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PaintGamma Property
See Also 
Leadtools Namespace > RasterImage Class : PaintGamma Property



Gets or sets the current gamma correction value for the image.

Syntax

Visual Basic (Declaration) 
Public Property PaintGamma As Integer
Visual Basic (Usage)Copy Code
Dim instance As RasterImage
Dim value As Integer
 
instance.PaintGamma = value
 
value = instance.PaintGamma
C# 
public int PaintGamma {get; set;}
C++/CLI 
public:
property int PaintGamma {
   int get();
   void set (    int value);
}

Property Value

The current gamma correction value.

Example

Visual BasicCopy Code
Public Sub IntensityExample()
      Dim f As IntensityForm = New IntensityForm()
      f.ShowDialog()
   End Sub

   Private Class IntensityForm : Inherits Form
      Private viewer As RasterImageViewer
      Private gammaTrackBar As TrackBar
      Private contrastTrackBar As TrackBar
      Private intensityTrackBar As TrackBar

      Public Sub New()
         ' Create the controls
         Size = New Size(800, 600)
         Dim controlsPanel As Panel = New Panel()
         controlsPanel.Size = New Size(400, 0)
         controlsPanel.BorderStyle = BorderStyle.Fixed3D
         controlsPanel.Dock = DockStyle.Left

         Dim labelLeft As Integer = 8
         Dim y As Integer = 16
         Dim trackBarLeft As Integer = 100

         Dim gammaLabel As Label = New Label()
         gammaLabel.Text = "Gamma:"
         gammaLabel.Location = New Point(labelLeft, y)
         gammaLabel.AutoSize = True
         controlsPanel.Controls.Add(gammaLabel)

         gammaTrackBar = New TrackBar()
         gammaTrackBar.Minimum = 1
         gammaTrackBar.Maximum = 100
         gammaTrackBar.TickFrequency = (gammaTrackBar.Maximum - gammaTrackBar.Minimum) \ 10
         gammaTrackBar.Location = New Point(trackBarLeft, y)
         gammaTrackBar.Width = 200
         AddHandler gammaTrackBar.Scroll, AddressOf gammaTrackBar_Scroll
         controlsPanel.Controls.Add(gammaTrackBar)
         gammaLabel.Top = gammaTrackBar.Top + (gammaTrackBar.Height - gammaLabel.Height) \ 2
         y = gammaTrackBar.Bottom + 8

         Dim contrastLabel As Label = New Label()
         contrastLabel.Text = "Contrast:"
         contrastLabel.Location = New Point(labelLeft, y)
         contrastLabel.AutoSize = True
         controlsPanel.Controls.Add(contrastLabel)

         contrastTrackBar = New TrackBar()
         contrastTrackBar.Minimum = -1000
         contrastTrackBar.Maximum = 1000
         contrastTrackBar.TickFrequency = (contrastTrackBar.Maximum - contrastTrackBar.Minimum) \ 10
         contrastTrackBar.Location = New Point(trackBarLeft, y)
         contrastTrackBar.Width = 200
         AddHandler contrastTrackBar.Scroll, AddressOf contrastTrackBar_Scroll
         controlsPanel.Controls.Add(contrastTrackBar)
         contrastLabel.Top = contrastTrackBar.Top + (contrastTrackBar.Height - contrastLabel.Height) \ 2
         y = contrastTrackBar.Bottom + 8

         Dim intensityLabel As Label = New Label()
         intensityLabel.Text = "Intensity:"
         intensityLabel.Location = New Point(labelLeft, y)
         intensityLabel.AutoSize = True
         controlsPanel.Controls.Add(intensityLabel)
         y = intensityLabel.Bottom + 8

         intensityTrackBar = New TrackBar()
         intensityTrackBar.Minimum = -1000
         intensityTrackBar.Maximum = 1000
         intensityTrackBar.TickFrequency = (intensityTrackBar.Maximum - intensityTrackBar.Minimum) \ 10
         intensityTrackBar.Location = New Point(trackBarLeft, y)
         intensityTrackBar.Width = 200
         AddHandler intensityTrackBar.Scroll, AddressOf intensityTrackBar_Scroll
         controlsPanel.Controls.Add(intensityTrackBar)
         intensityLabel.Top = intensityTrackBar.Top + (intensityTrackBar.Height - intensityLabel.Height) \ 2
         y = intensityTrackBar.Bottom + 8

         Dim defaultButton As Button = New Button()
         defaultButton.Text = "Default"
         defaultButton.Location = New Point(labelLeft, y)
         AddHandler defaultButton.Click, AddressOf defaultButton_Click
         controlsPanel.Controls.Add(defaultButton)

