Zoom In Zoom Out

Take the following steps to start a project and to add some code that zooms in and out:

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 "Zoom In and Zoom Out" 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 Leadtools For .NET "<LEADTOOLS_INSTALLDIR>\Bin\DotNet\Win32 " folder and select the following DLLs:
- Leadtools.dll
- Leadtools.Codecs.dll
- Leadtools.WinForms.dll
- Leadtools.Codecs.Cmp.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 and then select Leadtools.WinForms.DLL from "<LEADTOOLS_INSTALLDIR>\Bin\DotNet\Win32" and then click Open and then click OK.

From the toolbox (View->Toolbox ), add 3 Button controls as follows:

Name	Text
Button1	Zoom In
Button2	Zoom Out
Button3	Zoom None

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

[C#]

             
            using Leadtools;
            using Leadtools.Codecs;
            using Leadtools.WinForms;

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 the viewer
               Dim codecs As New RasterCodecs()
               rasterImageViewer1.Image = codecs.Load("C:\Users\Public\Documents\LEADTOOLS Images\Sample1.cmp")
               
               ' setup the viewer interactive mode to Zoom To Rectangle
               RasterImageViewer1.InteractiveMode = RasterViewerInteractiveMode.ZoomTo
               
               ' hook into the ScaleFactorChanged event to update the caption whenever the scale factor changes
               AddHandler RasterImageViewer1.ScaleFactorChanged, AddressOf rasterImageViewer1_ScaleFactorChanged
               
               ' change the scale factor momentaraly to update the caption
               RasterImageViewer1.BeginUpdate()
               RasterImageViewer1.ScaleFactor = RasterImageViewer1.ScaleFactor + 1
               RasterImageViewer1.ScaleFactor = RasterImageViewer1.ScaleFactor - 1
               RasterImageViewer1.EndUpdate()
            End Sub
            Private Sub rasterImageViewer1_ScaleFactorChanged(ByVal sender As Object, ByVal e As EventArgs)
               Text = String.Format("Current ScaleFactor: {0} - Use the buttons of click and drag a rectangle on the image to zoom to", RasterImageViewer1.ScaleFactor * 100)
            End Sub

[C#]

            private void Form1_Load(object sender, System.EventArgs e)
            {
               // Load an image into the viewer
               RasterCodecs codecs = new RasterCodecs();
               rasterImageViewer1.Image = codecs.Load(@"C:\Users\Public\Documents\LEADTOOLS Images\Sample1.cmp");
               // setup the viewer interactive mode to Zoom To Rectangle
               rasterImageViewer1.InteractiveMode = RasterViewerInteractiveMode.ZoomTo;
               // hook into the ScaleFactorChanged event to update the caption whenever the scale factor changes
               rasterImageViewer1.ScaleFactorChanged += new EventHandler(rasterImageViewer1_ScaleFactorChanged);
               //  change the scale factor momentaraly to update the caption
               rasterImageViewer1.BeginUpdate();
               rasterImageViewer1.ScaleFactor++;
               rasterImageViewer1.ScaleFactor--;
               rasterImageViewer1.EndUpdate();
            }
            private void rasterImageViewer1_ScaleFactorChanged(object sender, EventArgs e)
            {
               Text = String.Format("Current ScaleFactor: {0} - Use the buttons of click and drag a rectangle on the image to zoom to", rasterImageViewer1.ScaleFactor * 100);
            }

Double-click Button1 (Zoom In) on the form to add a handler for the Click event and add the following code:

[Visual Basic]

            Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
               ' zoom in
               RasterImageViewer1.ScaleFactor *= 1.2
            End Sub

[C#]

            private void button1_Click(object sender, System.EventArgs e)
            {
               // zoom in
               rasterImageViewer1.ScaleFactor *= 1.2;
            }

Double-click Button2 (Zoom OUT) on the form to add a handler for the Click event and add the following code:

[Visual Basic]

            Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
               ' zoom out
               RasterImageViewer1.ScaleFactor /= 1.2
            End Sub

[C#]

            private void button2_Click(object sender, System.EventArgs e)
            {
               // zoom out
               rasterImageViewer1.ScaleFactor /= 1.2;
            }

Double-click Button3 (Zoom None) on the form to add a handler for the Click event and add the following code:

[Visual Basic]

            Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
               ' no zoom (100)
               RasterImageViewer1.ScaleFactor = 1
            End Sub

[C#]

            private void button3_Click(object sender, System.EventArgs e)
            {
               // no zoom (100)
               rasterImageViewer1.ScaleFactor = 1;
            }

Build, and Run the program to test it.