✨ feat(AudioImage): 新增音频反向生成图片的游乐场，支持 PNG/JPG/BMP 及宽高参数，并注册到启动项

using NAudio.Wave;

using SixLabors.ImageSharp;

using SixLabors.ImageSharp.Formats;

using SixLabors.ImageSharp.Formats.Bmp;

using SixLabors.ImageSharp.Formats.Jpeg;

using SixLabors.ImageSharp.Formats.Png;

using SixLabors.ImageSharp.PixelFormats;

using Spectre.Console;

using TestV.Tools;

namespace TestV.Playgrounds;

public class AudioImage : IPlayground

{

    public string LaunchCmd { get; } = "ai";

    public string? Name { get; } = "Audio Image";

    public string? Description { get; } = "将音频采样反向变换为图片（默认PNG，可选JPG/BMP，可设置宽度或高度）";

    private const int BitsPerPixel = 32;   // 与 ImageAudio 对应：R/G/B/A 各 8 bit

    private const int FramesPerPixel = BitsPerPixel;

    public async Task Run(string[] args)

    {

        if (!Errors.ValidArgsLength(args, 1)) return;

        var opts = ParseOptions(args);

        if (opts is null) return;

        if (!File.Exists(opts.AudioPath))

        {

            AnsiConsole.MarkupLine("[red]文件不存在。[/]");

            return;

        }

        await Task.Run(() => Decode(opts));

    }

    private sealed class Options

    {

        public required string AudioPath { get; init; }

        public required string OutputPath { get; set; }

        public string Format { get; set; } = "png";

        public int? Width { get; set; }

        public int? Height { get; set; }

    }

    private static Options? ParseOptions(string[] args)

    {

        var audioPath = args[0];

        // 默认输出路径：与音频同目录，扩展名 png

        string outPath = Path.ChangeExtension(audioPath, ".png");

        var opts = new Options { AudioPath = audioPath, OutputPath = outPath };

        for (int i = 1; i < args.Length; i++)

        {

            var a = args[i];

            if (a is "--out" or "-o")

            {

                if (i + 1 >= args.Length) { Errors.NoArgs(1); return null; }

                opts.OutputPath = args[++i];

            }

            else if (a.StartsWith("--out="))

                opts.OutputPath = a["--out=".Length..];

            else if (a.StartsWith("--format="))

                opts.Format = a["--format=".Length..].ToLowerInvariant();

            else if (a is "--format")

            {

                if (i + 1 >= args.Length) { Errors.NoArgs(1); return null; }

                opts.Format = args[++i].ToLowerInvariant();

            }

            else if (a.StartsWith("--width=") && int.TryParse(a["--width=".Length..], out var w) && w > 0)

                opts.Width = w;

            else if (a.StartsWith("--height=") && int.TryParse(a["--height=".Length..], out var h) && h > 0)

                opts.Height = h;

            else

            {

                Errors.NotArrow("参数", "--out", "-o", "--out=", "--format", "--format=", "--width=", "--height=");

                return null;

            }

        }

        // 若未显式指定 --format，按输出扩展名推断

        if (!IsFormatArg(args))

        {

            var ext = Path.GetExtension(opts.OutputPath).TrimStart('.').ToLowerInvariant();

            if (ext is "png" or "jpg" or "jpeg" or "bmp")

                opts.Format = ext;

        }

        return opts;

    }

    private static bool IsFormatArg(string[] args)

    {

        foreach (var a in args)

            if (a is "--format" || a.StartsWith("--format=")) return true;

        return false;

    }

    private void Decode(Options opts)

    {

        using var reader = new AudioFileReader(opts.AudioPath);

        int audioChannels = reader.WaveFormat.Channels;

        if (audioChannels < 1)

        {

            AnsiConsole.MarkupLine("[red]无效的音频声道数。[/]");

            return;

        }

        long totalSamples = reader.Length / sizeof(float); // float 采样数

        long totalFrames = totalSamples / audioChannels;

        long totalPixels = totalFrames / FramesPerPixel;

        if (totalPixels <= 0)

        {

            AnsiConsole.MarkupLine("[red]音频太短，不足以还原出 1 个像素。[/]");

            return;

        }

        var (width, height) = ComputeDimensions(totalPixels, opts.Width, opts.Height);

        long usedPixels = (long)width * height;

