//// 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 System.Collections.Generic;using GrapeCity.Documents.Pdf;using GrapeCity.Documents.Pdf.Annotations;using GrapeCity.Documents.Pdf.Structure;using GrapeCity.Documents.Pdf.Recognition.Structure;
namespace DsPdfWeb.Demos{    // Highlight paragraphs which have associated structure tags.    public class ReadTagsShowParas    {        public int CreatePDF(Stream stream)        {            var user = "DsPdfWeb Demo";
            var doc = new GcPdfDocument();            using var s = File.OpenRead(Path.Combine("Resources", "PDFs", "C1Olap-QuickStart.pdf"));            doc.Load(s);
            // 1st step - remove all but the first 5 pages from the loaded PDF,            // also removing tags that point to the removed pages:            void removeStructNodesForPage(StructElementCollection ses, Page p)            {                for (int i = ses.Count - 1; i >= 0; --i)                {                    var se = ses[i];                    if (se.DefaultPage == p)                        ses.RemoveAt(i);                    else                        removeStructNodesForPage(se.Children, p);                }            }            for (int i = doc.Pages.Count - 1; i >= 5; --i)            {                removeStructNodesForPage(doc.StructTreeRoot.Children, doc.Pages[i]);                doc.Pages.RemoveAt(i);            }
            // 2nd step - get the logical structure, highlight paragraphs            // and add sticky notes to them:            void highlightParagraphs(IReadOnlyList<Element> items)            {                var color = Color.FromArgb(64, Color.Magenta);                foreach (var e in items)                {                    if (e.HasContentItems)                        foreach (var i in e.ContentItems)                        {                            if (i is ContentItem ci)                            {                                var p = ci.GetParagraph();                                if (p != null)                                {                                    var rc = p.GetCoords().ToRect();                                    rc.Offset(rc.Width, 0);                                    rc.Size = new SizeF(16, 12);                                    var ta = new TextAnnotation()                                    {                                        UserName = user,                                        Rect = rc,                                        Page = ci.Page,                                        Contents = p.GetText(),                                        Color = Color.Yellow,                                    };                                    ci.Page.Graphics.DrawPolygon(p.GetCoords(), color, 1, null);                                }                            }                        }                    if (e.HasChildren)                        highlightParagraphs(e.Children);                }            }            // Get the LogicalStructure and use it to highlight paragraphs:            LogicalStructure ls = doc.GetLogicalStructure();            highlightParagraphs(ls.Elements);
            // Done:            doc.Save(stream);            return doc.Pages.Count;        }    }}