1 /*
2 * Copyright (c) 1997, 2010, 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;
27
28 import java.awt.image.ColorModel;
29 import javax.tools.annotation.GenerateNativeHeader;
30 import sun.java2d.SunCompositeContext;
31
32 /**
33 * The <code>AlphaComposite</code> class implements basic alpha
34 * compositing rules for combining source and destination colors
35 * to achieve blending and transparency effects with graphics and
36 * images.
37 * The specific rules implemented by this class are the basic set
38 * of 12 rules described in
39 * T. Porter and T. Duff, "Compositing Digital Images", SIGGRAPH 84,
40 * 253-259.
41 * The rest of this documentation assumes some familiarity with the
42 * definitions and concepts outlined in that paper.
43 *
44 * <p>
45 * This class extends the standard equations defined by Porter and
46 * Duff to include one additional factor.
47 * An instance of the <code>AlphaComposite</code> class can contain
48 * an alpha value that is used to modify the opacity or coverage of
49 * every source pixel before it is used in the blending equations.
333 * and thus they would all match.
334 *
335 * <p>
336 * <li>
337 * Because of the technique of simplifying the equations for
338 * calculation efficiency, some implementations might perform
339 * differently when encountering result alpha values of 0.0
340 * on a non-premultiplied destination.
341 * Note that the simplification of removing the divide by alpha
342 * in the case of the SRC rule is technically not valid if the
343 * denominator (alpha) is 0.
344 * But, since the results should only be expected to be accurate
345 * when viewed in premultiplied form, a resulting alpha of 0
346 * essentially renders the resulting color components irrelevant
347 * and so exact behavior in this case should not be expected.
348 * </ul>
349 * @see Composite
350 * @see CompositeContext
351 */
352
353 /* No native methods here, but the constants are needed in the supporting JNI code */
354 @GenerateNativeHeader
355 public final class AlphaComposite implements Composite {
356 /**
357 * Both the color and the alpha of the destination are cleared
358 * (Porter-Duff Clear rule).
359 * Neither the source nor the destination is used as input.
360 *<p>
361 * <em>F<sub>s</sub></em> = 0 and <em>F<sub>d</sub></em> = 0, thus:
362 *<pre>
363 * <em>A<sub>r</sub></em> = 0
364 * <em>C<sub>r</sub></em> = 0
365 *</pre>
366 */
367 public static final int CLEAR = 1;
368
369 /**
370 * The source is copied to the destination
371 * (Porter-Duff Source rule).
372 * The destination is not used as input.
373 *<p>
374 * <em>F<sub>s</sub></em> = 1 and <em>F<sub>d</sub></em> = 0, thus:
375 *<pre>
376 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>
377 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>
378 *</pre>
379 */
380 public static final int SRC = 2;
381
382 /**
383 * The destination is left untouched
384 * (Porter-Duff Destination rule).
385 *<p>
386 * <em>F<sub>s</sub></em> = 0 and <em>F<sub>d</sub></em> = 1, thus:
387 *<pre>
388 * <em>A<sub>r</sub></em> = <em>A<sub>d</sub></em>
389 * <em>C<sub>r</sub></em> = <em>C<sub>d</sub></em>
390 *</pre>
391 * @since 1.4
392 */
393 public static final int DST = 9;
394 // Note that DST was added in 1.4 so it is numbered out of order...
395
396 /**
397 * The source is composited over the destination
398 * (Porter-Duff Source Over Destination rule).
399 *<p>
400 * <em>F<sub>s</sub></em> = 1 and <em>F<sub>d</sub></em> = (1-<em>A<sub>s</sub></em>), thus:
401 *<pre>
402 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em> + <em>A<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
403 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em> + <em>C<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
404 *</pre>
405 */
406 public static final int SRC_OVER = 3;
407
408 /**
409 * The destination is composited over the source and
410 * the result replaces the destination
411 * (Porter-Duff Destination Over Source rule).
412 *<p>
413 * <em>F<sub>s</sub></em> = (1-<em>A<sub>d</sub></em>) and <em>F<sub>d</sub></em> = 1, thus:
414 *<pre>
415 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>) + <em>A<sub>d</sub></em>
416 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>) + <em>C<sub>d</sub></em>
417 *</pre>
418 */
419 public static final int DST_OVER = 4;
420
421 /**
422 * The part of the source lying inside of the destination replaces
423 * the destination
424 * (Porter-Duff Source In Destination rule).
