inabox/InABox.Avalonia.Platform.Desktop/Desktop.PdfRenderer.cs

using InABox.Core;
using Syncfusion.Pdf;
using Syncfusion.Pdf.Graphics;
using Syncfusion.PdfToImageConverter;

namespace InABox.Avalonia.Platform.Desktop;

public class Desktop_PdfRenderer : IPdfRenderer
{
    public byte[]? PdfToImage(byte[]? pdf, int page, int dpi)
    {
        if (pdf?.Any() != true)
            return null;
        
        using (var inData = new MemoryStream(pdf))
        {
            using (var converter = new PdfToImageConverter(inData))
            {
                var output = converter.Convert(page, true, false) as MemoryStream;
                return output.ToArray();

            }
        }
        
    }

    public Task<byte[]?> PdfToImageAsync(byte[]? pdf, int page, int dpi)
        => Task.Run(() => PdfToImage(pdf, page, dpi));

    public byte[]? ImageToPdf(byte[]? image)
    { 
        if (image?.Any() != true)
            return null;

        using var imgStream = new MemoryStream(image);
        
        var bmp = new PdfBitmap(imgStream);
        
        var doc = new PdfDocument();
        
        var section = doc.Sections.Add();
        section.PageSettings.Margins.All = 0;
        section.PageSettings.Width = bmp.Width;
        section.PageSettings.Height = bmp.Height;
        
        var page = section.Pages.Add();
        page.Graphics.DrawImage(bmp, 0, 0, page.Size.Width, page.Size.Height);

        using var docStream = new MemoryStream();
        
        doc.Save(docStream);
        return docStream.GetBuffer();
    }

    public Task<byte[]?> ImageToPdfAsync(byte[]? image)
        => Task.Run(() => ImageToPdf(image));

    public Logger? Logger { get; set; }
}