1 /*
2 * Copyright 2000-2001 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.Point;
29 import java.awt.Rectangle;
30
31 /**
32 * A superclass of all classes describing how streams should be
33 * decoded or encoded. This class contains all the variables and
34 * methods that are shared by <code>ImageReadParam</code> and
35 * <code>ImageWriteParam</code>.
36 *
37 * <p> This class provides mechanisms to specify a source region and a
38 * destination region. When reading, the source is the stream and
39 * the in-memory image is the destination. When writing, these are
40 * reversed. In the case of writing, destination regions may be used
41 * only with a writer that supports pixel replacement.
42 * <p>
43 * Decimation subsampling may be specified for both readers
44 * and writers, using a movable subsampling grid.
45 * <p>
46 * Subsets of the source and destination bands may be selected.
47 *
48 */
49 public abstract class IIOParam {
50
51 /**
52 * The source region, on <code>null</code> if none is set.
53 */
54 protected Rectangle sourceRegion = null;
55
56 /**
57 * The decimation subsampling to be applied in the horizontal
58 * direction. By default, the value is <code>1</code>.
59 * The value must not be negative or 0.
60 */
61 protected int sourceXSubsampling = 1;
62
63 /**
64 * The decimation subsampling to be applied in the vertical
65 * direction. By default, the value is <code>1</code>.
66 * The value must not be negative or 0.
67 */
68 protected int sourceYSubsampling = 1;
69
70 /**
71 * A horizontal offset to be applied to the subsampling grid before
72 * subsampling. The first pixel to be used will be offset this
73 * amount from the origin of the region, or of the image if no
74 * region is specified.
75 */
76 protected int subsamplingXOffset = 0;
77
78 /**
79 * A vertical offset to be applied to the subsampling grid before
80 * subsampling. The first pixel to be used will be offset this
81 * amount from the origin of the region, or of the image if no
82 * region is specified.
83 */
84 protected int subsamplingYOffset = 0;
85
86 /**
87 * An array of <code>int</code>s indicating which source bands
88 * will be used, or <code>null</code>. If <code>null</code>, the
89 * set of source bands to be used is as described in the comment
90 * for the <code>setSourceBands</code> method. No value should
91 * be allowed to be negative.
92 */
93 protected int[] sourceBands = null;
94
95 /**
96 * An <code>ImageTypeSpecifier</code> to be used to generate a
97 * destination image when reading, or to set the output color type
98 * when writing. If non has been setm the value will be
99 * <code>null</code>. By default, the value is <code>null</code>.
100 */
101 protected ImageTypeSpecifier destinationType = null;
102
103 /**
104 * The offset in the destination where the upper-left decoded
105 * pixel should be placed. By default, the value is (0, 0).
106 */
107 protected Point destinationOffset = new Point(0, 0);
108
109 /**
110 * The default <code>IIOParamController</code> that will be
111 * used to provide settings for this <code>IIOParam</code>
112 * object when the <code>activateController</code> method
113 * is called. This default should be set by subclasses
114 * that choose to provide their own default controller,
115 * usually a GUI, for setting parameters.
116 *
117 * @see IIOParamController
118 * @see #getDefaultController
119 * @see #activateController
120 */
121 protected IIOParamController defaultController = null;
122
123 /**
124 * The <code>IIOParamController</code> that will be
125 * used to provide settings for this <code>IIOParam</code>
126 * object when the <code>activateController</code> method
127 * is called. This value overrides any default controller,
128 * even when null.
129 *
130 * @see IIOParamController
131 * @see #setController(IIOParamController)
132 * @see #hasController()
133 * @see #activateController()
134 */
135 protected IIOParamController controller = null;
136
137 /**
138 * Protected constructor may be called only by subclasses.
