001    /*
002     * $Id: CheckerboardPainter.java,v 1.6 2006/05/14 08:12:14 dmouse Exp $
003     *
004     * Copyright 2004 Sun Microsystems, Inc., 4150 Network Circle,
005     * Santa Clara, California 95054, U.S.A. All rights reserved.
006     *
007     * This library is free software; you can redistribute it and/or
008     * modify it under the terms of the GNU Lesser General Public
009     * License as published by the Free Software Foundation; either
010     * version 2.1 of the License, or (at your option) any later version.
011     * 
012     * This library is distributed in the hope that it will be useful,
013     * but WITHOUT ANY WARRANTY; without even the implied warranty of
014     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
015     * Lesser General Public License for more details.
016     * 
017     * You should have received a copy of the GNU Lesser General Public
018     * License along with this library; if not, write to the Free Software
019     * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
020     */
021    
022    package org.jdesktop.swingx.painter;
023    
024    import java.awt.Color;
025    import java.awt.Graphics2D;
026    import java.awt.Paint;
027    import java.awt.Rectangle;
028    import java.awt.TexturePaint;
029    import java.awt.image.BufferedImage;
030    import javax.swing.JComponent;
031    
032    /**
033     * <p>A Painter implementation that paints a checkerboard pattern. The light
034     * and dark colors (Paint instances) are configurable, as are the size of the
035     * squares (squareLength).</p>
036     * 
037     * <p>To configure a checkerboard pattern that used a gradient for the dark
038     * tiles and Color.WHITE for the light tiles, you could:
039     * <pre><code>
040     *  GradientPaint gp = new GradientPaint(
041     *      new Point2D.Double(0, 0),
042     *      Color.BLACK,
043     *      new Point2D.Double(0, 32),
044     *      Color.GRAY);
045     *  CheckerboardPainter p = new CheckerboardPainter();
046     *  p.setDarkPaint(gp);
047     *  p.setLightPaint(Color.WHITE);
048     *  p.setSquareLength(32);
049     *  panel.seBackgroundPainter(p);
050     * </code></pre></p>
051     * 
052     * <p>Note that in this example, the "32" in the GradientPaint matches the "32"
053     * set for the squareLength. This is necessary because GradientPaints don't
054     * readjust themselves for the size of the square. They are fixed and immutable
055     * at the time of creation.</p>
056     * 
057     * 
058     * 
059     * @author rbair
060     */
061    public class CheckerboardPainter extends AbstractPainter {
062        private transient Paint checkerPaint;
063        
064        private Paint darkPaint = new Color(204, 204, 204);
065        private Paint lightPaint = Color.WHITE;
066        private int squareLength = 8;
067        
068        /**
069         * Create a new CheckerboardPainter. By default the light color is Color.WHITE,
070         * the dark color is a light gray, and the square length is 8.
071         */
072        public CheckerboardPainter() {
073        }
074        
075        /**
076         * Create a new CheckerboardPainter with the specified light and dark paints.
077         * By default the square length is 8.
078         *
079         * @param darkPaint the paint used to draw the dark squares
080         * @param lightPaint the paint used to draw the light squares
081         */
082        public CheckerboardPainter(Paint darkPaint, Paint lightPaint) {
083            this(darkPaint, lightPaint, 8);
084        }
085        
086        /**
087         * Create a new CheckerboardPainter with the specified light and dark paints
088         * and the specified square size.
089         *
090         * @param darkPaint the paint used to draw the dark squares
091         * @param lightPaint the paint used to draw the light squares
092         * @param length the length of the checker board squares
093         */
094        public CheckerboardPainter(Paint darkPaint, Paint lightPaint, int length) {
095            this.darkPaint = darkPaint;
096            this.lightPaint = lightPaint;
097            this.squareLength = length;
098        }
099        
100        
101        /**
102         * Specifies the length of the squares. By default, it is 8. A length of <=
103         * 0 will cause an IllegalArgumentException to be thrown.
104         *
105         * @param length the length of one side of a square tile. Must be > 0.
106         */
107        public void setSquareLength(int length) {
108            if (length <= 0) {
109                throw new IllegalArgumentException("Length must be > 0");
110            }
111            
112            int old = getSquareLength();
113            this.squareLength = length;
114            checkerPaint = null;
115            firePropertyChange("squareLength", old, getSquareLength());
116        }
117        
118        /**
119         * @return the squareLength. Will be > 0
120         */
121        public int getSquareLength() {
122            return squareLength;
123        }
124        
125        /**
126         * Specifies the paint to use for dark tiles. This is a Paint and
127         * may be anything, including a TexturePaint for painting images. If null,
128         * the background color of the component is used.
129         *
130         * @param color the Paint to use for painting the "dark" tiles. May be null.
131         */
132        public void setDarkPaint(Paint color) {
133            Paint old = getDarkPaint();
134            this.darkPaint = color;
135            checkerPaint = null;
136            firePropertyChange("darkPaint", old, getDarkPaint());
137        }
138        
139        /**
140         * @return the Paint used for painting the "dark" tiles. May be null
141         */
142        public Paint getDarkPaint() {
143            return darkPaint;
144        }
145        
146        /**
147         * Specifies the paint to use for light tiles. This is a Paint and
148         * may be anything, including a TexturePaint for painting images. If null,
149         * the foreground color of the component is used.
150         *
151         * @param color the Paint to use for painting the "light" tiles. May be null.
152         */
153        public void setLightPaint(Paint color) {
154            Paint old = getLightPaint();
155            this.lightPaint = color;
156            checkerPaint = null;
157            firePropertyChange("lightPaint", old, getLightPaint());
158        }
159        
160        /**
161         * @return the Paint used for painting the "light" tiles. May be null
162         */
163        public Paint getLightPaint() {
164            return lightPaint;
165        }
166        
167        /**
168         * Helper method that creates and returns the Paint that incorporates the
169         * sizes and light and dark Paints in one TexturePaint. I may want to cache
170         * this value in the future for performance reasons
171         */
172        private Paint getCheckerPaint(JComponent c) {
173            if (checkerPaint == null) {
174                int sqlength = getSquareLength();
175                int length = sqlength * 2;
176                BufferedImage image = new BufferedImage(length, length, BufferedImage.TYPE_INT_ARGB);
177                Graphics2D gfx = image.createGraphics();
178                Paint p = getLightPaint();
179                if (p == null) {
180                    p = c.getForeground();
181                }
182                gfx.setPaint(p);
183                gfx.fillRect(0, 0, length, length);
184                p = getDarkPaint();
185                if (p == null) {
186                    p = c.getBackground();
187                }
188                gfx.setPaint(p);
189                gfx.fillRect(0, 0, sqlength - 1, sqlength - 1);
190                gfx.fillRect(sqlength, sqlength, sqlength - 1, sqlength - 1);
191                gfx.dispose();
192    
193                checkerPaint = new TexturePaint(image, new Rectangle(0, 0, image.getWidth(), image.getHeight()));
194            }
195            return checkerPaint;
196        }
197        
198        /**
199         * @inheritDoc
200         */
201        public void paintBackground(Graphics2D g, JComponent component) {
202            g.setPaint(getCheckerPaint(component));
203            g.fillRect(0, 0, component.getWidth(), component.getHeight());
204        }
205    }