How to Extract Text Formatting Information from PDFs using iTextSharp?

Use iTextSharp to obtain text format information

iTextSharp provides a simple text extraction system that can handle some basic markup. Although it does not handle color information, you can implement this functionality yourself. Here's a modified code snippet that combines various questions and answers to extract the text as HTML while capturing font information, including size and bold:

<code class="language-csharp">using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using iTextSharp.text.pdf.parser;
using iTextSharp.text.pdf;

namespace WindowsFormsApplication2
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            PdfReader reader = new PdfReader("Document.pdf");
            TextWithFontExtractionStategy S = new TextWithFontExtractionStategy();
            string F = iTextSharp.text.pdf.parser.PdfTextExtractor.GetTextFromPage(reader, 1, S);
            Console.WriteLine(F);

            this.Close();
        }

        public class TextWithFontExtractionStategy : iTextSharp.text.pdf.parser.ITextExtractionStrategy
        {
            //HTML缓冲区
            private StringBuilder result = new StringBuilder();

            //存储最后使用的属性
            private Vector lastBaseLine;
            private string lastFont;
            private float lastFontSize;

            //http://api.itextpdf.com/itext/com/itextpdf/text/pdf/parser/TextRenderInfo.html
            private enum TextRenderMode
            {
                FillText = 0,
                StrokeText = 1,
                FillThenStrokeText = 2,
                Invisible = 3,
                FillTextAndAddToPathForClipping = 4,
                StrokeTextAndAddToPathForClipping = 5,
                FillThenStrokeTextAndAddToPathForClipping = 6,
                AddTextToPaddForClipping = 7
            }



            public void RenderText(iTextSharp.text.pdf.parser.TextRenderInfo renderInfo)
            {
                string curFont = renderInfo.GetFont().PostscriptFontName;
                //检查是否使用了伪粗体
                if ((renderInfo.GetTextRenderMode() == (int)TextRenderMode.FillThenStrokeText))
                {
                    curFont += "-Bold";
                }

                //此代码假设如果基线发生变化，则表示换行
                Vector curBaseline = renderInfo.GetBaseline().GetStartPoint();
                Vector topRight = renderInfo.GetAscentLine().GetEndPoint();
                iTextSharp.text.Rectangle rect = new iTextSharp.text.Rectangle(curBaseline[Vector.I1], curBaseline[Vector.I2], topRight[Vector.I1], topRight[Vector.I2]);
                Single curFontSize = rect.Height;

                //查看是否有任何更改，例如基线、字体或字体大小
                if ((this.lastBaseLine == null) || (curBaseline[Vector.I2] != lastBaseLine[Vector.I2]) || (curFontSize != lastFontSize) || (curFont != lastFont))
                {
                    //如果我们已经放置了一个span标签，则关闭它
                    if ((this.lastBaseLine != null))
                    {
                        this.result.AppendLine("");
                    }
                    //如果基线已更改，则插入换行符
                    if ((this.lastBaseLine != null) &
                    curBaseline[Vector.I2] != lastBaseLine[Vector.I2])
                    {
                        this.result.AppendLine("<br />");
                    }
                    //创建具有适当样式的HTML标签
                    this.result.AppendFormat("</code>

Using this code, you can extract text from a PDF document while also capturing font properties such as font family, size, and bold. The code snippet is incomplete and needs to be supplemented to create and close the <span> tag and add text content to run completely.

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