public boolean contains(Viewport v) {
        // check for empty first
        return this.left < this.right && this.bottom < this.top
                // now check for containment
                && left <= v.left && top >= v.top && right >= v.right && bottom <= v.bottom;
    }
Returns true iff the specified viewport r is inside or equal to this viewport. An empty viewport never contains
another viewport.

@param v The viewport being tested for containment.
@return true iff the specified viewport r is inside or equal to this viewport
hellocharts-library/src/lecho/lib/hellocharts/model/Viewport.java