| 1 | /* IIOParam.java -- |
| 2 | Copyright (C) 2004 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GNU Classpath. |
| 5 | |
| 6 | GNU Classpath is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2, or (at your option) |
| 9 | any later version. |
| 10 | |
| 11 | GNU Classpath is distributed in the hope that it will be useful, but |
| 12 | WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with GNU Classpath; see the file COPYING. If not, write to the |
| 18 | Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 19 | 02110-1301 USA. |
| 20 | |
| 21 | Linking this library statically or dynamically with other modules is |
| 22 | making a combined work based on this library. Thus, the terms and |
| 23 | conditions of the GNU General Public License cover the whole |
| 24 | combination. |
| 25 | |
| 26 | As a special exception, the copyright holders of this library give you |
| 27 | permission to link this library with independent modules to produce an |
| 28 | executable, regardless of the license terms of these independent |
| 29 | modules, and to copy and distribute the resulting executable under |
| 30 | terms of your choice, provided that you also meet, for each linked |
| 31 | independent module, the terms and conditions of the license of that |
| 32 | module. An independent module is a module which is not derived from |
| 33 | or based on this library. If you modify this library, you may extend |
| 34 | this exception to your version of the library, but you are not |
| 35 | obligated to do so. If you do not wish to do so, delete this |
| 36 | exception statement from your version. */ |
| 37 | |
| 38 | |
| 39 | package javax.imageio; |
| 40 | |
| 41 | import java.awt.Point; |
| 42 | import java.awt.Rectangle; |
| 43 | |
| 44 | /** |
| 45 | * An IIOParam stores parameters used when encoding or decoding image |
| 46 | * streams. ImageReadParam and ImageWriteParam extend this abstract |
| 47 | * base class. |
| 48 | * |
| 49 | * IIOParams allow control over how source pixels converted into |
| 50 | * destination pixels. This conversion can take place between a |
| 51 | * stream and in-memory image data, when an image reader is doing the |
| 52 | * conversion, or a writer can be doing the conversion from an |
| 53 | * in-memory source to a stream destination. |
| 54 | * |
| 55 | * An image reader can be restricted to only read from a given region; |
| 56 | * likewise a writer can be restricted to only write output to a given |
| 57 | * region. |
| 58 | * |
| 59 | * For image readers and writers, IIOParam supports image pixelation |
| 60 | * -- where the input image is approximated by the output image using |
| 61 | * larger-sized pixel blocks. For example: FIXME |
| 62 | * |
| 63 | * IIOParams can control how pixels are combined into larger blocks |
| 64 | * using sub-sampling matrices. For example: FIXME |
| 65 | * |
| 66 | * They can also control which source bands are read and written; this |
| 67 | * example reads the RGBA (red, green, blue, transparency) data from a |
| 68 | * PNG image and outputs just the red and transparency bands: FIXME |
| 69 | * |
| 70 | * @author Thomas Fitzsimmons (fitzsim@redhat.com) |
| 71 | * @author Michael Koch (konqueror@gmx.de) |
| 72 | */ |
| 73 | public abstract class IIOParam |
| 74 | { |
| 75 | /** |
| 76 | * The controller called by this IIOParam to retrieve parameters. |
| 77 | */ |
| 78 | protected IIOParamController controller = null; |
| 79 | |
| 80 | /** |
| 81 | * The default controller called by this IIOParam to retrieve |
| 82 | * parameters. |
| 83 | */ |
| 84 | protected IIOParamController defaultController = null; |
| 85 | |
| 86 | /** |
| 87 | * The offset in the destination where the upper-left |
