1/* 2 * Copyright (c) 1997, 2014, 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 26package java.awt.image; 27 28import java.awt.color.ColorSpace; 29import java.awt.geom.Rectangle2D; 30import java.awt.AlphaComposite; 31import java.awt.Graphics2D; 32import java.awt.Rectangle; 33import java.awt.geom.Point2D; 34import java.awt.RenderingHints; 35import sun.awt.image.ImagingLib; 36 37/** 38 * This class performs a pixel-by-pixel rescaling of the data in the 39 * source image by multiplying the sample values for each pixel by a scale 40 * factor and then adding an offset. The scaled sample values are clipped 41 * to the minimum/maximum representable in the destination image. 42 * <p> 43 * The pseudo code for the rescaling operation is as follows: 44 * <pre> 45 *for each pixel from Source object { 46 * for each band/component of the pixel { 47 * dstElement = (srcElement*scaleFactor) + offset 48 * } 49 *} 50 * </pre> 51 * <p> 52 * For Rasters, rescaling operates on bands. The number of 53 * sets of scaling constants may be one, in which case the same constants 54 * are applied to all bands, or it must equal the number of Source 55 * Raster bands. 56 * <p> 57 * For BufferedImages, rescaling operates on color and alpha components. 58 * The number of sets of scaling constants may be one, in which case the 59 * same constants are applied to all color (but not alpha) components. 60 * Otherwise, the number of sets of scaling constants may 61 * equal the number of Source color components, in which case no 62 * rescaling of the alpha component (if present) is performed. 63 * If neither of these cases apply, the number of sets of scaling constants 64 * must equal the number of Source color components plus alpha components, 65 * in which case all color and alpha components are rescaled. 66 * <p> 67 * BufferedImage sources with premultiplied alpha data are treated in the same 68 * manner as non-premultiplied images for purposes of rescaling. That is, 69 * the rescaling is done per band on the raw data of the BufferedImage source 70 * without regard to whether the data is premultiplied. If a color conversion 71 * is required to the destination ColorModel, the premultiplied state of 72 * both source and destination will be taken into account for this step. 73 * <p> 74 * Images with an IndexColorModel cannot be rescaled. 75 * <p> 76 * If a RenderingHints object is specified in the constructor, the 77 * color rendering hint and the dithering hint may be used when color 78 * conversion is required. 79 * <p> 80 * Note that in-place operation is allowed (i.e. the source and destination can 81 * be the same object). 82 * @see java.awt.RenderingHints#KEY_COLOR_RENDERING 83 * @see java.awt.RenderingHints#KEY_DITHERING 84 */ 85public class RescaleOp implements BufferedImageOp, RasterOp { 86 float[] scaleFactors; 87 float[] offsets; 88 int length = 0; 89 RenderingHints hints; 90 91 private int srcNbits; 92 private int dstNbits; 93 94 95 /** 96 * Constructs a new RescaleOp with the desired scale factors 97 * and offsets. The length of the scaleFactor and offset arrays 98 * must meet the restrictions stated in the class comments above. 99 * The RenderingHints argument may be null. 100 * @param scaleFactors the specified scale factors 101 * @param offsets the specified offsets 102 * @param hints the specified {@code RenderingHints}, or 103 * {@code null} 104 */ 105 public RescaleOp (float[] scaleFactors, float[] offsets, 106 RenderingHints hints) { 107 length = scaleFactors.length; 108 if (length > offsets.length) length = offsets.length; 109 110 this.scaleFactors = new float[length]; 111 this.offsets = new float[length]; 112 for (int i=0; i < length; i++) { 113 this.scaleFactors[i] = scaleFactors[i]; 114 this.offsets[i] = offsets[i]; 115 } 116 this.hints = hints; 117 } 118 119 /** 120 * Constructs a new RescaleOp with the desired scale factor 121 * and offset. The scaleFactor and offset will be applied to 122 * all bands in a source Raster and to all color (but not alpha) 123 * components in a BufferedImage. 