         Controls.Add(controlsPanel)

         viewer = New RasterImageViewer()
         viewer.Dock = DockStyle.Fill
         Controls.Add(viewer)
         viewer.SizeMode = RasterPaintSizeMode.Fit
         viewer.BringToFront()

         ' Load the image
         Dim codecs As RasterCodecs = New RasterCodecs()

         Dim srcFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp")
         viewer.Image = codecs.Load(srcFileName)

         codecs.Dispose()

         gammaTrackBar.Value = viewer.Image.PaintGamma
         contrastTrackBar.Value = viewer.Image.PaintContrast
         intensityTrackBar.Value = viewer.Image.PaintIntensity
         UpdateValues()
      End Sub

      Private Sub UpdateValues()
         Dim str As String = String.Format("Gamma = {0}, Contrast = {1}, Intensity = {2}", viewer.Image.PaintGamma, viewer.Image.PaintContrast, viewer.Image.PaintIntensity)
         Text = str
      End Sub

      Private Sub gammaTrackBar_Scroll(ByVal sender As Object, ByVal e As EventArgs)
         Dim tb As TrackBar = CType(IIf(TypeOf sender Is TrackBar, sender, Nothing), TrackBar)
         viewer.Image.PaintGamma = tb.Value
         UpdateValues()
      End Sub

      Private Sub contrastTrackBar_Scroll(ByVal sender As Object, ByVal e As EventArgs)
         Dim tb As TrackBar = CType(IIf(TypeOf sender Is TrackBar, sender, Nothing), TrackBar)
         viewer.Image.PaintContrast = tb.Value
         UpdateValues()
      End Sub

      Private Sub intensityTrackBar_Scroll(ByVal sender As Object, ByVal e As EventArgs)
         Dim tb As TrackBar = CType(IIf(TypeOf sender Is TrackBar, sender, Nothing), TrackBar)
         viewer.Image.PaintIntensity = tb.Value
         UpdateValues()
      End Sub

      Private Sub defaultButton_Click(ByVal sender As Object, ByVal e As EventArgs)
         viewer.Image.PaintGamma = 100
         viewer.Image.PaintIntensity = 0
         viewer.Image.PaintContrast = 0

         gammaTrackBar.Value = viewer.Image.PaintGamma
         contrastTrackBar.Value = viewer.Image.PaintContrast
         intensityTrackBar.Value = viewer.Image.PaintIntensity

         UpdateValues()
      End Sub
   End Class

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class
C#Copy Code
public void IntensityExample()
   {
      IntensityForm f = new IntensityForm();
      f.ShowDialog();
   }
   class IntensityForm : Form
   {
      RasterImageViewer viewer;
      TrackBar gammaTrackBar;
      TrackBar contrastTrackBar;
      TrackBar intensityTrackBar;

      public IntensityForm()
      {
         // Create the controls
         Size = new Size(800, 600);
         Panel controlsPanel = new Panel();
         controlsPanel.Size = new Size(400, 0);
         controlsPanel.BorderStyle = BorderStyle.Fixed3D;
         controlsPanel.Dock = DockStyle.Left;

         int labelLeft = 8;
         int y = 16;
         int trackBarLeft = 100;

         Label gammaLabel = new Label();
         gammaLabel.Text = "Gamma:";
         gammaLabel.Location = new Point(labelLeft, y);
         gammaLabel.AutoSize = true;
         controlsPanel.Controls.Add(gammaLabel);

         gammaTrackBar = new TrackBar();
         gammaTrackBar.Minimum = 1;
         gammaTrackBar.Maximum = 100;
         gammaTrackBar.TickFrequency = (gammaTrackBar.Maximum - gammaTrackBar.Minimum) / 10;
         gammaTrackBar.Location = new Point(trackBarLeft, y);
         gammaTrackBar.Width = 200;
         gammaTrackBar.Scroll += new EventHandler(gammaTrackBar_Scroll);
         controlsPanel.Controls.Add(gammaTrackBar);
         gammaLabel.Top = gammaTrackBar.Top + (gammaTrackBar.Height - gammaLabel.Height) / 2;
         y = gammaTrackBar.Bottom + 8;

         Label contrastLabel = new Label();
         contrastLabel.Text = "Contrast:";
         contrastLabel.Location = new Point(labelLeft, y);
         contrastLabel.AutoSize = true;
         controlsPanel.Controls.Add(contrastLabel);

         contrastTrackBar = new TrackBar();
         contrastTrackBar.Minimum = -1000;
         contrastTrackBar.Maximum = 1000;
         contrastTrackBar.TickFrequency = (contrastTrackBar.Maximum - contrastTrackBar.Minimum) / 10;
         contrastTrackBar.Location = new Point(trackBarLeft, y);
         contrastTrackBar.Width = 200;
         contrastTrackBar.Scroll += new EventHandler(contrastTrackBar_Scroll);
         controlsPanel.Controls.Add(contrastTrackBar);
         contrastLabel.Top = contrastTrackBar.Top + (contrastTrackBar.Height - contrastLabel.Height) / 2;
         y = contrastTrackBar.Bottom + 8;