139 */
140 protected IIOParam() {
141 controller = defaultController;
142 }
143
144 /**
145 * Sets the source region of interest. The region of interest is
146 * described as a rectangle, with the upper-left corner of the
147 * source image as pixel (0, 0) and increasing values down and to
148 * the right. The actual number of pixels used will depend on
149 * the subsampling factors set by <code>setSourceSubsampling</code>.
150 * If subsampling has been set such that this number is zero,
151 * an <code>IllegalStateException</code> will be thrown.
152 *
153 * <p> The source region of interest specified by this method will
154 * be clipped as needed to fit within the source bounds, as well
155 * as the destination offsets, width, and height at the time of
156 * actual I/O.
157 *
158 * <p> A value of <code>null</code> for <code>sourceRegion</code>
159 * will remove any region specification, causing the entire image
160 * to be used.
161 *
162 * @param sourceRegion a <code>Rectangle</code> specifying the
163 * source region of interest, or <code>null</code>.
164 *
165 * @exception IllegalArgumentException if
166 * <code>sourceRegion</code> is non-<code>null</code> and either
167 * <code>sourceRegion.x</code> or <code>sourceRegion.y</code> is
168 * negative.
169 * @exception IllegalArgumentException if
170 * <code>sourceRegion</code> is non-<code>null</code> and either
171 * <code>sourceRegion.width</code> or
172 * <code>sourceRegion.height</code> is negative or 0.
173 * @exception IllegalStateException if subsampling is such that
174 * this region will have a subsampled width or height of zero.
175 *
176 * @see #getSourceRegion
177 * @see #setSourceSubsampling
178 * @see ImageReadParam#setDestinationOffset
179 * @see ImageReadParam#getDestinationOffset
180 */
181 public void setSourceRegion(Rectangle sourceRegion) {
182 if (sourceRegion == null) {
183 this.sourceRegion = null;
184 return;
185 }
186
187 if (sourceRegion.x < 0) {
188 throw new IllegalArgumentException("sourceRegion.x < 0!");
189 }
190 if (sourceRegion.y < 0){
191 throw new IllegalArgumentException("sourceRegion.y < 0!");
192 }
193 if (sourceRegion.width <= 0) {
194 throw new IllegalArgumentException("sourceRegion.width <= 0!");
195 }
196 if (sourceRegion.height <= 0) {
197 throw new IllegalArgumentException("sourceRegion.height <= 0!");
198 }
199
200 // Throw an IllegalStateException if region falls between subsamples
201 if (sourceRegion.width <= subsamplingXOffset) {
202 throw new IllegalStateException
203 ("sourceRegion.width <= subsamplingXOffset!");
204 }
205 if (sourceRegion.height <= subsamplingYOffset) {
206 throw new IllegalStateException
207 ("sourceRegion.height <= subsamplingYOffset!");
208 }
209
210 this.sourceRegion = (Rectangle)sourceRegion.clone();
211 }
212
213 /**
214 * Returns the source region to be used. The returned value is
215 * that set by the most recent call to
216 * <code>setSourceRegion</code>, and will be <code>null</code> if
217 * there is no region set.
218 *
219 * @return the source region of interest as a
220 * <code>Rectangle</code>, or <code>null</code>.
221 *
222 * @see #setSourceRegion
223 */
224 public Rectangle getSourceRegion() {
225 if (sourceRegion == null) {
226 return null;
227 }
228 return (Rectangle)sourceRegion.clone();
229 }
230
231 /**
232 * Specifies a decimation subsampling to apply on I/O. The
233 * <code>sourceXSubsampling</code> and
234 * <code>sourceYSubsampling</code> parameters specify the
235 * subsampling period (<i>i.e.</i>, the number of rows and columns
236 * to advance after every source pixel). Specifically, a period of
237 * 1 will use every row or column; a period of 2 will use every
238 * other row or column. The <code>subsamplingXOffset</code> and
239 * <code>subsamplingYOffset</code> parameters specify an offset
240 * from the region (or image) origin for the first subsampled pixel.
