Untitled

private void Button1Click(object sender, RoutedEventArgs e)
{
    Point relativePoint = buttonAnimation.TransformToVisual(CanvasAnimation).Transform(new Point(0, 0));

    var initialLeft = Canvas.GetLeft(rectAnimation);
    var initialTop = Canvas.GetTop(rectAnimation);

    var canvasWidth = myCanvas.ActualWidth;
    var canvasHeight = myCanvas.ActualHeight;

    var rectWidth = rectAnimation.ActualWidth;
    var rectHeight = rectAnimation.ActualHeight;

    var finalLeft = canvasWidth - rectWidth;
    var finalTop = canvasHeight - rectHeight;

    var displacementX = finalLeft - initialLeft;
    var displacementY = finalTop - initialTop;

    var moveAnimX = new DoubleAnimation(initialLeft, initialLeft + displacementX, new Duration(TimeSpan.FromSeconds(1)));
    var moveAnimY = new DoubleAnimation(initialTop, initialTop + displacementY, new Duration(TimeSpan.FromSeconds(1)));

    rectAnimation.BeginAnimation(Canvas.LeftProperty, moveAnimX);
    rectAnimation.BeginAnimation(Canvas.TopProperty, moveAnimY);
}