J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1999-2003 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.imageio; |
| 27 | |
| 28 | import java.awt.Dimension; |
| 29 | import java.awt.image.BufferedImage; |
| 30 | |
| 31 | /** |
| 32 | * A class describing how a stream is to be decoded. Instances of |
| 33 | * this class or its subclasses are used to supply prescriptive |
| 34 | * "how-to" information to instances of <code>ImageReader</code>. |
| 35 | * |
| 36 | * <p> An image encoded as part of a file or stream may be thought of |
| 37 | * extending out in multiple dimensions: the spatial dimensions of |
| 38 | * width and height, a number of bands, and a number of progressive |
| 39 | * decoding passes. This class allows a contiguous (hyper)rectangular |
| 40 | * subarea of the image in all of these dimensions to be selected for |
| 41 | * decoding. Additionally, the spatial dimensions may be subsampled |
| 42 | * discontinuously. Finally, color and format conversions may be |
| 43 | * specified by controlling the <code>ColorModel</code> and |
| 44 | * <code>SampleModel</code> of the destination image, either by |
| 45 | * providing a <code>BufferedImage</code> or by using an |
| 46 | * <code>ImageTypeSpecifier</code>. |
| 47 | * |
| 48 | * <p> An <code>ImageReadParam</code> object is used to specify how an |
| 49 | * image, or a set of images, will be converted on input from |
| 50 | * a stream in the context of the Java Image I/O framework. A plug-in for a |
| 51 | * specific image format will return instances of |
| 52 | * <code>ImageReadParam</code> from the |
| 53 | * <code>getDefaultReadParam</code> method of its |
| 54 | * <code>ImageReader</code> implementation. |
| 55 | * |
| 56 | * <p> The state maintained by an instance of |
| 57 | * <code>ImageReadParam</code> is independent of any particular image |
| 58 | * being decoded. When actual decoding takes place, the values set in |
| 59 | * the read param are combined with the actual properties of the image |
| 60 | * being decoded from the stream and the destination |
| 61 | * <code>BufferedImage</code> that will receive the decoded pixel |
| 62 | * data. For example, the source region set using |
| 63 | * <code>setSourceRegion</code> will first be intersected with the |
| 64 | * actual valid source area. The result will be translated by the |
| 65 | * value returned by <code>getDestinationOffset</code>, and the |
| 66 | * resulting rectangle intersected with the actual valid destination |
| 67 | * area to yield the destination area that will be written. |
| 68 | * |
| 69 | * <p> The parameters specified by an <code>ImageReadParam</code> are |
| 70 | * applied to an image as follows. First, if a rendering size has |
| 71 | * been set by <code>setSourceRenderSize</code>, the entire decoded |
| 72 | * image is rendered at the size given by |
| 73 | * <code>getSourceRenderSize</code>. Otherwise, the image has its |
| 74 | * natural size given by <code>ImageReader.getWidth</code> and |
| 75 | * <code>ImageReader.getHeight</code>. |
| 76 | * |
| 77 | * <p> Next, the image is clipped against the source region |
| 78 | * specified by <code>getSourceXOffset</code>, <code>getSourceYOffset</code>, |
| 79 | * <code>getSourceWidth</code>, and <code>getSourceHeight</code>. |
| 80 | * |
| 81 | * <p> The resulting region is then subsampled according to the |
| 82 | * factors given in {@link IIOParam#setSourceSubsampling |
| 83 | * <code>IIOParam.setSourceSubsampling</code>}. The first pixel, |
| 84 | * the number of pixels per row, and the number of rows all depend |
| 85 | * on the subsampling settings. |