241 * Adjusting the origin of the subsample grid is useful for avoiding
242 * seams when subsampling a very large source image into destination
243 * regions that will be assembled into a complete subsampled image.
244 * Most users will want to simply leave these parameters at 0.
245 *
246 * <p> The number of pixels and scanlines to be used are calculated
247 * as follows.
248 * <p>
249 * The number of subsampled pixels in a scanline is given by
250 * <p>
251 * <code>truncate[(width - subsamplingXOffset + sourceXSubsampling - 1)
252 * / sourceXSubsampling]</code>.
253 * <p>
254 * If the region is such that this width is zero, an
255 * <code>IllegalStateException</code> is thrown.
256 * <p>
257 * The number of scanlines to be used can be computed similarly.
258 *
259 * <p>The ability to set the subsampling grid to start somewhere
260 * other than the source region origin is useful if the
261 * region is being used to create subsampled tiles of a large image,
262 * where the tile width and height are not multiples of the
263 * subsampling periods. If the subsampling grid does not remain
264 * consistent from tile to tile, there will be artifacts at the tile
265 * boundaries. By adjusting the subsampling grid offset for each
266 * tile to compensate, these artifacts can be avoided. The tradeoff
267 * is that in order to avoid these artifacts, the tiles are not all
268 * the same size. The grid offset to use in this case is given by:
269 * <br>
270 * grid offset = [period - (region offset modulo period)] modulo period)
271 *
272 * <p> If either <code>sourceXSubsampling</code> or
273 * <code>sourceYSubsampling</code> is 0 or negative, an
274 * <code>IllegalArgumentException</code> will be thrown.
275 *
276 * <p> If either <code>subsamplingXOffset</code> or
277 * <code>subsamplingYOffset</code> is negative or greater than or
278 * equal to the corresponding period, an
279 * <code>IllegalArgumentException</code> will be thrown.
280 *
281 * <p> There is no <code>unsetSourceSubsampling</code> method;
282 * simply call <code>setSourceSubsampling(1, 1, 0, 0)</code> to
283 * restore default values.
284 *
285 * @param sourceXSubsampling the number of columns to advance
286 * between pixels.
287 * @param sourceYSubsampling the number of rows to advance between
288 * pixels.
289 * @param subsamplingXOffset the horizontal offset of the first subsample
290 * within the region, or within the image if no region is set.
291 * @param subsamplingYOffset the horizontal offset of the first subsample
292 * within the region, or within the image if no region is set.
293 * @exception IllegalArgumentException if either period is
294 * negative or 0, or if either grid offset is negative or greater than
295 * the corresponding period.
296 * @exception IllegalStateException if the source region is such that
297 * the subsampled output would contain no pixels.
298 */
299 public void setSourceSubsampling(int sourceXSubsampling,
300 int sourceYSubsampling,
301 int subsamplingXOffset,
302 int subsamplingYOffset) {
303 if (sourceXSubsampling <= 0) {
304 throw new IllegalArgumentException("sourceXSubsampling <= 0!");
305 }
306 if (sourceYSubsampling <= 0) {
307 throw new IllegalArgumentException("sourceYSubsampling <= 0!");
308 }
309 if (subsamplingXOffset < 0 ||
310 subsamplingXOffset >= sourceXSubsampling) {
311 throw new IllegalArgumentException
312 ("subsamplingXOffset out of range!");
313 }
314 if (subsamplingYOffset < 0 ||
315 subsamplingYOffset >= sourceYSubsampling) {
316 throw new IllegalArgumentException
317 ("subsamplingYOffset out of range!");
318 }
319
320 // Throw an IllegalStateException if region falls between subsamples
321 if (sourceRegion != null) {
322 if (subsamplingXOffset >= sourceRegion.width ||
323 subsamplingYOffset >= sourceRegion.height) {
324 throw new IllegalStateException("region contains no pixels!");
325 }
326 }
327
328 this.sourceXSubsampling = sourceXSubsampling;
329 this.sourceYSubsampling = sourceYSubsampling;
330 this.subsamplingXOffset = subsamplingXOffset;
331 this.subsamplingYOffset = subsamplingYOffset;
332 }
333
334 /**
335 * Returns the number of source columns to advance for each pixel.
