Contrast Effect

The Contrast effect can be used to increase or decrease the contrast of an image.

The value given is used to stretch the contrast within the image. Values greater than zero increase the amount of contrast while those less than zero decrease the contrast.

The following show the effect of increasing and decreasing contrast.

[C#]
void function() {
  using (Doc doc = new Doc()) {
    AddImagePage(doc, img2); // original image
    doc.Rendering.Save("EffectContrast.jpg");
    using (ImageLayer layer = AddImagePage(doc, img2)) {
      using (EffectOperation effect = new EffectOperation("Contrast")) {
        effect.Parameters["Amount"].Value = 25;
        effect.Apply(layer.PixMap);
      }
    }
    doc.Rendering.Save("EffectContrast25.jpg");
    using (ImageLayer layer = AddImagePage(doc, img2)) {
      using (EffectOperation effect = new EffectOperation("Contrast")) {
        effect.Parameters["Amount"].Value = 50;
        effect.Apply(layer.PixMap);
      }
    }
    doc.Rendering.Save("EffectContrast50.jpg");
    using (ImageLayer layer = AddImagePage(doc, img2)) {
      using (EffectOperation effect = new EffectOperation("Contrast")) {
        effect.Parameters["Amount"].Value = -50;
        effect.Apply(layer.PixMap);
      }
    }
    doc.Rendering.Save("EffectContrast-50.jpg");
  }
}

[Visual Basic]
Sub ...
  Using doc As New Doc()
    AddImagePage(doc, img2)
    ' original image
    doc.Rendering.Save("EffectContrast.jpg")
    Using layer As ImageLayer = AddImagePage(doc, img2)
      Using effect As New EffectOperation("Contrast")
        effect.Parameters("Amount").Value = 25
        effect.Apply(layer.PixMap)
      End Using
    End Using
    doc.Rendering.Save("EffectContrast25.jpg")
    Using layer As ImageLayer = AddImagePage(doc, img2)
      Using effect As New EffectOperation("Contrast")
        effect.Parameters("Amount").Value = 50
        effect.Apply(layer.PixMap)
      End Using
    End Using
    doc.Rendering.Save("EffectContrast50.jpg")
    Using layer As ImageLayer = AddImagePage(doc, img2)
      Using effect As New EffectOperation("Contrast")
        effect.Parameters("Amount").Value = -50
        effect.Apply(layer.PixMap)
      End Using
    End Using
    doc.Rendering.Save("EffectContrast-50.jpg")
  End Using
End Sub