425 *<p>
426 * <em>F<sub>s</sub></em> = <em>A<sub>d</sub></em> and <em>F<sub>d</sub></em> = 0, thus:
427 *<pre>
428 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>*<em>A<sub>d</sub></em>
429 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>*<em>A<sub>d</sub></em>
430 *</pre>
431 */
432 public static final int SRC_IN = 5;
433
434 /**
435 * The part of the destination lying inside of the source
436 * replaces the destination
437 * (Porter-Duff Destination In Source rule).
438 *<p>
439 * <em>F<sub>s</sub></em> = 0 and <em>F<sub>d</sub></em> = <em>A<sub>s</sub></em>, thus:
440 *<pre>
441 * <em>A<sub>r</sub></em> = <em>A<sub>d</sub></em>*<em>A<sub>s</sub></em>
442 * <em>C<sub>r</sub></em> = <em>C<sub>d</sub></em>*<em>A<sub>s</sub></em>
443 *</pre>
444 */
445 public static final int DST_IN = 6;
446
447 /**
448 * The part of the source lying outside of the destination
449 * replaces the destination
450 * (Porter-Duff Source Held Out By Destination rule).
451 *<p>
452 * <em>F<sub>s</sub></em> = (1-<em>A<sub>d</sub></em>) and <em>F<sub>d</sub></em> = 0, thus:
453 *<pre>
454 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>)
455 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>)
456 *</pre>
457 */
458 public static final int SRC_OUT = 7;
459
460 /**
461 * The part of the destination lying outside of the source
462 * replaces the destination
463 * (Porter-Duff Destination Held Out By Source rule).
464 *<p>
465 * <em>F<sub>s</sub></em> = 0 and <em>F<sub>d</sub></em> = (1-<em>A<sub>s</sub></em>), thus:
466 *<pre>
467 * <em>A<sub>r</sub></em> = <em>A<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
468 * <em>C<sub>r</sub></em> = <em>C<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
469 *</pre>
470 */
471 public static final int DST_OUT = 8;
472
473 // Rule 9 is DST which is defined above where it fits into the
474 // list logically, rather than numerically
475 //
476 // public static final int DST = 9;
477
478 /**
479 * The part of the source lying inside of the destination
480 * is composited onto the destination
481 * (Porter-Duff Source Atop Destination rule).
482 *<p>
483 * <em>F<sub>s</sub></em> = <em>A<sub>d</sub></em> and <em>F<sub>d</sub></em> = (1-<em>A<sub>s</sub></em>), thus:
484 *<pre>
485 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>*<em>A<sub>d</sub></em> + <em>A<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>) = <em>A<sub>d</sub></em>
486 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>*<em>A<sub>d</sub></em> + <em>C<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
487 *</pre>
488 * @since 1.4
489 */
490 public static final int SRC_ATOP = 10;
491
492 /**
493 * The part of the destination lying inside of the source
494 * is composited over the source and replaces the destination
495 * (Porter-Duff Destination Atop Source rule).
496 *<p>
497 * <em>F<sub>s</sub></em> = (1-<em>A<sub>d</sub></em>) and <em>F<sub>d</sub></em> = <em>A<sub>s</sub></em>, thus:
498 *<pre>
499 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>) + <em>A<sub>d</sub></em>*<em>A<sub>s</sub></em> = <em>A<sub>s</sub></em>
500 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>) + <em>C<sub>d</sub></em>*<em>A<sub>s</sub></em>
501 *</pre>
502 * @since 1.4
503 */
504 public static final int DST_ATOP = 11;
505
506 /**
507 * The part of the source that lies outside of the destination
508 * is combined with the part of the destination that lies outside
509 * of the source
510 * (Porter-Duff Source Xor Destination rule).
511 *<p>
512 * <em>F<sub>s</sub></em> = (1-<em>A<sub>d</sub></em>) and <em>F<sub>d</sub></em> = (1-<em>A<sub>s</sub></em>), thus:
513 *<pre>
514 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>) + <em>A<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
515 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>) + <em>C<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
516 *</pre>
517 * @since 1.4
518 */
519 public static final int XOR = 12;
520
521 /**
522 * <code>AlphaComposite</code> object that implements the opaque CLEAR rule
523 * with an alpha of 1.0f.
