//// This code is part of Document Solutions for PDF .NET demos.// Copyright (c) MESCIUS inc. All rights reserved.//using System.IO;using System.Drawing;using GrapeCity.Documents.Pdf;using GrapeCity.Documents.Pdf.Security;using GrapeCity.Documents.Text;
namespace DsPdfWeb.Demos{    // This example shows how to load a password protected PDF and try to read its metadata.    // Keep in mind that in some cases metadata in a PDF may also be encrypted, in which case    // reading it without the password is impossible.    // For reference, the loaded PDF is protected with the owner password 'owner' and user password 'user'.    public class NoPassGetMetadata    {        public int CreatePDF(Stream stream)        {            using var fs = File.OpenRead(Path.Combine("Resources", "PDFs", "Wetlands-password-user.pdf"));            // Set up DecryptionOptions to allow loading password protected PDFs without password:            var dopt = new DecryptionOptions() { ThrowExceptionIfInvalidPassword = false };            var docSrc = new GcPdfDocument();            docSrc.Load(fs, dopt);
            // The PDF to hold the results:            var doc = new GcPdfDocument();            var page = doc.NewPage();            // Set up a TextLayout to format the results:            var tl = page.Graphics.CreateTextLayout();            tl.DefaultFormat.Font = StandardFonts.Courier;            tl.DefaultFormat.FontSize = 14;            tl.MaxWidth = doc.PageSize.Width;            tl.MaxHeight = doc.PageSize.Height;            tl.MarginAll = tl.Resolution;            var captionFmt = new TextFormat(tl.DefaultFormat) { Font = StandardFonts.CourierBold, FontSize = tl.DefaultFormat.FontSize + 2 };
            // All security handlers before StandardSecurityHandlerRev4 always encrypted metadata,            // the StandardSecurityHandlerRev4 has EncryptMetadata property which we need to check:            bool metadataIsEncrypted = true;            if (docSrc.Security.EncryptHandler is StandardSecurityHandlerRev4 ssh)                metadataIsEncrypted = ssh.EncryptMetadata;
            if (!metadataIsEncrypted)            {                Metadata m = docSrc.Metadata;                tl.AppendLine("The PDF has unencrypted metadata:", captionFmt);                tl.AppendLine($"  Copyright: {m.Copyright}");                tl.AppendLine($"  CreatorTool: {m.CreatorTool}");                if (m.CreateDate.HasValue)                    tl.AppendLine($"  CreateDate: {m.CreateDate.Value.ToUniversalTime():R}");                tl.AppendLine($"  Description: {m.Description}");                if (m.ModifyDate.HasValue)                    tl.AppendLine($"  ModifyDate: {m.ModifyDate.Value.ToUniversalTime():R}");                tl.AppendLine($"  Producer: {m.Producer}");                tl.AppendLine($"  Title: {m.Title}");            }            else            {                tl.AppendLine("Cannot read metadata because the PDF metadata is encrypted.", captionFmt);            }
            // Render the results:            tl.PerformLayout(true);            while (true)            {                var splitResult = tl.Split(null, out TextLayout rest);                page.Graphics.DrawTextLayout(tl, PointF.Empty);                if (splitResult != SplitResult.Split)                    break;                tl = rest;                tl.MarginTop = tl.Resolution;                page = doc.Pages.Add();            }
            // Done:            doc.Save(stream);            return doc.Pages.Count;        }    }}