001 /*
002 * $Id: AbstractGradientPainter.java,v 1.3 2006/03/24 02:36:08 rbair 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.gradient;
023
024 import java.awt.Graphics2D;
025 import java.awt.Paint;
026 import javax.swing.JComponent;
027 import org.jdesktop.swingx.painter.AbstractPainter;
028 import org.jdesktop.swingx.util.Resize;
029
030 /**
031 * <p>An abstract base class from which the various gradient oriented painter
032 * classes extend. Gradient based painters perform an important task beyond what
033 * a MattePainter with a GradientPaint will do -- they resize the gradient to
034 * fit the Component regardless of its dimensions.</p>
035 *
036 * <p>AbstractGradientPainter has a resize property of type Resize that specifies
037 * whether the gradient should be resized horizontally, vertically, in both directions
038 * or not at all (in which case you should really probably be using MattePainter).
039 * Subclasses must implement calculateSizedPaint to return a new gradient paint
040 * instance that is resized in the proper ways. If no Paint is returned from
041 * this method call, then nothing is painted.</p>
042 *
043 * <p>By default, the resize property is set to BOTH.</p>
044 *
045 * <p>In order for resizing to work properly with GradientPaint, LinearGradientPaint,
046 * and RadialGradientPaint, it is necessary that the various control points used in
047 * these paints be specified in such a manner that they can be reliably resized.
048 * For example, BasicGradientPainter takes GradientPaints who's point1 and point2
049 * properties are specified between 0 and 1, representing at what percentage of
050 * the distance from the origin the gradient begins and ends. Thus, if I created
051 * a GradientPaint like this:
052 * <pre><code>
053 * GradientPaint gp = new GradientPaint(
054 * new Point2D.Double(.2d, 0),
055 * Color.BLUE,
056 * new Point2D.Double(.8d, 0),
057 * Color.WHITE);
058 * </code></pre>
059 *
060 * then when painted, the gradient will start with a BLUE at 20% of the width of
061 * the component, and finish with WHITE at 80% of the width of the component.</p>
062 *
063 * <p>See the various subclasses for more detailed examples.</p>
064 *
065 * @author rbair
066 */
067 public abstract class AbstractGradientPainter extends AbstractPainter {
068 /**
069 * Indicates in which direction (vertical, horizontal, both, none) to
070 * resize the gradient paint prior to painting
071 */
072 private Resize resize = Resize.BOTH;
073
074 /**
075 * Creates a new instance of AbstractGradientPainter
076 */
077 public AbstractGradientPainter() {
078 }
079
080 /**
081 * @inheritDoc
082 */
083 public void paintBackground(Graphics2D g, JComponent component) {
084 Paint p = calculateSizedPaint(component.getWidth(), component.getHeight());
085 if (p != null) {
086 g.setPaint(p);
087 g.fillRect(0, 0, component.getWidth(), component.getHeight());
088 }
089 }
090
091 /**
092 * @return a calculated Paint that fits within the given width/height. May
093 * be null.
094 *
095 * @param width the width used to calculate the new paint size
096 * @param height the height used to calculate the new paint size
097 */
098 protected abstract Paint calculateSizedPaint(int width, int height);
099
100 /**
101 * @return a value indicating how the paint will be resized to fit the
102 * component dimensions. Never returns null.
103 */
104 public Resize getResize() {
105 return resize;
106 }
107
108 /**
109 * Specifies how the paint will be resized based on the component dimensions.
110 *
111 * @param resize the new Resize value. May be null. If null, set to Resize.BOTH.
112 */
113 public void setResize(Resize resize) {
114 Resize old = getResize();
115 boolean rh = isResizeHorizontal();
116 boolean rv = isResizeVertical();
117
118 this.resize = resize == null ? Resize.BOTH : resize;
119
120 firePropertyChange("resize", old, getResize());
121 firePropertyChange("resizeHorizontal", rh, isResizeHorizontal());
122 firePropertyChange("resizeVertical", rv, isResizeVertical());
123 }
124
125 /**
126 * @return true if getResize() returns BOTH or HORIZONTAL.
127 */
128 protected boolean isResizeHorizontal() {
129 Resize r = getResize();
130 return r == Resize.BOTH || r == Resize.HORIZONTAL;
131 }
132
133 /**
134 * @return true if getResize() returns BOTH or VERTICAL.
135 */
136 protected boolean isResizeVertical() {
137 Resize r = getResize();
138 return r == Resize.BOTH || r == Resize.VERTICAL;
139 }
140 }