PDFDocMemory

1//
2// Copyright (c) 2001-2020 by PDFTron Systems Inc. All Rights Reserved.
3//
4
5using System;
6using System.IO;
7using System.Threading.Tasks;
8using Windows.Foundation;
9
10using pdftron.PDF;
11using pdftron.SDF;
12
13using PDFNetUniversalSamples.ViewModels;
14
15namespace PDFNetSamples
16{
17    public sealed class PDFDocMemoryTest : Sample
18    {
19        public PDFDocMemoryTest() :
20            base("PDFDocMemory", "The sample illustrates how to read/write a PDF document from/to memory buffer. This is useful for applications that work with dynamic PDFdocuments that don't need to be saved/read from a disk.")
21        {
22        }
23
24        public override IAsyncAction RunAsync()
25        {
26            return Task.Run(new System.Action(async () => {
27                WriteLine("--------------------------------");
28                WriteLine("Starting PDFDocMemory Test...");
29                WriteLine("--------------------------------\n");
30			    try  
31			    {
32				    // Read a PDF document from a IRandomAccessStream or pass-in a memory buffer...
33                    PDFDoc doc = new PDFDoc(Path.Combine(InputPath, "tiger.pdf"));
34				    doc.InitSecurityHandler();
35
36				    int num_pages = doc.GetPageCount();
37
38				    ElementWriter writer = new ElementWriter();
39				    ElementReader reader = new ElementReader();
40				    Element element;
41
42				    // Perform some document editing ...
43				    // Here we simply copy all elements from one page to another.
44				    for(int i = 1; i <= num_pages; ++i)
45				    {
46                        pdftron.PDF.Page pg = doc.GetPage(2 * i - 1);
47
48					    reader.Begin(pg);
49                        pdftron.PDF.Page new_page = doc.PageCreate(pg.GetMediaBox());
50					    doc.PageInsert(doc.GetPageIterator(2*i), new_page);
51
52					    writer.Begin(new_page);
53					    while ((element = reader.Next()) != null) 	// Read page contents
54					    {
55						    writer.WriteElement(element);
56					    }
57
58                        writer.End();
59					    reader.End();
60				    }
61
62                    string output_file_path = Path.Combine(OutputPath, "doc_memory_edit.pdf");
63                    await doc.SaveAsync(output_file_path, SDFDocSaveOptions.e_remove_unused);
64                    WriteLine("Done. Results saved in " + output_file_path);
65                    await AddFileToOutputList(output_file_path).ConfigureAwait(false);
66
67                    // Read some data from the file stored in memory
68				    reader.Begin(doc.GetPage(1));
69				    while ((element = reader.Next()) != null) {
70					    if (element.GetType() == ElementType.e_path)
71						    WriteLine("Path, ");
72				    }
73				    reader.End();
74				    doc.Destroy();
75			    }
76			    catch (Exception e) 
77                {
78                    WriteLine(GetExceptionMessage(e));
79                }
80
81                WriteLine("\n--------------------------------");
82                WriteLine("Done PDFDocMemory Test.");
83                WriteLine("--------------------------------\n");
84            })).AsAsyncAction();
85		}
86	}
87}