mirror of https://github.com/SixLabors/ImageSharp
James Jackson-South
7 years ago
23 changed files with 287 additions and 304 deletions
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// Copyright (c) Six Labors and contributors.
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// Licensed under the Apache License, Version 2.0.
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using System; |
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using System.Numerics; |
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using System.Runtime.CompilerServices; |
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using System.Runtime.InteropServices; |
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namespace SixLabors.ImageSharp.ColorSpaces.Companding |
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{ |
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/// <summary>
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/// Implements sRGB companding
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/// </summary>
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/// <remarks>
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/// For more info see:
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/// <see href="http://www.brucelindbloom.com/index.html?Eqn_RGB_to_XYZ.html"/>
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/// <see href="http://www.brucelindbloom.com/index.html?Eqn_XYZ_to_RGB.html"/>
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/// </remarks>
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public static class SRgbCompanding |
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{ |
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/// <summary>
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/// Expands the companded vectors to their linear equivalents with respect to the energy.
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/// </summary>
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/// <param name="vectors">The span of vectors.</param>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static void Expand(Span<Vector4> vectors) |
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{ |
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ref Vector4 baseRef = ref MemoryMarshal.GetReference(vectors); |
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for (int i = 0; i < vectors.Length; i++) |
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{ |
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ref Vector4 v = ref Unsafe.Add(ref baseRef, i); |
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v.X = Expand(v.X); |
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v.Y = Expand(v.Y); |
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v.Z = Expand(v.Z); |
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} |
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} |
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/// <summary>
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/// Compresses the uncompanded vectors to their nonlinear equivalents with respect to the energy.
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/// </summary>
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/// <param name="vectors">The span of vectors.</param>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static void Compress(Span<Vector4> vectors) |
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{ |
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ref Vector4 baseRef = ref MemoryMarshal.GetReference(vectors); |
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for (int i = 0; i < vectors.Length; i++) |
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{ |
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ref Vector4 v = ref Unsafe.Add(ref baseRef, i); |
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v.X = Compress(v.X); |
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v.Y = Compress(v.Y); |
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v.Z = Compress(v.Z); |
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} |
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} |
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/// <summary>
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/// Expands a companded vector to its linear equivalent with respect to the energy.
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/// </summary>
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/// <param name="vector">The vector.</param>
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/// <returns>The <see cref="Vector4"/> representing the linear channel values.</returns>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static Vector4 Expand(Vector4 vector) => new Vector4(Expand(vector.X), Expand(vector.Y), Expand(vector.Z), vector.W); |
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/// <summary>
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/// Compresses an uncompanded vector (linear) to its nonlinear equivalent.
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/// </summary>
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/// <param name="vector">The vector.</param>
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/// <returns>The <see cref="Vector4"/> representing the nonlinear channel values.</returns>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static Vector4 Compress(Vector4 vector) => new Vector4(Compress(vector.X), Compress(vector.Y), Compress(vector.Z), vector.W); |
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/// <summary>
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/// Expands a companded channel to its linear equivalent with respect to the energy.
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/// </summary>
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/// <param name="channel">The channel value.</param>
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/// <returns>The <see cref="float"/> representing the linear channel value.</returns>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static float Expand(float channel) => channel <= 0.04045F ? channel / 12.92F : MathF.Pow((channel + 0.055F) / 1.055F, 2.4F); |
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/// <summary>
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/// Compresses an uncompanded channel (linear) to its nonlinear equivalent.
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/// </summary>
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/// <param name="channel">The channel value.</param>
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/// <returns>The <see cref="float"/> representing the nonlinear channel value.</returns>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static float Compress(float channel) => channel <= 0.0031308F ? 12.92F * channel : (1.055F * MathF.Pow(channel, 0.416666666666667F)) - 0.055F; |
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} |
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} |
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@ -1,35 +0,0 @@ |
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// Copyright (c) Six Labors and contributors.
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// Licensed under the Apache License, Version 2.0.
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using System; |
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using System.Runtime.CompilerServices; |
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namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation |
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{ |
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/// <summary>
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/// Implements sRGB companding
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/// </summary>
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/// <remarks>
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/// For more info see:
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/// <see href="http://www.brucelindbloom.com/index.html?Eqn_RGB_to_XYZ.html"/>
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/// <see href="http://www.brucelindbloom.com/index.html?Eqn_XYZ_to_RGB.html"/>
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/// </remarks>
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public static class SRgbCompanding |
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{ |
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/// <summary>
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/// Expands a companded channel to its linear equivalent with respect to the energy.