| 88 | * decoded/encoded pixel should be located. |
| 89 | */ |
| 90 | protected Point destinationOffset = new Point(0, 0); |
| 91 | |
| 92 | /** |
| 93 | * Sets the output colour type when writing or the destination image |
| 94 | * type when reading. |
| 95 | */ |
| 96 | protected ImageTypeSpecifier destinationType = null; |
| 97 | |
| 98 | /** |
| 99 | * An array indicating which source bands will be used or null. |
| 100 | */ |
| 101 | protected int[] sourceBands = null; |
| 102 | |
| 103 | /** |
| 104 | * The source pixel region or null. |
| 105 | */ |
| 106 | protected Rectangle sourceRegion = null; |
| 107 | |
| 108 | /** |
| 109 | * Sample every sourceXSubsampling'th pixel in the source image when |
| 110 | * pixelating the destination image in the horizontal direction. |
| 111 | */ |
| 112 | protected int sourceXSubsampling = 1; |
| 113 | |
| 114 | /** |
| 115 | * Sample every sourceYSubsampling'th pixel in the source image when |
| 116 | * pixelating the destination image in the vertical direction. |
| 117 | */ |
| 118 | protected int sourceYSubsampling = 1; |
| 119 | |
| 120 | /** |
| 121 | * Start sampling at this horizontal offset within the source region |
| 122 | * when pixelating the destination image in the horizontal |
| 123 | * direction. |
| 124 | */ |
| 125 | protected int subsamplingXOffset = 0; |
| 126 | |
| 127 | /** |
| 128 | * Start sampling at this vertical offset within the source region |
| 129 | * when pixelating the destination image in the vertical direction. |
| 130 | */ |
| 131 | protected int subsamplingYOffset = 0; |
| 132 | |
| 133 | /** |
| 134 | * Indicates whether or not the controller has been explicitly set |
| 135 | * to null. |
| 136 | */ |
| 137 | private boolean no_controller = false; |
| 138 | |
| 139 | /** |
| 140 | * Constructs an IIOParam object. |
| 141 | */ |
| 142 | protected IIOParam() |
| 143 | { |
| 144 | } |
| 145 | |
| 146 | /** |
| 147 | * Activates the parameter controller by calling its activate method |
| 148 | * and passing it this IIOParam. A true return value indicates that |
| 149 | * this IIOParam's values are ready for the next read or write |
| 150 | * operation. A return value of false means that this IIOParam's |
| 151 | * values have not been affected because the controller operations |
| 152 | * were cancelled. |
| 153 | * |
| 154 | * @return true if parameters were successfully set, false if |
| 155 | * parameters were not changed |
| 156 | */ |
| 157 | public boolean activateController() |
| 158 | { |
| 159 | if (controller == null) |
| 160 | { |
| 161 | if (defaultController == null || no_controller) |
| 162 | return false; |
| 163 | else |
| 164 | return defaultController.activate (this); |
| 165 | } |
| 166 | else |
| 167 | return controller.activate(this); |
| 168 | } |
| 169 | |
| 170 | /** |
| 171 | * Retrieve the currently set controller if one has been set, or the |
| 172 | * default controller, or null if the controller has been explicitly |
| 173 | * set to null. |
| 174 | * |
| 175 | * @return the currently used controller or null |
| 176 | */ |
| 177 | public IIOParamController getController() |
| 178 | { |
| 179 | return controller == null ? |
| 180 | (no_controller ? null : defaultController) : controller; |
| 181 | } |
| 182 | |
| 183 | /** |
| 184 | * Retrieve the default controller regardless of whether or not a |
| 185 | * non-default controller has been set. The default controller may |
| 186 | * be null. |
| 187 | * |
| 188 | * @return the default controller or null |
| 189 | */ |
| 190 | public IIOParamController getDefaultController() |
| 191 | { |
| 192 | return defaultController; |
| 193 | } |
| 194 | |
| 195 | /** |
| 196 | * Retrieve the offset in the destination where the upper-left |
