jfreechart example source code file (GradientBarPainter.java)

This example jfreechart source code file (GradientBarPainter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - jfreechart tags/keywords

awt, barpainter, barrenderer, color, color, geometry, gradientbarpainter, gradientbarpainter, gradientpaint, gradientpaint, io, paint, rectangle2d, rectangle2d, rectangleedge, rectangularshape, serializable

The jfreechart GradientBarPainter.java source code

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * -----------------------
 * GradientBarPainter.java
 * -----------------------
 * (C) Copyright 2008, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * Changes:
 * --------
 * 19-Jun-2008 : Version 1 (DG);
 * 15-Aug-2008 : Use outline paint and shadow paint (DG);
 *
 */

package org.jfree.chart.renderer.category;

import java.awt.Color;
import java.awt.GradientPaint;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.Stroke;
import java.awt.geom.Rectangle2D;
import java.awt.geom.RectangularShape;
import java.io.Serializable;

import org.jfree.chart.HashUtilities;
import org.jfree.ui.RectangleEdge;

/**
 * An implementation of the {@link BarPainter} interface that uses several
 * gradient fills to enrich the appearance of the bars.
 *
 * @since 1.0.11
 */
public class GradientBarPainter implements BarPainter, Serializable {

    /** The division point between the first and second gradient regions. */
    private double g1;

    /** The division point between the second and third gradient regions. */
    private double g2;

    /** The division point between the third and fourth gradient regions. */
    private double g3;

    /**
     * Creates a new instance.
     */
    public GradientBarPainter() {
        this(0.10, 0.20, 0.80);
    }

    /**
     * Creates a new instance.
     *
     * @param g1
     * @param g2
     * @param g3
     */
    public GradientBarPainter(double g1, double g2, double g3) {
        this.g1 = g1;
        this.g2 = g2;
        this.g3 = g3;
    }

    /**
     * Paints a single bar instance.
     *
     * @param g2  the graphics target.
     * @param renderer  the renderer.
     * @param row  the row index.
     * @param column  the column index.
     * @param bar  the bar
     * @param base  indicates which side of the rectangle is the base of the
     *              bar.
     */
    public void paintBar(Graphics2D g2, BarRenderer renderer, int row,
            int column, RectangularShape bar, RectangleEdge base) {

        Paint itemPaint = renderer.getItemPaint(row, column);

        Color c0, c1;
        if (itemPaint instanceof Color) {
            c0 = (Color) itemPaint;
            c1 = c0.brighter();
        }
        else if (itemPaint instanceof GradientPaint) {
            GradientPaint gp = (GradientPaint) itemPaint;
            c0 = gp.getColor1();
            c1 = gp.getColor2();
        }
        else {
            c0 = Color.blue;
            c1 = Color.blue.brighter();
        }

        // as a special case, if the bar colour has alpha == 0, we draw
        // nothing.
        if (c0.getAlpha() == 0) {
            return;
        }

        if (base == RectangleEdge.TOP || base == RectangleEdge.BOTTOM) {
            Rectangle2D[] regions = splitVerticalBar(bar, this.g1, this.g2,
                    this.g3);
            GradientPaint gp = new GradientPaint((float) regions[0].getMinX(),
                    0.0f, c0, (float) regions[0].getMaxX(), 0.0f, Color.white);
            g2.setPaint(gp);
            g2.fill(regions[0]);

            gp = new GradientPaint((float) regions[1].getMinX(), 0.0f,
                    Color.white, (float) regions[1].getMaxX(), 0.0f, c0);
            g2.setPaint(gp);
            g2.fill(regions[1]);

            gp = new GradientPaint((float) regions[2].getMinX(), 0.0f, c0,
                    (float) regions[2].getMaxX(), 0.0f, c1);
            g2.setPaint(gp);
            g2.fill(regions[2]);

