mirror of https://github.com/SixLabors/ImageSharp
James Jackson-South
9 years ago
3 changed files with 394 additions and 63 deletions
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// <copyright file="Vector4BlendTransforms.cs" company="James Jackson-South">
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// Copyright (c) James Jackson-South and contributors.
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// Licensed under the Apache License, Version 2.0.
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// </copyright>
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namespace ImageSharp |
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{ |
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using System; |
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using System.Numerics; |
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/// <summary>
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/// Transform algorithms that match the equations defined in the W3C Compositing and Blending Level 1 specification.
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/// <see href="https://www.w3.org/TR/compositing-1/"/>
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/// </summary>
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public class Vector4BlendTransforms |
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{ |
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/// <summary>
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/// The epsilon for comparing floating point numbers.
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/// </summary>
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private const float Epsilon = 0.001F; |
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/// <summary>
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/// The blending formula simply selects the source vector.
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/// </summary>
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/// <param name="backdrop">The backdrop vector.</param>
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/// <param name="source">The source vector.</param>
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/// <returns>
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/// The <see cref="Vector4"/>.
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/// </returns>
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public static Vector4 Normal(Vector4 backdrop, Vector4 source) |
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{ |
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return new Vector4(source.X, source.Y, source.Z, source.W); |
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} |
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/// <summary>
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/// Blends two vectors by multiplication.
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/// </summary>
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/// <param name="backdrop">The backdrop vector.</param>
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/// <param name="source">The source vector.</param>
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/// <returns>
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/// The <see cref="Vector4"/>.
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/// </returns>
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public static Vector4 Multiply(Vector4 backdrop, Vector4 source) |
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{ |
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Vector4 multiply = backdrop * source; |
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multiply.W = backdrop.W; |
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return multiply; |
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} |
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/// <summary>
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/// Multiplies the complements of the backdrop and source vector values, then complements the result.
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/// </summary>
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/// <param name="backdrop">The backdrop vector.</param>
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/// <param name="source">The source vector.</param>
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/// <returns>
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/// The <see cref="Vector4"/>.
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/// </returns>
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public static Vector4 Screen(Vector4 backdrop, Vector4 source) |
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{ |
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Vector4 subtract = backdrop + source - (backdrop * source); |
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subtract.W = backdrop.W; |
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return subtract; |
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} |
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/// <summary>
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/// Multiplies or screens the colors, depending on the source vector value.
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/// </summary>
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/// <param name="backdrop">The backdrop vector.</param>
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/// <param name="source">The source vector.</param>
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/// <returns>
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/// The <see cref="Vector4"/>.
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/// </returns>
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public static Vector4 HardLight(Vector4 backdrop, Vector4 source) |
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{ |
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return new Vector4(BlendOverlay(source.X, backdrop.X), BlendOverlay(source.Y, backdrop.Y), BlendOverlay(source.Z, backdrop.Z), backdrop.W); |
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} |
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/// <summary>
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/// Multiplies or screens the vectors, depending on the backdrop vector value.
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/// </summary>
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/// <param name="backdrop">The backdrop vector.</param>
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/// <param name="source">The source vector.</param>
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/// <returns>
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/// The <see cref="Vector4"/>.
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/// </returns>
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public static Vector4 Overlay(Vector4 backdrop, Vector4 source) |
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{ |
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return new Vector4(BlendOverlay(backdrop.X, source.X), BlendOverlay(backdrop.Y, source.Y), BlendOverlay(backdrop.Z, source.Z), backdrop.W); |
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} |
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/// <summary>
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/// Selects the minimum of the backdrop and source vectors.
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/// </summary>
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/// <param name="backdrop">The backdrop vector.</param>
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/// <param name="source">The source vector.</param>
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/// <returns>
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/// The <see cref="Vector4"/>.
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/// </returns>
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public static Vector4 Darken(Vector4 backdrop, Vector4 source) |
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{ |
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Vector4 result = Vector4.Min(backdrop, source); |
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result.W = backdrop.W; |
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return result; |
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} |
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/// <summary>
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/// Selects the max of the backdrop and source vector.
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/// </summary>
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/// <param name="backdrop">The backdrop vector.</param>
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/// <param name="source">The source vector.</param>
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/// <returns>
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/// The <see cref="Vector4"/>.
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/// </returns>
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public static Vector4 Lighten(Vector4 backdrop, Vector4 source) |
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{ |
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Vector4 result = Vector4.Max(backdrop, source); |
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result.W = backdrop.W; |
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return result; |
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} |
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/// <summary>
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/// Selects the maximum or minimum of the vectors, depending on the source vector value.
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/// </summary>
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/// <param name="backdrop">The backdrop vector.</param>
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/// <param name="source">The source vector.</param>
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/// <returns>
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/// The <see cref="Vector4"/>.
