//// 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.Actions;using System.Linq;
namespace DsPdfWeb.Demos{    // This sample shows how to find and remove all links to a certain URL from a PDF.    // The code first finds all link annotations with ActionURI pointing to the URL    // that needs to be removed, then uses redact to erase all content within the found link areas.    // Red overlay is used by the redacts to visualize the erased areas.    //    // The PDF used by this sample, but with links intact, can be seen in the FindAndHighlight sample.    public class RedactLinks    {        public int CreatePDF(Stream stream)        {            // Load the PDF with links that need to be remove:            var doc = new GcPdfDocument();            using var fs = File.OpenRead(Path.Combine("Resources", "PDFs", "fendo-13-1005722.pdf"));            doc.Load(fs);
            // Remove all links containing this string:            const string targetUrl = "frontiersin.org";
            // Find all relevant link annotations:            var linkAnnotations = new HashSet<LinkAnnotation>();            foreach (var page in doc.Pages)            {                foreach (var a in page.Annotations)                {                    if (a is LinkAnnotation la && la.Action is ActionURI actUri)                    {                        if (!string.IsNullOrEmpty(actUri.URI) && actUri.URI.Contains(targetUrl))                        {                            linkAnnotations.Add(la);                        }                    }                }            }            // Loop through the found links, add redact annotations for each:            foreach (var la in linkAnnotations)            {                foreach (var page in la.Pages)                {                    // We must make a copy of page.Annotations to be able to add redact annotations in a foreach loop:                    var annots = page.Annotations.Where(a_ => a_ == la).ToList();                    foreach (var a in annots)                    {                        page.Annotations.Add(new RedactAnnotation()                        {                            Rect = la.Rect,                            OverlayFillColor = Color.Red                        });                    }                }            }            // Apply the redacts:            doc.Redact();
            // Done:            doc.Save(stream);            return doc.Pages.Count;        }    }}