         Label intensityLabel = new Label();
         intensityLabel.Text = "Intensity:";
         intensityLabel.Location = new Point(labelLeft, y);
         intensityLabel.AutoSize = true;
         controlsPanel.Controls.Add(intensityLabel);
         y = intensityLabel.Bottom + 8;

         intensityTrackBar = new TrackBar();
         intensityTrackBar.Minimum = -1000;
         intensityTrackBar.Maximum = 1000;
         intensityTrackBar.TickFrequency = (intensityTrackBar.Maximum - intensityTrackBar.Minimum) / 10;
         intensityTrackBar.Location = new Point(trackBarLeft, y);
         intensityTrackBar.Width = 200;
         intensityTrackBar.Scroll += new EventHandler(intensityTrackBar_Scroll);
         controlsPanel.Controls.Add(intensityTrackBar);
         intensityLabel.Top = intensityTrackBar.Top + (intensityTrackBar.Height - intensityLabel.Height) / 2;
         y = intensityTrackBar.Bottom + 8;

         Button defaultButton = new Button();
         defaultButton.Text = "Default";
         defaultButton.Location = new Point(labelLeft, y);
         defaultButton.Click += new EventHandler(defaultButton_Click);
         controlsPanel.Controls.Add(defaultButton);

         Controls.Add(controlsPanel);

         viewer = new RasterImageViewer();
         viewer.Dock = DockStyle.Fill;
         Controls.Add(viewer);
         viewer.SizeMode = RasterPaintSizeMode.Fit;
         viewer.BringToFront();

         // Load the image
         RasterCodecs codecs = new RasterCodecs();

         string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp");
         viewer.Image = codecs.Load(srcFileName);

         codecs.Dispose();

         gammaTrackBar.Value = viewer.Image.PaintGamma;
         contrastTrackBar.Value = viewer.Image.PaintContrast;
         intensityTrackBar.Value = viewer.Image.PaintIntensity;
         UpdateValues();
      }

      void UpdateValues()
      {
         string str = string.Format(
            "Gamma = {0}, Contrast = {1}, Intensity = {2}",
            viewer.Image.PaintGamma, viewer.Image.PaintContrast, viewer.Image.PaintIntensity);
         Text = str;
      }

      void gammaTrackBar_Scroll(object sender, EventArgs e)
      {
         TrackBar tb = sender as TrackBar;
         viewer.Image.PaintGamma = tb.Value;
         UpdateValues();
      }

      void contrastTrackBar_Scroll(object sender, EventArgs e)
      {
         TrackBar tb = sender as TrackBar;
         viewer.Image.PaintContrast = tb.Value;
         UpdateValues();
      }

      void intensityTrackBar_Scroll(object sender, EventArgs e)
      {
         TrackBar tb = sender as TrackBar;
         viewer.Image.PaintIntensity = tb.Value;
         UpdateValues();
      }

      void defaultButton_Click(object sender, EventArgs e)
      {
         viewer.Image.PaintGamma = 100;
         viewer.Image.PaintIntensity = 0;
         viewer.Image.PaintContrast = 0;

         gammaTrackBar.Value = viewer.Image.PaintGamma;
         contrastTrackBar.Value = viewer.Image.PaintContrast;
         intensityTrackBar.Value = viewer.Image.PaintIntensity;

         UpdateValues();
      }
   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}
SilverlightCSharpCopy Code
SilverlightVBCopy Code

Remarks

The paint gamma value can be any number greater than 0. The default value is 100.

Because this is an unsigned integer, it is 100 times the actual gamma value. For example, use 235 to set a gamma value of 2.35. Intensity values ideally follow a logarithmic progression, because the eye perceives changes in intensity as being equal when the ratio of change is equal. For example, we would see a change from 0.1 to 0.2 as being equal to a change from 0.2 to 0.4.

Gamma is a standard constant that is used to calculate the progression. For most CRTs the gamma constant is in the range of 2.2 to 2.5.

For more information, refer to Changing Brightness and Contrast.

Requirements

Target Platforms: Silverlight, Windows XP, Windows Server 2003 family, Windows Server 2008 family, Windows Vista, Windows 7, MAC OS/X (Intel Only), Windows Phone 7

See Also