* Registered listeners are notified that the axis has been modified, but
     * only if the crosshair is visible.
     *
     * @param value  the new value.
     * @param notify  a flag that controls whether or not listeners are 
     *                notified.
     */
    public void setRangeCrosshairValue(double value, boolean notify) {

        this.rangeCrosshairValue = value;
        if (isRangeCrosshairVisible() && notify) {
            notifyListeners(new PlotChangeEvent(this));
        }

    }

    /**
     * Returns the Stroke used to draw the crosshair (if visible).
     *
     * @return The crosshair stroke.
     */
    public Stroke getRangeCrosshairStroke() {
        return this.rangeCrosshairStroke;
    }

    /**
     * Sets the Stroke used to draw the crosshairs (if visible) and notifies
     * registered listeners that the axis has been modified.
     *
     * @param stroke  the new crosshair stroke.
     */
    public void setRangeCrosshairStroke(Stroke stroke) {
        this.rangeCrosshairStroke = stroke;
        notifyListeners(new PlotChangeEvent(this));
    }

    /**
     * Returns the range crosshair color.
     *
     * @return The crosshair color.
     */
    public Paint getRangeCrosshairPaint() {
        return this.rangeCrosshairPaint;
    }

    /**
     * Sets the Paint used to color the crosshairs (if visible) and notifies
     * registered listeners that the axis has been modified.
     *
     * @param paint the new crosshair paint.
     */
    public void setRangeCrosshairPaint(Paint paint) {
        this.rangeCrosshairPaint = paint;
        notifyListeners(new PlotChangeEvent(this));
    }

    /**
     * Returns the tool tip generator.
     *
     * @return The tool tip generator (possibly null).
     */
    public ContourToolTipGenerator getToolTipGenerator() {
        return this.toolTipGenerator;
    }

    /**
     * Sets the tool tip generator.
     *
     * @param generator  the tool tip generator (null permitted).
     */
    public void setToolTipGenerator(ContourToolTipGenerator generator) {

        //Object oldValue = this.toolTipGenerator;
        this.toolTipGenerator = generator;

    }

    /**
     * Returns the URL generator for HTML image maps.
     *
     * @return The URL generator (possibly null).
     */
    public XYURLGenerator getURLGenerator() {
        return this.urlGenerator;
    }

    /**
     * Sets the URL generator for HTML image maps.
     *
     * @param urlGenerator  the URL generator (null permitted).
     */
    public void setURLGenerator(XYURLGenerator urlGenerator) {

        //Object oldValue = this.urlGenerator;
        this.urlGenerator = urlGenerator;

    }

    /**
     * Draws a vertical line on the chart to represent a 'range marker'.
     *
     * @param g2  the graphics device.
     * @param plot  the plot.
     * @param domainAxis  the domain axis.
     * @param marker  the marker line.
     * @param dataArea  the axis data area.
     */
    public void drawDomainMarker(Graphics2D g2,
                                 ContourPlot plot,
                                 ValueAxis domainAxis,
                                 Marker marker,
                                 Rectangle2D dataArea) {

        if (marker instanceof ValueMarker) {
            ValueMarker vm = (ValueMarker) marker;
            double value = vm.getValue();
            Range range = domainAxis.getRange();
            if (!range.contains(value)) {
                return;
            }
  
            double x = domainAxis.valueToJava2D(
                value, dataArea, RectangleEdge.BOTTOM
            );
            Line2D line = new Line2D.Double(
                x, dataArea.getMinY(), x, dataArea.getMaxY()
            );
            Paint paint = marker.getOutlinePaint();
            Stroke stroke = marker.getOutlineStroke();
            g2.setPaint(paint != null ? paint : Plot.DEFAULT_OUTLINE_PAINT);
            g2.setStroke(stroke != null ? stroke : Plot.DEFAULT_OUTLINE_STROKE);
            g2.draw(line);
        }

    }

    /**
     * Draws a horizontal line across the chart to represent a 'range marker'.
     *
     * @param g2  the graphics device.
     * @param plot  the plot.
     * @param rangeAxis  the range axis.
     * @param marker  the marker line.
     * @param dataArea  the axis data area.
     */
    public void drawRangeMarker(Graphics2D g2,
                                ContourPlot plot,
                                ValueAxis rangeAxis,
                                Marker marker,
                                Rectangle2D dataArea) {

        if (marker instanceof ValueMarker) {
            ValueMarker vm = (ValueMarker) marker;
            double value = vm.getValue();
            Range range = rangeAxis.getRange();
            if (!range.contains(value)) {
                return;
            }

            double y = rangeAxis.valueToJava2D(
                value, dataArea, RectangleEdge.LEFT
            );
            Line2D line = new Line2D.Double(
                dataArea.getMinX(), y, dataArea.getMaxX(), y
            );
            Paint paint = marker.getOutlinePaint();
            Stroke stroke = marker.getOutlineStroke();
            g2.setPaint(paint != null ? paint : Plot.DEFAULT_OUTLINE_PAINT);
            g2.setStroke(stroke != null ? stroke : Plot.DEFAULT_OUTLINE_STROKE);
            g2.draw(line);
        }

    }

    /**
     * Returns the clipPath.
     * @return ClipPath
     */
    public ClipPath getClipPath() {
        return this.clipPath;
    }

