/// <summary>
/// Update ellipse with the most recent touch device data. If an ellipse has not
/// been created yet, create one.
/// </summary>
/// <param name="touchDevice">the touch device to diagram</param>
private void UpdateEllipse(TouchDevice touchDevice)
{
UIElement relativeTo = this;
// Create an ellipse if one does not exist already.
if (twoToneEllipse == null)
{
// Request an ellipse with the proper dimensions and RenderTransform.
twoToneEllipse = touchDevice.GetEllipse(relativeTo);
// Give the ellipse a two color fill.
LinearGradientBrush twoToneBrush = new LinearGradientBrush();
twoToneBrush.StartPoint = new Point(1.0, 0.5);
twoToneBrush.EndPoint = new Point(0.0, 0.5);
GradientStopCollection gradientStops = new GradientStopCollection();
gradientStops.Add(new GradientStop(Color.FromArgb(0xFF, 0xF1, 0x57, 0x27), 0.49));
gradientStops.Add(new GradientStop(Color.FromArgb(0xFF, 0xF3, 0x7A, 0x53), 0.51));
twoToneBrush.GradientStops = gradientStops;
twoToneEllipse.Fill = twoToneBrush;
// Add the ellipse to the MainCanvas.
MainCanvas.Children.Add(twoToneEllipse);
// Give the Ellipse a lower ZIndex than the ConnectingLine and Description
// so it is not drawn on top of them.
Canvas.SetZIndex(twoToneEllipse, -1);
}
else
{
// This diagram already has an ellipse. Update the existing ellipse
// dimensions and RenderTransform so the shape will match the touchDevice.
touchDevice.UpdateEllipse(twoToneEllipse, relativeTo);
}
}