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/// </summary>
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/// <param name="channel">The channel value</param>
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/// <returns>The <see cref="float"/> representing the linear channel value.</returns>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static float Expand(float channel) => channel <= 0.04045F ? channel / 12.92F : MathF.Pow((channel + 0.055F) / 1.055F, 2.4F); |
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/// <summary>
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/// Compresses an uncompanded channel (linear) to its nonlinear equivalent.
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/// </summary>
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/// <param name="channel">The channel value</param>
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/// <returns>The <see cref="float"/> representing the nonlinear channel value.</returns>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static float Compress(float channel) => channel <= 0.0031308F ? 12.92F * channel : (1.055F * MathF.Pow(channel, 0.416666666666667F)) - 0.055F; |
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} |
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} |
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@ -1,156 +0,0 @@ |
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// Copyright (c) Six Labors and contributors.
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// Licensed under the Apache License, Version 2.0.
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using System; |
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using System.Numerics; |
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using System.Runtime.CompilerServices; |
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using System.Runtime.InteropServices; |
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using SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation; |
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using SixLabors.ImageSharp.PixelFormats; |
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namespace SixLabors.ImageSharp |
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{ |
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/// <summary>
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/// Extension methods for the <see cref="Vector4"/> struct.
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/// </summary>
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internal static class Vector4Extensions |
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{ |
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/// <summary>
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/// Pre-multiplies the "x", "y", "z" components of a vector by its "w" component leaving the "w" component intact.
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/// </summary>
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/// <param name="source">The <see cref="Vector4"/> to premultiply</param>
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/// <returns>The <see cref="Vector4"/></returns>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static Vector4 Premultiply(this Vector4 source) |
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{ |
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float w = source.W; |
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Vector4 premultiplied = source * w; |
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premultiplied.W = w; |
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return premultiplied; |
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} |
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/// <summary>
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/// Reverses the result of premultiplying a vector via <see cref="Premultiply(Vector4)"/>.
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/// </summary>
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/// <param name="source">The <see cref="Vector4"/> to premultiply</param>
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/// <returns>The <see cref="Vector4"/></returns>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static Vector4 UnPremultiply(this Vector4 source) |
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{ |
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float w = source.W; |
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Vector4 unpremultiplied = source / w; |
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unpremultiplied.W = w; |
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return unpremultiplied; |
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} |
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/// <summary>
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/// Bulk variant of <see cref="Premultiply(System.Numerics.Vector4)"/>
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/// </summary>
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/// <param name="vectors">The span of vectors</param>
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public static void Premultiply(Span<Vector4> vectors) |
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{ |
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// TODO: This method can be AVX2 optimized using Vector<float>
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ref Vector4 baseRef = ref MemoryMarshal.GetReference(vectors); |
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for (int i = 0; i < vectors.Length; i++) |
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{ |
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ref Vector4 v = ref Unsafe.Add(ref baseRef, i); |
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var s = new Vector4(v.W) |
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{ |
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W = 1 |
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}; |
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v *= s; |
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} |
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} |
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/// <summary>
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/// Bulk variant of <see cref="UnPremultiply(System.Numerics.Vector4)"/>
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/// </summary>
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/// <param name="vectors">The span of vectors</param>
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public static void UnPremultiply(Span<Vector4> vectors) |
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{ |
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// TODO: This method can be AVX2 optimized using Vector<float>
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ref Vector4 baseRef = ref MemoryMarshal.GetReference(vectors); |
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for (int i = 0; i < vectors.Length; i++) |
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{ |
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ref Vector4 v = ref Unsafe.Add(ref baseRef, i); |
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var s = new Vector4(1 / v.W) |
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{ |
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W = 1 |
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}; |
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v *= s; |
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} |
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} |
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/// <summary>
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/// Compresses a linear color signal to its sRGB equivalent.
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/// <see href="http://www.4p8.com/eric.brasseur/gamma.html#formulas"/>
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/// <see href="http://entropymine.com/imageworsener/srgbformula/"/>
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/// </summary>
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/// <param name="linear">The <see cref="Vector4"/> whose signal to compress.</param>
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/// <returns>The <see cref="Vector4"/>.</returns>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static Vector4 Compress(this Vector4 linear) |
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{ |
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// TODO: Is there a faster way to do this?
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return new Vector4( |
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SRgbCompanding.Compress(linear.X), |
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SRgbCompanding.Compress(linear.Y), |
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SRgbCompanding.Compress(linear.Z), |
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linear.W); |
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} |
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/// <summary>
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/// Expands an sRGB color signal to its linear equivalent.
