package com.onaro.util.chart;

import ilog.views.chart.IlvDisplayPoint;
import ilog.views.chart.IlvStyle;
import ilog.views.chart.event.ChartHighlightInteractionEvent;
import ilog.views.chart.event.ChartInteractionEvent;
import ilog.views.chart.event.ChartInteractionListener;
import ilog.views.chart.graphic.IlvDataRenderingHint;



/**
 * Associates a <code>HighlightHint</code> with the current highlighted point.
 * This listener will be notified each time the highlighted state of
 * a data point changes.
 */
public class HighlightListener implements ChartInteractionListener {
    /**
     * The rendering hint used to set a patterned style.
     */
    IlvDataRenderingHint highlightHint = new HighlightHint();

    /**
     * Called when an interaction has been performed.
     */
    public void interactionPerformed(ChartInteractionEvent evt) {
        // The IlvChartHighlightInteractor fires a specific type of event
        // to get information on the highlighted state of the point.
        ChartHighlightInteractionEvent hevt = (ChartHighlightInteractionEvent) evt;
        IlvDisplayPoint dp = hevt.getDisplayPoint();
        if (hevt.isHighlighted()) {
            // A new point has been highlighted. In this case, we set a
            // rendering hint only for this given data point. This rendering hint
            // will be used each time the data point is drawn by the renderer.
            // Moreover, a data label annotation is set to display the data value.
            dp.getRenderer().setRenderingHint(dp.getDataSet(), dp.getIndex(), highlightHint);
        } else {
            // A previously highlighted point has been unselected. We remove the
            // rendering hint and data annotation previously set.
            dp.getRenderer().setRenderingHint(dp.getDataSet(), dp.getIndex(), null);
        }
    }

    /**
     * A rendering hint associated with highlighted data points.
     */
    private static class HighlightHint implements IlvDataRenderingHint {
        IlvStyle.Change change = new IlvStyle.IntensityChange(1);

        /**
         * Returns the rendering style used to display the specified display point.
         * This implementation returns a brighter version of the default style.
         */
        public IlvStyle getStyle(IlvDisplayPoint dp, IlvStyle defaultStyle) {
            return change.change(defaultStyle);
        }
    }
}