1 /*
2 * Copyright (c) 1997, 2000, Oracle and/or its affiliates. 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.awt.image;
27
28 import java.awt.color.ColorSpace;
29 import java.awt.geom.Rectangle2D;
30 import java.awt.Rectangle;
31 import java.awt.geom.Point2D;
32 import java.awt.RenderingHints;
33 import sun.awt.image.ImagingLib;
34
35 /**
36 * This class performs a pixel-by-pixel rescaling of the data in the
37 * source image by multiplying the sample values for each pixel by a scale
38 * factor and then adding an offset. The scaled sample values are clipped
39 * to the minimum/maximum representable in the destination image.
40 * <p>
41 * The pseudo code for the rescaling operation is as follows:
42 * <pre>
43 *for each pixel from Source object {
44 * for each band/component of the pixel {
45 * dstElement = (srcElement*scaleFactor) + offset
46 * }
47 *}
48 * </pre>
49 * <p>
50 * For Rasters, rescaling operates on bands. The number of
51 * sets of scaling constants may be one, in which case the same constants
52 * are applied to all bands, or it must equal the number of Source
53 * Raster bands.
54 * <p>
55 * For BufferedImages, rescaling operates on color and alpha components.
56 * The number of sets of scaling constants may be one, in which case the
57 * same constants are applied to all color (but not alpha) components.
58 * Otherwise, the number of sets of scaling constants may
59 * equal the number of Source color components, in which case no
60 * rescaling of the alpha component (if present) is performed.
61 * If neither of these cases apply, the number of sets of scaling constants
62 * must equal the number of Source color components plus alpha components,
63 * in which case all color and alpha components are rescaled.
64 * <p>
65 * BufferedImage sources with premultiplied alpha data are treated in the same
66 * manner as non-premultiplied images for purposes of rescaling. That is,
67 * the rescaling is done per band on the raw data of the BufferedImage source
68 * without regard to whether the data is premultiplied. If a color conversion
69 * is required to the destination ColorModel, the premultiplied state of
70 * both source and destination will be taken into account for this step.
71 * <p>
72 * Images with an IndexColorModel cannot be rescaled.
73 * <p>
74 * If a RenderingHints object is specified in the constructor, the
75 * color rendering hint and the dithering hint may be used when color
76 * conversion is required.
77 * <p>
78 * Note that in-place operation is allowed (i.e. the source and destination can
79 * be the same object).
80 * @see java.awt.RenderingHints#KEY_COLOR_RENDERING
81 * @see java.awt.RenderingHints#KEY_DITHERING
82 */
83 public class RescaleOp implements BufferedImageOp, RasterOp {
84 float[] scaleFactors;
85 float[] offsets;
86 int length = 0;
87 RenderingHints hints;
88
89 private int srcNbits;
90 private int dstNbits;
91
92
93 /**
94 * Constructs a new RescaleOp with the desired scale factors
95 * and offsets. The length of the scaleFactor and offset arrays
96 * must meet the restrictions stated in the class comments above.
97 * The RenderingHints argument may be null.
98 * @param scaleFactors the specified scale factors
99 * @param offsets the specified offsets
100 * @param hints the specified <code>RenderingHints</code>, or
101 * <code>null</code>
102 */
103 public RescaleOp (float[] scaleFactors, float[] offsets,
104 RenderingHints hints) {
105 length = scaleFactors.length;
106 if (length > offsets.length) length = offsets.length;
107
108 this.scaleFactors = new float[length];
109 this.offsets = new float[length];
110 for (int i=0; i < length; i++) {
111 this.scaleFactors[i] = scaleFactors[i];
112 this.offsets[i] = offsets[i];
113 }
114 this.hints = hints;
115 }
116
117 /**
118 * Constructs a new RescaleOp with the desired scale factor
119 * and offset. The scaleFactor and offset will be applied to
120 * all bands in a source Raster and to all color (but not alpha)
121 * components in a BufferedImage.
122 * The RenderingHints argument may be null.
123 * @param scaleFactor the specified scale factor
124 * @param offset the specified offset
125 * @param hints the specified <code>RenderingHints</code>, or
126 * <code>null</code>
127 */
128 public RescaleOp (float scaleFactor, float offset, RenderingHints hints) {
129 length = 1;
130 this.scaleFactors = new float[1];
131 this.offsets = new float[1];
132 this.scaleFactors[0] = scaleFactor;
133 this.offsets[0] = offset;
134 this.hints = hints;
135 }
136
137 /**
138 * Returns the scale factors in the given array. The array is also
139 * returned for convenience. If scaleFactors is null, a new array
140 * will be allocated.