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/// <see href="http://www.4p8.com/eric.brasseur/gamma.html#formulas"/>
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/// <see href="http://entropymine.com/imageworsener/srgbformula/"/>
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/// </summary>
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/// <param name="gamma">The <see cref="Rgba32"/> whose signal to expand.</param>
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/// <returns>The <see cref="Vector4"/>.</returns>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static Vector4 Expand(this Vector4 gamma) |
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{ |
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// TODO: Is there a faster way to do this?
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return new Vector4( |
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SRgbCompanding.Expand(gamma.X), |
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SRgbCompanding.Expand(gamma.Y), |
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SRgbCompanding.Expand(gamma.Z), |
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gamma.W); |
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} |
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/// <summary>
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/// Bulk variant of <see cref="Compress(System.Numerics.Vector4)"/>
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/// </summary>
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/// <param name="vectors">The span of vectors</param>
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public static void Compress(Span<Vector4> vectors) |
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{ |
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ref Vector4 baseRef = ref MemoryMarshal.GetReference(vectors); |
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for (int i = 0; i < vectors.Length; i++) |
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{ |
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ref Vector4 v = ref Unsafe.Add(ref baseRef, i); |
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v.X = SRgbCompanding.Compress(v.X); |
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v.Y = SRgbCompanding.Compress(v.Y); |
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v.Z = SRgbCompanding.Compress(v.Z); |
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} |
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} |
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/// <summary>
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/// Bulk variant of <see cref="Expand(System.Numerics.Vector4)"/>
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/// </summary>
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/// <param name="vectors">The span of vectors</param>
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public static void Expand(Span<Vector4> vectors) |
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{ |
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ref Vector4 baseRef = ref MemoryMarshal.GetReference(vectors); |
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for (int i = 0; i < vectors.Length; i++) |
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{ |
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ref Vector4 v = ref Unsafe.Add(ref baseRef, i); |
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v.X = SRgbCompanding.Expand(v.X); |
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v.Y = SRgbCompanding.Expand(v.Y); |
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v.Z = SRgbCompanding.Expand(v.Z); |
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} |
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} |
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} |
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} |
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// Copyright (c) Six Labors and contributors.
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// Licensed under the Apache License, Version 2.0.
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using System; |
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using System.Numerics; |
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using System.Runtime.CompilerServices; |
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using System.Runtime.InteropServices; |
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namespace SixLabors.ImageSharp |
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{ |
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/// <summary>
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/// Utility methods for the <see cref="Vector4"/> struct.
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/// </summary>
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internal static class Vector4Utils |
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{ |
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/// <summary>
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/// Pre-multiplies the "x", "y", "z" components of a vector by its "w" component leaving the "w" component intact.
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/// </summary>
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/// <param name="source">The <see cref="Vector4"/> to premultiply</param>
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/// <returns>The <see cref="Vector4"/></returns>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static Vector4 Premultiply(Vector4 source) |
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{ |
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float w = source.W; |
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Vector4 premultiplied = source * w; |
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premultiplied.W = w; |
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return premultiplied; |
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} |
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/// <summary>
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/// Reverses the result of premultiplying a vector via <see cref="Premultiply(Vector4)"/>.
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/// </summary>
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/// <param name="source">The <see cref="Vector4"/> to premultiply</param>
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/// <returns>The <see cref="Vector4"/></returns>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static Vector4 UnPremultiply(Vector4 source) |
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{ |
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float w = source.W; |
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Vector4 unpremultiplied = source / w; |
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unpremultiplied.W = w; |
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return unpremultiplied; |
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} |
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/// <summary>
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/// Bulk variant of <see cref="Premultiply(Vector4)"/>
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/// </summary>
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/// <param name="vectors">The span of vectors</param>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static void Premultiply(Span<Vector4> vectors) |
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{ |
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// TODO: This method can be AVX2 optimized using Vector<float>
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ref Vector4 baseRef = ref MemoryMarshal.GetReference(vectors); |
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for (int i = 0; i < vectors.Length; i++) |
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{ |
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ref Vector4 v = ref Unsafe.Add(ref baseRef, i); |
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var s = new Vector4(v.W) |
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{ |
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W = 1 |
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}; |
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v *= s; |
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} |
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} |
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/// <summary>
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/// Bulk variant of <see cref="UnPremultiply(Vector4)"/>
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/// </summary>
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/// <param name="vectors">The span of vectors</param>
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[MethodImpl(InliningOptions.ShortMethod)] |
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public static void UnPremultiply(Span<Vector4> vectors) |
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{ |
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// TODO: This method can be AVX2 optimized using Vector<float>
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ref Vector4 baseRef = ref MemoryMarshal.GetReference(vectors); |
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for (int i = 0; i < vectors.Length; i++) |
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{ |
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ref Vector4 v = ref Unsafe.Add(ref baseRef, i); |
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var s = new Vector4(1 / v.W) |
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{ |
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W = 1 |
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}; |
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v *= s; |
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} |
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} |
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} |
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} |
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@ -1,74 +0,0 @@ |
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// Copyright (c) Six Labors and contributors.
