//// This code is part of Document Solutions for PDF .NET demos.// Copyright (c) MESCIUS inc. All rights reserved.//using System;using System.IO;using GrapeCity.Documents.Pdf;using System.Collections.Generic;
namespace DsPdfWeb.Demos{    // When merging PDFs that contain identical images, by default the resulting PDF    // will end up containing several copies of the same image.    // To ensure that the PDF is not larger than necessary, DsPdf provides the method    // GcPdfDocument.RemoveDuplicateImages() that scans the PDF, finds and removes duplicates.    // The MergeDocumentOptions class also has the property RemoveDuplicateImages,    // which allows you to scan for/remove duplicates at once when merging PDFs,    // but by default it is false. This is because the occurrence of duplicate images    // in merged PDFs is not a very common scenario, while scanning for duplicates    // may affect the performance of the merge. Also, if you are merging multiple PDFs    // that contain duplicate images, it is better to merge all PDFs first, and then    // remove all duplicates from the final PDF at once with a single call to    // GcPdfDocument.RemoveDuplicateImages(), as demonstrated by this demo.    //    // In this demo we merge several sample invoices that include the same company logo,    // and then call GcPdfDocument.RemoveDuplicateImages() and compare the sizes of the    // resulting PDF before and after that call.    //     // See also OptimizeFonts.    public class RemoveDuplicateImages    {        static FileStream MergePDFs(GcPdfDocument dest, string fpath)        {            GcPdfDocument d = new GcPdfDocument();            var fs = File.OpenRead(fpath);            d.Load(fs);            dest.MergeWithDocument(d);            return fs;        }
        public int CreatePDF(Stream stream)        {            // Input file names:            const int N = 7;            var fpaths = new List<string>(N);            for (int i = 1; i <= 7; i++)                fpaths.Add(Path.Combine("Resources", "PDFs", $"DsDemoInvoice{i}.pdf"));            // Facilitate clean up:            var fss = new List<FileStream>();            string tempPdfBefore = null, tempPdfAfter = null;            try            {                var doc = new GcPdfDocument();                // Merge the invoices into a single PDF:                for (int i = 0; i < N; i++)                    fss.Add(MergePDFs(doc, fpaths[i]));
                // Compare the merged PDF size before and after removing duplicates:                tempPdfBefore = Path.GetTempFileName();                doc.Save(tempPdfBefore);                var sizeBefore = new FileInfo(tempPdfBefore).Length;                doc.RemoveDuplicateImages();                tempPdfAfter = Path.GetTempFileName();                doc.Save(tempPdfAfter);                var sizeAfter = new FileInfo(tempPdfAfter).Length;                Common.Util.AddNote(String.Format(                    "Using the GcPdfDocument.RemoveDuplicateImages() method on this document (which was produced by merging " +                    "several demo invoices with the same company logo) reduced the size of the merged PDF from {0:N0} to {1:N0} bytes.",                    sizeBefore, sizeAfter),                    doc.Pages.Insert(0));                doc.Save(stream);                return doc.Pages.Count;            }            finally            {                if (tempPdfBefore != null)                    File.Delete(tempPdfBefore);                if (tempPdfAfter != null)                    File.Delete(tempPdfAfter);                fss.ForEach(fs_ => fs_.Dispose());            }        }    }}