private void gradientToolStripMenuItem_Click(object sender, EventArgs e)
{
lastSelected = "gradient";
OnPaintAction = cr =>
{
Gradient pat = new LinearGradient(0.0, 0.0, 0.0, 256.0);
pat.AddColorStopRgba(1, 0, 0, 0, 1);
pat.AddColorStopRgba(0, 1, 1, 1, 1);
cr.Rectangle(0, 0, 256, 256);
cr.SetSource(pat);
cr.Fill();
pat.Dispose();
pat = new RadialGradient(115.2, 102.4, 25.6,
102.4, 102.4, 128.0);
pat.AddColorStopRgba(0, 1, 1, 1, 1);
pat.AddColorStopRgba(1, 0, 0, 0, 1);
cr.SetSource(pat);
cr.Arc(128.0, 128.0, 76.8, 0, 2 * Math.PI);
cr.Fill();
pat.Dispose();
};
Invalidate();
}