function fitRect(x, y, w, h) {
        
        // Calculate bounds
        var opBoundX = w + x;
        var opBoundY = h + y;
        
        // Determine max width
        var resizeWidth;
        if (opBoundX > layer.width)
            resizeWidth = opBoundX;
        else
            resizeWidth = layer.width;

        // Determine max height
        var resizeHeight;
        if (opBoundY > layer.height)
            resizeHeight = opBoundY;
        else
            resizeHeight = layer.height;

        // Resize if necessary
        layer.resize(resizeWidth, resizeHeight);

    }
Given the X and Y coordinates of the upper-left corner of a rectangle
and the rectangle's width and height, resize the backing canvas element
as necessary to ensure that the rectangle fits within the canvas
element's coordinate space. This function will only make the canvas
larger. If the rectangle already fits within the canvas element's
coordinate space, the canvas is left unchanged.

@private
@param {Number} x The X coordinate of the upper-left corner of the
                  rectangle to fit.
@param {Number} y The Y coordinate of the upper-left corner of the
                  rectangle to fit.
@param {Number} w The width of the the rectangle to fit.
@param {Number} h The height of the the rectangle to fit.