Imposition

1//---------------------------------------------------------------------------------------
2// Copyright (c) 2001-2019 by PDFTron Systems Inc. All Rights Reserved.
3// Consult legal.txt regarding legal and license information.
4//---------------------------------------------------------------------------------------
5
6import PDFNet
7import Foundation
8
9//-----------------------------------------------------------------------------------
10// The sample illustrates how multiple pages can be combined/imposed
11// using PDFNet. Page imposition can be used to arrange/order pages
12// prior to printing or to assemble a 'master' page from several 'source'
13// pages. Using PDFNet API it is possible to write applications that can
14// re-order the pages such that they will display in the correct order
15// when the hard copy pages are compiled and folded correctly.
16//-----------------------------------------------------------------------------------
17func runImpositionTest() -> Int {
18    return autoreleasepool {
19        var ret: Int = 0
20        
21        
22        // Relative path to the folder containing test files.
23        let input_path: String? = Bundle.main.path(forResource: "newsletter", ofType: "pdf")
24        let output_path: String = URL(fileURLWithPath: NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]).appendingPathComponent("newsletter_booklet.pdf").path
25        
26        do {
27            try PTPDFNet.catchException {
28                print("-------------------------------------------------")
29                print("Opening the input pdf...")
30                
31                let filein: String? = input_path
32                let fileout: String = output_path
33                
34                let in_doc: PTPDFDoc = PTPDFDoc(filepath: filein)
35                in_doc.initSecurityHandler()
36                
37                // Create a list of pages to import from one PDF document to another.
38                let import_pages: PTVectorPage = PTVectorPage()
39                let itr: PTPageIterator = in_doc.getPageIterator(1)
40                while itr.hasNext() {
41                    import_pages.add(itr.current())
42                    itr.next()
43                }
44                
45                let new_doc: PTPDFDoc = PTPDFDoc()
46                let imported_pages: PTVectorPage = new_doc.importPages(import_pages, import_bookmarks: false)
47                
48                // Paper dimension for A3 format in points. Because one inch has
49                // 72 points, 11.69 inch 72 = 841.69 points
50                let media_box: PTPDFRect = PTPDFRect(x1: 0, y1: 0, x2: 1190.88, y2: 841.69)
51                let mid_point: Double = media_box.width() / 2
52                
53                let builder: PTElementBuilder = PTElementBuilder()
54                let writer: PTElementWriter = PTElementWriter()
55                
56                var i: Int32 = 0
57                while i < imported_pages.size() {
58                    // Create a blank new A3 page and place on it two pages from the input document.
59                    let new_page: PTPage = new_doc.pageCreate(media_box)
60                    
61                    writer.writerBegin(with: new_page, placement: e_ptoverlay, page_coord_sys: true, compress: true, resources: nil)
62                
63                    // Place the first page
64                    var src_page: PTPage = imported_pages.get(i)
65                    var element: PTElement = builder.createForm(with: src_page)
66                    
67                    var sc_x: Double = mid_point / src_page.getWidth(e_ptcrop)
68                    var sc_y: Double = media_box.height() / src_page.getHeight(e_ptcrop)
69                    var scale: Double = sc_x < sc_y ? sc_x : sc_y // min(sc_x, sc_y)
70                    element.getGState().setTransform(scale, b: 0, c: 0, d: scale, h: 0, v: 0)
71                    writer.writePlacedElement(element)
72                    
73                    // Place the second page
74                    i += 1
75                    if i < imported_pages.size() {
76                        src_page = imported_pages.get(i)
77                        element = builder.createForm(with: src_page)
78                        sc_x = mid_point / src_page.getWidth(e_ptcrop)
79                        sc_y = media_box.height() / src_page.getHeight(e_ptcrop)
80                        scale = sc_x < sc_y ? sc_x : sc_y
81                        // min(sc_x, sc_y)
82                        element.getGState().setTransform(scale, b: 0, c: 0, d: scale, h: mid_point, v: 0)
83                        writer.writePlacedElement(element)
84                    }
85                    
86                    writer.end()
87                    new_doc.pagePushBack(new_page)
88                    i += 1
89                }
90                
91                new_doc.save(toFile: fileout, flags: e_ptlinearized.rawValue)
92                print("Done. Result saved in newsletter_booklet.pdf...")
93            }
94        } catch let e as NSError {
95            print("\(e)")
96            ret = 1
97        }
98        
99        print("Done.")
100        return ret
101    }
102}