524 * @see #CLEAR
525 */
526 public static final AlphaComposite Clear = new AlphaComposite(CLEAR);
527
528 /**
529 * <code>AlphaComposite</code> object that implements the opaque SRC rule
530 * with an alpha of 1.0f.
531 * @see #SRC
532 */
533 public static final AlphaComposite Src = new AlphaComposite(SRC);
534
535 /**
536 * <code>AlphaComposite</code> object that implements the opaque DST rule
537 * with an alpha of 1.0f.
538 * @see #DST
539 * @since 1.4
589 * @since 1.4
590 */
591 public static final AlphaComposite SrcAtop = new AlphaComposite(SRC_ATOP);
592
593 /**
594 * <code>AlphaComposite</code> object that implements the opaque DST_ATOP rule
595 * with an alpha of 1.0f.
596 * @see #DST_ATOP
597 * @since 1.4
598 */
599 public static final AlphaComposite DstAtop = new AlphaComposite(DST_ATOP);
600
601 /**
602 * <code>AlphaComposite</code> object that implements the opaque XOR rule
603 * with an alpha of 1.0f.
604 * @see #XOR
605 * @since 1.4
606 */
607 public static final AlphaComposite Xor = new AlphaComposite(XOR);
608
609 private static final int MIN_RULE = CLEAR;
610 private static final int MAX_RULE = XOR;
611
612 float extraAlpha;
613 int rule;
614
615 private AlphaComposite(int rule) {
616 this(rule, 1.0f);
617 }
618
619 private AlphaComposite(int rule, float alpha) {
620 if (rule < MIN_RULE || rule > MAX_RULE) {
621 throw new IllegalArgumentException("unknown composite rule");
622 }
623 if (alpha >= 0.0f && alpha <= 1.0f) {
624 this.rule = rule;
625 this.extraAlpha = alpha;
626 } else {
627 throw new IllegalArgumentException("alpha value out of range");
628 }
629 }
630
|
1 /*
2 * Copyright (c) 1997, 2013, 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;
27
28 import java.awt.image.ColorModel;
29 import java.lang.annotation.Native;
30 import sun.java2d.SunCompositeContext;
31
32 /**
33 * The <code>AlphaComposite</code> class implements basic alpha
34 * compositing rules for combining source and destination colors
35 * to achieve blending and transparency effects with graphics and
36 * images.
37 * The specific rules implemented by this class are the basic set
38 * of 12 rules described in
39 * T. Porter and T. Duff, "Compositing Digital Images", SIGGRAPH 84,
40 * 253-259.
41 * The rest of this documentation assumes some familiarity with the
42 * definitions and concepts outlined in that paper.
43 *
44 * <p>
45 * This class extends the standard equations defined by Porter and
46 * Duff to include one additional factor.
47 * An instance of the <code>AlphaComposite</code> class can contain
48 * an alpha value that is used to modify the opacity or coverage of
49 * every source pixel before it is used in the blending equations.
333 * and thus they would all match.
334 *
335 * <p>
336 * <li>
337 * Because of the technique of simplifying the equations for
338 * calculation efficiency, some implementations might perform
339 * differently when encountering result alpha values of 0.0
340 * on a non-premultiplied destination.
341 * Note that the simplification of removing the divide by alpha
342 * in the case of the SRC rule is technically not valid if the
343 * denominator (alpha) is 0.
344 * But, since the results should only be expected to be accurate
345 * when viewed in premultiplied form, a resulting alpha of 0
346 * essentially renders the resulting color components irrelevant
347 * and so exact behavior in this case should not be expected.
348 * </ul>
349 * @see Composite
350 * @see CompositeContext
351 */
352
353 public final class AlphaComposite implements Composite {
354 /**
355 * Both the color and the alpha of the destination are cleared
356 * (Porter-Duff Clear rule).
357 * Neither the source nor the destination is used as input.
358 *<p>
359 * <em>F<sub>s</sub></em> = 0 and <em>F<sub>d</sub></em> = 0, thus:
360 *<pre>
361 * <em>A<sub>r</sub></em> = 0
362 * <em>C<sub>r</sub></em> = 0
363 *</pre>
364 */
365 @Native public static final int CLEAR = 1;
366
367 /**
368 * The source is copied to the destination
369 * (Porter-Duff Source rule).
