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Zoom In and Zoom Out
Take the following steps to start a project and to add some code that zooms in and out:
  1. Start Visual Studio .NET.
  2. Choose File->New->Project… from the menu.
  3. 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.
  4. Type the project name as "Zoom In and Zoom Out" in the Project Name field, and then choose OK. If desired, type a new location for your project or select a directory using the Browse button, and then choose OK .
  5. 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 "\LEAD Technologies\LEADTOOLS 16.5\Bin\DotNet\Win32 " folder and select the following DLLs:
    • Leadtools.dll
    • Leadtools.Codecs.dll
    • Leadtools.WinForms.dll
    Click the Select button and then press the OK button to add the above DLLs to the application.
  6. 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 "C:\Program Files (x86)\LEAD Technologies\LEADTOOLS 16.5\Bin\DotNet\Win32" and then click Open and then click OK.
  7. From the toolbox (View->Toolbox ), add 3 Button controls as follows:
    NameText
    Button1Zoom In
    Button2Zoom Out
    Button3Zoom None
  8. 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;
  9. 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
   RasterCodecs.Startup()
   Dim codecs As New RasterCodecs()
   rasterImageViewer1.Image = codecs.Load("C:\Users\Public\Documents\LEADTOOLS Images\Sample1.cmp")
   RasterCodecs.Shutdown()
   
   ' 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.Startup();
   RasterCodecs codecs = new RasterCodecs();
   rasterImageViewer1.Image = codecs.Load(@"C)
   RasterImageViewer1.ScaleFactor = 1
End Sub
    [C#] 
    
private void button3_Click(object sender, System.EventArgs e)
{
   // no zoom (100%)
   rasterImageViewer1.ScaleFactor = 1;
}
  10. Build, and Run the program to test it.