124 * The RenderingHints argument may be null. 125 * @param scaleFactor the specified scale factor 126 * @param offset the specified offset 127 * @param hints the specified {@code RenderingHints}, or 128 * {@code null} 129 */ 130 public RescaleOp (float scaleFactor, float offset, RenderingHints hints) { 131 length = 1; 132 this.scaleFactors = new float[1]; 133 this.offsets = new float[1]; 134 this.scaleFactors[0] = scaleFactor; 135 this.offsets[0] = offset; 136 this.hints = hints; 137 } 138 139 /** 140 * Returns the scale factors in the given array. The array is also 141 * returned for convenience. If scaleFactors is null, a new array 142 * will be allocated. 143 * @param scaleFactors the array to contain the scale factors of 144 * this {@code RescaleOp} 145 * @return the scale factors of this {@code RescaleOp}. 146 */ 147 public final float[] getScaleFactors (float scaleFactors[]) { 148 if (scaleFactors == null) { 149 return this.scaleFactors.clone(); 150 } 151 System.arraycopy (this.scaleFactors, 0, scaleFactors, 0, 152 Math.min(this.scaleFactors.length, 153 scaleFactors.length)); 154 return scaleFactors; 155 } 156 157 /** 158 * Returns the offsets in the given array. The array is also returned 159 * for convenience. If offsets is null, a new array 160 * will be allocated. 161 * @param offsets the array to contain the offsets of 162 * this {@code RescaleOp} 163 * @return the offsets of this {@code RescaleOp}. 164 */ 165 public final float[] getOffsets(float offsets[]) { 166 if (offsets == null) { 167 return this.offsets.clone(); 168 } 169 170 System.arraycopy (this.offsets, 0, offsets, 0, 171 Math.min(this.offsets.length, offsets.length)); 172 return offsets; 173 } 174 175 /** 176 * Returns the number of scaling factors and offsets used in this 177 * RescaleOp. 178 * @return the number of scaling factors and offsets of this 179 * {@code RescaleOp}. 180 */ 181 public final int getNumFactors() { 182 return length; 183 } 184 185 186 /** 187 * Creates a ByteLookupTable to implement the rescale. 188 * The table may have either a SHORT or BYTE input. 189 * @param nElems Number of elements the table is to have. 190 * This will generally be 256 for byte and 191 * 65536 for short. 192 */ 193 private ByteLookupTable createByteLut(float scale[], 194 float off[], 195 int nBands, 196 int nElems) { 197 198 byte[][] lutData = new byte[nBands][nElems]; 199 int band; 200 201 for (band=0; band<scale.length; band++) { 202 float bandScale = scale[band]; 203 float bandOff = off[band]; 204 byte[] bandLutData = lutData[band]; 205 for (int i=0; i<nElems; i++) { 206 int val = (int)(i*bandScale + bandOff); 207 if ((val & 0xffffff00) != 0) { 208 if (val < 0) { 209 val = 0; 210 } else { 211 val = 255; 212 } 213 } 214 bandLutData[i] = (byte)val; 215 } 216 217 } 218 int maxToCopy = (nBands == 4 && scale.length == 4) ? 4 : 3; 219 while (band < lutData.length && band < maxToCopy) { 220 System.arraycopy(lutData[band-1], 0, lutData[band], 0, nElems); 221 band++; 222 } 223 if (nBands == 4 && band < nBands) { 224 byte[] bandLutData = lutData[band]; 225 for (int i=0; i<nElems; i++) { 226 bandLutData[i] = (byte)i; 227 } 228 } 229 230 return new ByteLookupTable(0, lutData); 231 } 232 233 /** 234 * Creates a ShortLookupTable to implement the rescale. 235 * The table may have either a SHORT or BYTE input. 236 * @param nElems Number of elements the table is to have. 237 * This will generally be 256 for byte and 238 * 65536 for short. 239 */ 240 private ShortLookupTable createShortLut(float scale[], 241 float off[], 242 int nBands, 243 int nElems) { 244 245 short[][] lutData = new short[nBands][nElems]; 246 int band = 0; 247 248 for (band=0; band<scale.length; band++) { 249 float bandScale = scale[band]; 250 float bandOff = off[band]; 251 short[] bandLutData = lutData[band]; 252 for (int i=0; i<nElems; i++) { 253 int val = (int)(i*bandScale + bandOff); 254 if ((val & 0xffff0000) != 0) { 255 if (val < 0) { 256 val = 0; 257 } else { 258 val = 65535; 259 } 260 } 261 bandLutData[i] = (short)val; 262 } 263 } 264 int maxToCopy = (nBands == 4 && scale.length == 4) ? 4 : 3; 265 while (band < lutData.length && band < maxToCopy) { 266 System.arraycopy(lutData[band-1], 0, lutData[band], 0, nElems); 267 band++; 268 } 269 if (nBands == 4 && band < nBands) { 270 short[] bandLutData = lutData[band]; 271 for (int i=0; i<nElems; i++) { 272 bandLutData[i] = (short)i; 273 } 274 } 275 276 return new ShortLookupTable(0, lutData); 277 } 278 279 280 /** 281 * Determines if the rescale can be performed as a lookup. 