1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 /** 18 * @author Igor V. Stolyarov 19 * @version $Revision$ 20 */ 21 22 package java.awt; 23 24 import java.awt.Composite; 25 import java.awt.CompositeContext; 26 import java.awt.RenderingHints; 27 import java.awt.image.ColorModel; 28 29 import org.apache.harmony.awt.gl.ICompositeContext; 30 import org.apache.harmony.awt.internal.nls.Messages; 31 32 /** 33 * The AlphaComposite class defines a basic alpha compositing rules for 34 * combining source and destination colors to achieve blending and transparency 35 * effects with graphics and images. 36 * 37 * @since Android 1.0 38 */ 39 public final class AlphaComposite implements Composite { 40 41 /** 42 * The Constant CLEAR indicates that both the color and the alpha of the 43 * destination are cleared (Porter-Duff Clear rule). 44 */ 45 public static final int CLEAR = 1; 46 47 /** 48 * The Constant SRC indicates that the source is copied to the destination 49 * (Porter-Duff Source rule). 50 */ 51 public static final int SRC = 2; 52 53 /** 54 * The Constant DST indicates that the destination is left untouched 55 * (Porter-Duff Destination rule). 56 */ 57 public static final int DST = 9; 58 59 /** 60 * The Constant SRC_OVER indicates that the source is composited over the 61 * destination (Porter-Duff Source Over Destination rule). 62 */ 63 public static final int SRC_OVER = 3; 64 65 /** 66 * The Constant DST_OVER indicates that The destination is composited over 67 * the source and the result replaces the destination (Porter-Duff 68 * Destination Over Source rule). 69 */ 70 public static final int DST_OVER = 4; 71 72 /** 73 * The Constant SRC_IN indicates that the part of the source lying inside of 74 * the destination replaces the destination (Porter-Duff Source In 75 * Destination rule). 76 */ 77 public static final int SRC_IN = 5; 78 79 /** 80 * The Constant DST_IN indicates that the part of the destination lying 81 * inside of the source replaces the destination (Porter-Duff Destination In 82 * Source rule). 83 */ 84 public static final int DST_IN = 6; 85 86 /** 87 * The Constant SRC_OUT indicates that the part of the source lying outside 88 * of the destination replaces the destination (Porter-Duff Source Held Out 89 * By Destination rule). 90 */ 91 public static final int SRC_OUT = 7; 92 93 /** 94 * The Constant DST_OUT indicates that the part of the destination lying 95 * outside of the source replaces the destination (Porter-Duff Destination 96 * Held Out By Source rule). 97 */ 98 public static final int DST_OUT = 8; 99 100 /** 101 * The Constant SRC_ATOP indicates that the part of the source lying inside 102 * of the destination is composited onto the destination (Porter-Duff Source 103 * Atop Destination rule). 104 */ 105 public static final int SRC_ATOP = 10; 106 107 /** 108 * The Constant DST_ATOP indicates that the part of the destination lying 109 * inside of the source is composited over the source and replaces the 110 * destination (Porter-Duff Destination Atop Source rule). 111 */ 112 public static final int DST_ATOP = 11; 113 114 /** 115 * The Constant XOR indicates that the part of the source that lies outside 116 * of the destination is combined with the part of the destination that lies 117 * outside of the source (Porter-Duff Source Xor Destination rule). 118 */ 119 public static final int XOR = 12; 120 121 /** 122 * AlphaComposite object with the opaque CLEAR rule and an alpha of 1.0f. 123 */ 124 public static final AlphaComposite Clear = new AlphaComposite(CLEAR); 125 126 /** 127 * AlphaComposite object with the opaque SRC rule and an alpha of 1.0f. 128 */ 129 public static final AlphaComposite Src = new AlphaComposite(SRC); 130 131 /** 132 * AlphaComposite object with the opaque DST rule and an alpha of 1.0f. 133 */ 134 public static final AlphaComposite Dst = new AlphaComposite(DST); 135 136 /** 137 * AlphaComposite object with the opaque SRC_OVER rule and an alpha of 1.0f. 138 */ 139 public static final AlphaComposite SrcOver = new AlphaComposite(SRC_OVER); 140 141 /** 142 * AlphaComposite object with the opaque DST_OVER rule and an alpha of 1.0f. 143 */ 144 public static final AlphaComposite DstOver = new AlphaComposite(DST_OVER); 145 146 /** 147 * AlphaComposite object with the opaque SRC_IN rule and an alpha of 1.0f. 148 */ 149 public static final AlphaComposite SrcIn = new AlphaComposite(SRC_IN); 150 151 /** 152 * AlphaComposite object with the opaque DST_IN rule and an alpha of 1.0f. 153 */ 154 public static final AlphaComposite DstIn = new AlphaComposite(DST_IN); 155 156 /** 157 * AlphaComposite object with the opaque SRC_OUT rule and an alpha of 1.0f. 158 */ 159 public static final AlphaComposite SrcOut = new AlphaComposite(SRC_OUT); 160 161 /** 162 * AlphaComposite object with the opaque DST_OUT rule and an alpha of 1.0f. 163 */ 164 public static final AlphaComposite DstOut = new AlphaComposite(DST_OUT); 165 166 /** 167 * AlphaComposite object with the opaque SRC_ATOP rule and an alpha of 1.0f. 168 */ 169 public static final AlphaComposite SrcAtop = new AlphaComposite(SRC_ATOP); 170 171 /** 172 * AlphaComposite object with the opaque DST_ATOP rule and an alpha of 1.0f. 173 */ 174 public static final AlphaComposite DstAtop = new AlphaComposite(DST_ATOP); 175 176 /** 177 * AlphaComposite object with the opaque XOR rule and an alpha of 1.0f. 178 */ 179 public static final AlphaComposite Xor = new AlphaComposite(XOR); 180 181 /** 182 * The rule. 183 */ 184 private int rule; 185 186 /** 187 * The alpha. 