 +16,7 @@ namespace ImageSharp
         /// <summary>
         /// The maximum byte value.
         /// </summary>
-        private static readonly Vector4 MaxBytes = new Vector4(255);
+        private static readonly Vector2 MaxBytes = new Vector2(255);
 
         /// <summary>
         /// The half the maximum byte value.
@@ -113,6 +113,7 @@ namespace ImageSharp
             vector *= 255;
             vector += Half;
             vector += Round;
+            vector = Vector2.Clamp(vector, Vector2.Zero, MaxBytes);
 
             switch (componentOrder)
             {

src/ImageSharp/Colors/PackedPixel/Short4.cs

@@ -0,0 +1,216 @@
+// <copyright file="Short4.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 16-bit signed integer values.
+    /// </summary>
+    public struct Short4 : IPackedPixel<ulong>, IEquatable<Short4>
+    {
+        /// <summary>
+        /// The maximum byte value.
+        /// </summary>
+        private static readonly Vector4 MaxBytes = new Vector4(255);
+
+        /// <summary>
+        /// The half the maximum byte value.
+        /// </summary>
+        private static readonly Vector4 Half = new Vector4(127);
+
+        /// <summary>
+        /// The vector value used for rounding.
+        /// </summary>
+        private static readonly Vector4 Round = new Vector4(.5F);
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Short4"/> struct. 
+        /// </summary>
+        /// <param name="vector">A vector containing the initial values for the components.</param>
+        public Short4(Vector4 vector)
+        {
+            this.PackedValue = Pack(vector.X, vector.Y, vector.Z, vector.W);
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Short4"/> 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 Short4(float x, float y, float z, float w)
+        {
+            this.PackedValue = Pack(x, y, z, w);
+        }
+
+        /// <inheritdoc />
+        public ulong PackedValue { get; set; }
+
+        /// <summary>
+        /// Compares two <see cref="Short4"/> objects for equality.
+        /// </summary>
+        /// <param name="left">
+        /// The <see cref="Short4"/> on the left side of the operand.
+        /// </param>
+        /// <param name="right">
+        /// The <see cref="Short4"/> 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 ==(Short4 left, Short4 right)
+        {
+            return left.PackedValue == right.PackedValue;
+        }
+
+        /// <summary>
+        /// Compares two <see cref="Short4"/> objects for equality.
+        /// </summary>
+        /// <param name="left">
+        /// The <see cref="Short4"/> on the left side of the operand.
+        /// </param>
+        /// <param name="right">
+        /// The <see cref="Short4"/> 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 !=(Short4 left, Short4 right)
+        {
+            return left.PackedValue != right.PackedValue;
+        }
+
+        /// <inheritdoc />
+        public void PackFromVector4(Vector4 vector)
+        {
+            this.PackedValue = Pack(vector.X, vector.Y, vector.Z, vector.W);
+        }
+
+        /// <inheritdoc />
+        public Vector4 ToVector4()
+        {
+            return new Vector4(
+                (short)(this.PackedValue & 0xFFFF),
+                (short)((this.PackedValue >> 0x10) & 0xFFFF),
+                (short)((this.PackedValue >> 0x20) & 0xFFFF),
+                (short)((this.PackedValue >> 0x30) & 0xFFFF));
+        }
+
+        /// <inheritdoc />
+        public void PackFromBytes(byte x, byte y, byte z, byte w)
+        {
+            Vector4 vector = new Vector4(x, y, z, w) / 255;
+            vector *= 65534;
+            vector -= new Vector4(32767);
+            this.PackedValue = Pack(vector.X, vector.Y, vector.Z, vector.W);
+        }
+
+        /// <inheritdoc />
+        public void ToBytes(byte[] bytes, int startIndex, ComponentOrder componentOrder)
+        {
+            Vector4 vector = this.ToVector4();
+            vector /= 65534;
+            vector *= 255;
+            vector += Half;
+            vector += Round;
+            vector = Vector4.Clamp(vector, Vector4.Zero, MaxBytes);
+
+            switch (componentOrder)
+            {
+                case ComponentOrder.ZYX:
+                    bytes[startIndex] = (byte)(float)Math.Round(vector.Z);
+                    bytes[startIndex + 1] = (byte)(float)Math.Round(vector.Y);
+                    bytes[startIndex + 2] = (byte)(float)Math.Round(vector.X);
+                    break;
+                case ComponentOrder.ZYXW:
+                    bytes[startIndex] = (byte)(float)Math.Round(vector.Z);
+                    bytes[startIndex + 1] = (byte)(float)Math.Round(vector.Y);
+                    bytes[startIndex + 2] = (byte)(float)Math.Round(vector.X);
+                    bytes[startIndex + 3] = (byte)(float)Math.Round(vector.W);
+                    break;
+                case ComponentOrder.XYZ:
+                    bytes[startIndex] = (byte)(float)Math.Round(vector.X);
+                    bytes[startIndex + 1] = (byte)(float)Math.Round(vector.Y);
+                    bytes[startIndex + 2] = (byte)(float)Math.Round(vector.Z);
+                    break;
+                case ComponentOrder.XYZW:
+                    bytes[startIndex] = (byte)(float)Math.Round(vector.X);
+                    bytes[startIndex + 1] = (byte)(float)Math.Round(vector.Y);
+                    bytes[startIndex + 2] = (byte)(float)Math.Round(vector.Z);
+                    bytes[startIndex + 3] = (byte)(float)Math.Round(vector.W);
+                    break;
+                default:
+                    throw new NotSupportedException();
+            }
+        }
+
+        /// <summary>
+        /// Returns a value that indicates whether the current instance is equal to a specified object.
+        /// </summary>
+        /// <param name="obj">The object with which to make the comparison.</param>
+        /// <returns>true if the current instance is equal to the specified object; false otherwise.</returns>
+        public override bool Equals(object obj)
+        {
+            return (obj is Short4) && this == (Short4)obj;
+        }
+
+        /// <summary>
+        /// Returns a value that indicates whether the current instance is equal to a specified object.
+        /// </summary>
+        /// <param name="other">The object with which to make the comparison.</param>
+        /// <returns>true if the current instance is equal to the specified object; false otherwise.</returns>
+        public bool Equals(Short4 other)
+        {
+            return this == other;
+        }
+
+        /// <summary>
+        /// Gets the hash code for the current instance.
+        /// </summary>
+        /// <returns>Hash code for the instance.</returns>
+        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("x16");
+        }
+
+        /// <summary>
+        /// Packs the components into a <see cref="ulong"/>.
+        /// </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>
+        /// <returns>The <see cref="ulong"/> containing the packed values.</returns>
+        private static ulong Pack(float x, float y, float z, float w)
+        {
+            // Largest two byte positive number 0xFFFF >> 1;
+            const float MaxPos = 0x7FFF;
+
+            // Two's complement
+            const float MinNeg = ~(int)MaxPos;
+
+            // Clamp the value between min and max values
+            ulong word4 = ((ulong)Math.Round(x.Clamp(MinNeg, MaxPos)) & 0xFFFF) << 0x00;
+            ulong word3 = ((ulong)Math.Round(y.Clamp(MinNeg, MaxPos)) & 0xFFFF) << 0x10;
+            ulong word2 = ((ulong)Math.Round(z.Clamp(MinNeg, MaxPos)) & 0xFFFF) << 0x20;
+            ulong word1 = ((ulong)Math.Round(w.Clamp(MinNeg, MaxPos)) & 0xFFFF) << 0x30;
+
+            return word4 | word3 | word2 | word1;
+        }
+    }
+}