141 * @param scaleFactors the array to contain the scale factors of
142 * this <code>RescaleOp</code>
143 * @return the scale factors of this <code>RescaleOp</code>.
144 */
145 final public float[] getScaleFactors (float scaleFactors[]) {
146 if (scaleFactors == null) {
147 return (float[]) this.scaleFactors.clone();
148 }
149 System.arraycopy (this.scaleFactors, 0, scaleFactors, 0,
150 Math.min(this.scaleFactors.length,
151 scaleFactors.length));
152 return scaleFactors;
153 }
154
155 /**
156 * Returns the offsets in the given array. The array is also returned
157 * for convenience. If offsets is null, a new array
158 * will be allocated.
159 * @param offsets the array to contain the offsets of
160 * this <code>RescaleOp</code>
161 * @return the offsets of this <code>RescaleOp</code>.
162 */
163 final public float[] getOffsets(float offsets[]) {
164 if (offsets == null) {
165 return (float[]) this.offsets.clone();
166 }
167
168 System.arraycopy (this.offsets, 0, offsets, 0,
169 Math.min(this.offsets.length, offsets.length));
170 return offsets;
171 }
172
173 /**
174 * Returns the number of scaling factors and offsets used in this
175 * RescaleOp.
176 * @return the number of scaling factors and offsets of this
177 * <code>RescaleOp</code>.
178 */
179 final public int getNumFactors() {
180 return length;
181 }
182
183
184 /**
185 * Creates a ByteLookupTable to implement the rescale.
186 * The table may have either a SHORT or BYTE input.
187 * @param nElems Number of elements the table is to have.
188 * This will generally be 256 for byte and
189 * 65536 for short.
190 */
191 private ByteLookupTable createByteLut(float scale[],
192 float off[],
193 int nBands,
194 int nElems) {
195
196 byte[][] lutData = new byte[scale.length][nElems];
197
198 for (int band=0; band<scale.length; band++) {
199 float bandScale = scale[band];
200 float bandOff = off[band];
201 byte[] bandLutData = lutData[band];
202 for (int i=0; i<nElems; i++) {
203 int val = (int)(i*bandScale + bandOff);
204 if ((val & 0xffffff00) != 0) {
205 if (val < 0) {
206 val = 0;
207 } else {
208 val = 255;
209 }
210 }
211 bandLutData[i] = (byte)val;
212 }
213
214 }
215
216 return new ByteLookupTable(0, lutData);
217 }
218
219 /**
220 * Creates a ShortLookupTable to implement the rescale.
221 * The table may have either a SHORT or BYTE input.
222 * @param nElems Number of elements the table is to have.
223 * This will generally be 256 for byte and
224 * 65536 for short.
225 */
226 private ShortLookupTable createShortLut(float scale[],
227 float off[],
228 int nBands,
229 int nElems) {
230
231 short[][] lutData = new short[scale.length][nElems];
232
233 for (int band=0; band<scale.length; band++) {
234 float bandScale = scale[band];
235 float bandOff = off[band];
236 short[] bandLutData = lutData[band];
237 for (int i=0; i<nElems; i++) {
238 int val = (int)(i*bandScale + bandOff);
239 if ((val & 0xffff0000) != 0) {
240 if (val < 0) {
241 val = 0;
242 } else {
243 val = 65535;
244 }
245 }
246 bandLutData[i] = (short)val;
247 }
248 }
249
250 return new ShortLookupTable(0, lutData);
251 }
252
253
254 /**
255 * Determines if the rescale can be performed as a lookup.
256 * The dst must be a byte or short type.
257 * The src must be less than 16 bits.
258 * All source band sizes must be the same and all dst band sizes
259 * must be the same.
260 */
261 private boolean canUseLookup(Raster src, Raster dst) {
262
263 //
264 // Check that the src datatype is either a BYTE or SHORT
265 //
266 int datatype = src.getDataBuffer().getDataType();
267 if(datatype != DataBuffer.TYPE_BYTE &&
268 datatype != DataBuffer.TYPE_USHORT) {
269 return false;
270 }
271
272 //
273 // Check dst sample sizes. All must be 8 or 16 bits.
