public aa_test(ImageFormats format)
: base(format)
{
m_idx = (-1);
m_gamma = new AGG.UI.SliderWidget(3, 3, 480 - 3, 8);
m_x[0] = 100; m_y[0] = 100;
m_x[1] = 500; m_y[1] = 350;
AddChild(m_gamma);
m_gamma.label("gamma={0:F3}");
m_gamma.range(0.0, 3.0);
m_gamma.value(1.8);
}