| 86 | * Call the minimum X and Y coordinates of the resulting rectangle |
| 87 | * (<code>minX</code>, <code>minY</code>), its width <code>w</code> |
| 88 | * and its height <code>h</code>. |
| 89 | * |
| 90 | * <p> This rectangle is offset by |
| 91 | * (<code>getDestinationOffset().x</code>, |
| 92 | * <code>getDestinationOffset().y</code>) and clipped against the |
| 93 | * destination bounds. If no destination image has been set, the |
| 94 | * destination is defined to have a width of |
| 95 | * <code>getDestinationOffset().x</code> + <code>w</code>, and a |
| 96 | * height of <code>getDestinationOffset().y</code> + <code>h</code> so |
| 97 | * that all pixels of the source region may be written to the |
| 98 | * destination. |
| 99 | * |
| 100 | * <p> Pixels that land, after subsampling, within the destination |
| 101 | * image, and that are written in one of the progressive passes |
| 102 | * specified by <code>getSourceMinProgressivePass</code> and |
| 103 | * <code>getSourceNumProgressivePasses</code> are passed along to the |
| 104 | * next step. |
| 105 | * |
| 106 | * <p> Finally, the source samples of each pixel are mapped into |
| 107 | * destination bands according to the algorithm described in the |
| 108 | * comment for <code>setDestinationBands</code>. |
| 109 | * |
| 110 | * <p> Plug-in writers may extend the functionality of |
| 111 | * <code>ImageReadParam</code> by providing a subclass that implements |
| 112 | * additional, plug-in specific interfaces. It is up to the plug-in |
| 113 | * to document what interfaces are available and how they are to be |
| 114 | * used. Readers will silently ignore any extended features of an |
| 115 | * <code>ImageReadParam</code> subclass of which they are not aware. |
| 116 | * Also, they may ignore any optional features that they normally |
| 117 | * disable when creating their own <code>ImageReadParam</code> |
| 118 | * instances via <code>getDefaultReadParam</code>. |
| 119 | * |
| 120 | * <p> Note that unless a query method exists for a capability, it must |
| 121 | * be supported by all <code>ImageReader</code> implementations |
| 122 | * (<i>e.g.</i> source render size is optional, but subsampling must be |
| 123 | * supported). |
| 124 | * |
| 125 | * |
| 126 | * @see ImageReader |
| 127 | * @see ImageWriter |
| 128 | * @see ImageWriteParam |
| 129 | */ |
| 130 | public class ImageReadParam extends IIOParam { |
| 131 | |
| 132 | /** |
| 133 | * <code>true</code> if this <code>ImageReadParam</code> allows |
| 134 | * the source rendering dimensions to be set. By default, the |
| 135 | * value is <code>false</code>. Subclasses must set this value |
| 136 | * manually. |
| 137 | * |
| 138 | * <p> <code>ImageReader</code>s that do not support setting of |
| 139 | * the source render size should set this value to |
| 140 | * <code>false</code>. |
| 141 | */ |
| 142 | protected boolean canSetSourceRenderSize = false; |
| 143 | |
| 144 | /** |
| 145 | * The desired rendering width and height of the source, if |
| 146 | * <code>canSetSourceRenderSize</code> is <code>true</code>, or |
| 147 | * <code>null</code>. |
| 148 | * |
| 149 | * <p> <code>ImageReader</code>s that do not support setting of |
| 150 | * the source render size may ignore this value. |
| 151 | */ |
| 152 | protected Dimension sourceRenderSize = null; |
| 153 | |
| 154 | /** |
| 155 | * The current destination <code>BufferedImage</code>, or |
| 156 | * <code>null</code> if none has been set. By default, the value |
| 157 | * is <code>null</code>. |
| 158 | */ |
| 159 | protected BufferedImage destination = null; |
| 160 | |
| 161 | /** |
| 162 | * The set of destination bands to be used, as an array of |