274 //
275 SampleModel dstSM = dst.getSampleModel();
276 dstNbits = dstSM.getSampleSize(0);
277
278 if (!(dstNbits == 8 || dstNbits == 16)) {
279 return false;
280 }
281 for (int i=1; i<src.getNumBands(); i++) {
282 int bandSize = dstSM.getSampleSize(i);
283 if (bandSize != dstNbits) {
284 return false;
285 }
286 }
287
288 //
289 // Check src sample sizes. All must be the same size
290 //
291 SampleModel srcSM = src.getSampleModel();
292 srcNbits = srcSM.getSampleSize(0);
293 if (srcNbits > 16) {
294 return false;
295 }
296 for (int i=1; i<src.getNumBands(); i++) {
297 int bandSize = srcSM.getSampleSize(i);
298 if (bandSize != srcNbits) {
299 return false;
300 }
301 }
302
303 return true;
304 }
305
306 /**
307 * Rescales the source BufferedImage.
308 * If the color model in the source image is not the same as that
309 * in the destination image, the pixels will be converted
310 * in the destination. If the destination image is null,
311 * a BufferedImage will be created with the source ColorModel.
312 * An IllegalArgumentException may be thrown if the number of
313 * scaling factors/offsets in this object does not meet the
314 * restrictions stated in the class comments above, or if the
315 * source image has an IndexColorModel.
316 * @param src the <code>BufferedImage</code> to be filtered
317 * @param dst the destination for the filtering operation
318 * or <code>null</code>
319 * @return the filtered <code>BufferedImage</code>.
320 * @throws IllegalArgumentException if the <code>ColorModel</code>
321 * of <code>src</code> is an <code>IndexColorModel</code>,
322 * or if the number of scaling factors and offsets in this
323 * <code>RescaleOp</code> do not meet the requirements
324 * stated in the class comments.
325 */
326 public final BufferedImage filter (BufferedImage src, BufferedImage dst) {
327 ColorModel srcCM = src.getColorModel();
328 ColorModel dstCM;
329 int numBands = srcCM.getNumColorComponents();
330
331
332 if (srcCM instanceof IndexColorModel) {
333 throw new
334 IllegalArgumentException("Rescaling cannot be "+
335 "performed on an indexed image");
336 }
337 if (length != 1 && length != numBands &&
338 length != srcCM.getNumComponents())
339 {
340 throw new IllegalArgumentException("Number of scaling constants "+
341 "does not equal the number of"+
342 " of color or color/alpha "+
343 " components");
344 }
345
346 boolean needToConvert = false;
347
348 // Include alpha
349 if (length > numBands && srcCM.hasAlpha()) {
350 length = numBands+1;
351 }
352
353 int width = src.getWidth();
354 int height = src.getHeight();
355
356 if (dst == null) {
357 dst = createCompatibleDestImage(src, null);
358 dstCM = srcCM;
359 }
360 else {
361 if (width != dst.getWidth()) {
362 throw new
363 IllegalArgumentException("Src width ("+width+
364 ") not equal to dst width ("+
365 dst.getWidth()+")");
366 }
367 if (height != dst.getHeight()) {
368 throw new
369 IllegalArgumentException("Src height ("+height+
370 ") not equal to dst height ("+
371 dst.getHeight()+")");
372 }
373
374 dstCM = dst.getColorModel();
375 if(srcCM.getColorSpace().getType() !=
376 dstCM.getColorSpace().getType()) {
377 needToConvert = true;
378 dst = createCompatibleDestImage(src, null);
379 }
380
381 }
382
383 BufferedImage origDst = dst;
384
385 //
386 // Try to use a native BI rescale operation first
387 //
388 if (ImagingLib.filter(this, src, dst) == null) {
389 //
390 // Native BI rescale failed - convert to rasters
391 //
392 WritableRaster srcRaster = src.getRaster();
393 WritableRaster dstRaster = dst.getRaster();
394
395 if (srcCM.hasAlpha()) {
396 if (numBands-1 == length || length == 1) {
397 int minx = srcRaster.getMinX();
398 int miny = srcRaster.getMinY();
399 int[] bands = new int[numBands-1];
400 for (int i=0; i < numBands-1; i++) {
401 bands[i] = i;
402 }
403 srcRaster =
404 srcRaster.createWritableChild(minx, miny,
405 srcRaster.getWidth(),
406 srcRaster.getHeight(),
407 minx, miny,
408 bands);
409 }
410 }
411 if (dstCM.hasAlpha()) {
412 int dstNumBands = dstRaster.getNumBands();
413 if (dstNumBands-1 == length || length == 1) {
414 int minx = dstRaster.getMinX();
415 int miny = dstRaster.getMinY();
416 int[] bands = new int[numBands-1];
417 for (int i=0; i < numBands-1; i++) {
418 bands[i] = i;
419 }
420 dstRaster =
421 dstRaster.createWritableChild(minx, miny,
422 dstRaster.getWidth(),
423 dstRaster.getHeight(),
424 minx, miny,
425 bands);
426 }
427 }
428
429 //
430 // Call the raster filter method
431 //
432 filter(srcRaster, dstRaster);
433
434 }
435
436 if (needToConvert) {
437 // ColorModels are not the same
438 ColorConvertOp ccop = new ColorConvertOp(hints);
439 ccop.filter(dst, origDst);
440 }
441
442 return origDst;
443 }
444
445 /**
446 * Rescales the pixel data in the source Raster.