336 *
337 * <p>If <code>setSourceSubsampling</code> has not been called, 1
338 * is returned (which is the correct value).
339 *
340 * @return the source subsampling X period.
341 *
342 * @see #setSourceSubsampling
343 * @see #getSourceYSubsampling
344 */
345 public int getSourceXSubsampling() {
346 return sourceXSubsampling;
347 }
348
349 /**
350 * Returns the number of rows to advance for each pixel.
351 *
352 * <p>If <code>setSourceSubsampling</code> has not been called, 1
353 * is returned (which is the correct value).
354 *
355 * @return the source subsampling Y period.
356 *
357 * @see #setSourceSubsampling
358 * @see #getSourceXSubsampling
359 */
360 public int getSourceYSubsampling() {
361 return sourceYSubsampling;
362 }
363
364 /**
365 * Returns the horizontal offset of the subsampling grid.
366 *
367 * <p>If <code>setSourceSubsampling</code> has not been called, 0
368 * is returned (which is the correct value).
369 *
370 * @return the source subsampling grid X offset.
371 *
372 * @see #setSourceSubsampling
373 * @see #getSubsamplingYOffset
374 */
375 public int getSubsamplingXOffset() {
376 return subsamplingXOffset;
377 }
378
379 /**
380 * Returns the vertical offset of the subsampling grid.
381 *
382 * <p>If <code>setSourceSubsampling</code> has not been called, 0
383 * is returned (which is the correct value).
384 *
385 * @return the source subsampling grid Y offset.
386 *
387 * @see #setSourceSubsampling
388 * @see #getSubsamplingXOffset
389 */
390 public int getSubsamplingYOffset() {
391 return subsamplingYOffset;
392 }
393
394 /**
395 * Sets the indices of the source bands to be used. Duplicate
396 * indices are not allowed.
397 *
398 * <p> A <code>null</code> value indicates that all source bands
399 * will be used.
400 *
401 * <p> At the time of reading, an
402 * <code>IllegalArgumentException</code> will be thrown by the
403 * reader or writer if a value larger than the largest available
404 * source band index has been specified or if the number of source
405 * bands and destination bands to be used differ. The
406 * <code>ImageReader.checkReadParamBandSettings</code> method may
407 * be used to automate this test.
408 *
409 * <p> Semantically, a copy is made of the array; changes to the
410 * array contents subsequent to this call have no effect on
411 * this <code>IIOParam</code>.
412 *
413 * @param sourceBands an array of integer band indices to be
414 * used.
415 *
416 * @exception IllegalArgumentException if <code>sourceBands</code>
417 * contains a negative or duplicate value.
418 *
419 * @see #getSourceBands
420 * @see ImageReadParam#setDestinationBands
421 * @see ImageReader#checkReadParamBandSettings
422 */
423 public void setSourceBands(int[] sourceBands) {
424 if (sourceBands == null) {
425 this.sourceBands = null;
426 } else {
427 int numBands = sourceBands.length;
428 for (int i = 0; i < numBands; i++) {
429 int band = sourceBands[i];
430 if (band < 0) {
431 throw new IllegalArgumentException("Band value < 0!");
432 }
433 for (int j = i + 1; j < numBands; j++) {
434 if (band == sourceBands[j]) {
435 throw new IllegalArgumentException("Duplicate band value!");
436 }
437 }
438
439 }
440 this.sourceBands = (int[])(sourceBands.clone());
441 }
442 }
443
444 /**
445 * Returns the set of of source bands to be used. The returned
446 * value is that set by the most recent call to
447 * <code>setSourceBands</code>, or <code>null</code> if there have
448 * been no calls to <code>setSourceBands</code>.
