/*
 * Copyright (c) 2010 by Intevation GmbH
 *
 * This program is free software under the LGPL (>=v2.1)
 * Read the file LGPL.txt coming with the software for details
 * or visit http://www.gnu.org/licenses/ if it does not exist.
 */

package de.intevation.gnv.jfreechart;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.Shape;

import java.awt.geom.GeneralPath;

import java.awt.geom.Rectangle2D.Double;

import java.awt.geom.Rectangle2D;

import java.util.ArrayList;

import org.apache.log4j.Logger;

import org.jfree.chart.axis.ValueAxis;

import org.jfree.data.Range;

import org.jfree.text.TextUtilities;

import org.jfree.ui.RectangleEdge;

/**
 * This renderer is used to draw polygons into a Graphics object.
 *
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
 */
public class PolygonRenderer
{
	private static Logger log = Logger.getLogger(
		PolygonRenderer.class);

        /**
         * This interfaces describes a single method to retrieve a Paint object
         * for a given index.
         */
        public interface PaintLookup {

            /**
             *
             * @param index Index.
             * @return Paint
             */
            Paint getPaint(int index);

    } // interface PaintLookup

        /**
         * This class is used to generate labels for a given series.
         */
        public static class DefaultLabelGenerator
    implements          PolygonSeriesLabelGenerator
    {
            /**
             * Construts an empty DefaultLabelGenerator.
             */
            public DefaultLabelGenerator() {
        }

            /**
             *
             * @param series A PolygonSeries.
             * @return The label of series.
             */
            public String generateLabel(PolygonSeries series) {
            Object label = series.getAttribute("label");
            return label != null
                ? toString(label)
                : null;
        }

            /**
             *
             * @param label Object
             * @return String representaton of label.
             */
            protected String toString(Object label) {
            return label.toString();
        }
    } // class DefaultLabelGenerator

        /**
         * Constructor.
         */
        public static final PolygonSeriesLabelGenerator
        DEFAULT_LABEL_GENERATOR_INSTANCE = new DefaultLabelGenerator();

        protected PaintLookup                 lookup;

    protected PolygonSeriesLabelGenerator labelGenerator;


    public PolygonRenderer(PaintLookup lookup) {
        this(lookup, null);
    }


    public PolygonRenderer(
        PaintLookup                 lookup,
        PolygonSeriesLabelGenerator labelGenerator
    ) {
        this.lookup         = lookup;
        this.labelGenerator = labelGenerator;
    }

    /**
     * This method draws polygons of each series in <code>dataset</code> into
     * the given graphics object. If a polygon has no attribute 'fill', we
     * expect that it is a line, otherwise the polygon is filled.
     *
     */
    public void drawPolygons(
        Graphics2D     graphics,
        PolygonPlot    plot,
        Rectangle2D    area,
        PolygonDataset dataset
    ) {
        int seriesCount = dataset.getSeriesCount();
        for (int i = 0; i < seriesCount; i++) {
            PolygonSeries series   = dataset.getSeries(i);
            Integer       colorIdx = (Integer)series.getAttribute("fill");

            if (colorIdx != null) {
                Paint paint = lookup.getPaint(colorIdx.intValue());
                graphics.setPaint(paint != null ? paint : Color.black);
                graphics.fill(constructShape(plot, area, series, true));
            }
            else {
                Number lineWidth = (Number)series.getAttribute("line.width");
                BasicStroke stroke = new BasicStroke(
                    lineWidth != null ? lineWidth.floatValue() : 1f);
                graphics.setStroke(stroke);
                graphics.setPaint(Color.black);
                graphics.draw(constructShape(plot, area, series, false));
            }
        }
    }

    /**
     * Draw labels at each item of a series in the given dataset. If the series
     * has no label attritue, no label is drawn.
     *
     */
    public void drawLabels(
        final Graphics2D  graphics,
        final PolygonPlot plot,
        final Rectangle2D area,
        PolygonDataset    dataset
    ) {
        if (labelGenerator == null) {
            return;
        }

        final ArrayList<Rectangle2D> bboxes = new ArrayList<Rectangle2D>();

