//// This code is part of Document Solutions for PDF .NET demos.// Copyright (c) MESCIUS inc. All rights reserved.//using System;using System.IO;using System.Drawing;using GrapeCity.Documents.Pdf;using GrapeCity.Documents.Text;using GrapeCity.Documents.Pdf.Structure;using GrapeCity.Documents.Pdf.MarkedContent;
namespace DsPdfWeb.Demos.Basics{    // This sample shows how to create tagged (structured) PDF and attach    // tags to individual paragraphs in a TextLayout that is used to render    // them together, splitting between pages.    // The code generating the document is similar to that used in PaginatedText,    // but adds tags.    // To see/explore the tags, open the document in Adobe Acrobat Pro and go to    // View | Navigation Panels | Tags.    public class TagTextLayout    {        public int CreatePDF(Stream stream)        {            var doc = new GcPdfDocument();
            // Create a Part element, it will contain P (paragraph) elements:            var sePart = new StructElement("Part");            doc.StructTreeRoot.Children.Add(sePart);
            // Create and set up a TextLayout to render paragraphs:            var tl = new TextLayout(72);            tl.DefaultFormat.Font = StandardFonts.Times;            tl.DefaultFormat.FontSize = 12;            tl.FirstLineIndent = 72 / 2;            tl.MaxWidth = doc.PageSize.Width;            tl.MaxHeight = doc.PageSize.Height;            tl.MarginAll = tl.Resolution;            //            // Append the text (20 paragraphs so they would not fit on a single page)            // (note that TextLayout interprets "\r\n" as paragraph delimiter):            //            // Get the text (20 paragraphs):            var text = Common.Util.LoremIpsum(20);            // In order to tag the individual paragraphs, we need to split the text into paragraphs,            // and use each paragraph format's Tag property (which is not related to PDF tags,             // it is just an arbitrary data that can be associated with a TextFormat) to add the            // paragraph's index to the paragraph:            var pars = text.Split(new char[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);            for (int i = 0; i < pars.Length; ++i)            {                var tf = new TextFormat(tl.DefaultFormat) { Tag = i };                tl.AppendLine(pars[i], tf);            }
            // Layout the text:            tl.PerformLayout(true);            // Use split options to provide widow/orphan control:            var to = new TextSplitOptions(tl)            {                MinLinesInFirstParagraph = 2,                MinLinesInLastParagraph = 2,            };            // TextLayoutHandler implements ITextLayoutHandler, which            // allows tagging the text as it is rendered:            var tlh = new TextLayoutHandler() { ParentElement = sePart };
            // In a loop, split and render the text:            while (true)            {                // 'rest' will accept the text that did not fit:                var splitResult = tl.Split(to, out TextLayout rest);                var page = doc.Pages.Add();                var g = page.Graphics;                // Tell the TextLayoutHandler which page we're on:                tlh.Page = page;                // ..and associate it with the graphics:                g.TextLayoutHandler = tlh;                // Draw the text that fits on the current page, and advance to next page unless we're done:                g.DrawTextLayout(tl, PointF.Empty);                if (splitResult != SplitResult.Split)                    break;                tl = rest;            }            // Mark document as tagged:            doc.MarkInfo.Marked = true;
            // Done:            doc.Save(stream);            return doc.Pages.Count;        }
        // Custom class that allows tagging content as it is rendered by TextLayout:        private class TextLayoutHandler : ITextLayoutHandler        {            private int _tagIndex;            private int _currentParagraphIndex = -1;            private StructElement _currentparagraphElement;            public StructElement ParentElement;            public Page Page;
            public void TextTagBegin(GcPdfGraphics graphics, TextLayout textLayout, object tag)            {                int paragraphIndex;                if (tag is int)                    paragraphIndex = (int)tag;                else                    paragraphIndex = -1;
                StructElement paragraphElement;                if (_currentParagraphIndex == paragraphIndex)                {                    paragraphElement = _currentparagraphElement;                }                else                {                    if (paragraphIndex >= 0)                    {                        paragraphElement = new StructElement("P");                        ParentElement.Children.Add(paragraphElement);                        _currentparagraphElement = paragraphElement;                        _currentParagraphIndex = paragraphIndex;                    }                    else                    {                        paragraphElement = null;                        _currentparagraphElement = paragraphElement;                        _currentParagraphIndex = paragraphIndex;                    }                }
                //                if (paragraphElement != null)                {                    graphics.BeginMarkedContent(new TagMcid("P", _tagIndex));                    var mcil = new McrContentItemLink();                    mcil.MCID = _tagIndex;                    mcil.Page = Page;                    paragraphElement.ContentItems.Add(mcil);                    _tagIndex++;                }            }
            public void TextTagEnd(GcPdfGraphics graphics, TextLayout textLayout, object tag)            {                if (_currentparagraphElement != null)                    graphics.EndMarkedContent();            }
            public void AddTextArea(RectangleF bounds)            {            }        }    }}