| 163 | * <code>int</code>s. By default, the value is <code>null</code>, |
| 164 | * indicating all destination bands should be written in order. |
| 165 | */ |
| 166 | protected int[] destinationBands = null; |
| 167 | |
| 168 | /** |
| 169 | * The minimum index of a progressive pass to read from the |
| 170 | * source. By default, the value is set to 0, which indicates |
| 171 | * that passes starting with the first available pass should be |
| 172 | * decoded. |
| 173 | * |
| 174 | * <p> Subclasses should ensure that this value is |
| 175 | * non-negative. |
| 176 | */ |
| 177 | protected int minProgressivePass = 0; |
| 178 | |
| 179 | /** |
| 180 | * The maximum number of progressive passes to read from the |
| 181 | * source. By default, the value is set to |
| 182 | * <code>Integer.MAX_VALUE</code>, which indicates that passes up |
| 183 | * to and including the last available pass should be decoded. |
| 184 | * |
| 185 | * <p> Subclasses should ensure that this value is positive. |
| 186 | * Additionally, if the value is not |
| 187 | * <code>Integer.MAX_VALUE</code>, then <code>minProgressivePass + |
| 188 | * numProgressivePasses - 1</code> should not exceed |
| 189 | * <code>Integer.MAX_VALUE</code>. |
| 190 | */ |
| 191 | protected int numProgressivePasses = Integer.MAX_VALUE; |
| 192 | |
| 193 | /** |
| 194 | * Constructs an <code>ImageReadParam</code>. |
| 195 | */ |
| 196 | public ImageReadParam() {} |
| 197 | |
| 198 | // Comment inherited |
| 199 | public void setDestinationType(ImageTypeSpecifier destinationType) { |
| 200 | super.setDestinationType(destinationType); |
| 201 | setDestination(null); |
| 202 | } |
| 203 | |
| 204 | /** |
| 205 | * Supplies a <code>BufferedImage</code> to be used as the |
| 206 | * destination for decoded pixel data. The currently set image |
| 207 | * will be written to by the <code>read</code>, |
| 208 | * <code>readAll</code>, and <code>readRaster</code> methods, and |
| 209 | * a reference to it will be returned by those methods. |
| 210 | * |
| 211 | * <p> Pixel data from the aforementioned methods will be written |
| 212 | * starting at the offset specified by |
| 213 | * <code>getDestinationOffset</code>. |
| 214 | * |
| 215 | * <p> If <code>destination</code> is <code>null</code>, a |
| 216 | * newly-created <code>BufferedImage</code> will be returned by |
| 217 | * those methods. |
| 218 | * |
| 219 | * <p> At the time of reading, the image is checked to verify that |
| 220 | * its <code>ColorModel</code> and <code>SampleModel</code> |
| 221 | * correspond to one of the <code>ImageTypeSpecifier</code>s |
| 222 | * returned from the <code>ImageReader</code>'s |
| 223 | * <code>getImageTypes</code> method. If it does not, the reader |
| 224 | * will throw an <code>IIOException</code>. |
| 225 | * |
| 226 | * @param destination the BufferedImage to be written to, or |
| 227 | * <code>null</code>. |
| 228 | * |
| 229 | * @see #getDestination |
| 230 | */ |
| 231 | public void setDestination(BufferedImage destination) { |
| 232 | this.destination = destination; |
| 233 | } |
| 234 | |
| 235 | /** |
| 236 | * Returns the <code>BufferedImage</code> currently set by the |
| 237 | * <code>setDestination</code> method, or <code>null</code> |
| 238 | * if none is set. |
| 239 | * |
| 240 | * @return the BufferedImage to be written to. |
| 241 | * |
| 242 | * @see #setDestination |
| 243 | */ |
| 244 | public BufferedImage getDestination() { |
| 245 | return destination; |
| 246 | } |
| 247 | |
| 248 | /** |
| 249 | * Sets the indices of the destination bands where data |
| 250 | * will be placed. Duplicate indices are not allowed. |
