tests/PdfEncoder.CompatSpike/Program.cs - master - afanasevn/PdfEncoder

tests/PdfEncoder.CompatSpike/Program.cs
199 строк6 KB
IBS\NAfanasev
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01 июл 2026, 14:54
01 июл 2026, 14:548414644
using Docnet.Core;
using Docnet.Core.Models;
using TesseractOCR;
using TesseractOCR.Enums;
using TesseractOCR.Pix;
using UglyToad.PdfPig;

/// <summary>
/// PoC совместимости PdfPig + Docnet + TesseractOCR на .NET 10 (A-05).
/// </summary>
return await CompatSpike.RunAsync(args);

internal static class CompatSpike
{
    /// <summary>
    /// Запускает проверки native-зависимостей и возвращает код выхода.
    /// </summary>
    public static async Task<int> RunAsync(string[] args)
    {
        var repoRoot = FindRepoRoot() ?? Directory.GetCurrentDirectory();
        var tessdataPath = ResolveTessdataPath(repoRoot, args);

        var pdfPath = Path.Combine(Path.GetTempPath(), $"pdfencoder-spike-{Guid.NewGuid():N}.pdf");
        await File.WriteAllBytesAsync(pdfPath, MinimalPdfBytes);

        try
        {
            Console.WriteLine("[1/3] PdfPig: reading text layer...");
            var pdfText = ReadPdfText(pdfPath);
            Console.WriteLine($"      Text: \"{pdfText.Trim()}\"");

            Console.WriteLine("[2/3] Docnet: rendering page 1...");
            var imagePath = RenderPageToPgm(pdfPath);
            Console.WriteLine($"      Image: {imagePath}");

            Console.WriteLine("[3/3] TesseractOCR: OCR (rus+eng)...");
            if (tessdataPath is null)
            {
                Console.WriteLine("      SKIP: tessdata not found. Place rus.traineddata and eng.traineddata in ./tessdata");
                Console.WriteLine("Compat spike: PdfPig + Docnet OK. OCR skipped.");
                return 0;
            }

            var ocrText = RunOcr(imagePath, tessdataPath);
            Console.WriteLine($"      OCR: \"{ocrText.Trim()}\"");

            Console.WriteLine("Compat spike: all checks passed.");
            return 0;
        }
        catch (Exception ex)
        {
            Console.Error.WriteLine($"Compat spike failed: {ex}");
            return 1;
        }
        finally
        {
            if (File.Exists(pdfPath))
            {
                File.Delete(pdfPath);
            }
        }
    }

    private static string ReadPdfText(string pdfPath)
    {
        using var document = PdfDocument.Open(pdfPath);
        var page = document.GetPage(1);
        return string.Join(' ', page.GetWords().Select(word => word.Text));
    }

    private static string RenderPageToPgm(string pdfPath)
    {
        var pdfBytes = File.ReadAllBytes(pdfPath);
        var imagePath = Path.Combine(Path.GetTempPath(), $"pdfencoder-spike-{Guid.NewGuid():N}.pgm");

        using var reader = DocLib.Instance.GetDocReader(pdfBytes, new PageDimensions(1080, 1920));
        using var pageReader = reader.GetPageReader(0);

        var width = pageReader.GetPageWidth();
        var height = pageReader.GetPageHeight();
        var bgra = pageReader.GetImage();
        var grayscale = ConvertBgraToGrayscale(bgra);

        WritePgm(imagePath, width, height, grayscale);
        return imagePath;
    }

    private static string RunOcr(
        string imagePath,
        string tessdataPath)
    {
        using var engine = new Engine(tessdataPath, "rus+eng", EngineMode.Default);
        using var img = Image.LoadFromFile(imagePath);
        using var page = engine.Process(img);
        return page.Text;
    }

    private static byte[] ConvertBgraToGrayscale(byte[] bgra)
    {
        var pixels = bgra.Length / 4;
        var grayscale = new byte[pixels];

        for (var i = 0; i < pixels; i++)
        {
            var offset = i * 4;
            var b = bgra[offset];
            var g = bgra[offset + 1];
            var r = bgra[offset + 2];
            grayscale[i] = (byte)((r * 299 + g * 587 + b * 114) / 1000);
        }

        return grayscale;
    }

    private static void WritePgm(
        string path,
        int width,
        int height,
        byte[] grayscale)
    {
        using var stream = File.Create(path);
        using var writer = new StreamWriter(stream);
        writer.WriteLine("P5");
        writer.WriteLine($"{width} {height}");
        writer.WriteLine("255");
        writer.Flush();
        stream.Write(grayscale);
    }

    private static string? ResolveTessdataPath(
        string repoRoot,
        string[] args)
    {
        if (args.Length > 0 && Directory.Exists(args[0]))
        {
            return args[0];
        }

        var candidates = new[]
        {
            Path.Combine(repoRoot, "tessdata"),
            Path.Combine(Directory.GetCurrentDirectory(), "tessdata")
        };

        foreach (var candidate in candidates)
        {
            if (Directory.Exists(candidate)
                && File.Exists(Path.Combine(candidate, "rus.traineddata"))
                && File.Exists(Path.Combine(candidate, "eng.traineddata")))
            {
                return candidate;
            }
        }

        return null;
    }

    private static string? FindRepoRoot()
    {
        var directory = new DirectoryInfo(Directory.GetCurrentDirectory());

        while (directory is not null)
        {
            if (File.Exists(Path.Combine(directory.FullName, "PdfEncoder.slnx"))
                || File.Exists(Path.Combine(directory.FullName, "global.json")))
            {
                return directory.FullName;
            }

            directory = directory.Parent;
        }

        return null;
    }

    private static readonly byte[] MinimalPdfBytes =
    """
    %PDF-1.4
    1 0 obj<< /Type /Catalog /Pages 2 0 R >>endobj
    2 0 obj<< /Type /Pages /Kids [3 0 R] /Count 1 >>endobj
    3 0 obj<< /Type /Page /Parent 2 0 R /MediaBox [0 0 300 144] /Contents 4 0 R /Resources<< /Font<< /F1 5 0 R >> >> >>endobj
    4 0 obj<< /Length 44 >>stream
    BT /F1 24 Tf 50 80 Td (Hello PdfEncoder) Tj ET
    endstream endobj
    5 0 obj<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica >>endobj
    xref
    0 6
    0000000000 65535 f 
    0000000009 00000 n 
    0000000058 00000 n 
    0000000115 00000 n 
    0000000270 00000 n 
    0000000363 00000 n 
    trailer<< /Size 6 /Root 1 0 R >>
    startxref
    445
    %%EOF
    """u8.ToArray();
}