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/// </returns>
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public static Vector4 SoftLight(Vector4 backdrop, Vector4 source) |
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{ |
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return new Vector4(BlendSoftLight(backdrop.X, source.X), BlendSoftLight(backdrop.Y, source.Y), BlendSoftLight(backdrop.Z, source.Z), backdrop.W); |
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} |
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/// <summary>
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/// Increases the backdrop vector to reflect the source vector.
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/// </summary>
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/// <param name="backdrop">The backdrop vector.</param>
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/// <param name="source">The source vector.</param>
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/// <returns>
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/// The <see cref="Vector4"/>.
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/// </returns>
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public static Vector4 Dodge(Vector4 backdrop, Vector4 source) |
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{ |
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return new Vector4(BlendDodge(backdrop.X, source.X), BlendDodge(backdrop.Y, source.Y), BlendDodge(backdrop.Z, source.Z), backdrop.W); |
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} |
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/// <summary>
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/// Decreases the backdrop vector to reflect the source vector.
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/// </summary>
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/// <param name="backdrop">The backdrop vector.</param>
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/// <param name="source">The source vector.</param>
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/// <returns>
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/// The <see cref="Vector4"/>.
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/// </returns>
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public static Vector4 Burn(Vector4 backdrop, Vector4 source) |
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{ |
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return new Vector4(BlendBurn(backdrop.X, source.X), BlendBurn(backdrop.Y, source.Y), BlendBurn(backdrop.Z, source.Z), backdrop.W); |
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} |
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/// <summary>
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/// Subtracts the minimum of the two constituent vectors from the maximum vector.
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/// </summary>
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/// <param name="backdrop">The backdrop vector.</param>
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/// <param name="source">The source vector.</param>
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/// <returns>
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/// The <see cref="Vector4"/>.
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/// </returns>
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public static Vector4 Difference(Vector4 backdrop, Vector4 source) |
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{ |
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Vector4 result = Vector4.Abs(backdrop - source); |
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result.W = backdrop.W; |
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return result; |
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} |
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/// <summary>
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/// Produces an effect similar to that of the <see cref="Difference"/> mode but lower in magnitude.
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/// </summary>
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/// <param name="backdrop">The backdrop vector.</param>
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/// <param name="source">The source vector.</param>
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/// <returns>
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/// The <see cref="Vector4"/>.
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/// </returns>
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public static Vector4 Exclusion(Vector4 backdrop, Vector4 source) |
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{ |
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return new Vector4(BlendExclusion(backdrop.X, source.X), BlendExclusion(backdrop.Y, source.Y), BlendExclusion(backdrop.Z, source.Z), backdrop.W); |
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} |
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/// <summary>
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/// Multiplies or screens the color component, depending on the component value.
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/// </summary>
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/// <param name="b">The backdrop component.</param>
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/// <param name="s">The source component.</param>
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/// <returns>
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/// The <see cref="float"/>.
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/// </returns>
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private static float BlendOverlay(float b, float s) |
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{ |
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return b <= .5F ? (2F * b * s) : (1F - (2F * (1F - b) * (1F - s))); |
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} |
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/// <summary>
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/// Darkens or lightens the backdrop component, depending on the source component value.
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/// </summary>
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/// <param name="b">The backdrop component.</param>
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/// <param name="s">The source component.</param>
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/// <returns>
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/// The <see cref="float"/>.
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/// </returns>
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private static float BlendSoftLight(float b, float s) |
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{ |
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return s <= .5F ? (2F * b * s + b * b * (1F - 2F * s)) : (float)(Math.Sqrt(b) * (2F * s - 1F) + 2F * b * (1F - s)); |
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} |
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/// <summary>
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/// Brightens the backdrop component to reflect the source component.
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/// </summary>
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/// <param name="b">The backdrop component.</param>
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/// <param name="s">The source component.</param>
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/// <returns>
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/// The <see cref="float"/>.
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/// </returns>
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private static float BlendDodge(float b, float s) |
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{ |
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return Math.Abs(s - 1F) < Epsilon ? s : Math.Min(b / (1F - s), 1F); |
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} |
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/// <summary>
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/// Darkens the backdrop component to reflect the source component.
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/// </summary>
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/// <param name="b">The backdrop component.</param>
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/// <param name="s">The source component.</param>
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/// <returns>
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/// The <see cref="float"/>.
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/// </returns>
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private static float BlendBurn(float b, float s) |
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{ |
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return Math.Abs(s) < Epsilon ? s : Math.Max(1F - ((1F - b) / s), 0F); |
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} |
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/// <summary>
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/// Darkens the backdrop component to reflect the source component.
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/// </summary>
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/// <param name="b">The backdrop component.</param>
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/// <param name="s">The source component.</param>
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/// <returns>
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/// The <see cref="float"/>.
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/// </returns>
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private static float BlendExclusion(float b, float s) |
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{ |
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return b + s - 2F * b * s; |
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} |
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} |
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} |
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