        AnsiConsole.MarkupLine($"[grey]音频: {Path.GetFileName(opts.AudioPath)} ({audioChannels}ch, {reader.WaveFormat.SampleRate}Hz)[/]");

        AnsiConsole.MarkupLine($"[grey]可用像素: {totalPixels:N0}[/]");

        AnsiConsole.MarkupLine($"[grey]输出尺寸: {width}x{height} = {usedPixels:N0} 像素" +

                               (usedPixels < totalPixels ? $" [yellow](丢弃 {totalPixels - usedPixels:N0} 像素采样)[/]" : "") + "[/]");

        using var image = new Image<Rgba32>(width, height);

        var rowBuf = new float[width * FramesPerPixel * audioChannels];

        long decodedPixels = 0;

        for (int y = 0; y < height; y++)

        {

            int read = reader.Read(rowBuf, 0, rowBuf.Length);

            if (read < rowBuf.Length)

                Array.Clear(rowBuf, read, rowBuf.Length - read);

            image.ProcessPixelRows(accessor =>

            {

                var row = accessor.GetRowSpan(y);

                for (int x = 0; x < width; x++)

                {

                    long pixelIdx = (long)y * width + x;

                    row[x] = DecodePixel(rowBuf, x * FramesPerPixel, audioChannels, pixelIdx);

                }

            });

            decodedPixels += width;

            if (read < rowBuf.Length) break; // EOF：剩余行保持默认（透明）

        }

        Save(image, opts.OutputPath, opts.Format);

        AnsiConsole.MarkupLine($"[green]已写入: {opts.OutputPath} ({opts.Format})[/]");

    }

    private static (int width, int height) ComputeDimensions(long totalPixels, int? reqWidth, int? reqHeight)

    {

        // 两者都设置：固定尺寸，多余采样丢弃

        if (reqWidth is { } w && reqHeight is { } h)

            return (w, h);

        // 只设置宽度：高度自动 = totalPixels / width

        if (reqWidth is { } w2)

            return (w2, (int)Math.Max(1, totalPixels / w2));

        // 只设置高度：宽度自动 = totalPixels / height

        if (reqHeight is { } h2)

            return ((int)Math.Max(1, totalPixels / h2), h2);

        // 都未设置：尽量正方形

        int side = (int)Math.Ceiling(Math.Sqrt(totalPixels));

        side = Math.Max(1, side);

        int autoHeight = (int)Math.Ceiling((double)totalPixels / side);

        return (side, autoHeight);

    }

    /// <summary>

    /// 从 32 个音频帧还原 1 个 Rgba32 像素。

    /// 奇数像素取左声道，偶数像素取右声道（与 ImageAudio 正向映射对应）；

    /// 采样值 > 0 → bit 1，否则 → bit 0。

    /// </summary>

    private static Rgba32 DecodePixel(float[] buf, int frameBase, int audioChannels, long pixelIdx)

    {

        bool useLeft = (pixelIdx & 1) != 0;

        int channelOffset = useLeft ? 0 : (audioChannels >= 2 ? 1 : 0);

        byte r = 0, g = 0, b = 0, a = 0;

        for (int j = 0; j < FramesPerPixel; j++)

        {

            float v = buf[(frameBase + j) * audioChannels + channelOffset];

            if (v > 0f)

            {

                byte mask = (byte)(1 << (j & 7));

                switch (j >> 3)

                {

                    case 0: r |= mask; break;

                    case 1: g |= mask; break;

                    case 2: b |= mask; break;

                    case 3: a |= mask; break;

                }

            }

        }

        return new Rgba32(r, g, b, a);

    }

    private static void Save(Image image, string path, string format)

    {

        IImageEncoder encoder = format switch

        {

            "jpg" or "jpeg" => new JpegEncoder(),

            "bmp" => new BmpEncoder(),

            _ => new PngEncoder(),

        };

        image.Save(path, encoder);

    }

}

using System.Diagnostics;

using System.Diagnostics;

using System.Globalization;

using System.Numerics;

using System.Reflection;

                .Add<Factorial>()

                .Add<SubProgram>()

                .Add<ImageAudio>()

                .Add<AudioImage>()

                .Add<Exp1>();

            play.Startup(args);