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// Licensed under the Apache License, Version 2.0.
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using System; |
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using System.Linq; |
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using System.Numerics; |
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using Xunit; |
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namespace SixLabors.ImageSharp.Tests.Helpers |
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{ |
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public class Vector4ExtensionsTests |
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{ |
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[Theory] |
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[InlineData(0)] |
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[InlineData(1)] |
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[InlineData(30)] |
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public void Premultiply_VectorSpan(int length) |
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{ |
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var rnd = new Random(42); |
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Vector4[] source = rnd.GenerateRandomVectorArray(length, 0, 1); |
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Vector4[] expected = source.Select(v => v.Premultiply()).ToArray(); |
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Vector4Extensions.Premultiply(source); |
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Assert.Equal(expected, source, new ApproximateFloatComparer(1e-6f)); |
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} |
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[Theory] |
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[InlineData(0)] |
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[InlineData(1)] |
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[InlineData(30)] |
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public void UnPremultiply_VectorSpan(int length) |
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{ |
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var rnd = new Random(42); |
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Vector4[] source = rnd.GenerateRandomVectorArray(length, 0, 1); |
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Vector4[] expected = source.Select(v => v.UnPremultiply()).ToArray(); |
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Vector4Extensions.UnPremultiply(source); |
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Assert.Equal(expected, source, new ApproximateFloatComparer(1e-6f)); |
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} |
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[Theory] |
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[InlineData(0)] |
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[InlineData(1)] |
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[InlineData(30)] |
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public void Expand_VectorSpan(int length) |
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{ |
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var rnd = new Random(42); |
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Vector4[] source = rnd.GenerateRandomVectorArray(length, 0, 1); |
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Vector4[] expected = source.Select(v => v.Expand()).ToArray(); |
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Vector4Extensions.Expand(source); |
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Assert.Equal(expected, source, new ApproximateFloatComparer(1e-6f)); |
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} |
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[Theory] |
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[InlineData(0)] |
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[InlineData(1)] |
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[InlineData(30)] |
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public void Compress_VectorSpan(int length) |
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{ |
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var rnd = new Random(42); |
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Vector4[] source = rnd.GenerateRandomVectorArray(length, 0, 1); |
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Vector4[] expected = source.Select(v => v.Compress()).ToArray(); |
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Vector4Extensions.Compress(source); |
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Assert.Equal(expected, source, new ApproximateFloatComparer(1e-6f)); |
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} |
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} |
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} |
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@ -0,0 +1,44 @@ |
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// Copyright (c) Six Labors and contributors.
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// Licensed under the Apache License, Version 2.0.
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|
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using System; |
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using System.Linq; |
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using System.Numerics; |
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|
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using Xunit; |
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namespace SixLabors.ImageSharp.Tests.Helpers |
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{ |
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public class Vector4UtilsTests |
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{ |
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[Theory] |
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[InlineData(0)] |
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[InlineData(1)] |
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[InlineData(30)] |
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public void Premultiply_VectorSpan(int length) |
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{ |
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var rnd = new Random(42); |
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Vector4[] source = rnd.GenerateRandomVectorArray(length, 0, 1); |
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Vector4[] expected = source.Select(v => Vector4Utils.Premultiply(v)).ToArray(); |
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Vector4Utils.Premultiply(source); |
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Assert.Equal(expected, source, new ApproximateFloatComparer(1e-6f)); |
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} |
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[Theory] |
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[InlineData(0)] |
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[InlineData(1)] |
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[InlineData(30)] |
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public void UnPremultiply_VectorSpan(int length) |
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{ |
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var rnd = new Random(42); |
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Vector4[] source = rnd.GenerateRandomVectorArray(length, 0, 1); |
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Vector4[] expected = source.Select(v => Vector4Utils.UnPremultiply(v)).ToArray(); |
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Vector4Utils.UnPremultiply(source); |
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Assert.Equal(expected, source, new ApproximateFloatComparer(1e-6f)); |
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} |
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} |
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} |
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