447 * If the destination Raster is null, a new Raster will be created.
448 * The source and destination must have the same number of bands.
449 * Otherwise, an IllegalArgumentException is thrown.
450 * Note that the number of scaling factors/offsets in this object must
451 * meet the restrictions stated in the class comments above.
452 * Otherwise, an IllegalArgumentException is thrown.
453 * @param src the <code>Raster</code> to be filtered
454 * @param dst the destination for the filtering operation
455 * or <code>null</code>
456 * @return the filtered <code>WritableRaster</code>.
457 * @throws IllegalArgumentException if <code>src</code> and
458 * <code>dst</code> do not have the same number of bands,
459 * or if the number of scaling factors and offsets in this
460 * <code>RescaleOp</code> do not meet the requirements
461 * stated in the class comments.
462 */
463 public final WritableRaster filter (Raster src, WritableRaster dst) {
464 int numBands = src.getNumBands();
465 int width = src.getWidth();
466 int height = src.getHeight();
467 int[] srcPix = null;
468 int step = 0;
469 int tidx = 0;
470
471 // Create a new destination Raster, if needed
472 if (dst == null) {
473 dst = createCompatibleDestRaster(src);
474 }
475 else if (height != dst.getHeight() || width != dst.getWidth()) {
476 throw new
477 IllegalArgumentException("Width or height of Rasters do not "+
478 "match");
479 }
480 else if (numBands != dst.getNumBands()) {
481 // Make sure that the number of bands are equal
482 throw new IllegalArgumentException("Number of bands in src "
483 + numBands
484 + " does not equal number of bands in dest "
485 + dst.getNumBands());
486 }
487 // Make sure that the arrays match
488 // Make sure that the low/high/constant arrays match
489 if (length != 1 && length != src.getNumBands()) {
490 throw new IllegalArgumentException("Number of scaling constants "+
491 "does not equal the number of"+
492 " of bands in the src raster");
493 }
494
495
496 //
497 // Try for a native raster rescale first
498 //
499 if (ImagingLib.filter(this, src, dst) != null) {
500 return dst;
501 }
502
503 //
504 // Native raster rescale failed.
505 // Try to see if a lookup operation can be used
506 //
507 if (canUseLookup(src, dst)) {
508 int srcNgray = (1 << srcNbits);
509 int dstNgray = (1 << dstNbits);
510
511 if (dstNgray == 256) {
512 ByteLookupTable lut = createByteLut(scaleFactors, offsets,
513 numBands, srcNgray);
514 LookupOp op = new LookupOp(lut, hints);
515 op.filter(src, dst);
516 } else {
517 ShortLookupTable lut = createShortLut(scaleFactors, offsets,
518 numBands, srcNgray);
519 LookupOp op = new LookupOp(lut, hints);
520 op.filter(src, dst);
521 }
522 } else {
523 //
524 // Fall back to the slow code
525 //
526 if (length > 1) {
527 step = 1;
528 }
529
530 int sminX = src.getMinX();
531 int sY = src.getMinY();
532 int dminX = dst.getMinX();
533 int dY = dst.getMinY();
534 int sX;
535 int dX;
536
537 //
538 // Determine bits per band to determine maxval for clamps.