188 */ 189 private float alpha; 190 191 /** 192 * Instantiates a new alpha composite. Creates a context for the compositing 193 * operation. The context contains state that is used in performing the 194 * compositing operation. 195 * 196 * @param rule 197 * the rule. 198 * @param alpha 199 * the alpha. 200 */ 201 private AlphaComposite(int rule, float alpha) { 202 if (rule < CLEAR || rule > XOR) { 203 // awt.11D=Unknown rule 204 throw new IllegalArgumentException(Messages.getString("awt.11D")); //$NON-NLS-1$ 205 } 206 if (alpha < 0.0f || alpha > 1.0f) { 207 // awt.11E=Wrong alpha value 208 throw new IllegalArgumentException(Messages.getString("awt.11E")); //$NON-NLS-1$ 209 } 210 211 this.rule = rule; 212 this.alpha = alpha; 213 } 214 215 /** 216 * Instantiates a new alpha composite. 217 * 218 * @param rule 219 * the rule. 220 */ 221 private AlphaComposite(int rule) { 222 this(rule, 1.0f); 223 } 224 225 /** 226 * Creates a CompositeContext object with the specified source ColorModel, 227 * destination ColorModel and RenderingHints parameters for a composing 228 * operation. 229 * 230 * @param srcColorModel 231 * the source's ColorModel. 232 * @param dstColorModel 233 * the destination's ColorModel. 234 * @param hints 235 * the RenderingHints object. 236 * @return the CompositeContext object. 237 * @see java.awt.Composite#createContext(java.awt.image.ColorModel, 238 * java.awt.image.ColorModel, java.awt.RenderingHints) 239 */ 240 public CompositeContext createContext(ColorModel srcColorModel, ColorModel dstColorModel, 241 RenderingHints hints) { 242 return new ICompositeContext(this, srcColorModel, dstColorModel); 243 } 244 245 /** 246 * Compares the AlphaComposite object with the specified object. 247 * 248 * @param obj 249 * the Object to be compared. 250 * @return true, if the AlphaComposite object is equal to the specified 251 * object. 252 */ 253 @Override 254 public boolean equals(Object obj) { 255 if (!(obj instanceof AlphaComposite)) { 256 return false; 257 } 258 AlphaComposite other = (AlphaComposite)obj; 259 return (this.rule == other.getRule() && this.alpha == other.getAlpha()); 260 } 261 262 /** 263 * Returns the hash code of the AlphaComposite object. 264 * 265 * @return the hash code of the AlphaComposite object. 266 */ 267 @Override 268 public int hashCode() { 269 int hash = Float.floatToIntBits(alpha); 270 int tmp = hash >>> 24; 271 hash <<= 8; 272 hash |= tmp; 273 hash ^= rule; 274 return hash; 275 } 276 277 /** 278 * Gets the compositing rule of this AlphaComposite object. 279 * 280 * @return the compositing rule of this AlphaComposite object. 281 */ 282 public int getRule() { 283 return rule; 284 } 285 286 /** 287 * Gets the alpha value of this AlphaComposite object; returns 1.0 if this 288 * AlphaComposite object doesn't have alpha value. 289 * 290 * @return the alpha value of this AlphaComposite object or 1.0 if this 291 * AlphaComposite object doesn't have alpha value. 292 */ 293 public float getAlpha() { 294 return alpha; 295 } 296 297 /** 298 * Gets the AlphaComposite instance with the specified rule and alpha value. 299 * 300 * @param rule 301 * the compositing rule. 302 * @param alpha 303 * the alpha value. 304 * @return the AlphaComposite instance. 305 */ 306 public static AlphaComposite getInstance(int rule, float alpha) { 307 if (alpha == 1.0f) { 308 return getInstance(rule); 309 } 310 return new AlphaComposite(rule, alpha); 311 } 312 313 /** 314 * Gets the AlphaComposite instance with the specified rule. 315 * 316 * @param rule 317 * the compositing rule. 318 * @return the AlphaComposite instance. 319 */ 320 public static AlphaComposite getInstance(int rule) { 321 switch (rule) { 322 case CLEAR: 323 return Clear; 324 case SRC: 325 return Src; 326 case DST: 327 return Dst; 328 case SRC_OVER: 329 return SrcOver; 330 case DST_OVER: 331 return DstOver; 332 case SRC_IN: 333 return SrcIn; 334 case DST_IN: 335 return DstIn; 336 case SRC_OUT: 337 return SrcOut; 338 case DST_OUT: 339 return DstOut; 340 case SRC_ATOP: 341 return SrcAtop; 342 case DST_ATOP: 343 return DstAtop; 344 case XOR: 345 return Xor; 346 default: 347 // awt.11D=Unknown rule 348 throw new IllegalArgumentException(Messages.getString("awt.11D")); //$NON-NLS-1$ 349 } 350 } 351 352 } 353
