UndoRedoTest

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;
14using pdftron.Common;
15
16namespace PDFNetSamples
17{
18    public sealed class UndoRedoTest : Sample
19    {
20        public UndoRedoTest() :
21            base("UndoRedo", "The following sample illustrates how to use the UndoRedo API.")
22        {
23        }
24
25        public override IAsyncAction RunAsync()
26        {
27            return Task.Run(new System.Action(async () => {
28                WriteLine("--------------------------------");
29                WriteLine("Starting UndoRedo Test...");
30                WriteLine("--------------------------------\n");
31
32                bool error = await UndoRedoTestAsync();
33
34                if (error)
35                {
36                    WriteLine("UndoRedo failed");
37                }
38                else
39                {
40                    WriteLine("UndoRedo succeeded");
41                }
42
43                WriteLine("\n--------------------------------");
44                WriteLine("Done UndoRedo Test.");
45                WriteLine("--------------------------------\n");
46            })).AsAsyncAction();
47        }
48
49        private async Task<bool> UndoRedoTestAsync()
50        {
51            bool error = false;
52
53            // Relative path to the folder containing test files.
54            string inputPath = Path.Combine(InputPath, "newsletter.pdf");
55            string inputImagePath = Path.Combine(InputPath, "peppers.jpg");
56            string outputPath = Path.Combine(OutputPath, "addimage.pdf");
57            string outputUndoPath = Path.Combine(OutputPath, "addimage_undone.pdf");
58            string outputRedoPath = Path.Combine(OutputPath, "addimage_redone.pdf");
59
60            try
61            {
62                // Open the PDF document.
63                PDFDoc document = new PDFDoc(inputPath);
64                ElementBuilder elementBuilder = new ElementBuilder(); // Used to build new Element objects	
65                ElementWriter elementWriter = new ElementWriter();	// Used to write Elements to the page                	
66
67                UndoManager undoManager = document.GetUndoManager();
68
69                // Take a snapshot to which we can undo after making changes.
70                ResultSnapshot snapshot0 = undoManager.TakeSnapshot();
71                DocSnapshot snapshot0State = snapshot0.CurrentState();
72
73                Page page = document.PageCreate();   // Start a new page
74
75                elementWriter.Begin(page);		// Begin writing to this page
76
77                // ----------------------------------------------------------
78                // Add JPEG image to the file
79                Image image = Image.Create(document.GetSDFDoc(), inputImagePath);
80                Element element = elementBuilder.CreateImage(image, new Matrix2D(200, 0, 0, 250, 50, 500));
81                elementWriter.WritePlacedElement(element);
82                elementWriter.End();	// Finish writing to the page
83                document.PagePushFront(page);
84
85                // Take a snapshot after making changes, so that we can redo later (after undoing first).
86                ResultSnapshot snapshot1 = undoManager.TakeSnapshot();
87                if (snapshot1.PreviousState().Equals(snapshot0State))
88                {
89                    WriteLine("snapshot1 previous state equals snapshot0State; previous state is correct");
90                }
91
92                DocSnapshot snapshot1State = snapshot1.CurrentState();
93
94                await document.SaveAsync(outputPath, SDFDocSaveOptions.e_incremental);
95                await AddFileToOutputList(outputPath).ConfigureAwait(false);
96
97                if (undoManager.CanUndo())
98                {
99                    ResultSnapshot undoSnapshot = undoManager.Undo();
100
101                    await document.SaveAsync(outputUndoPath, SDFDocSaveOptions.e_incremental);
102                    await AddFileToOutputList(outputUndoPath).ConfigureAwait(false);
103
104                    DocSnapshot undoSnapshotState = undoSnapshot.CurrentState();
105                    if (undoSnapshotState.Equals(snapshot0State))
106                    {
107                        WriteLine("undoSnapshotState equals snapshot0State; undo was successful");
108                    }
109
110                    if (undoManager.CanRedo())
111                    {
112                        ResultSnapshot redoSnapshot = undoManager.Redo();
113
114                        await document.SaveAsync(outputRedoPath, SDFDocSaveOptions.e_incremental);
115                        await AddFileToOutputList(outputRedoPath).ConfigureAwait(false);
116
117                        if (redoSnapshot.PreviousState().Equals(undoSnapshotState))
118                        {
119                            WriteLine("redoSnapshot previous state equals undoSnapshotState; previous state is correct");
120                        }
121
122                        DocSnapshot redoSnapshotState = redoSnapshot.CurrentState();
123                        if (redoSnapshotState.Equals(snapshot1State))
124                        {
125                            WriteLine("snapshot1 and redoSnapshot are equal; redo was successful");
126                        }
127                    }
128                    else
129                    {
130                        WriteLine("Problem encountered - cannot redo.");
131                    }
132                }
133                else
134                {
135                    WriteLine("Problem encountered - cannot undo.");
136                }
137
138            }
139            catch (Exception e)
140            {
141                WriteLine(GetExceptionMessage(e));
142                error = true;
143            }
144
145            return error;
146        }
147    }
148}