/// <summary>
/// Update the bounding rectangle with the most recent touch device info. If a
/// rectangle has not been created yet, create one.
/// </summary>
/// <param name="touchDevice">the touch device to diagram</param>
/// <param name="showBoundingRectangle">Whether or not the rectangle should be shown</param>
private void UpdateRectangle(TouchDevice touchDevice, bool showBoundingRectangle)
{
// Create an rectangle if one does not exist already.
if(boundingRectangle == null)
{
// Make a new Rectangle
boundingRectangle = new Rectangle();
// Give the rectangle a fill.
boundingRectangle.Fill = new SolidColorBrush(Color.FromArgb(0xFF, 0xE6, 0xE6, 0xE6));
// Add the rectangle to the MainCanvas.
MainCanvas.Children.Add(boundingRectangle);
// Give the rectangle a lower ZIndex than everything else on the main canvas
// so it is not drawn on top of anything else
Canvas.SetZIndex(boundingRectangle, int.MinValue );
}
// Get the bounding rect for the touchDevice
Rect touchDeviceRect = touchDevice.GetBounds(this);
Rect bounds = new Rect(touchDeviceRect.X, touchDeviceRect.Y, touchDeviceRect.Width, touchDeviceRect.Height);
// Update the properties of boundingRectangle
boundingRectangle.Height = bounds.Height;
boundingRectangle.Width = bounds.Width;
Canvas.SetLeft(boundingRectangle, bounds.Left);
Canvas.SetTop(boundingRectangle, bounds.Top);
// Hide the rectangle if the user does not want to view bounding rectangles
boundingRectangle.Visibility = showBoundingRectangle ? Visibility.Visible : Visibility.Hidden;
}
