Leadtools.WinForms Send comments on this topic. | Back to Introduction - All Topics | Help Version 15.8.31
AutoScrollSmallChange Property
See Also  Example
Leadtools.WinForms Namespace > RasterImageViewer Class : AutoScrollSmallChange Property




Gets or sets the amount that the scroll bar is incremented or decremented for a small scroll.

Syntax

Visual Basic (Declaration) 
<BrowsableAttribute(False)>
Public Overridable ReadOnly Property AutoScrollSmallChange As Size
Visual Basic (Usage)Copy Code
Dim instance As RasterImageViewer
Dim value As Size
 
value = instance.AutoScrollSmallChange
C# 
[BrowsableAttribute(false)]
public virtual Size AutoScrollSmallChange {get;}
Managed Extensions for C++ 
[BrowsableAttribute(false)]
public: __property virtual Size get_AutoScrollSmallChange();
C++/CLI 
[BrowsableAttribute(false)]
public:
virtual property Size AutoScrollSmallChange {
   Size get();
}

Return Value

The amount that the scroll bar is incremented or decremented.

Example

This example hides the RasterImageViewer control scroll bars and creates two custom scrollbars.

Visual BasicCopy Code
Private Class MyForm3 : Inherits Form
   Public viewer As RasterImageViewer
   Private panel As Panel
   Private myHScroll As HScrollBar
   Private myVScroll As VScrollBar
   Public Sub New(ByVal title As String)
      Text = title

      Me.Size = New Size(750, 450)

      panel = New Panel()
      panel.Dock = DockStyle.Fill
      Controls.Add(panel)

      ' Create the raster viewer
      viewer = New RasterImageViewer()
      viewer.Dock = DockStyle.Fill
      viewer.Width = 500
      viewer.DoubleBuffer = True
      panel.Controls.Add(viewer)

      ' Load an image into the viewer
      RasterCodecs.Startup()
      Dim codecs As RasterCodecs = New RasterCodecs()
      viewer.Image = codecs.Load("C:\Program Files\LEAD Technologies\LEADTOOLS 15\Images\Sample1.cmp")
      codecs.Dispose()
      RasterCodecs.Shutdown()

      viewer.AutoScroll = False
      Dim size As Size = viewer.AutoScrollMinSize

      ' Create two scrollbar controls for scrolling

      myHScroll = New HScrollBar()
      myHScroll.Location = New Point(100, 50)
      myHScroll.Dock = DockStyle.Top
      myHScroll.Height *= 2
      myHScroll.Minimum = 0
      myHScroll.Maximum = viewer.Image.Width
      AddHandler myHScroll.ValueChanged, AddressOf hScroll_ValueChanged
      panel.Controls.Add(myHScroll)
      myHScroll.BringToFront()

      myVScroll = New VScrollBar()
      myVScroll.Dock = DockStyle.Left
      myVScroll.Location = New Point(100, 100)
      myVScroll.Width *= 2
      myVScroll.Minimum = 0
      myVScroll.Maximum = viewer.Image.Height
      AddHandler myVScroll.ValueChanged, AddressOf vScroll_ValueChanged
      panel.Controls.Add(myVScroll)
      myVScroll.BringToFront()

      viewer.BringToFront()

      OnSizeChanged(EventArgs.Empty)
   End Sub

   Private Sub vScroll_ValueChanged(ByVal sender As Object, ByVal e As EventArgs)
      viewer.ScrollPosition = New Point(myHScroll.Value, myVScroll.Value)
   End Sub

   Private Sub hScroll_ValueChanged(ByVal sender As Object, ByVal e As EventArgs)
      viewer.ScrollPosition = New Point(myHScroll.Value, myVScroll.Value)
   End Sub

   Protected Overrides Sub OnSizeChanged(ByVal e As EventArgs)
      If (Not myHScroll Is Nothing) AndAlso (Not myVScroll Is Nothing) Then
         myHScroll.SmallChange = viewer.AutoScrollSmallChange.Width
         myHScroll.LargeChange = viewer.AutoScrollLargeChange.Width
         myVScroll.SmallChange = viewer.AutoScrollSmallChange.Height
         myVScroll.LargeChange = viewer.AutoScrollLargeChange.Height

         Console.WriteLine("AutoScrollSmallChange {0}", viewer.AutoScrollSmallChange)
         Console.WriteLine("AutoScrollLargeChange {0}", viewer.AutoScrollLargeChange)
         Console.WriteLine("AutoScrollMinSize {0}", viewer.AutoScrollMinSize)
         Console.WriteLine("SmallScrollChangeRatio {0}", viewer.SmallScrollChangeRatio)
         Console.WriteLine("HScroll {0}", viewer.HScroll)
         Console.WriteLine("VScroll {0}", viewer.VScroll)
         Console.WriteLine("")

         myHScroll.Enabled = viewer.HScroll
         myVScroll.Enabled = viewer.VScroll
      End If
      MyBase.OnSizeChanged(e)
   End Sub