370 * The destination is not used as input.
371 *<p>
372 * <em>F<sub>s</sub></em> = 1 and <em>F<sub>d</sub></em> = 0, thus:
373 *<pre>
374 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>
375 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>
376 *</pre>
377 */
378 @Native public static final int SRC = 2;
379
380 /**
381 * The destination is left untouched
382 * (Porter-Duff Destination rule).
383 *<p>
384 * <em>F<sub>s</sub></em> = 0 and <em>F<sub>d</sub></em> = 1, thus:
385 *<pre>
386 * <em>A<sub>r</sub></em> = <em>A<sub>d</sub></em>
387 * <em>C<sub>r</sub></em> = <em>C<sub>d</sub></em>
388 *</pre>
389 * @since 1.4
390 */
391 @Native public static final int DST = 9;
392 // Note that DST was added in 1.4 so it is numbered out of order...
393
394 /**
395 * The source is composited over the destination
396 * (Porter-Duff Source Over Destination rule).
397 *<p>
398 * <em>F<sub>s</sub></em> = 1 and <em>F<sub>d</sub></em> = (1-<em>A<sub>s</sub></em>), thus:
399 *<pre>
400 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em> + <em>A<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
401 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em> + <em>C<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
402 *</pre>
403 */
404 @Native public static final int SRC_OVER = 3;
405
406 /**
407 * The destination is composited over the source and
408 * the result replaces the destination
409 * (Porter-Duff Destination Over Source rule).
410 *<p>
411 * <em>F<sub>s</sub></em> = (1-<em>A<sub>d</sub></em>) and <em>F<sub>d</sub></em> = 1, thus:
412 *<pre>
413 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>) + <em>A<sub>d</sub></em>
414 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>) + <em>C<sub>d</sub></em>
415 *</pre>
416 */
417 @Native public static final int DST_OVER = 4;
418
419 /**
420 * The part of the source lying inside of the destination replaces
421 * the destination
422 * (Porter-Duff Source In Destination rule).
423 *<p>
424 * <em>F<sub>s</sub></em> = <em>A<sub>d</sub></em> and <em>F<sub>d</sub></em> = 0, thus:
425 *<pre>
426 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>*<em>A<sub>d</sub></em>
427 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>*<em>A<sub>d</sub></em>
428 *</pre>
429 */
430 @Native public static final int SRC_IN = 5;
431
432 /**
433 * The part of the destination lying inside of the source
434 * replaces the destination
435 * (Porter-Duff Destination In Source rule).
436 *<p>
437 * <em>F<sub>s</sub></em> = 0 and <em>F<sub>d</sub></em> = <em>A<sub>s</sub></em>, thus:
438 *<pre>
439 * <em>A<sub>r</sub></em> = <em>A<sub>d</sub></em>*<em>A<sub>s</sub></em>
440 * <em>C<sub>r</sub></em> = <em>C<sub>d</sub></em>*<em>A<sub>s</sub></em>
441 *</pre>
442 */
443 @Native public static final int DST_IN = 6;
444
445 /**
446 * The part of the source lying outside of the destination
447 * replaces the destination
448 * (Porter-Duff Source Held Out By Destination rule).
449 *<p>
450 * <em>F<sub>s</sub></em> = (1-<em>A<sub>d</sub></em>) and <em>F<sub>d</sub></em> = 0, thus:
451 *<pre>
452 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>)
453 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>)
454 *</pre>
455 */
456 @Native public static final int SRC_OUT = 7;
457
458 /**
459 * The part of the destination lying outside of the source
460 * replaces the destination
461 * (Porter-Duff Destination Held Out By Source rule).
462 *<p>
463 * <em>F<sub>s</sub></em> = 0 and <em>F<sub>d</sub></em> = (1-<em>A<sub>s</sub></em>), thus:
464 *<pre>
465 * <em>A<sub>r</sub></em> = <em>A<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
466 * <em>C<sub>r</sub></em> = <em>C<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
467 *</pre>
468 */
469 @Native public static final int DST_OUT = 8;
470
471 // Rule 9 is DST which is defined above where it fits into the
472 // list logically, rather than numerically
473 //
474 // public static final int DST = 9;
475
476 /**
477 * The part of the source lying inside of the destination
478 * is composited onto the destination
479 * (Porter-Duff Source Atop Destination rule).
