Updating a Gauge and Detecting a User Interrupt

Take the following steps to start a project and to add some code that updates a gauge during processing and detects a user interrupt:

Start Visual Studio .NET.
Choose File->New->Project… from the menu.
In the New Project dialog box, choose either "Visual C# Projects" or "Visual Basic Projects" in the Projects Type List, and choose "Windows Application " in the Templates List.
Type the project name as "Updating a Guage and Detecting User Interrupt" in the Project Name field, and then click OK. If desired, type a new location for your project or select a directory using the Browse button, and then click OK .
In the "Solution Explorer" window, right-click on the "References" folder, and select "Add Reference…" from the context menu. In the "Add Reference" dialog box, select the ".NET" tab and browse to the "<LEADTOOLS_INSTALLDIR>\Bin\DotNet\Win32 " folder and select the following DLLs:
- Leadtools.dll
- Leadtools.Codecs.dll
- Leadtools.Codecs.Cmp.dll
- Leadtools.WinForms.dll
- Leadtools.ImageProcessing.Core.dll
Click the Select button and then press the OK button to add the above DLLs to the application.
Make sure Form1 is in design view. Go to the toolbox (View->Toolbox) and Drag and drop an instance of RasterImageViewer to the form. If you do not have RasterImageViewer in your toolbox, select Tools->Add Remove Toolbox Items from the menu. Click Browse, select Leadtools.WinForms.DLL from the "C:\LEADTOOLS 18\Bin\DotNet\Win32" folder, click Open, and then click OK.
From the toolbox (View->Toolbox), add a ProgressBar, a Button (Text = "Median") and and another Button (Text = "Cancel").

Switch to Form1 code view (right-click Form1 in the solution explorer then select View Code ) and add the following lines at the beginning of the file: [Visual Basic]


            Imports Leadtools
            Imports Leadtools.Codecs
            Imports Leadtools.WinForms
            Imports Leadtools.ImageProcessing
            Imports Leadtools.ImageProcessing.Core

[C#]


             
            using Leadtools;
            using Leadtools.Codecs;
            using Leadtools.WinForms;
            using Leadtools.ImageProcessing;
            using Leadtools.ImageProcessing.Core;

Add an event handler to the Form1 Load event and add the following code: [Visual Basic]


            Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
               ' load an image into our viewer
               Dim codecs As New RasterCodecs()
               rasterImageViewer1.Image = codecs.Load("C:\Users\Public\Documents\LEADTOOLS Images\Image3.cmp")
               
               ' disable the cancel button for now
               Button2.Enabled = False
            End Sub

[C#]


            private void Form1_Load(object sender, System.EventArgs e)
            {
               // load an image into our viewer
               RasterCodecs codecs = new RasterCodecs();
               rasterImageViewer1.Image = codecs.Load(@"C:\Users\Public\Documents\LEADTOOLS Images\Image3.cmp");
               
               // disable the cancel button for now
               button2.Enabled = false;
            }

Double-click the "median" button on the form to add the event handler for it and add the following code: [Visual Basic]


            Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
               canceled = False
               ProgressBar1.Value = 0
               
               ' disable the median button and enable the cancel button
               Button1.Enabled = False
               Button2.Enabled = True
               
               Dim command As New MedianCommand(40)
               
               ' subscribe to the progress event
               AddHandler command.Progress, AddressOf median_Progress
               
               ' run the median command
               command.Run(RasterImageViewer1.Image)
               
               ' enable the median button and disable the cancel button
               Button1.Enabled = True
               Button2.Enabled = False
               ProgressBar1.Value = 0
            End Sub

[C#]


            private void button1_Click(object sender, System.EventArgs e)
            {
               canceled = false;
               progressBar1.Value = 0;
               
               // disable the median button and enable the cancel button
               button1.Enabled = false;
               button2.Enabled = true;
               
               MedianCommand command = new MedianCommand(40);
               
               // subscribe to the progress event
               command.Progress += new EventHandler<RasterCommandProgressEventArgs>(median_Progress);
               
               // run the median command
               command.Run(rasterImageViewer1.Image);
               
               // enable the median button and disable the cancel button
               button1.Enabled = true;
               button2.Enabled = false;
               progressBar1.Value = 0;
            }

Double-click the "cancel" button on the form to add the event handler for it and add the following code: [Visual Basic]


            Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
               ' Cancel the median command
               canceled = True
            End Sub

[C#]


            private void button2_Click(object sender, System.EventArgs e)
            {
               // Cancel the median command
               canceled = true;
            }

Add the below code to the Form1 class: [Visual Basic]


            Private canceled As Boolean
            Private Sub median_Progress(ByVal sender As System.Object, ByVal e As RasterCommandProgressEventArgs)
               ' update the value of the progress bar
               ProgressBar1.Value = e.Percent
               
               ' determine whether the cancel button has been pressed
               If (canceled) Then
                  e.Cancel = True
               End If
               
               Application.DoEvents()
            End Sub

[C#]


            private bool canceled;
            private void median_Progress(object sender, RasterCommandProgressEventArgs e)
            {
               // update the value of the progress bar
               progressBar1.Value = e.Percent;
               
               // determine whether the cancel button has been pressed
               if(canceled)
                  e.Cancel = true;
               
               Application.DoEvents();
            }

Build, and Run the program to test it.