UndoRedoTest

1//---------------------------------------------------------------------------------------
2// Copyright (c) 2001-2021 by PDFTron Systems Inc. All Rights Reserved.
3// Consult legal.txt regarding legal and license information.     
4//---------------------------------------------------------------------------------------
5
6using System;
7using pdftron;
8using pdftron.Common;
9using pdftron.PDF;
10using pdftron.SDF;
11
12using NUnit.Framework;
13
14namespace MiscellaneousSamples
15{
16	/// <summary>
17	//---------------------------------------------------------------------------------------
18	// The following sample illustrates how to use the UndoRedo API.
19	//---------------------------------------------------------------------------------------
20	/// </summary>
21	[TestFixture]
22	public class UndoRedoTest
23	{
24		
25		/// <summary>
26		/// The main entry point for the application.
27		/// </summary>
28		[Test]
29		public static void Sample()
30		{
31			// The first step in every application using PDFNet is to initialize the 
32			// library and set the path to common PDF resources. The library is usually 
33			// initialized only once, but calling Initialize() multiple times is also fine.
34
35			// Relative path to the folder containing test files.
36			const string input_path =  "TestFiles/";
37
38			try  
39			{
40				// Open the PDF document.
41                using (PDFDoc doc = new PDFDoc(Utils.GetAssetTempFile(input_path + "newsletter.pdf")))
42                using (ElementBuilder bld = new ElementBuilder())	// Used to build new Element objects
43                using (ElementWriter writer = new ElementWriter())	// Used to write Elements to the page	
44                {
45                    UndoManager undo_manager = doc.GetUndoManager();
46
47					// Take a snapshot to which we can undo after making changes.
48                    ResultSnapshot snap0 = undo_manager.TakeSnapshot();
49
50                    DocSnapshot snap0_state = snap0.CurrentState();
51
52                    Page page = doc.PageCreate();	// Start a new page
53
54                        writer.Begin(page);		// Begin writing to this page
55
56                    // ----------------------------------------------------------
57                    // Add JPEG image to the file
58                    Image img = Image.Create(doc, Utils.GetAssetTempFile(input_path + "peppers.jpg"));
59                    Element element = bld.CreateImage(img, new Matrix2D(200, 0, 0, 250, 50, 500));
60                    writer.WritePlacedElement(element);
61
62                    writer.End();	// Finish writing to the page
63                    doc.PagePushFront(page);
64
65					// Take a snapshot after making changes, so that we can redo later (after undoing first).
66                    ResultSnapshot snap1 = undo_manager.TakeSnapshot();
67
68                    if (snap1.PreviousState().Equals(snap0_state))
69                    {
70                        Console.WriteLine("snap1 previous state equals snap0_state; previous state is correct");
71                    }
72
73                    DocSnapshot snap1_state = snap1.CurrentState();
74
75                    doc.Save(Utils.CreateExternalFile("addimage.pdf"), SDFDoc.SaveOptions.e_incremental);
76
77					if (undo_manager.CanUndo())
78					{
79						ResultSnapshot undo_snap = undo_manager.Undo();
80
81						doc.Save(Utils.CreateExternalFile("addimage_undone.pdf"), SDFDoc.SaveOptions.e_incremental);
82
83						DocSnapshot undo_snap_state = undo_snap.CurrentState();
84
85						if (undo_snap_state.Equals(snap0_state))
86						{
87							Console.WriteLine("undo_snap_state equals snap0_state; undo was successful");
88						}
89
90						if (undo_manager.CanRedo())
91						{
92							ResultSnapshot redo_snap = undo_manager.Redo();
93							
94							doc.Save(Utils.CreateExternalFile("addimage_redone.pdf"), SDFDoc.SaveOptions.e_incremental);
95
96							if (redo_snap.PreviousState().Equals(undo_snap_state))
97							{
98								Console.WriteLine("redo_snap previous state equals undo_snap_state; previous state is correct");
99							}
100
101							DocSnapshot redo_snap_state = redo_snap.CurrentState();
102
103							if (redo_snap_state.Equals(snap1_state))
104							{
105								Console.WriteLine("Snap1 and redo_snap are equal; redo was successful");
106							}
107						}
108						else
109						{
110							Console.WriteLine("Problem encountered - cannot redo.");
111						}
112					}
113					else
114					{
115						Console.WriteLine("Problem encountered - cannot undo.");
116					}
117                }
118			}
119			catch (PDFNetException e) 
120			{
121				Console.WriteLine(e.Message);
122				Assert.True(false);
123			}
124		}
125    }
126}