ImageExtract

1//
2// Copyright (c) 2001-2021 by PDFTron Systems Inc. All Rights Reserved.
3//
4
5using System;
6using System.Drawing;
7
8using pdftron;
9using pdftron.Common;
10using pdftron.PDF;
11using pdftron.SDF;
12using pdftron.Filters;
13
14using NUnit.Framework;
15
16namespace MiscellaneousSamples
17{
18	[TestFixture]
19	public class ImageExtractTest
20	{
21		/// <summary>
22		///-----------------------------------------------------------------------------------
23		/// This sample illustrates one approach to PDF image extraction 
24		/// using PDFNet.
25		/// 
26		/// Note: Besides direct image export, you can also convert PDF images 
27		/// to GDI+ Bitmap, or extract uncompressed/compressed image data directly 
28		/// using element.GetImageData() (e.g. as illustrated in ElementReaderAdv 
29		/// sample project).
30		///-----------------------------------------------------------------------------------
31		/// </summary>
32
33
34		static int image_counter = 0;
35
36		// Relative path to the folder containing test files.
37		const string input_path =  "TestFiles/";
38
39		static void ImageExtract(PDFDoc doc, ElementReader reader) 
40		{
41			Element element; 
42			while ((element = reader.Next()) != null)
43			{
44				switch (element.GetType()) 
45				{
46					case Element.Type.e_image:
47					case Element.Type.e_inline_image:
48					{
49						Console.WriteLine("--> Image: {0}", ++image_counter);
50						Console.WriteLine("    Width: {0}", element.GetImageWidth());
51						Console.WriteLine("    Height: {0}", element.GetImageHeight());
52						Console.WriteLine("    BPC: {0}", element.GetBitsPerComponent());
53
54						Matrix2D ctm = element.GetCTM();
55						double x2=1, y2=1, y1=ctm.m_v;
56						ctm.Mult(ref x2, ref y2);
57                        // Write the coords to 3 decimal places.
58						Console.WriteLine("    Coords: x1={0:N2}, y1={1:N2}, x2={2:N2}, y2={3:N2}", ctm.m_h, ctm.m_v, x2, y2);
59						pdftron.PDF.Image image = null;
60						if (element.GetType() == Element.Type.e_image) 
61						{
62							image = new pdftron.PDF.Image(element.GetXObject());
63
64							string fname = Utils.CreateExternalFile("image_extract1_") + image_counter.ToString();
65							image.Export(fname);  // or ExporAsPng() or ExporAsTiff() ...
66						}
67						break;
68					}
69					case Element.Type.e_form: // Process form XObjects
70					{
71						reader.FormBegin(); 
72						ImageExtract(doc, reader);
73						reader.End(); 
74						break; 
75					}
76				}
77			}
78		}
79
80		[Test]
81		public static void Sample()
82		{
83			
84			// Example 1: 
85			// Extract images by traversing the display list for 
86			// every page. With this approach it is possible to obtain 
87			// image positioning information and DPI.
88			try	
89			{
90				using (PDFDoc doc = new PDFDoc(Utils.GetAssetTempFile(input_path + "newsletter.pdf")))
91				using (ElementReader reader = new ElementReader())
92				{
93					doc.InitSecurityHandler();
94					PageIterator itr;
95					for (itr=doc.GetPageIterator(); itr.HasNext(); itr.Next())	
96					{				
97						reader.Begin(itr.Current());
98						ImageExtract(doc, reader);
99						reader.End();
100					}
101
102					Console.WriteLine("Done.");
103				}
104			}
105			catch (PDFNetException e)
106			{
107				Console.WriteLine(e.Message);
108				Assert.True(false);
109			}
110
111			Console.WriteLine("----------------------------------------------------------------");
112
113			// Example 2: 
114			// Extract images by scanning the low-level document.
115			try	
116			{
117				using (PDFDoc doc = new PDFDoc(Utils.GetAssetTempFile(input_path + "newsletter.pdf")))
118				{
119					doc.InitSecurityHandler();
120					image_counter = 0;
121
122					SDFDoc cos_doc = doc.GetSDFDoc();
123					int num_objs = cos_doc.XRefSize();
124					for (int i=1; i<num_objs; ++i)
125					{
126						Obj obj = cos_doc.GetObj(i);
127						if (obj!=null && !obj.IsFree()&& obj.IsStream()) 
128						{
129							// Process only images
130							DictIterator itr = obj.Find("Subtype");
131							if (!itr.HasNext() || itr.Value().GetName() != "Image") 
132								continue; 
133
134							itr = obj.Find("Type");
135							if (!itr.HasNext() || itr.Value().GetName() != "XObject") 
136								continue;
137
138							pdftron.PDF.Image image = new pdftron.PDF.Image(obj);
139
140							Console.WriteLine("--> Image: {0}", ++image_counter);
141							Console.WriteLine("    Width: {0}", image.GetImageWidth());
142							Console.WriteLine("    Height: {0}", image.GetImageHeight());
143							Console.WriteLine("    BPC: {0}", image.GetBitsPerComponent());
144
145							string fname = Utils.CreateExternalFile("image_extract2_") + image_counter.ToString();
146							image.Export(fname);  // or ExporAsPng() or ExporAsTiff() ...
147
148							// Convert PDF bitmap to GDI+ Bitmap...
149							//Bitmap bmp = image.GetBitmap();
150							//bmp.Save(fname, ImageFormat.Png);
151							//bmp.Dispose();
152
153							// Instead of converting PDF images to a Bitmap, you can also extract 
154							// uncompressed/compressed image data directly using element.GetImageData() 
155							// as illustrated in ElementReaderAdv sample project.
156						}
157					}
158                    Console.WriteLine("Done.");
159                }
160			}
161			catch (PDFNetException e)
162			{
163				Console.WriteLine(e.Message);
164				Assert.True(false);
165			}
166
167		}
168	}
169}