package de.intevation.flys.jfree;

import de.intevation.flys.artifacts.math.Function;

import java.awt.Shape;

import java.awt.geom.Rectangle2D;

import java.util.Iterator;

import org.jfree.chart.entity.ChartEntity;
import org.jfree.chart.entity.EntityCollection;

import org.w3c.dom.Document;

public class JFreeUtil {

    /** Do not instantiate. */
    private JFreeUtil() {
    }


    /**
     * True if \param hotspot collides with a Entity in \param entities.
     * @param hotspot Shape to compare against other shapes (bounds only).
     * @param entities entities against which to compare shape.
     * @param exclusiveEntityClass If not null, consider only entities of
     *        given class.
     * @return true if a collision (non-zero intersection) exists between
     *        shapes.
     */
    public static boolean collides(Shape hotspot, EntityCollection entities,
        Class exclusiveEntityClass) {
        if (entities == null) return false;

        Rectangle2D hotspotBox = hotspot.getBounds2D();

        for (Iterator i = entities.iterator(); i.hasNext(); ) {
            Object next = i.next();
            ChartEntity entity = (ChartEntity) next;
            if (exclusiveEntityClass == null
                || exclusiveEntityClass.isInstance(entity))
                {
                if (entity.getArea().intersects(hotspotBox)) {
                    // Found collision, early stop.
                    return true;
                }
            }
        }

        return false;
    }


    public static StyledXYSeries sampleFunction2D(
        Function func,
        Document theme,
        String   seriesKey,
        int      samples,
        double   start,
        double   end
    ) {
        StyledXYSeries series = new StyledXYSeries(seriesKey, theme);

        double step = (end - start) / (samples - 1);

        for (int i = 0; i < samples; i++) {
            double x = start + (step * i);
            series.add(x, func.value(x));
        }

        return series;
    }
}
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