public void setIntervalPositionFactor(double d) {
        this.intervalDelegate.setIntervalPositionFactor(d);
        fireDatasetChanged();
    }

    /**
     * returns the full interval width.
     *
     * @return The interval width to use.
     */
    public double getIntervalWidth() {
        return this.intervalDelegate.getIntervalWidth();
    }

    /**
     * Sets the interval width to a fixed value, and sends a
     * {@link DatasetChangeEvent} to all registered listeners.
     *
     * @param d  the new interval width (must be > 0).
     */
    public void setIntervalWidth(double d) {
        this.intervalDelegate.setFixedIntervalWidth(d);
        fireDatasetChanged();
    }

    /**
     * Returns whether the interval width is automatically calculated or not.
     *
     * @return A flag that determines whether or not the interval width is
     *         automatically calculated.
     */
    public boolean isAutoWidth() {
        return this.intervalDelegate.isAutoWidth();
    }

    /**
     * Sets the flag that indicates whether the interval width is automatically
     * calculated or not.
     *
     * @param b  a boolean.
     */
    public void setAutoWidth(boolean b) {
        this.intervalDelegate.setAutoWidth(b);
        fireDatasetChanged();