| 251 | * |
| 252 | * <p> A <code>null</code> value indicates that all destination |
| 253 | * bands will be used. |
| 254 | * |
| 255 | * <p> Choosing a destination band subset will not affect the |
| 256 | * number of bands in the output image of a read if no destination |
| 257 | * image is specified; the created destination image will still |
| 258 | * have the same number of bands as if this method had never been |
| 259 | * called. If a different number of bands in the destination |
| 260 | * image is desired, an image must be supplied using the |
| 261 | * <code>ImageReadParam.setDestination</code> method. |
| 262 | * |
| 263 | * <p> At the time of reading or writing, an |
| 264 | * <code>IllegalArgumentException</code> will be thrown by the |
| 265 | * reader or writer if a value larger than the largest destination |
| 266 | * band index has been specified, or if the number of source bands |
| 267 | * and destination bands to be used differ. The |
| 268 | * <code>ImageReader.checkReadParamBandSettings</code> method may |
| 269 | * be used to automate this test. |
| 270 | * |
| 271 | * @param destinationBands an array of integer band indices to be |
| 272 | * used. |
| 273 | * |
| 274 | * @exception IllegalArgumentException if <code>destinationBands</code> |
| 275 | * contains a negative or duplicate value. |
| 276 | * |
| 277 | * @see #getDestinationBands |
| 278 | * @see #getSourceBands |
| 279 | * @see ImageReader#checkReadParamBandSettings |
| 280 | */ |
| 281 | public void setDestinationBands(int[] destinationBands) { |
| 282 | if (destinationBands == null) { |
| 283 | this.destinationBands = null; |
| 284 | } else { |
| 285 | int numBands = destinationBands.length; |
| 286 | for (int i = 0; i < numBands; i++) { |
| 287 | int band = destinationBands[i]; |
| 288 | if (band < 0) { |
| 289 | throw new IllegalArgumentException("Band value < 0!"); |
| 290 | } |
| 291 | for (int j = i + 1; j < numBands; j++) { |
| 292 | if (band == destinationBands[j]) { |
| 293 | throw new IllegalArgumentException("Duplicate band value!"); |
| 294 | } |
| 295 | } |
| 296 | } |
| 297 | this.destinationBands = (int[])destinationBands.clone(); |
| 298 | } |
| 299 | } |
| 300 | |
| 301 | /** |
| 302 | * Returns the set of band indices where data will be placed. |
| 303 | * If no value has been set, <code>null</code> is returned to |
| 304 | * indicate that all destination bands will be used. |
| 305 | * |
| 306 | * @return the indices of the destination bands to be used, |
| 307 | * or <code>null</code>. |
| 308 | * |
| 309 | * @see #setDestinationBands |
| 310 | */ |
| 311 | public int[] getDestinationBands() { |
| 312 | if (destinationBands == null) { |
| 313 | return null; |
| 314 | } else { |
| 315 | return (int[])(destinationBands.clone()); |
| 316 | } |
| 317 | } |
| 318 | |
| 319 | /** |
| 320 | * Returns <code>true</code> if this reader allows the source |
| 321 | * image to be rendered at an arbitrary size as part of the |
| 322 | * decoding process, by means of the |
| 323 | * <code>setSourceRenderSize</code> method. If this method |
| 324 | * returns <code>false</code>, calls to |
| 325 | * <code>setSourceRenderSize</code> will throw an |
| 326 | * <code>UnsupportedOperationException</code>. |
| 327 | * |
| 328 | * @return <code>true</code> if setting source rendering size is |
| 329 | * supported. |
| 330 | * |
| 331 | * @see #setSourceRenderSize |
| 332 | */ |
| 333 | public boolean canSetSourceRenderSize() { |
| 334 | return canSetSourceRenderSize; |
| 335 | } |
| 336 | |
| 337 | /** |
| 338 | * If the image is able to be rendered at an arbitrary size, sets |