| 197 | * decoded/encoded pixel should be located. (0, 0) by default. |
| 198 | * |
| 199 | * @return the destination offset |
| 200 | */ |
| 201 | public Point getDestinationOffset() |
| 202 | { |
| 203 | return destinationOffset; |
| 204 | } |
| 205 | |
| 206 | /** |
| 207 | * Retrieve the currently set image-type specifier or null if none |
| 208 | * has been set. |
| 209 | * |
| 210 | * @return the current image-type specifier or null |
| 211 | */ |
| 212 | public ImageTypeSpecifier getDestinationType() |
| 213 | { |
| 214 | return destinationType; |
| 215 | } |
| 216 | |
| 217 | /** |
| 218 | * Retrieve the current source band values or null if source band |
| 219 | * values have not been set. |
| 220 | * |
| 221 | * The returned array is a copy of this IIOParam's source band |
| 222 | * array. |
| 223 | * |
| 224 | * @return the current set of source band values or null |
| 225 | */ |
| 226 | public int[] getSourceBands() |
| 227 | { |
| 228 | if (sourceBands == null) |
| 229 | return null; |
| 230 | |
| 231 | int[] sourceBandsCopy = new int[sourceBands.length]; |
| 232 | System.arraycopy (sourceBands, 0, sourceBandsCopy, 0, sourceBands.length); |
| 233 | return sourceBandsCopy; |
| 234 | } |
| 235 | |
| 236 | /** |
| 237 | * Retrieve the source rectangle from which pixels should be read or |
| 238 | * null if no source region has been set. |
| 239 | * |
| 240 | * @return the current source region or null |
| 241 | */ |
| 242 | public Rectangle getSourceRegion() |
| 243 | { |
| 244 | return sourceRegion; |
| 245 | } |
| 246 | |
| 247 | /** |
| 248 | * Retrieve the number of pixel columns to advance before taking a |
| 249 | * pixel sample. |
| 250 | * |
| 251 | * @return the horizontal sub-sampling interval |
| 252 | */ |
| 253 | public int getSourceXSubsampling() |
| 254 | { |
| 255 | return sourceXSubsampling; |
| 256 | } |
| 257 | |
| 258 | /** |
| 259 | * Retrieve the number of pixel rows to advance before taking a |
| 260 | * pixel sample. |
| 261 | * |
| 262 | * @return the vertical sub-sampling interval |
| 263 | */ |
| 264 | public int getSourceYSubsampling() |
| 265 | { |
| 266 | return sourceYSubsampling; |
| 267 | } |
| 268 | |
| 269 | /** |
| 270 | * Retrieve the number of pixel columns to advance before taking any |
| 271 | * pixel samples. |
| 272 | * |
| 273 | * @return the horizontal sub-sampling offset |
| 274 | */ |
| 275 | public int getSubsamplingXOffset() |
| 276 | { |
| 277 | return subsamplingXOffset; |
| 278 | } |
| 279 | |
| 280 | /** |
| 281 | * Retrieve the number of pixel rows to advance before taking any |
| 282 | * pixel samples. |
| 283 | * |
| 284 | * @return the vertical sub-sampling offset |
| 285 | */ |
| 286 | public int getSubsamplingYOffset() |
| 287 | { |
| 288 | return subsamplingYOffset; |
| 289 | } |
| 290 | |
| 291 | /** |
| 292 | * Check if a non-null controller is currently available. |
| 293 | * |
| 294 | * @return true if getController returns a non-null value, false if |
| 295 | * getController returns null |
| 296 | */ |
| 297 | public boolean hasController() |
| 298 | { |
| 299 | return getController() != null; |
| 300 | } |
| 301 | |
| 302 | /** |
| 303 | * Sets the controller for this IIOParam. This is the controller |
| 304 | * that will be activated when activateController is called. The |
| 305 | * argument controller overrides this IIOParam's default controller. |
| 306 | * If the argument is null then no controller will be set, not even |
| 307 | * the default one. To reset the default controller call |
| 308 | * setController(getDefaultController()). |
| 309 | * |
| 310 | * @param controller the controller to set or null |
| 311 | */ |
| 312 | public void setController(IIOParamController controller) |
