//// This code is part of Document Solutions for PDF .NET demos.// Copyright (c) MESCIUS inc. All rights reserved.//using System.IO;using System.Linq;using GrapeCity.Documents.Pdf;using GrapeCity.Documents.Pdf.Structure;using GrapeCity.Documents.Pdf.Recognition.Structure;
namespace DsPdfWeb.Demos{    // Find tables and read their data using structure tags.    public class ReadTagsToOutlines    {        public int CreatePDF(Stream stream)        {            var doc = new GcPdfDocument();            using var s = File.OpenRead(Path.Combine("Resources", "PDFs", "C1Olap-QuickStart.pdf"));            doc.Load(s);
            // Get the LogicalStructure and top parent element:            LogicalStructure ls = doc.GetLogicalStructure();            Element root = ls.Elements[0];
            // Iterate over elements and select all heading elements (H1, H2, H3 etc.):            OutlineNodeCollection outlines = doc.Outlines;            int outlinesLevel = 1;            foreach (Element e in root.Children)            {                string type = e.StructElement.Type;                if (string.IsNullOrEmpty(type) || !type.StartsWith("H"))                    continue;                // Note: topmost level is 1:                if (!int.TryParse(type.Substring(1), out int headingLevel) || headingLevel < 1)                    continue;                // Get the element text:                string text = e.GetText();                // Find the target page:                var page = FindPage(e.StructElement);                if (page != null)                {                    var o = new OutlineNode(text, new DestinationFit(page));                    if (headingLevel > outlinesLevel)                    {                        ++outlinesLevel;                        outlines = outlines.Last().Children;                    }                    else if (headingLevel < outlinesLevel)                    {                        --outlinesLevel;                        var p = ((OutlineNode)outlines.Owner).Parent;                        outlines = p == null ? doc.Outlines : p.Children;                    }                    outlines.Add(o);                }            }            doc.Save(stream);            return doc.Pages.Count;        }
        private Page FindPage(StructElement se)        {            if (se.DefaultPage != null)                return se.DefaultPage;            if (se.HasChildren)                foreach (var child in se.Children)                {                    var p = FindPage(child);                    if (p != null)                        return p;                }            return null;        }    }}