AddCaretAnnotation.cs
// 完毕:
using System;
using System.IO;
using System.Drawing;
using GrapeCity.Documents.Pdf;
using GrapeCity.Documents.Text;
using GrapeCity.Documents.Pdf.Annotations;

namespace DsPdfWeb.Demos
{
    // This example shows how to create a caret annotation used to indicate a specific position in a text.
    public class AddCaretAnnotation
    {
        public int CreatePDF(Stream stream)
        {
            using var fs = File.OpenRead(Path.Combine("Resources", "PDFs", "Wetlands.pdf"));
            var doc = new GcPdfDocument();
            doc.Load(fs);

            foreach (var page in doc.Pages)
            {
                var tm = page.GetTextMap();
                // insert the CaretAnnotation after "The Importance" text
                tm.FindText(new FindTextParams("wetlands", false, false), (fp_) =>
                {
                    // Add a CaretAnnotation near the found text:
                    var r = fp_.Bounds[0].ToRect();
                    var ca = new CaretAnnotation();
                    ca.Page = page;
                    ca.Rect = new RectangleF(r.Left - 8, r.Bottom - 16, 16, 16);
                });
            }
            // Done:
            doc.Save(stream);
            return doc.Pages.Count;
        }
    }
}