Imposition

1//
2// Copyright (c) 2001-2020 by PDFTron Systems Inc. All Rights Reserved.
3//
4
5using System;
6using System.Collections.Generic;
7using System.IO;
8using System.Threading.Tasks;
9using Windows.Foundation;
10
11using pdftron.PDF;
12using pdftron.SDF;
13
14using PDFNetUniversalSamples.ViewModels;
15
16namespace PDFNetSamples
17{
18    public sealed class ImpositionTest : Sample
19    {
20        public ImpositionTest() :
21            base("Imposition", "The sample illustrates how multiple pages can be combined/imposed using PDFNet. Page imposition can be used to arrange/order pages prior to printing or to assemble a 'master' page from several 'source' pages. Using PDFNet API it is possible to write applications that can re-order the pages such that they will display in the correct order when the hard copy pages are compiled and folded correctly.")
22        {
23        }
24
25        public override IAsyncAction RunAsync()
26        {
27            return Task.Run(new System.Action(async () => {
28                WriteLine("--------------------------------");
29                WriteLine("Starting Imposition Test...");
30                WriteLine("--------------------------------\n");
31			    try	
32			    {
33                    string input_file_path = Path.Combine(InputPath, "newsletter.pdf");
34                    WriteLine("Opening input file " + input_file_path);
35                    PDFDoc in_doc = new PDFDoc(input_file_path);
36				    in_doc.InitSecurityHandler();
37
38				    // Create a list of pages to import from one PDF document to another.
39                    IList<pdftron.PDF.Page> import_list = new List<pdftron.PDF.Page>();
40				    for (PageIterator itr = in_doc.GetPageIterator(); itr.HasNext(); itr.Next()) 
41					    import_list.Add(itr.Current());
42
43				    PDFDoc new_doc = new PDFDoc(); //  Create a new document
44                    IList<pdftron.PDF.Page> imported_pages = new_doc.ImportPages(import_list);
45
46				    // Paper dimension for A3 format in points. Because one inch has 
47				    // 72 points, 11.69 inch 72 = 841.69 points
48                    pdftron.PDF.Rect media_box = new pdftron.PDF.Rect(0, 0, 1190.88, 841.69); 
49				    double mid_point = media_box.Width()/2;
50
51				    ElementBuilder builder = new ElementBuilder();
52				    ElementWriter  writer  = new ElementWriter();
53
54				    for (int i=0; i<imported_pages.Count; ++i)
55				    {
56					    // Create a blank new A3 page and place on it two pages from the input document.
57                        pdftron.PDF.Page new_page = new_doc.PageCreate(media_box);
58					    writer.Begin(new_page);
59
60					    // Place the first page
61                        pdftron.PDF.Page src_page = (pdftron.PDF.Page)imported_pages[i];
62					    Element element = builder.CreateForm(src_page);
63
64					    double sc_x = mid_point / src_page.GetPageWidth();
65					    double sc_y = media_box.Height() / src_page.GetPageHeight();
66					    double scale = Math.Min(sc_x, sc_y);
67					    element.GetGState().SetTransform(scale, 0, 0, scale, 0, 0);
68					    writer.WritePlacedElement(element);
69
70					    // Place the second page
71					    ++i; 
72					    if (i<imported_pages.Count)	
73					    {
74                            src_page = (pdftron.PDF.Page)imported_pages[i];
75						    element = builder.CreateForm(src_page);
76						    sc_x = mid_point / src_page.GetPageWidth();
77						    sc_y = media_box.Height() / src_page.GetPageHeight();
78						    scale = Math.Min(sc_x, sc_y);
79						    element.GetGState().SetTransform(scale, 0, 0, scale, mid_point, 0);
80						    writer.WritePlacedElement(element);
81					    }
82
83                        writer.End();
84					    new_doc.PagePushBack(new_page);
85				    }
86
87                    string output_file_path = Path.Combine(OutputPath, "newsletter_booklet.pdf");
88                    await new_doc.SaveAsync(output_file_path, SDFDocSaveOptions.e_linearized);
89                    new_doc.Destroy();
90                    in_doc.Destroy();
91                    WriteLine("Done. Results saved in " + output_file_path);
92                    await AddFileToOutputList(output_file_path).ConfigureAwait(false);
93			    }
94			    catch (Exception e)
95			    {
96                    WriteLine(GetExceptionMessage(e));
97                }
98
99                WriteLine("\n--------------------------------");
100                WriteLine("Done Annotation Test.");
101                WriteLine("--------------------------------\n");
102            })).AsAsyncAction();
103		}
104	}
105}