        Font font = graphics.getFont();
        font = font.deriveFont(Font.PLAIN, Math.max(8, font.getSize()-3));
        graphics.setFont(font);
        FontMetrics metrics = graphics.getFontMetrics(font);

        for (int i = dataset.getSeriesCount()-1; i >= 0; --i) {
            PolygonSeries series = dataset.getSeries(i);

            String label = labelGenerator.generateLabel(series);
            if (label == null) {
                continue;
            }

            final Rectangle2D box = TextUtilities.getTextBounds(
                label, graphics, metrics);

            for (int j = series.getItemCount()-1; j >= 0; --j) {
                final CompactXYItems ring = series.getItem(j);
                LevelOrderIndices loi = new LevelOrderIndices(ring.size()-1);
                Rectangle2D r = (Rectangle2D)loi.visit(
                    new LevelOrderIndices.Visitor()
                {
                    ValueAxis          da = plot.getDomainAxis();
                    ValueAxis          ra = plot.getRangeAxis();
                    RectangleEdge      de = plot.getDomainAxisEdge();
                    RectangleEdge      re = plot.getRangeAxisEdge();
                    Rectangle2D.Double r  = new Rectangle2D.Double(
                        0d, 0d, box.getWidth(), box.getHeight());

                    public Object visit(int index) {
                        r.x = da.valueToJava2D(ring.getX(index), area, de)
                            - 0.5*box.getWidth();
                        r.y = ra.valueToJava2D(ring.getY(index), area, re)
                            + 0.5*box.getHeight();

                        for (Rectangle2D b: bboxes) {
                            if (b.intersects(r)) {
                                return null;
                            }
                        }
                        return r;
                    }
                });

                if (r != null) {
                    bboxes.add(r);
                    graphics.drawString(
                        label, (float)r.getX(), (float)r.getY());
                }
            } // for all items in series
        } // for all series
    }

    /**
     * Creates a shape made up of the CompactXYItems object stored in the given
     * series.
     *
     * @param plot The plot.
     * @param area The boundary.
     * @param series The series storing the items.
     * @param close Specifies if the polygon should be closed or not.
     * @return the constructed shape.
     */
    protected Shape constructShape(
        PolygonPlot   plot,
        Rectangle2D   area,
        PolygonSeries series,
        boolean       close
    ) {
        ValueAxis     da = plot.getDomainAxis();
        ValueAxis     ra = plot.getRangeAxis();
        RectangleEdge de = plot.getDomainAxisEdge();
        RectangleEdge re = plot.getRangeAxisEdge();

        CompactXYItems [] rings = series.getRings();
        GeneralPath       path  = new GeneralPath();

        for (int i = 0; i < rings.length; ++i) {

            CompactXYItems ring = rings[i];

            double [] data = ring.getData();

            if (data.length >= 2) {
                path.moveTo(
                    (float)da.valueToJava2D(data[0], area, de),
                    (float)ra.valueToJava2D(data[1], area, re));
            }
            for (int j = 2; j < data.length;) {
                path.lineTo(
                    (float)da.valueToJava2D(data[j++], area, de),
                    (float)ra.valueToJava2D(data[j++], area, re));
            }
            if (close) {
                path.closePath();
            }
        }
        return path;
    }

    /**
     * Retrieves the bounding box of a dataset.
     */
    public Rectangle2D getBoundingBox(PolygonDataset dataset) {
        Rectangle2D bbox = null;

        for (int i = 0, N = dataset.getSeriesCount(); i < N; i++) {
            Range domain = dataset.getSeries(i).getDomainBounds();
            Range range  = dataset.getSeries(i).getRangeBounds();

            double x = domain.getLowerBound();
            double y = range.getLowerBound();
            double w = Math.abs(domain.getUpperBound() - x);
            double h = Math.abs(range.getUpperBound() - y);

            if (bbox == null) {
                bbox = new Rectangle2D.Double(x, y, w, h);
            }
            else {
                bbox.add(new Rectangle2D.Double(x, y, w, h));
            }
        }

        return bbox;
    }

    /**
     *
     * @return the bounds of a series.
     */
    public Rectangle2D getBounds(PolygonSeries series) {

        Range domain = series.getDomainBounds();
        Range range  = series.getRangeBounds();

        return new Rectangle2D.Double(
            domain.getLowerBound(), range.getLowerBound(),
            domain.getUpperBound(), range.getUpperBound()
        );
    }
}
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