    001    /* ===========================================================
    002     * JFreeChart : a free chart library for the Java(tm) platform
    003     * ===========================================================
    004     *
    005     * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
    006     *
    007     * Project Info:  http://www.jfree.org/jfreechart/index.html
    008     *
    009     * This library is free software; you can redistribute it and/or modify it
    010     * under the terms of the GNU Lesser General Public License as published by
    011     * the Free Software Foundation; either version 2.1 of the License, or
    012     * (at your option) any later version.
    013     *
    014     * This library is distributed in the hope that it will be useful, but
    015     * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    016     * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
    017     * License for more details.
    018     *
    019     * You should have received a copy of the GNU Lesser General Public
    020     * License along with this library; if not, write to the Free Software
    021     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
    022     * USA.
    023     *
    024     * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
    025     * in the United States and other countries.]
    026     *
    027     * ---------------
    028     * EmptyBlock.java
    029     * ---------------
    030     * (C) Copyright 2004-2008, by Object Refinery Limited.
    031     *
    032     * Original Author:  David Gilbert (for Object Refinery Limited);
    033     * Contributor(s):   -;
    034     *
    035     * Changes:
    036     * --------
    037     * 22-Oct-2004 : Version 1 (DG);
    038     * 04-Feb-2005 : Now cloneable and serializable (DG);
    039     * 20-Apr-2005 : Added new draw() method (DG);
    040     * 08-Apr-2008 : Added support for margin and border (DG);
    041     * 08-May-2008 : Updated arrange() method to recognise
    042     *               incoming constraint (DG);
    043     *
    044     */
    045
    046    package org.jfree.chart.block;
    047
    048    import java.awt.Graphics2D;
    049    import java.awt.geom.Rectangle2D;
    050    import java.io.Serializable;
    051
    052    import org.jfree.ui.Size2D;
    053    import org.jfree.util.PublicCloneable;
    054
    055    /**
    056     * An empty block with a fixed size.
    057     */
    058    public class EmptyBlock extends AbstractBlock
    059            implements Block, Cloneable, PublicCloneable, Serializable {
    060
    061        /** For serialization. */
    062        private static final long serialVersionUID = -4083197869412648579L;
    063
    064        /**
    065         * Creates a new block with the specified width and height.
    066         *
    067         * @param width  the width.
    068         * @param height  the height.
    069         */
    070        public EmptyBlock(double width, double height) {
    071            setWidth(width);
    072            setHeight(height);
    073        }
    074
    075        /**
    076         * Arranges the contents of the block, within the given constraints, and
    077         * returns the block size.
    078         *
    079         * @param g2  the graphics device.
    080         * @param constraint  the constraint (<code>null</code> not permitted).
    081         *
    082         * @return The block size (in Java2D units, never <code>null</code>).
    083         */
    084        public Size2D arrange(Graphics2D g2, RectangleConstraint constraint) {
    085            Size2D base = new Size2D(calculateTotalWidth(getWidth()),
    086                    calculateTotalHeight(getHeight()));
    087            return constraint.calculateConstrainedSize(base);
    088    }
    089
    090        /**
    091         * Draws the block.  Since the block is empty, there is nothing to draw
    092         * except the optional border.
    093         *
    094         * @param g2  the graphics device.
    095         * @param area  the area.
    096         */
    097        public void draw(Graphics2D g2, Rectangle2D area) {
    098            draw(g2, area, null);
    099        }
    100
    101        /**
    102         * Draws the block within the specified area.  Since the block is empty,
    103         * there is nothing to draw except the optional border.
    104         *
    105         * @param g2  the graphics device.
    106         * @param area  the area.
    107         * @param params  ignored (<code>null</code> permitted).
    108         *
    109         * @return Always <code>null</code>.
    110         */
    111        public Object draw(Graphics2D g2, Rectangle2D area, Object params) {
    112            area = trimMargin(area);
    113            drawBorder(g2, area);
    114            return null;
    115        }
    116
    117        /**
    118         * Returns a clone of the block.
    119         *
    120         * @return A clone.
    121         *
    122         * @throws CloneNotSupportedException if there is a problem cloning.
    123         */
    124        public Object clone() throws CloneNotSupportedException {
    125            return super.clone();
    126        }
    127
    128    }