End Class

Public Sub RasterImageViewer_HScroll(ByVal title As String)
   Dim form As MyForm3 = New MyForm3(title)
   form.ShowDialog()
End Sub
C#Copy Code
class MyForm3 : Form 
{ 
   public RasterImageViewer viewer; 
   Panel panel; 
   HScrollBar hScroll; 
   VScrollBar vScroll; 
   public MyForm3(string title) 
   { 
      Text = title; 
 
      Size = new Size(750, 450); 
 
      panel = new Panel(); 
      panel.Dock = DockStyle.Fill; 
      Controls.Add(panel); 
 
      // Create the raster viewer 
      viewer = new RasterImageViewer(); 
      viewer.Dock = DockStyle.Fill; 
      viewer.Width = 500; 
      viewer.DoubleBuffer = true; 
      panel.Controls.Add(viewer); 
 
      // Load an image into the viewer 
      RasterCodecs.Startup(); 
      RasterCodecs codecs = new RasterCodecs(); 
      viewer.Image = codecs.Load(@"C:\Program Files\LEAD Technologies\LEADTOOLS 15\Images\Sample1.cmp"); 
      codecs.Dispose(); 
      RasterCodecs.Shutdown(); 
 
      viewer.AutoScroll = false; 
      Size size = viewer.AutoScrollMinSize; 
 
      // Create two scrollbar controls for scrolling 
 
      hScroll = new HScrollBar(); 
      hScroll.Location = new Point(100, 50); 
      hScroll.Dock = DockStyle.Top; 
      hScroll.Height *= 2; 
      hScroll.Minimum = 0; 
      hScroll.Maximum = viewer.Image.Width; 
      hScroll.ValueChanged += new EventHandler(hScroll_ValueChanged); 
      panel.Controls.Add(hScroll); 
      hScroll.BringToFront(); 
 
      vScroll = new VScrollBar(); 
      vScroll.Dock = DockStyle.Left; 
      vScroll.Location = new Point(100, 100); 
      vScroll.Width *= 2; 
      vScroll.Minimum = 0; 
      vScroll.Maximum = viewer.Image.Height; 
      vScroll.ValueChanged += new EventHandler(vScroll_ValueChanged); 
      panel.Controls.Add(vScroll); 
      vScroll.BringToFront(); 
 
      viewer.BringToFront(); 
 
      OnSizeChanged(EventArgs.Empty); 
   } 
 
   void vScroll_ValueChanged(object sender, EventArgs e) 
   { 
      viewer.ScrollPosition = new Point(hScroll.Value, vScroll.Value); 
   } 
 
   void hScroll_ValueChanged(object sender, EventArgs e) 
   { 
      viewer.ScrollPosition = new Point(hScroll.Value, vScroll.Value); 
   } 
 
   protected override void OnSizeChanged(EventArgs e) 
   { 
      if((hScroll != null) && (vScroll != null)) 
      { 
         hScroll.SmallChange = viewer.AutoScrollSmallChange.Width; 
         hScroll.LargeChange = viewer.AutoScrollLargeChange.Width; 
         vScroll.SmallChange = viewer.AutoScrollSmallChange.Height; 
         vScroll.LargeChange = viewer.AutoScrollLargeChange.Height; 
 
         Console.WriteLine("AutoScrollSmallChange  {0}", viewer.AutoScrollSmallChange); 
         Console.WriteLine("AutoScrollLargeChange  {0}", viewer.AutoScrollLargeChange); 
         Console.WriteLine("AutoScrollMinSize      {0}", viewer.AutoScrollMinSize); 
         Console.WriteLine("SmallScrollChangeRatio {0}", viewer.SmallScrollChangeRatio); 
         Console.WriteLine("HScroll                {0}", viewer.HScroll); 
         Console.WriteLine("VScroll                {0}", viewer.VScroll); 
         Console.WriteLine(""); 
 
         hScroll.Enabled = viewer.HScroll; 
         vScroll.Enabled = viewer.VScroll; 
      } 
      base.OnSizeChanged(e); 
   } 
 
} 
 
public void RasterImageViewer_HScroll(string title) 
{ 
   MyForm3 form = new MyForm3(title); 
   form.ShowDialog(); 
}

Remarks

A small scroll (or a line scroll) occurs when the user clicks an arrow.

Requirements

Target Platforms: Microsoft .NET Framework 2.0, Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also