| 313 | { |
| 314 | if (controller == defaultController) |
| 315 | { |
| 316 | this.controller = null; |
| 317 | no_controller = false; |
| 318 | } |
| 319 | else |
| 320 | { |
| 321 | no_controller = (controller == null); |
| 322 | this.controller = controller; |
| 323 | } |
| 324 | } |
| 325 | |
| 326 | /** |
| 327 | * Set the destination image type. |
| 328 | * |
| 329 | * If this value is set on an image reader then its read method will |
| 330 | * return a new BufferedImage of the specified destination type. In |
| 331 | * this case any destination image set using setDestination() is |
| 332 | * ignored. |
| 333 | * |
| 334 | * If this is set on an image writer then the destination type |
| 335 | * affects only the colour model of the destination image. The |
| 336 | * destination type's SampleModel is ignored. The destination |
| 337 | * type's ColorModel will override the source image's colour model. |
| 338 | * |
| 339 | * @param destinationType the sample and colour models of the |
| 340 | * destination image |
| 341 | */ |
| 342 | public void setDestinationType (ImageTypeSpecifier destinationType) |
| 343 | { |
| 344 | this.destinationType = destinationType; |
| 345 | } |
| 346 | |
| 347 | /** |
| 348 | * Specify the destination pixel offset. Image writers are only |
| 349 | * affected by this setting when ImageWriter.replacePixels is called |
| 350 | * in which case the offset is into the region of pixels being |
| 351 | * changed. |
| 352 | * |
| 353 | * @param destinationOffset the offset where pixel writing should |
| 354 | * begin |
| 355 | */ |
| 356 | public void setDestinationOffset(Point destinationOffset) |
| 357 | { |
| 358 | if (destinationOffset == null) |
| 359 | throw new IllegalArgumentException("destinationOffset is null"); |
| 360 | |
| 361 | this.destinationOffset = destinationOffset; |
| 362 | } |
| 363 | |
| 364 | /** |
| 365 | * Set the indices of the source bands to be used. Duplicate |
| 366 | * indices are not allowed. A value of null means use all source |
| 367 | * bands. The argument array is copied and stored, so subsequent |
| 368 | * updates to it will not be reflected in this IIOParam. |
| 369 | * |
| 370 | * @param sourceBands the array of source bands to use |
| 371 | */ |
| 372 | public void setSourceBands(int[] sourceBands) |
| 373 | { |
| 374 | int[] sourceBandsCopy = new int[sourceBands.length]; |
| 375 | System.arraycopy (sourceBands, 0, sourceBandsCopy, 0, sourceBands.length); |
| 376 | this.sourceBands = sourceBandsCopy; |
| 377 | } |
| 378 | |
| 379 | /** |
| 380 | * Set the source region from which to read. The number of pixels |
| 381 | * sampled from the source region depends on the source sub-sampling |
| 382 | * settings. If the combination of this sourceRegion and the |
| 383 | * current sub-sampling settings would result in no pixels being |
| 384 | * sampled then an IllegalStateException will be thrown. |
| 385 | * |
| 386 | * The source region is specified in the source image coordinate |
| 387 | * system which has point (0, 0) at the top-left and increases down |
| 388 | * and to the right. The argument source region is clipped to the |
| 389 | * image boundaries at read-time. |
| 390 | * |
| 391 | * A null argument sets the source region to null meaning that the |
| 392 | * whole image should be read. |
| 393 | * |
| 394 | * @param sourceRegion the rectangular source region |
| 395 | * |
| 396 | * @exception IllegalArgumentException if sourceRegion has width or |
| 397 | * height <= 0 or x or y < 0 |
| 398 | * @exception IllegalStateException if the given sourceRegion and |
| 399 | * the current sampling settings would produce zero samples |
| 400 | */ |
| 401 | public void setSourceRegion(Rectangle sourceRegion) |