480 *<p>
481 * <em>F<sub>s</sub></em> = <em>A<sub>d</sub></em> and <em>F<sub>d</sub></em> = (1-<em>A<sub>s</sub></em>), thus:
482 *<pre>
483 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>*<em>A<sub>d</sub></em> + <em>A<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>) = <em>A<sub>d</sub></em>
484 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>*<em>A<sub>d</sub></em> + <em>C<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
485 *</pre>
486 * @since 1.4
487 */
488 @Native public static final int SRC_ATOP = 10;
489
490 /**
491 * The part of the destination lying inside of the source
492 * is composited over the source and replaces the destination
493 * (Porter-Duff Destination Atop Source rule).
494 *<p>
495 * <em>F<sub>s</sub></em> = (1-<em>A<sub>d</sub></em>) and <em>F<sub>d</sub></em> = <em>A<sub>s</sub></em>, thus:
496 *<pre>
497 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>) + <em>A<sub>d</sub></em>*<em>A<sub>s</sub></em> = <em>A<sub>s</sub></em>
498 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>) + <em>C<sub>d</sub></em>*<em>A<sub>s</sub></em>
499 *</pre>
500 * @since 1.4
501 */
502 @Native public static final int DST_ATOP = 11;
503
504 /**
505 * The part of the source that lies outside of the destination
506 * is combined with the part of the destination that lies outside
507 * of the source
508 * (Porter-Duff Source Xor Destination rule).
509 *<p>
510 * <em>F<sub>s</sub></em> = (1-<em>A<sub>d</sub></em>) and <em>F<sub>d</sub></em> = (1-<em>A<sub>s</sub></em>), thus:
511 *<pre>
512 * <em>A<sub>r</sub></em> = <em>A<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>) + <em>A<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
513 * <em>C<sub>r</sub></em> = <em>C<sub>s</sub></em>*(1-<em>A<sub>d</sub></em>) + <em>C<sub>d</sub></em>*(1-<em>A<sub>s</sub></em>)
514 *</pre>
515 * @since 1.4
516 */
517 @Native public static final int XOR = 12;
518
519 /**
520 * <code>AlphaComposite</code> object that implements the opaque CLEAR rule
521 * with an alpha of 1.0f.
522 * @see #CLEAR
523 */
524 public static final AlphaComposite Clear = new AlphaComposite(CLEAR);
525
526 /**
527 * <code>AlphaComposite</code> object that implements the opaque SRC rule
528 * with an alpha of 1.0f.
529 * @see #SRC
530 */
531 public static final AlphaComposite Src = new AlphaComposite(SRC);
532
533 /**
534 * <code>AlphaComposite</code> object that implements the opaque DST rule
535 * with an alpha of 1.0f.
536 * @see #DST
537 * @since 1.4
587 * @since 1.4
588 */
589 public static final AlphaComposite SrcAtop = new AlphaComposite(SRC_ATOP);
590
591 /**
592 * <code>AlphaComposite</code> object that implements the opaque DST_ATOP rule
593 * with an alpha of 1.0f.
594 * @see #DST_ATOP
595 * @since 1.4
596 */
597 public static final AlphaComposite DstAtop = new AlphaComposite(DST_ATOP);
598
599 /**
600 * <code>AlphaComposite</code> object that implements the opaque XOR rule
601 * with an alpha of 1.0f.
602 * @see #XOR
603 * @since 1.4
604 */
605 public static final AlphaComposite Xor = new AlphaComposite(XOR);
606
607 @Native private static final int MIN_RULE = CLEAR;
608 @Native private static final int MAX_RULE = XOR;
609
610 float extraAlpha;
611 int rule;
612
613 private AlphaComposite(int rule) {
614 this(rule, 1.0f);
615 }
616
617 private AlphaComposite(int rule, float alpha) {
618 if (rule < MIN_RULE || rule > MAX_RULE) {
619 throw new IllegalArgumentException("unknown composite rule");
620 }
621 if (alpha >= 0.0f && alpha <= 1.0f) {
622 this.rule = rule;
623 this.extraAlpha = alpha;
624 } else {
625 throw new IllegalArgumentException("alpha value out of range");
626 }
627 }
628
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