            gp = new GradientPaint((float) regions[3].getMinX(), 0.0f, c1,
                     (float) regions[3].getMaxX(), 0.0f, c0);
            g2.setPaint(gp);
            g2.fill(regions[3]);
        }
        else if (base == RectangleEdge.LEFT || base == RectangleEdge.RIGHT) {
            Rectangle2D[] regions = splitHorizontalBar(bar, this.g1, this.g2,
                    this.g3);
            GradientPaint gp = new GradientPaint(0.0f,
                    (float) regions[0].getMinY(), c0, 0.0f,
                    (float) regions[0].getMaxX(), Color.white);
            g2.setPaint(gp);
            g2.fill(regions[0]);

            gp = new GradientPaint(0.0f, (float) regions[1].getMinY(),
                    Color.white, 0.0f, (float) regions[1].getMaxY(), c0);
            g2.setPaint(gp);
            g2.fill(regions[1]);

            gp = new GradientPaint(0.0f, (float) regions[2].getMinY(), c0,
                    0.0f, (float) regions[2].getMaxY(), c1);
            g2.setPaint(gp);
            g2.fill(regions[2]);

            gp = new GradientPaint(0.0f, (float) regions[3].getMinY(), c1,
                     0.0f, (float) regions[3].getMaxY(), c0);
            g2.setPaint(gp);
            g2.fill(regions[3]);

        }

        // draw the outline...
        if (renderer.isDrawBarOutline()
            /*&& state.getBarWidth() > renderer.BAR_OUTLINE_WIDTH_THRESHOLD*/) {
            Stroke stroke = renderer.getItemOutlineStroke(row, column);
            Paint paint = renderer.getItemOutlinePaint(row, column);
            if (stroke != null && paint != null) {
                g2.setStroke(stroke);
                g2.setPaint(paint);
                g2.draw(bar);
            }
        }

    }

    /**
     * Paints a single bar instance.
     *
     * @param g2  the graphics target.
     * @param renderer  the renderer.
     * @param row  the row index.
     * @param column  the column index.
     * @param bar  the bar
     * @param base  indicates which side of the rectangle is the base of the
     *              bar.
     * @param pegShadow  peg the shadow to the base of the bar?
     */
    public void paintBarShadow(Graphics2D g2, BarRenderer renderer, int row,
            int column, RectangularShape bar, RectangleEdge base,
            boolean pegShadow) {

        // handle a special case - if the bar colour has alpha == 0, it is
        // invisible so we shouldn't draw any shadow
        Paint itemPaint = renderer.getItemPaint(row, column);
        if (itemPaint instanceof Color) {
            Color c = (Color) itemPaint;
            if (c.getAlpha() == 0) {
                return;
            }
        }

        RectangularShape shadow = createShadow(bar, renderer.getShadowXOffset(),
                renderer.getShadowYOffset(), base, pegShadow);
        g2.setPaint(renderer.getShadowPaint());
        g2.fill(shadow);

    }

    /**
     * Creates a shadow for the bar.
     *
     * @param bar  the bar shape.
     * @param xOffset  the x-offset for the shadow.
     * @param yOffset  the y-offset for the shadow.
     * @param base  the edge that is the base of the bar.
     * @param pegShadow  peg the shadow to the base?
     *
     * @return A rectangle for the shadow.
     */
    private Rectangle2D createShadow(RectangularShape bar, double xOffset,
            double yOffset, RectangleEdge base, boolean pegShadow) {
        double x0 = bar.getMinX();
        double x1 = bar.getMaxX();
        double y0 = bar.getMinY();
        double y1 = bar.getMaxY();
        if (base == RectangleEdge.TOP) {
            x0 += xOffset;
            x1 += xOffset;
            if (!pegShadow) {
                y0 += yOffset;
            }
            y1 += yOffset;
        }
        else if (base == RectangleEdge.BOTTOM) {
            x0 += xOffset;
            x1 += xOffset;
            y0 += yOffset;
            if (!pegShadow) {
                y1 += yOffset;
            }
        }
        else if (base == RectangleEdge.LEFT) {
            if (!pegShadow) {
                x0 += xOffset;
            }
            x1 += xOffset;
            y0 += yOffset;
            y1 += yOffset;
        }
        else if (base == RectangleEdge.RIGHT) {
            x0 += xOffset;
            if (!pegShadow) {
                x1 += xOffset;
            }
            y0 += yOffset;
            y1 += yOffset;
        }
        return new Rectangle2D.Double(x0, y0, (x1 - x0), (y1 - y0));
    }