| 339 | * the source width and height to the supplied values. Note that |
| 340 | * the values returned from the <code>getWidth</code> and |
| 341 | * <code>getHeight</code> methods on <code>ImageReader</code> are |
| 342 | * not affected by this method; they will continue to return the |
| 343 | * default size for the image. Similarly, if the image is also |
| 344 | * tiled the tile width and height are given in terms of the default |
| 345 | * size. |
| 346 | * |
| 347 | * <p> Typically, the width and height should be chosen such that |
| 348 | * the ratio of width to height closely approximates the aspect |
| 349 | * ratio of the image, as returned from |
| 350 | * <code>ImageReader.getAspectRatio</code>. |
| 351 | * |
| 352 | * <p> If this plug-in does not allow the rendering size to be |
| 353 | * set, an <code>UnsupportedOperationException</code> will be |
| 354 | * thrown. |
| 355 | * |
| 356 | * <p> To remove the render size setting, pass in a value of |
| 357 | * <code>null</code> for <code>size</code>. |
| 358 | * |
| 359 | * @param size a <code>Dimension</code> indicating the desired |
| 360 | * width and height. |
| 361 | * |
| 362 | * @exception IllegalArgumentException if either the width or the |
| 363 | * height is negative or 0. |
| 364 | * @exception UnsupportedOperationException if image resizing |
| 365 | * is not supported by this plug-in. |
| 366 | * |
| 367 | * @see #getSourceRenderSize |
| 368 | * @see ImageReader#getWidth |
| 369 | * @see ImageReader#getHeight |
| 370 | * @see ImageReader#getAspectRatio |
| 371 | */ |
| 372 | public void setSourceRenderSize(Dimension size) |
| 373 | throws UnsupportedOperationException { |
| 374 | if (!canSetSourceRenderSize()) { |
| 375 | throw new UnsupportedOperationException |
| 376 | ("Can't set source render size!"); |
| 377 | } |
| 378 | |
| 379 | if (size == null) { |
| 380 | this.sourceRenderSize = null; |
| 381 | } else { |
| 382 | if (size.width <= 0 || size.height <= 0) { |
| 383 | throw new IllegalArgumentException("width or height <= 0!"); |
| 384 | } |
| 385 | this.sourceRenderSize = (Dimension)size.clone(); |
| 386 | } |
| 387 | } |
| 388 | |
| 389 | /** |
| 390 | * Returns the width and height of the source image as it |
| 391 | * will be rendered during decoding, if they have been set via the |
| 392 | * <code>setSourceRenderSize</code> method. A |
| 393 | * <code>null</code>value indicates that no setting has been made. |
| 394 | * |
| 395 | * @return the rendered width and height of the source image |
| 396 | * as a <code>Dimension</code>. |
| 397 | * |
| 398 | * @see #setSourceRenderSize |
| 399 | */ |
| 400 | public Dimension getSourceRenderSize() { |
| 401 | return (sourceRenderSize == null) ? |
| 402 | null : (Dimension)sourceRenderSize.clone(); |
| 403 | } |
| 404 | |
| 405 | /** |
| 406 | * Sets the range of progressive passes that will be decoded. |
| 407 | * Passes outside of this range will be ignored. |
| 408 | * |
| 409 | * <p> A progressive pass is a re-encoding of the entire image, |
| 410 | * generally at progressively higher effective resolutions, but |
| 411 | * requiring greater transmission bandwidth. The most common use |
| 412 | * of progressive encoding is found in the JPEG format, where |
| 413 | * successive passes include more detailed representations of the |
| 414 | * high-frequency image content. |
| 415 | * |
| 416 | * <p> The actual number of passes to be decoded is determined |
| 417 | * during decoding, based on the number of actual passes available |
| 418 | * in the stream. Thus if <code>minPass + numPasses - 1</code> is |
| 419 | * larger than the index of the last available passes, decoding |