tests/ImageSharp.Tests/Colors/PackedPixelTests.cs

@@ -760,6 +760,63 @@ namespace ImageSharp.Tests.Colors
             Assert.Equal(rgba, new byte[] { 20, 38, 0, 255 });
         }
 
+        [Fact]
+        public void Short4()
+        {
+            // Test the limits.
+            Assert.Equal((ulong)0x0, new Short4(Vector4.Zero).PackedValue);
+            Assert.Equal((ulong)0x7FFF7FFF7FFF7FFF, new Short4(Vector4.One * 0x7FFF).PackedValue);
+            Assert.Equal(0x8000800080008000, new Short4(Vector4.One * -0x8000).PackedValue);
+
+            // Test ToVector4.
+            Assert.Equal(Vector4.One * 0x7FFF, new Short4(Vector4.One * 0x7FFF).ToVector4());
+            Assert.Equal(Vector4.Zero, new Short4(Vector4.Zero).ToVector4());
+            Assert.Equal(Vector4.One * -0x8000, new Short4(Vector4.One * -0x8000).ToVector4());
+            Assert.Equal(Vector4.UnitX * 0x7FFF, new Short4(Vector4.UnitX * 0x7FFF).ToVector4());
+            Assert.Equal(Vector4.UnitY * 0x7FFF, new Short4(Vector4.UnitY * 0x7FFF).ToVector4());
+            Assert.Equal(Vector4.UnitZ * 0x7FFF, new Short4(Vector4.UnitZ * 0x7FFF).ToVector4());
+            Assert.Equal(Vector4.UnitW * 0x7FFF, new Short4(Vector4.UnitW * 0x7FFF).ToVector4());
+
+            // Test clamping.
+            Assert.Equal(Vector4.One * 0x7FFF, new Short4(Vector4.One * 1234567.0f).ToVector4());
+            Assert.Equal(Vector4.One * -0x8000, new Short4(Vector4.One * -1234567.0f).ToVector4());
+
+            // Test Ordering
+            float x = 0.1f;
+            float y = -0.3f;
+            float z = 0.5f;
+            float w = -0.7f;
+            Assert.Equal(18446462598732840960, new Short4(x, y, z, w).PackedValue);
+
+            x = 11547;
+            y = 12653;
+            z = 29623;
+            w = 193;
+            Assert.Equal((ulong)0x00c173b7316d2d1b, new Short4(x, y, z, w).PackedValue);
+
+            byte[] rgb = new byte[3];
+            byte[] rgba = new byte[4];
+            byte[] bgr = new byte[3];
+            byte[] bgra = new byte[4];
+
+            new Short4(x, y, z, w).ToBytes(rgb, 0, ComponentOrder.XYZ);
+            Assert.Equal(rgb, new byte[] { 172, 177, 243 });
+
+            new Short4(x, y, z, w).ToBytes(rgba, 0, ComponentOrder.XYZW);
+            Assert.Equal(rgba, new byte[] { 172, 177, 243, 128 });
+
+            new Short4(x, y, z, w).ToBytes(bgr, 0, ComponentOrder.ZYX);
+            Assert.Equal(bgr, new byte[] { 243, 177, 172 });
+
+            new Short4(x, y, z, w).ToBytes(bgra, 0, ComponentOrder.ZYXW);
+            Assert.Equal(bgra, new byte[] { 243, 177, 172, 128 });
+
+            Short4 r = new Short4();
+            r.PackFromBytes(20, 38, 0, 255);
+            r.ToBytes(rgba, 0, ComponentOrder.XYZW);
+            Assert.Equal(rgba, new byte[] { 20, 38, 0, 255 });
+        }
+
         // Comparison helpers with small tolerance to allow for floating point rounding during computations.
         public static bool Equal(float a, float b)
         {