    /**
     * Sets the clipPath.
     * @param clipPath The clipPath to set
     */
    public void setClipPath(ClipPath clipPath) {
        this.clipPath = clipPath;
    }

    /**
     * Returns the ptSizePct.
     * @return double
     */
    public double getPtSizePct() {
        return this.ptSizePct;
    }

    /**
     * Returns the renderAsPoints.
     * @return boolean
     */
    public boolean isRenderAsPoints() {
        return this.renderAsPoints;
    }

    /**
     * Sets the ptSizePct.
     * @param ptSizePct The ptSizePct to set
     */
    public void setPtSizePct(double ptSizePct) {
        this.ptSizePct = ptSizePct;
    }

    /**
     * Sets the renderAsPoints.
     * @param renderAsPoints The renderAsPoints to set
     */
    public void setRenderAsPoints(boolean renderAsPoints) {
        this.renderAsPoints = renderAsPoints;
    }

    /**
     * Receives notification of a change to one of the plot's axes.
     *
     * @param event  information about the event.
     */
    public void axisChanged(AxisChangeEvent event) {
        Object source = event.getSource();
        if (source.equals(this.rangeAxis) || source.equals(this.domainAxis)) {
            ColorBar cba = this.colorBar;
            if (this.colorBar.getAxis().isAutoRange()) {
                cba.getAxis().configure();
            }

        }
        super.axisChanged(event);
    }

    /**
     * Returns the visible z-range.
     *
     * @param data  the dataset.
     * @param x  the x range.
     * @param y  the y range.
     *
     * @return The range.
     */
    public Range visibleRange(ContourDataset data, Range x, Range y) {
        Range range = null;
        range = data.getZValueRange(x, y);
        return range;
    }

    /**
     * Returns the missingPaint.
     * @return Paint
     */
    public Paint getMissingPaint() {
        return this.missingPaint;
    }

    /**
     * Sets the missingPaint.
     * 
     * @param paint  the missingPaint to set.
     */
    public void setMissingPaint(Paint paint) {
        this.missingPaint = paint;
    }
    
    /**
     * Multiplies the range on the domain axis/axes by the specified factor 
     * (to be implemented).
     * 
     * @param x  the x-coordinate (in Java2D space).
     * @param y  the y-coordinate (in Java2D space).
     * @param factor  the zoom factor.
     */
    public void zoomDomainAxes(double x, double y, double factor) {
        // TODO: to be implemented
    }
    
    /**
     * Zooms the domain axes (not yet implemented).
     * 
     * @param x  the x-coordinate (in Java2D space).
     * @param y  the y-coordinate (in Java2D space).
     * @param lowerPercent  the new lower bound.
     * @param upperPercent  the new upper bound.
     */
    public void zoomDomainAxes(double x, double y, double lowerPercent, 
                               double upperPercent) {
        // TODO: to be implemented
    }
    
    /**
     * Multiplies the range on the range axis/axes by the specified factor.
     * 
     * @param x  the x-coordinate (in Java2D space).
     * @param y  the y-coordinate (in Java2D space).
     * @param factor  the zoom factor.
     */
    public void zoomRangeAxes(double x, double y, double factor) {
        // TODO: to be implemented
    }

    /**
     * Zooms the range axes (not yet implemented).
     * 
     * @param x  the x-coordinate (in Java2D space).
     * @param y  the y-coordinate (in Java2D space).
     * @param lowerPercent  the new lower bound.
     * @param upperPercent  the new upper bound.
     */
    public void zoomRangeAxes(double x, double y, double lowerPercent, 
                              double upperPercent) {
        // TODO: to be implemented
    }

    /**
     * Returns <code>false</code>.
     * 
     * @return A boolean.
     */
    public boolean isDomainZoomable() {
        return false;
    }
    
    /**
     * Returns <code>false</code>.
     * 
     * @return A boolean.
     */
    public boolean isRangeZoomable() {
        return false;
    }

    /** 
     * Extends plot cloning to this plot type
     * @see org.jfree.chart.plot.Plot#clone()
     */
    public Object clone() throws CloneNotSupportedException {
        ContourPlot clone = (ContourPlot) super.clone();
        
        if (this.domainAxis != null) {
            clone.domainAxis = (ValueAxis) this.domainAxis.clone();
            clone.domainAxis.setPlot(clone);
            clone.domainAxis.addChangeListener(clone);
        }
        if (this.rangeAxis != null) {
            clone.rangeAxis = (ValueAxis) this.rangeAxis.clone();
            clone.rangeAxis.setPlot(clone);
            clone.rangeAxis.addChangeListener(clone);
        }

        if (clone.dataset != null) {
            clone.dataset.addChangeListener(clone); 
        }
    
        if (this.colorBar != null) {
            clone.colorBar = (ColorBar) this.colorBar.clone();
        }

        clone.domainMarkers = (List) ObjectUtilities.deepClone(
            this.domainMarkers
        );
        clone.rangeMarkers = (List) ObjectUtilities.deepClone(
            this.rangeMarkers
        );
        clone.annotations = (List) ObjectUtilities.deepClone(this.annotations);

        if (this.clipPath != null) {
            clone.clipPath = (ClipPath) this.clipPath.clone(); 
        }

        return clone;
    }

}