539 // The min is assumed to be zero.
540 // REMIND: This must change if we ever support signed data types.
541 //
542 int nbits;
543 int dstMax[] = new int[numBands];
544 int dstMask[] = new int[numBands];
545 SampleModel dstSM = dst.getSampleModel();
546 for (int z=0; z<numBands; z++) {
547 nbits = dstSM.getSampleSize(z);
548 dstMax[z] = (1 << nbits) - 1;
549 dstMask[z] = ~(dstMax[z]);
550 }
551
552 int val;
553 for (int y=0; y < height; y++, sY++, dY++) {
554 dX = dminX;
555 sX = sminX;
556 for (int x = 0; x < width; x++, sX++, dX++) {
557 // Get data for all bands at this x,y position
558 srcPix = src.getPixel(sX, sY, srcPix);
559 tidx = 0;
560 for (int z=0; z<numBands; z++, tidx += step) {
561 val = (int)(srcPix[z]*scaleFactors[tidx]
562 + offsets[tidx]);
563 // Clamp
564 if ((val & dstMask[z]) != 0) {
565 if (val < 0) {
566 val = 0;
567 } else {
568 val = dstMax[z];
569 }
570 }
571 srcPix[z] = val;
572
573 }
574
575 // Put it back for all bands
576 dst.setPixel(dX, dY, srcPix);
577 }
578 }
579 }
580 return dst;
581 }
582
583 /**
584 * Returns the bounding box of the rescaled destination image. Since
585 * this is not a geometric operation, the bounding box does not
586 * change.
587 */
588 public final Rectangle2D getBounds2D (BufferedImage src) {
589 return getBounds2D(src.getRaster());
590 }
591
592 /**
593 * Returns the bounding box of the rescaled destination Raster. Since
594 * this is not a geometric operation, the bounding box does not
595 * change.
596 * @param src the rescaled destination <code>Raster</code>
597 * @return the bounds of the specified <code>Raster</code>.
598 */
599 public final Rectangle2D getBounds2D (Raster src) {
600 return src.getBounds();
601 }
602
603 /**
604 * Creates a zeroed destination image with the correct size and number of
605 * bands.
606 * @param src Source image for the filter operation.
607 * @param destCM ColorModel of the destination. If null, the
608 * ColorModel of the source will be used.
609 * @return the zeroed-destination image.
610 */
611 public BufferedImage createCompatibleDestImage (BufferedImage src,
612 ColorModel destCM) {
613 BufferedImage image;
614 if (destCM == null) {
615 ColorModel cm = src.getColorModel();
616 image = new BufferedImage(cm,
617 src.getRaster().createCompatibleWritableRaster(),
618 cm.isAlphaPremultiplied(),
619 null);
620 }
621 else {
622 int w = src.getWidth();
623 int h = src.getHeight();
624 image = new BufferedImage (destCM,
625 destCM.createCompatibleWritableRaster(w, h),
626 destCM.isAlphaPremultiplied(), null);
627 }
628
629 return image;
630 }
631
632 /**
633 * Creates a zeroed-destination <code>Raster</code> with the correct
634 * size and number of bands, given this source.
635 * @param src the source <code>Raster</code>
636 * @return the zeroed-destination <code>Raster</code>.
637 */
638 public WritableRaster createCompatibleDestRaster (Raster src) {
639 return src.createCompatibleWritableRaster(src.getWidth(), src.getHeight());
640 }
641
642 /**
643 * Returns the location of the destination point given a
644 * point in the source. If dstPt is non-null, it will
645 * be used to hold the return value. Since this is not a geometric
646 * operation, the srcPt will equal the dstPt.
647 * @param srcPt a point in the source image
648 * @param dstPt the destination point or <code>null</code>
649 * @return the location of the destination point.
650 */
651 public final Point2D getPoint2D (Point2D srcPt, Point2D dstPt) {
652 if (dstPt == null) {
653 dstPt = new Point2D.Float();
654 }
655 dstPt.setLocation(srcPt.getX(), srcPt.getY());
656 return dstPt;
657 }
658
659 /**
660 * Returns the rendering hints for this op.
661 * @return the rendering hints of this <code>RescaleOp</code>.
662 */
663 public final RenderingHints getRenderingHints() {
664 return hints;
665 }
666 }