ElementReader

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 ElementReaderTest : Sample
18    {
19        public ElementReaderTest() :
20            base("ElementReader", "Illustrates how to traverse page display list using ElementReader.")
21        {
22        }
23
24        public override IAsyncAction RunAsync()
25        {
26            return Task.Run(new System.Action(() => {
27                WriteLine("--------------------------------");
28                WriteLine("Starting ElementReader Test...");
29                WriteLine("--------------------------------\n");
30                try {
31                    WriteLine("-------------------------------------------------");
32                    WriteLine("Extract text data from all pages in the document.");
33
34                    // Open the test file
35                    string input_file_path = Path.Combine(InputPath, "newsletter.pdf");
36                    WriteLine("Opening input file: " + input_file_path);
37                    PDFDoc doc = new PDFDoc(input_file_path);
38                    doc.InitSecurityHandler();
39
40                    PageIterator itr;
41                    pdftron.PDF.ElementReader page_reader = new pdftron.PDF.ElementReader();
42
43                    //int i = 0;
44                    for (itr = doc.GetPageIterator(); itr.HasNext(); itr.Next())		//  Read every page
45                    {
46                        int pageNo = itr.GetPageNumber();
47                        WriteLine(String.Format("Page {0:d} ----------------------------------------", pageNo));
48
49                        page_reader.Begin(itr.Current());
50                        String result = ProcessElements(page_reader);
51                        WriteLine(result);
52                        page_reader.End();
53                    }
54                    WriteLine("Done.");
55                    doc.Destroy();
56                }
57                catch (Exception e) {
58                    WriteLine(GetExceptionMessage(e));
59                }
60
61                WriteLine("\n--------------------------------");
62                WriteLine("Done ElementReader Test.");
63                WriteLine("--------------------------------\n");
64            })).AsAsyncAction();
65        }
66        
67        String ProcessElements(ElementReader reader)
68        {
69            String result = "";
70            Element element;
71            //int i = 0;
72            while ((element = reader.Next()) != null) 	// Read page contents
73            {
74                switch (element.GetType())
75                {
76                    case ElementType.e_path:						// Process path data...
77                        {
78                            result += "Process Element.Type.e_path\n";
79                            //PathData data = element.GetPathData();
80                            //double[] points = data.get_pts();// points;
81                            break;
82                        }
83                    case ElementType.e_image:                       // Process images...
84                    case ElementType.e_inline_image:
85                        {
86                            result += "Process Element.Type.e_image\n";
87                            break;
88                        }
89                    case ElementType.e_text: 				// Process text strings...
90                        {
91                            result += "Process Element.Type.e_text\n";
92                            //String txt = element.GetTextString();
93                            // Message+=(txt);
94                            break;
95                        }
96                    case ElementType.e_form:				// Process form XObjects
97                        {
98                            result += "Process Element.Type.e_form\n";
99                            reader.FormBegin();
100                            result += ProcessElements(reader);
101                            reader.End();
102                            break;
103                        }
104                }
105            }
106            return result;
107        }
108    }
109}