public boolean contains(float x, float y) {
        return left < right && bottom < top // check for empty first
                && x >= left && x < right && y >= bottom && y < top;
    }
Returns true if (x,y) is inside the viewport. The left and top are considered to be inside, while the right and
bottom are not. This means that for a x,y to be contained: {@code left <= x < right and bottom <= y < top}. An
empty viewport never contains any point.

@param x The X coordinate of the point being tested for containment
@param y The Y coordinate of the point being tested for containment
@return true iff (x,y) are contained by the viewport, where containment means {@code left <= x < right and top <=
y < bottom}
hellocharts-library/src/lecho/lib/hellocharts/model/Viewport.java