001/* GradientPaint.java -- 002 Copyright (C) 2002, 2005, Free Software Foundation, Inc. 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038 039package java.awt; 040 041import java.awt.geom.AffineTransform; 042import java.awt.geom.Point2D; 043import java.awt.geom.Rectangle2D; 044import java.awt.image.ColorModel; 045import gnu.java.awt.GradientPaintContext; 046 047/** 048 * A paint object that can be used to color a region by blending two colors. 049 * Instances of this class are immutable. 050 */ 051public class GradientPaint implements Paint 052{ 053 private final float x1; 054 private final float y1; 055 private final Color c1; 056 private final float x2; 057 private final float y2; 058 private final Color c2; 059 private final boolean cyclic; 060 061 /** 062 * Creates a new acyclic <code>GradientPaint</code>. 063 * 064 * @param x1 the x-coordinate of the anchor point for color 1. 065 * @param y1 the y-coordinate of the anchor point for color 1. 066 * @param c1 color 1 (<code>null</code> not permitted). 067 * @param x2 the x-coordinate of the anchor point for color 2. 068 * @param y2 the y-coordinate of the anchor point for color 2. 069 * @param c2 the second color (<code>null</code> not permitted). 070 */ 071 public GradientPaint(float x1, float y1, Color c1, 072 float x2, float y2, Color c2) 073 { 074 this(x1, y1, c1, x2, y2, c2, false); 075 } 076 077 /** 078 * Creates a new acyclic <code>GradientPaint</code>. 079 * 080 * @param p1 anchor point 1 (<code>null</code> not permitted). 081 * @param c1 color 1 (<code>null</code> not permitted). 082 * @param p2 anchor point 2 (<code>null</code> not permitted). 083 * @param c2 color 2 (<code>null</code> not permitted). 084 */ 085 public GradientPaint(Point2D p1, Color c1, Point2D p2, Color c2) 086 { 087 this((float) p1.getX(), (float) p1.getY(), c1, 088 (float) p2.getX(), (float) p2.getY(), c2, false); 089 } 090 091 /** 092 * Creates a new cyclic or acyclic <code>GradientPaint</code>. 093 * 094 * @param x1 the x-coordinate of the anchor point for color 1. 095 * @param y1 the y-coordinate of the anchor point for color 1. 096 * @param c1 color 1 (<code>null</code> not permitted). 097 * @param x2 the x-coordinate of the anchor point for color 2. 098 * @param y2 the y-coordinate of the anchor point for color 2. 099 * @param c2 the second color (<code>null</code> not permitted). 100 * @param cyclic a flag that controls whether the gradient is cyclic or 101 * acyclic. 102 */ 103 public GradientPaint(float x1, float y1, Color c1, 104 float x2, float y2, Color c2, boolean cyclic) 105 { 106 if (c1 == null || c2 == null) 107 throw new NullPointerException(); 108 this.x1 = x1; 109 this.y1 = y1; 110 this.c1 = c1; 111 this.x2 = x2; 112 this.y2 = y2; 113 this.c2 = c2; 114 this.cyclic = cyclic; 115 } 116 117 /** 118 * Creates a new cyclic or acyclic <code>GradientPaint</code>. 119 * 120 * @param p1 anchor point 1 (<code>null</code> not permitted). 121 * @param c1 color 1 (<code>null</code> not permitted). 122 * @param p2 anchor point 2 (<code>null</code> not permitted). 123 * @param c2 color 2 (<code>null</code> not permitted). 124 * @param cyclic a flag that controls whether the gradient is cyclic or 125 * acyclic. 126 */ 127 public GradientPaint(Point2D p1, Color c1, Point2D p2, Color c2, 128 boolean cyclic) 129 { 130 this((float) p1.getX(), (float) p1.getY(), c1, 131 (float) p2.getX(), (float) p2.getY(), c2, cyclic); 132 } 133 134 /** 135 * Returns a point with the same coordinates as the anchor point for color 1. 136 * Note that if you modify this point, the <code>GradientPaint</code> remains 137 * unchanged. 138 * 139 * @return A point with the same coordinates as the anchor point for color 1. 140 */ 141 public Point2D getPoint1() 142 { 143 return new Point2D.Float(x1, y1); 144 } 145 146 /** 147 * Returns the first color. 148 * 149 * @return The color (never <code>null</code>). 150 */ 151 public Color getColor1() 152 { 153 return c1; 154 } 155 156 /** 157 * Returns a point with the same coordinates as the anchor point for color 2. 158 * Note that if you modify this point, the <code>GradientPaint</code> remains 159 * unchanged. 160 * 161 * @return A point with the same coordinates as the anchor point for color 2. 162 */ 163 public Point2D getPoint2() 164 { 165 return new Point2D.Float(x2, y2); 166 } 167 168 /** 169 * Returns the second color. 170 * 171 * @return The color (never <code>null</code>). 172 */ 173 public Color getColor2() 174 { 175 return c2; 176 } 177 178 /** 179 * Returns <code>true</code> if this <code>GradientPaint</code> instance is 180 * cyclic, and <code>false</code> otherwise. 181 * 182 * @return A boolean. 183 */ 184 public boolean isCyclic() 185 { 186 return cyclic; 187 } 188 189 /** 190 * Returns the {@link PaintContext} used to generate the color pattern. 191 * 192 * @param cm the color model, used as a hint (ignored in this 193 * implementation). 194 * @param deviceBounds the device space bounding box of the painted area. 195 * @param userBounds the user space bounding box of the painted area. 196 * @param xform the transformation from user space to device space. 197 * @param hints any hints for choosing between rendering alternatives. 198 * 199 * @return The context for performing the paint 200 */ 201 public PaintContext createContext(ColorModel cm, Rectangle deviceBounds, 202 Rectangle2D userBounds, 203 AffineTransform xform, 204 RenderingHints hints) 205 { 206 Point2D xp1 = xform.transform(getPoint1(), null); 207 Point2D xp2 = xform.transform(getPoint2(), null); 208 return new GradientPaintContext((float) xp1.getX(), (float) xp1.getY(), c1, 209 (float) xp2.getX(), (float) xp2.getY(), c2, cyclic); 210 } 211 212 /** 213 * Returns the transparency code for this <code>GradientPaint</code> instance. 214 * This is derived from the two {@link Color} objects used in creating this 215 * object: if both colors are opaque, this method returns 216 * {@link Transparency#OPAQUE}, otherwise it returns 217 * {@link Transparency#TRANSLUCENT}. 218 * 219 * @return {@link Transparency#OPAQUE} or {@link Transparency#TRANSLUCENT}. 220 */ 221 public int getTransparency() 222 { 223 if (c1.getAlpha() == 255 && c2.getAlpha() == 255) 224 return Transparency.OPAQUE; 225 else 226 return Transparency.TRANSLUCENT; 227 } 228 229} // class GradientPaint