449 *
450 * <p> Semantically, the array returned is a copy; changes to
451 * array contents subsequent to this call have no effect on this
452 * <code>IIOParam</code>.
453 *
454 * @return the set of source bands to be used, or
455 * <code>null</code>.
456 *
457 * @see #setSourceBands
458 */
459 public int[] getSourceBands() {
460 if (sourceBands == null) {
461 return null;
462 }
463 return (int[])(sourceBands.clone());
464 }
465
466 /**
467 * Sets the desired image type for the destination image, using an
468 * <code>ImageTypeSpecifier</code>.
469 *
470 * <p> When reading, if the layout of the destination has been set
471 * using this method, each call to an <code>ImageReader</code>
472 * <code>read</code> method will return a new
473 * <code>BufferedImage</code> using the format specified by the
474 * supplied type specifier. As a side effect, any destination
475 * <code>BufferedImage</code> set by
476 * <code>ImageReadParam.setDestination(BufferedImage)</code> will
477 * no longer be set as the destination. In other words, this
478 * method may be thought of as calling
479 * <code>setDestination((BufferedImage)null)</code>.
480 *
481 * <p> When writing, the destination type maybe used to determine
482 * the color type of the image. The <code>SampleModel</code>
483 * information will be ignored, and may be <code>null</code>. For
484 * example, a 4-banded image could represent either CMYK or RGBA
485 * data. If a destination type is set, its
486 * <code>ColorModel</code> will override any
487 * <code>ColorModel</code> on the image itself. This is crucial
488 * when <code>setSourceBands</code> is used since the image's
489 * <code>ColorModel</code> will refer to the entire image rather
490 * than to the subset of bands being written.
491 *
492 * @param destinationType the <code>ImageTypeSpecifier</code> to
493 * be used to determine the destination layout and color type.
494 *
495 * @see #getDestinationType
496 */
497 public void setDestinationType(ImageTypeSpecifier destinationType) {
498 this.destinationType = destinationType;
499 }
500
501 /**
502 * Returns the type of image to be returned by the read, if one
503 * was set by a call to
504 * <code>setDestination(ImageTypeSpecifier)</code>, as an
505 * <code>ImageTypeSpecifier</code>. If none was set,
506 * <code>null</code> is returned.
507 *
508 * @return an <code>ImageTypeSpecifier</code> describing the
509 * destination type, or <code>null</code>.
510 *
511 * @see #setDestinationType
512 */
513 public ImageTypeSpecifier getDestinationType() {
514 return destinationType;
515 }
516
517 /**
518 * Specifies the offset in the destination image at which future
519 * decoded pixels are to be placed, when reading, or where a
520 * region will be written, when writing.
521 *
522 * <p> When reading, the region to be written within the
523 * destination <code>BufferedImage</code> will start at this
524 * offset and have a width and height determined by the source
525 * region of interest, the subsampling parameters, and the
526 * destination bounds.
527 *
528 * <p> Normal writes are not affected by this method, only writes
529 * performed using <code>ImageWriter.replacePixels</code>. For
530 * such writes, the offset specified is within the output stream
531 * image whose pixels are being modified.
532 *
533 * <p> There is no <code>unsetDestinationOffset</code> method;
534 * simply call <code>setDestinationOffset(new Point(0, 0))</code> to
535 * restore default values.
536 *
537 * @param destinationOffset the offset in the destination, as a
538 * <code>Point</code>.
539 *
540 * @exception IllegalArgumentException if
541 * <code>destinationOffset</code> is <code>null</code>.
542 *
543 * @see #getDestinationOffset
544 * @see ImageWriter#replacePixels
545 */
546 public void setDestinationOffset(Point destinationOffset) {
547 if (destinationOffset == null) {
548 throw new IllegalArgumentException("destinationOffset == null!");
549 }
550 this.destinationOffset = (Point)destinationOffset.clone();
551 }
552
553 /**
554 * Returns the offset in the destination image at which pixels are
555 * to be placed.
