Manipulation event on canvas
private void Canvas1_ManipulationDelta(object sender, ManipulationDeltaEventArgs e)
    {
        Canvas CSender = (Canvas)sender;
        ScaleTransform scale = (ScaleTransform)CSender.RenderTransform;

        if ((e.DeltaManipulation.Translation.X != 0 || e.DeltaManipulation.Translation.Y != 0) && (scale.ScaleX != 1 || scale.ScaleY != 1))
        {

            scale.CenterX -= e.DeltaManipulation.Translation.X;
            scale.CenterY -= e.DeltaManipulation.Translation.Y;

        }
        else if (e.DeltaManipulation.Scale.X != 0 || e.DeltaManipulation.Scale.Y != 0)
        {
            double factor = (e.DeltaManipulation.Scale.X >= e.DeltaManipulation.Scale.Y) ? e.DeltaManipulation.Scale.X : e.DeltaManipulation.Scale.Y;

            if (e.CumulativeManipulation.Scale.X == 1 && e.CumulativeManipulation.Scale.Y == 1)
            {
                scale.CenterX -= e.DeltaManipulation.Translation.X;
                scale.CenterY -= e.DeltaManipulation.Translation.Y;

            }
            if (scale.ScaleX * factor <= MIN_ZOOM || scale.ScaleY * factor <= MIN_ZOOM)
            {
                scale.ScaleX = MIN_ZOOM;
                scale.ScaleY = MIN_ZOOM;
                foreach (Rectangles R in RectanglesList)
                {
                    R.X = R.X* scale.ScaleX;
                    R.Y = R.Y* scale.ScaleY;
                }

            }

            else if (scale.ScaleX * factor >= MAX_ZOOM || scale.ScaleY * factor >= MAX_ZOOM)
            {
                scale.ScaleX = MAX_ZOOM;
                scale.ScaleY = MAX_ZOOM;

                foreach (Rectangles R in RectanglesList)
                {
                    R.X = R.X * scale.ScaleX;
                    R.Y = R.Y * scale.ScaleY;
                }
            }
            else
            {
                scale.ScaleX *= factor;
                scale.ScaleY *= factor;
                foreach (Rectangles R in RectanglesList)
                {
                    R.X = R.X * scale.ScaleX;
                    R.Y = R.Y * scale.ScaleY;
                }
           }
        }