    /**
     * Splits a bar into subregions (elsewhere, these subregions will have
     * different gradients applied to them).
     *
     * @param bar  the bar shape.
     * @param a  the first division.
     * @param b  the second division.
     * @param c  the third division.
     *
     * @return An array containing four subregions.
     */
    private Rectangle2D[] splitVerticalBar(RectangularShape bar, double a,
            double b, double c) {
        Rectangle2D[] result = new Rectangle2D[4];
        double x0 = bar.getMinX();
        double x1 = Math.rint(x0 + (bar.getWidth() * a));
        double x2 = Math.rint(x0 + (bar.getWidth() * b));
        double x3 = Math.rint(x0 + (bar.getWidth() * c));
        result[0] = new Rectangle2D.Double(bar.getMinX(), bar.getMinY(),
                x1 - x0, bar.getHeight());
        result[1] = new Rectangle2D.Double(x1, bar.getMinY(), x2 - x1,
                bar.getHeight());
        result[2] = new Rectangle2D.Double(x2, bar.getMinY(), x3 - x2,
                bar.getHeight());
        result[3] = new Rectangle2D.Double(x3, bar.getMinY(),
                bar.getMaxX() - x3, bar.getHeight());
        return result;
    }

    /**
     * Splits a bar into subregions (elsewhere, these subregions will have
     * different gradients applied to them).
     *
     * @param bar  the bar shape.
     * @param a  the first division.
     * @param b  the second division.
     * @param c  the third division.
     *
     * @return An array containing four subregions.
     */
    private Rectangle2D[] splitHorizontalBar(RectangularShape bar, double a,
            double b, double c) {
        Rectangle2D[] result = new Rectangle2D[4];
        double y0 = bar.getMinY();
        double y1 = Math.rint(y0 + (bar.getHeight() * a));
        double y2 = Math.rint(y0 + (bar.getHeight() * b));
        double y3 = Math.rint(y0 + (bar.getHeight() * c));
        result[0] = new Rectangle2D.Double(bar.getMinX(), bar.getMinY(),
                bar.getWidth(), y1 - y0);
        result[1] = new Rectangle2D.Double(bar.getMinX(), y1, bar.getWidth(),
                y2 - y1);
        result[2] = new Rectangle2D.Double(bar.getMinX(), y2, bar.getWidth(),
                y3 - y2);
        result[3] = new Rectangle2D.Double(bar.getMinX(), y3, bar.getWidth(),
                bar.getMaxY() - y3);
        return result;
    }

    /**
     * Tests this instance for equality with an arbitrary object.
     *
     * @param obj  the obj (<code>null permitted).
     *
     * @return A boolean.
     */
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof GradientBarPainter)) {
            return false;
        }
        GradientBarPainter that = (GradientBarPainter) obj;
        if (this.g1 != that.g1) {
            return false;
        }
        if (this.g2 != that.g2) {
            return false;
        }
        if (this.g3 != that.g3) {
            return false;
        }
        return true;
    }

    /**
     * Returns a hash code for this instance.
     *
     * @return A hash code.
     */
    public int hashCode() {
        int hash = 37;
        hash = HashUtilities.hashCode(hash, this.g1);
        hash = HashUtilities.hashCode(hash, this.g2);
        hash = HashUtilities.hashCode(hash, this.g3);
        return hash;
    }

}