| 402 | { |
| 403 | if (sourceRegion != null |
| 404 | && (sourceRegion.x < 0 |
| 405 | || sourceRegion.y < 0 |
| 406 | || sourceRegion.width <= 0 |
| 407 | || sourceRegion.height <= 0)) |
| 408 | throw new IllegalArgumentException("illegal source region"); |
| 409 | |
| 410 | if (sourceRegion != null) |
| 411 | { |
| 412 | int num_rows = |
| 413 | (sourceRegion.height - subsamplingYOffset + sourceYSubsampling - 1) |
| 414 | / sourceYSubsampling; |
| 415 | |
| 416 | int num_columns = |
| 417 | (sourceRegion.width - subsamplingXOffset + sourceXSubsampling - 1) |
| 418 | / sourceXSubsampling; |
| 419 | |
| 420 | if (num_rows <= 0 || num_columns <= 0) |
| 421 | throw new IllegalStateException("zero pixels in source region"); |
| 422 | } |
| 423 | |
| 424 | this.sourceRegion = sourceRegion; |
| 425 | } |
| 426 | |
| 427 | /** |
| 428 | * Set the source sampling intervals and offsets. Every |
| 429 | * sourceXSubsampling'th pixel horizontally and |
| 430 | * sourceYSubsampling'th pixel vertically will be sampled. Sampling |
| 431 | * will being a the subsamplingXOffset'th column and the |
| 432 | * subsamplingYOffset'th row. |
| 433 | * |
| 434 | * Horizontally, the number of sampled pixels will be: |
| 435 | * |
| 436 | * floor((width - subsamplingXOffset + sourceXSubsampling - 1) / sourceXSubsampling) |
| 437 | * |
| 438 | * Vertically: |
| 439 | * |
| 440 | * floor((height - subsamplingYOffset + sourceYSubsampling - 1) / sourceYSubsampling) |
| 441 | * |
| 442 | * If the current source region setting is such that the given |
| 443 | * sub-sampling arguments would produce zero pixel samples, an |
| 444 | * IllegalStateException is thrown. |
| 445 | * |
| 446 | * The offset parameters can be used to make source regions overlap |
| 447 | * when tiling across an image. This can eliminate seams and |
| 448 | * better-tile images whose width or height is not a multiple of the |
| 449 | * sampling interval. |
| 450 | * |
| 451 | * @param sourceXSubsampling the horizontal sampling interval |
| 452 | * @param sourceYSubsampling the vertical sampling interval |
| 453 | * @param subsamplingXOffset the horizontal offset of the initial |
| 454 | * sample |
| 455 | * @param subsamplingYOffset the vertical offset of the initial |
| 456 | * sample |
| 457 | * |
| 458 | * @exception IllegalArgumentException if either subsamplingXOffset |
| 459 | * or subsamplingYOffset is < 0 |
| 460 | * @exception IllegalStateException if the current source region |
| 461 | * combined with the given sub-sampling parameters would produce |
| 462 | * zero pixel samples |
| 463 | */ |
| 464 | public void setSourceSubsampling(int sourceXSubsampling, int sourceYSubsampling, |
| 465 | int subsamplingXOffset, int subsamplingYOffset) |
| 466 | { |
| 467 | if (subsamplingXOffset < 0 || subsamplingYOffset < 0) |
| 468 | throw new IllegalArgumentException("subsampling offset < 0"); |
| 469 | |
| 470 | if (sourceRegion != null) |
| 471 | { |
| 472 | int num_rows = |
| 473 | (sourceRegion.height - subsamplingYOffset + sourceYSubsampling - 1) |
| 474 | / sourceYSubsampling; |
| 475 | |
| 476 | int num_columns = |
| 477 | (sourceRegion.width - subsamplingXOffset + sourceXSubsampling - 1) |
| 478 | / sourceXSubsampling; |
| 479 | |
| 480 | if (num_rows <= 0 || num_columns <= 0) |
| 481 | throw new IllegalStateException("subsampling parameters would" |
| 482 | + " produce zero pixel samples" |
| 483 | + " in source region"); |
| 484 | } |
| 485 | |
| 486 | this.sourceXSubsampling = sourceXSubsampling; |
| 487 | this.sourceYSubsampling = sourceYSubsampling; |
| 488 | this.subsamplingXOffset = subsamplingXOffset; |
| 489 | this.subsamplingYOffset = subsamplingYOffset; |
| 490 | } |
| 491 | } |