282 * The dst must be a byte or short type. 283 * The src must be less than 16 bits. 284 * All source band sizes must be the same and all dst band sizes 285 * must be the same. 286 */ 287 private boolean canUseLookup(Raster src, Raster dst) { 288 289 // 290 // Check that the src datatype is either a BYTE or SHORT 291 // 292 int datatype = src.getDataBuffer().getDataType(); 293 if(datatype != DataBuffer.TYPE_BYTE && 294 datatype != DataBuffer.TYPE_USHORT) { 295 return false; 296 } 297 298 // 299 // Check dst sample sizes. All must be 8 or 16 bits. 300 // 301 SampleModel dstSM = dst.getSampleModel(); 302 dstNbits = dstSM.getSampleSize(0); 303 304 if (!(dstNbits == 8 || dstNbits == 16)) { 305 return false; 306 } 307 for (int i=1; i<src.getNumBands(); i++) { 308 int bandSize = dstSM.getSampleSize(i); 309 if (bandSize != dstNbits) { 310 return false; 311 } 312 } 313 314 // 315 // Check src sample sizes. All must be the same size 316 // 317 SampleModel srcSM = src.getSampleModel(); 318 srcNbits = srcSM.getSampleSize(0); 319 if (srcNbits > 16) { 320 return false; 321 } 322 for (int i=1; i<src.getNumBands(); i++) { 323 int bandSize = srcSM.getSampleSize(i); 324 if (bandSize != srcNbits) { 325 return false; 326 } 327 } 328 329 if (dstSM instanceof ComponentSampleModel) { 330 ComponentSampleModel dsm = (ComponentSampleModel)dstSM; 331 if (dsm.getPixelStride() != dst.getNumBands()) { 332 return false; 333 } 334 } 335 if (srcSM instanceof ComponentSampleModel) { 336 ComponentSampleModel csm = (ComponentSampleModel)srcSM; 337 if (csm.getPixelStride() != src.getNumBands()) { 338 return false; 339 } 340 } 341 342 return true; 343 } 344 345 /** 346 * Rescales the source BufferedImage. 347 * If the color model in the source image is not the same as that 348 * in the destination image, the pixels will be converted 349 * in the destination. If the destination image is null, 350 * a BufferedImage will be created with the source ColorModel. 351 * An IllegalArgumentException may be thrown if the number of 352 * scaling factors/offsets in this object does not meet the 353 * restrictions stated in the class comments above, or if the 354 * source image has an IndexColorModel. 355 * @param src the {@code BufferedImage} to be filtered 356 * @param dst the destination for the filtering operation 357 * or {@code null} 358 * @return the filtered {@code BufferedImage}. 359 * @throws IllegalArgumentException if the {@code ColorModel} 360 * of {@code src} is an {@code IndexColorModel}, 361 * or if the number of scaling factors and offsets in this 362 * {@code RescaleOp} do not meet the requirements 363 * stated in the class comments. 364 */ 365 public final BufferedImage filter (BufferedImage src, BufferedImage dst) { 366 ColorModel srcCM = src.getColorModel(); 367 ColorModel dstCM; 368 int numSrcColorComp = srcCM.getNumColorComponents(); 369 int scaleConst = length; 370 371 if (srcCM instanceof IndexColorModel) { 372 throw new 373 IllegalArgumentException("Rescaling cannot be "+ 374 "performed on an indexed image"); 375 } 376 if (scaleConst != 1 && scaleConst != numSrcColorComp && 377 scaleConst != srcCM.getNumComponents()) 378 { 379 throw new IllegalArgumentException("Number of scaling constants "+ 380 "does not equal the number of"+ 381 " of color or color/alpha "+ 382 " components"); 383 } 384 385 boolean needToConvert = false; 386 boolean needToDraw = false; 387 388 // Include alpha 389 if (scaleConst > numSrcColorComp && srcCM.hasAlpha()) { 390 scaleConst = numSrcColorComp+1; 391 } 392 393 int width = src.getWidth(); 394 int height = src.getHeight(); 395 396 BufferedImage origDst = dst; 397 if (dst == null) { 398 dst = createCompatibleDestImage(src, null); 399 dstCM = srcCM; 400 } 401 else { 402 if (width != dst.getWidth()) { 403 throw new 404 IllegalArgumentException("Src width ("+width+ 405 ") not equal to dst width ("+ 406 dst.getWidth()+")"); 407 } 408 if (height != dst.getHeight()) { 409 throw new 410 IllegalArgumentException("Src height ("+height+ 411 ") not equal to dst height ("+ 412 dst.getHeight()+")"); 413 } 414 415 dstCM = dst.getColorModel(); 416 if(srcCM.getColorSpace().getType() != 417 dstCM.getColorSpace().getType()) { 418 needToConvert = true; 419 dst = createCompatibleDestImage(src, null); 420 } 421 422 } 423 424 // 425 // Try to use a native BI rescale operation first 426 // 427 if (ImagingLib.filter(this, src, dst) == null) { 428 if (src.getRaster().getNumBands() != 429 dst.getRaster().getNumBands()) { 430 needToDraw = true; 431 dst = createCompatibleDestImage(src, null); 432 } 433 434 // 435 // Native BI rescale failed - convert to rasters 436 // 437 WritableRaster srcRaster = src.getRaster(); 438 WritableRaster dstRaster = dst.getRaster(); 439 440 // 441 // Call the raster filter method 442 // 443 filterRasterImpl(srcRaster, dstRaster, scaleConst, false); 444 } 445 446 if (needToDraw) { 447 Graphics2D g = origDst.createGraphics(); 448 g.setComposite(AlphaComposite.Src); 449 g.drawImage(dst, 0, 0, width, height, null); 450 g.dispose(); 451 } 452 if (needToConvert) { 453 // ColorModels are not the same 454 ColorConvertOp ccop = new ColorConvertOp(hints); 455 dst = ccop.filter(dst, origDst); 456 } 457 return dst; 458 } 459 460 /** 461 * Rescales the pixel data in the source Raster. 462 * If the destination Raster is null, a new Raster will be created. 463 * The source and destination must have the same number of bands. 464 * Otherwise, an IllegalArgumentException is thrown. 465 * Note that the number of scaling factors/offsets in this object must 466 * meet the restrictions stated in the class comments above. 467 * Otherwise, an IllegalArgumentException is thrown. 468 * @param src the {@code Raster} to be filtered 469 * @param dst the destination for the filtering operation 470 * or {@code null} 471 * @return the filtered {@code WritableRaster}. 472 * @throws IllegalArgumentException if {@code src} and 473 * {@code dst} do not have the same number of bands, 474 * or if the number of scaling factors and offsets in this 475 * {@code RescaleOp} do not meet the requirements 476 * stated in the class comments. 477 */ 478 public final WritableRaster filter (Raster src, WritableRaster dst) { 479 return filterRasterImpl(src, dst, length, true); 480 } 481 482 private WritableRaster filterRasterImpl(Raster src, WritableRaster dst, 483 int scaleConst, boolean sCheck) { 484 int numBands = src.getNumBands(); 485 int width = src.getWidth(); 486 int height = src.getHeight(); 487 int[] srcPix = null; 488 int step = 0; 489 int tidx = 0; 490 491 // Create a new destination Raster, if needed 492 if (dst == null) { 493 dst = createCompatibleDestRaster(src); 494 } 495 else if (height != dst.getHeight() || width != dst.getWidth()) { 496 throw new 497 IllegalArgumentException("Width or height of Rasters do not "+ 498 "match"); 499 } 500 else if (numBands != dst.getNumBands()) { 501 // Make sure that the number of bands are equal 502 throw new IllegalArgumentException("Number of bands in src " 503 + numBands 504 + " does not equal number of bands in dest " 505 + dst.getNumBands()); 506 } 507 508 // Make sure that the arrays match 509 // Make sure that the low/high/constant arrays match 510 if (sCheck && scaleConst != 1 && scaleConst != src.getNumBands()) { 511 throw new IllegalArgumentException("Number of scaling constants "+ 512 "does not equal the number of"+ 513 " of bands in the src raster"); 514 } 515 516 // 517 // Try for a native raster rescale first 518 // 519 if (ImagingLib.filter(this, src, dst) != null) { 520 return dst; 521 } 522 523 // 524 // Native raster rescale failed. 525 // Try to see if a lookup operation can be used 526 // 527 if (canUseLookup(src, dst)) { 528 int srcNgray = (1 << srcNbits); 529 int dstNgray = (1 << dstNbits); 530 531 if (dstNgray == 256) { 532 ByteLookupTable lut = createByteLut(scaleFactors, offsets, 533 numBands, srcNgray); 534 LookupOp op = new LookupOp(lut, hints); 535 op.filter(src, dst); 536 } else { 537 ShortLookupTable lut = createShortLut(scaleFactors, offsets, 538 numBands, srcNgray); 539 LookupOp op = new LookupOp(lut, hints); 540 op.filter(src, dst); 541 } 542 } else { 543 // 544 // Fall back to the slow code 545 // 546 if (scaleConst > 1) { 547 step = 1; 548 } 549 550 int sminX = src.getMinX(); 551 int sY = src.getMinY(); 552 int dminX = dst.getMinX(); 553 int dY = dst.getMinY(); 554 int sX; 555 int dX; 556 557 // 558 // Determine bits per band to determine maxval for clamps. 