| 420 | * will end with that pass. |
| 421 | * |
| 422 | * <p> A value of <code>numPasses</code> of |
| 423 | * <code>Integer.MAX_VALUE</code> indicates that all passes from |
| 424 | * <code>minPass</code> forward should be read. Otherwise, the |
| 425 | * index of the last pass (<i>i.e.</i>, <code>minPass + numPasses |
| 426 | * - 1</code>) must not exceed <code>Integer.MAX_VALUE</code>. |
| 427 | * |
| 428 | * <p> There is no <code>unsetSourceProgressivePasses</code> |
| 429 | * method; the same effect may be obtained by calling |
| 430 | * <code>setSourceProgressivePasses(0, Integer.MAX_VALUE)</code>. |
| 431 | * |
| 432 | * @param minPass the index of the first pass to be decoded. |
| 433 | * @param numPasses the maximum number of passes to be decoded. |
| 434 | * |
| 435 | * @exception IllegalArgumentException if <code>minPass</code> is |
| 436 | * negative, <code>numPasses</code> is negative or 0, or |
| 437 | * <code>numPasses</code> is smaller than |
| 438 | * <code>Integer.MAX_VALUE</code> but <code>minPass + |
| 439 | * numPasses - 1</code> is greater than |
| 440 | * <code>INTEGER.MAX_VALUE</code>. |
| 441 | * |
| 442 | * @see #getSourceMinProgressivePass |
| 443 | * @see #getSourceMaxProgressivePass |
| 444 | */ |
| 445 | public void setSourceProgressivePasses(int minPass, int numPasses) { |
| 446 | if (minPass < 0) { |
| 447 | throw new IllegalArgumentException("minPass < 0!"); |
| 448 | } |
| 449 | if (numPasses <= 0) { |
| 450 | throw new IllegalArgumentException("numPasses <= 0!"); |
| 451 | } |
| 452 | if ((numPasses != Integer.MAX_VALUE) && |
| 453 | (((minPass + numPasses - 1) & 0x80000000) != 0)) { |
| 454 | throw new IllegalArgumentException |
| 455 | ("minPass + numPasses - 1 > INTEGER.MAX_VALUE!"); |
| 456 | } |
| 457 | |
| 458 | this.minProgressivePass = minPass; |
| 459 | this.numProgressivePasses = numPasses; |
| 460 | } |
| 461 | |
| 462 | /** |
| 463 | * Returns the index of the first progressive pass that will be |
| 464 | * decoded. If no value has been set, 0 will be returned (which is |
| 465 | * the correct value). |
| 466 | * |
| 467 | * @return the index of the first pass that will be decoded. |
| 468 | * |
| 469 | * @see #setSourceProgressivePasses |
| 470 | * @see #getSourceNumProgressivePasses |
| 471 | */ |
| 472 | public int getSourceMinProgressivePass() { |
| 473 | return minProgressivePass; |
| 474 | } |
| 475 | |
| 476 | /** |
| 477 | * If <code>getSourceNumProgressivePasses</code> is equal to |
| 478 | * <code>Integer.MAX_VALUE</code>, returns |
| 479 | * <code>Integer.MAX_VALUE</code>. Otherwise, returns |
| 480 | * <code>getSourceMinProgressivePass() + |
| 481 | * getSourceNumProgressivePasses() - 1</code>. |
| 482 | * |
| 483 | * @return the index of the last pass to be read, or |
| 484 | * <code>Integer.MAX_VALUE</code>. |
| 485 | */ |
| 486 | public int getSourceMaxProgressivePass() { |
| 487 | if (numProgressivePasses == Integer.MAX_VALUE) { |
| 488 | return Integer.MAX_VALUE; |
| 489 | } else { |
| 490 | return minProgressivePass + numProgressivePasses - 1; |
| 491 | } |
| 492 | } |
| 493 | |
| 494 | /** |
| 495 | * Returns the number of the progressive passes that will be |
| 496 | * decoded. If no value has been set, |
| 497 | * <code>Integer.MAX_VALUE</code> will be returned (which is the |
| 498 | * correct value). |
| 499 | * |
| 500 | * @return the number of the passes that will be decoded. |
| 501 | * |
| 502 | * @see #setSourceProgressivePasses |
| 503 | * @see #getSourceMinProgressivePass |
| 504 | */ |
| 505 | public int getSourceNumProgressivePasses() { |
| 506 | return numProgressivePasses; |
| 507 | } |
| 508 | } |