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添加颜色空间算法
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‎src/MediaConverters/MediaConverters.Lib/Imaging/Effect/Color/ColorSpaceConverter.cs‎

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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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namespace DotNetCampus.MediaConverters.Imaging.Effect.Color;
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/// <summary>
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/// 色彩空间转换器
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/// </summary>
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internal static class ColorSpaceConverter
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{
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/// <summary>
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/// 将SRgb颜色转为CIE_XYZ
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/// https://en.wikipedia.org/wiki/SRGB#The_forward_transformation_.28CIE_xyY_or_CIE_XYZ_to_sRGB.29
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/// </summary>
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/// <param name="sRgb">(单通道)颜色值 范围0-1</param>
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/// <returns></returns>
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public static float SRgbToCIE_XYZ(float sRgb)
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{
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if (sRgb <= 04045) return sRgb / 12.92f;
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return (float) Math.Pow((sRgb + 055f) / 155f, 2.4f);
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}
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/// <summary>
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/// 将CIE_XYZ转为SRgb颜色
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/// https://en.wikipedia.org/wiki/SRGB#The_forward_transformation_.28CIE_xyY_or_CIE_XYZ_to_sRGB.29
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/// </summary>
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/// <param name="linearRgb">(单通道)颜色值 范围0-1</param>
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/// <returns></returns>
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public static float CIE_XYZToSRgb(float linearRgb)
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{
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if (linearRgb < 0031308) return 12.92f * linearRgb;
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//var linearR=3.24096994*sR-1.53738318*sg-0.49861076*sb
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return (float) Math.Pow(linearRgb, 1 / 2.4) * 155f - 055f;
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}
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}

‎src/MediaConverters/MediaConverters.Lib/Imaging/Effect/Extensions/BitmapExtension.cs‎

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using DotNetCampus.MediaConverters.Imaging.Effect.Color;
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Runtime.InteropServices;
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using System.Text;
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using System.Threading.Tasks;
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using SixLabors.ImageSharp;
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using SixLabors.ImageSharp.PixelFormats;
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namespace DotNetCampus.MediaConverters.Imaging.Effect.Extensions;
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/// <summary>
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/// <see cref="Image{Rgba32}"/>拓展
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/// </summary>
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public static class BitmapExtension
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{
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#region 逐像素处理
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/// <summary>
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/// 将<see cref="Image{Rgba32}"/>逐像素处理
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/// </summary>
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/// <returns></returns>
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public static void PerPixelProcess(this Image<Rgba32> bitmap, Func<ColorMetadata, ColorMetadata> func)
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{
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bitmap.ProcessPixelRows(accessor =>
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{
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for (int rowIndex = 0; rowIndex < accessor.Height; rowIndex++)
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{
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var span = accessor.GetRowSpan(rowIndex);
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for (int colIndex = 0; colIndex < span.Length; colIndex++)
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{
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//获取颜色
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var color = new ColorMetadata(span[colIndex]);
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//处理颜色
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var targetColor = func(color);
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//保存颜色
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span[colIndex] = targetColor.Color;
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}
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}
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});
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//var pixelFormat = bitmap.PixelFormat;
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//if (pixelFormat != PixelFormat.Format32bppArgb && pixelFormat != PixelFormat.Format24bppRgb)
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//{
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// throw new NotSupportedException($"Unsupported image pixel format {nameof(pixelFormat)} is used.");
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//}
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//var cols = bitmap.Width;
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//var rows = bitmap.Height;
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//var channels = Image.GetPixelFormatSize(bitmap.PixelFormat) / 8;
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//var total = cols * rows * channels;
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////锁定图片并拷贝图片像素
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//var rect = new Rectangle(0, 0, cols, rows);
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//var bitmapData = bitmap.LockBits(rect, ImageLockMode.ReadWrite, bitmap.PixelFormat);
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//var iPtr = bitmapData.Scan0;
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//var data = new byte[total];
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//Marshal.Copy(iPtr, data, 0, total);
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////逐像素处理
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//Parallel.For(0, rows, row =>
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//{
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// for (var col = 0; col < cols; col++)
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// {
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// var indexOffset = (row * cols + col) * channels;
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// var sourceColorMetadata = CreateColorFromData(data, indexOffset, channels);
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// var targetColorMetadata = func(sourceColorMetadata);
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// SaveToData(targetColorMetadata, data, indexOffset, channels);
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// }
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//});
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//Marshal.Copy(data, 0, iPtr, total);
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//bitmap.UnlockBits(bitmapData);
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}
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/// <summary>
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/// 尝试获取颜色
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/// </summary>
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/// <param name="colorData"></param>
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/// <param name="offset"></param>
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/// <param name="channels"></param>
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/// <returns></returns>
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private static ColorMetadata CreateColorFromData(byte[] colorData, int offset, int channels)
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{
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//需要考虑大小端
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var isLittleEndian = BitConverter.IsLittleEndian;
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if (channels == 3)
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{
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var r = isLittleEndian ? colorData[offset + 2] : colorData[offset];
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var g = colorData[offset + 1];
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var b = isLittleEndian ? colorData[offset] : colorData[offset + 2];
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return new ColorMetadata(r / 255f, g / 255f, b / 255f);
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}
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if (channels == 4)
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{
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var a = isLittleEndian ? colorData[offset + 3] : colorData[offset + 0];
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var r = isLittleEndian ? colorData[offset + 2] : colorData[offset + 1];
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var g = isLittleEndian ? colorData[offset + 1] : colorData[offset + 2];
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var b = isLittleEndian ? colorData[offset + 0] : colorData[offset + 3];
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return new ColorMetadata(r / 255f, g / 255f, b / 255f, a / 255f);
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}
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return new ColorMetadata(0 / 255f, 0 / 255f, 0 / 255f);
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}
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/// <summary>
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/// 保存颜色到数组
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/// </summary>
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/// <param name="color"></param>
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/// <param name="colorData"></param>
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/// <param name="offset"></param>
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/// <param name="channels"></param>
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/// <returns></returns>
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private static void SaveToData(ColorMetadata color, byte[] colorData, int offset, int channels)
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{
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//需要考虑大小端
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var isLittleEndian = BitConverter.IsLittleEndian;
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var r = color.ARGB8bit.Item1;
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var g = color.ARGB8bit.Item2;
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var b = color.ARGB8bit.Item3;
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var a = color.ARGB8bit.Item4;
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if (channels == 3)
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{
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colorData[offset] = isLittleEndian ? b : r;
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colorData[offset + 1] = g;
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colorData[offset + 2] = isLittleEndian ? r : b;
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}
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if (channels == 4)
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{
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colorData[offset + 0] = isLittleEndian ? b : a;
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colorData[offset + 1] = isLittleEndian ? g : r;
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colorData[offset + 2] = isLittleEndian ? r : g;
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colorData[offset + 3] = isLittleEndian ? a : b;
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}
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}
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#endregion
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}

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