public static void addOverlay(Canvas canvas)
{
if (viewportLayer != null)
{
removeOverlay();
}
viewportLayer = new Image();
lineLayer = new Image();
currentCanvas = canvas;
UIElementCollection children = canvas.Children;
canvas.Children.Add(viewportLayer);
canvas.Children.Add(lineLayer);
for (int i = 0; i < canvas.Children.Count - 2; i++)
{
System.Windows.UIElement element = children.ElementAt(0);
canvas.Children.Remove(element);
canvas.Children.Add(element);
}
updateOverlay();
addAnimation();
checkTimer = new DispatcherTimer();
checkTimer.Interval = TimeSpan.FromSeconds(0.2);
checkTimer.Tick += delegate
{
checkChange();
};
checkTimer.Start();
}