559 // The min is assumed to be zero. 560 // REMIND: This must change if we ever support signed data types. 561 // 562 int nbits; 563 int dstMax[] = new int[numBands]; 564 int dstMask[] = new int[numBands]; 565 SampleModel dstSM = dst.getSampleModel(); 566 for (int z=0; z<numBands; z++) { 567 nbits = dstSM.getSampleSize(z); 568 dstMax[z] = (1 << nbits) - 1; 569 dstMask[z] = ~(dstMax[z]); 570 } 571 572 int val; 573 for (int y=0; y < height; y++, sY++, dY++) { 574 dX = dminX; 575 sX = sminX; 576 for (int x = 0; x < width; x++, sX++, dX++) { 577 // Get data for all bands at this x,y position 578 srcPix = src.getPixel(sX, sY, srcPix); 579 tidx = 0; 580 for (int z=0; z<numBands; z++, tidx += step) { 581 if ((scaleConst == 1 || scaleConst == 3) && 582 (z == 3) && (numBands == 4)) { 583 val = srcPix[z]; 584 } else { 585 val = (int)(srcPix[z]*scaleFactors[tidx] 586 + offsets[tidx]); 587 588 } 589 // Clamp 590 if ((val & dstMask[z]) != 0) { 591 if (val < 0) { 592 val = 0; 593 } else { 594 val = dstMax[z]; 595 } 596 } 597 srcPix[z] = val; 598 599 } 600 601 // Put it back for all bands 602 dst.setPixel(dX, dY, srcPix); 603 } 604 } 605 } 606 return dst; 607 } 608 609 /** 610 * Returns the bounding box of the rescaled destination image. Since 611 * this is not a geometric operation, the bounding box does not 612 * change. 613 */ 614 public final Rectangle2D getBounds2D (BufferedImage src) { 615 return getBounds2D(src.getRaster()); 616 } 617 618 /** 619 * Returns the bounding box of the rescaled destination Raster. Since 620 * this is not a geometric operation, the bounding box does not 621 * change. 622 * @param src the rescaled destination {@code Raster} 623 * @return the bounds of the specified {@code Raster}. 624 */ 625 public final Rectangle2D getBounds2D (Raster src) { 626 return src.getBounds(); 627 } 628 629 /** 630 * Creates a zeroed destination image with the correct size and number of 631 * bands. 632 * @param src Source image for the filter operation. 633 * @param destCM ColorModel of the destination. If null, the 634 * ColorModel of the source will be used. 635 * @return the zeroed-destination image. 636 */ 637 public BufferedImage createCompatibleDestImage (BufferedImage src, 638 ColorModel destCM) { 639 BufferedImage image; 640 if (destCM == null) { 641 ColorModel cm = src.getColorModel(); 642 image = new BufferedImage(cm, 643 src.getRaster().createCompatibleWritableRaster(), 644 cm.isAlphaPremultiplied(), 645 null); 646 } 647 else { 648 int w = src.getWidth(); 649 int h = src.getHeight(); 650 image = new BufferedImage (destCM, 651 destCM.createCompatibleWritableRaster(w, h), 652 destCM.isAlphaPremultiplied(), null); 653 } 654 655 return image; 656 } 657 658 /** 659 * Creates a zeroed-destination {@code Raster} with the correct 660 * size and number of bands, given this source. 661 * @param src the source {@code Raster} 662 * @return the zeroed-destination {@code Raster}. 663 */ 664 public WritableRaster createCompatibleDestRaster (Raster src) { 665 return src.createCompatibleWritableRaster(src.getWidth(), src.getHeight()); 666 } 667 668 /** 669 * Returns the location of the destination point given a 670 * point in the source. If dstPt is non-null, it will 671 * be used to hold the return value. Since this is not a geometric 672 * operation, the srcPt will equal the dstPt. 673 * @param srcPt a point in the source image 674 * @param dstPt the destination point or {@code null} 675 * @return the location of the destination point. 676 */ 677 public final Point2D getPoint2D (Point2D srcPt, Point2D dstPt) { 678 if (dstPt == null) { 679 dstPt = new Point2D.Float(); 680 } 681 dstPt.setLocation(srcPt.getX(), srcPt.getY()); 682 return dstPt; 683 } 684 685 /** 686 * Returns the rendering hints for this op. 687 * @return the rendering hints of this {@code RescaleOp}. 688 */ 689 public final RenderingHints getRenderingHints() { 690 return hints; 691 } 692} 693