556 *
557 * <p> If <code>setDestinationOffsets</code> has not been called,
558 * a <code>Point</code> with zero X and Y values is returned
559 * (which is the correct value).
560 *
561 * @return the destination offset as a <code>Point</code>.
562 *
563 * @see #setDestinationOffset
564 */
565 public Point getDestinationOffset() {
566 return (Point)destinationOffset.clone();
567 }
568
569 /**
570 * Sets the <code>IIOParamController</code> to be used
571 * to provide settings for this <code>IIOParam</code>
572 * object when the <code>activateController</code> method
573 * is called, overriding any default controller. If the
574 * argument is <code>null</code>, no controller will be
575 * used, including any default. To restore the default, use
576 * <code>setController(getDefaultController())</code>.
577 *
578 * @param controller An appropriate
579 * <code>IIOParamController</code>, or <code>null</code>.
580 *
581 * @see IIOParamController
582 * @see #getController
583 * @see #getDefaultController
584 * @see #hasController
585 * @see #activateController()
586 */
587 public void setController(IIOParamController controller) {
588 this.controller = controller;
589 }
590
591 /**
592 * Returns whatever <code>IIOParamController</code> is currently
593 * installed. This could be the default if there is one,
594 * <code>null</code>, or the argument of the most recent call
595 * to <code>setController</code>.
596 *
597 * @return the currently installed
598 * <code>IIOParamController</code>, or <code>null</code>.
599 *
600 * @see IIOParamController
601 * @see #setController
602 * @see #getDefaultController
603 * @see #hasController
604 * @see #activateController()
605 */
606 public IIOParamController getController() {
607 return controller;
608 }
609
610 /**
611 * Returns the default <code>IIOParamController</code>, if there
612 * is one, regardless of the currently installed controller. If
613 * there is no default controller, returns <code>null</code>.
614 *
615 * @return the default <code>IIOParamController</code>, or
616 * <code>null</code>.
617 *
618 * @see IIOParamController
619 * @see #setController(IIOParamController)
620 * @see #getController
621 * @see #hasController
622 * @see #activateController()
623 */
624 public IIOParamController getDefaultController() {
625 return defaultController;
626 }
627
628 /**
629 * Returns <code>true</code> if there is a controller installed
630 * for this <code>IIOParam</code> object. This will return
631 * <code>true</code> if <code>getController</code> would not
632 * return <code>null</code>.
633 *
634 * @return <code>true</code> if a controller is installed.
635 *
636 * @see IIOParamController
637 * @see #setController(IIOParamController)
638 * @see #getController
639 * @see #getDefaultController
640 * @see #activateController()
641 */
642 public boolean hasController() {
643 return (controller != null);
644 }
645
646 /**
647 * Activates the installed <code>IIOParamController</code> for
648 * this <code>IIOParam</code> object and returns the resulting
649 * value. When this method returns <code>true</code>, all values
650 * for this <code>IIOParam</code> object will be ready for the
651 * next read or write operation. If <code>false</code> is
652 * returned, no settings in this object will have been disturbed
653 * (<i>i.e.</i>, the user canceled the operation).
654 *
655 * <p> Ordinarily, the controller will be a GUI providing a user
656 * interface for a subclass of <code>IIOParam</code> for a
657 * particular plug-in. Controllers need not be GUIs, however.
658 *
659 * @return <code>true</code> if the controller completed normally.
660 *
661 * @exception IllegalStateException if there is no controller
662 * currently installed.
663 *
664 * @see IIOParamController
665 * @see #setController(IIOParamController)
666 * @see #getController
667 * @see #getDefaultController
668 * @see #hasController
669 */
670 public boolean activateController() {
671 if (!hasController()) {
672 throw new IllegalStateException("hasController() == false!");
673 }
674 return getController().activate(this);
675 }
676 }
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