1/* 2 * Copyright (c) 2007, 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 sun.java2d.pisces; 27 28import java.awt.Shape; 29import java.awt.BasicStroke; 30import java.awt.geom.Path2D; 31import java.awt.geom.AffineTransform; 32import java.awt.geom.PathIterator; 33 34import sun.awt.geom.PathConsumer2D; 35import sun.java2d.pipe.Region; 36import sun.java2d.pipe.RenderingEngine; 37import sun.java2d.pipe.AATileGenerator; 38 39public class PiscesRenderingEngine extends RenderingEngine { 40 private static enum NormMode {OFF, ON_NO_AA, ON_WITH_AA} 41 42 /** 43 * Create a widened path as specified by the parameters. 44 * <p> 45 * The specified {@code src} {@link Shape} is widened according 46 * to the specified attribute parameters as per the 47 * {@link BasicStroke} specification. 48 * 49 * @param src the source path to be widened 50 * @param width the width of the widened path as per {@code BasicStroke} 51 * @param caps the end cap decorations as per {@code BasicStroke} 52 * @param join the segment join decorations as per {@code BasicStroke} 53 * @param miterlimit the miter limit as per {@code BasicStroke} 54 * @param dashes the dash length array as per {@code BasicStroke} 55 * @param dashphase the initial dash phase as per {@code BasicStroke} 56 * @return the widened path stored in a new {@code Shape} object 57 * @since 1.7 58 */ 59 public Shape createStrokedShape(Shape src, 60 float width, 61 int caps, 62 int join, 63 float miterlimit, 64 float dashes[], 65 float dashphase) 66 { 67 final Path2D p2d = new Path2D.Float(); 68 69 strokeTo(src, 70 null, 71 width, 72 NormMode.OFF, 73 caps, 74 join, 75 miterlimit, 76 dashes, 77 dashphase, 78 new PathConsumer2D() { 79 public void moveTo(float x0, float y0) { 80 p2d.moveTo(x0, y0); 81 } 82 public void lineTo(float x1, float y1) { 83 p2d.lineTo(x1, y1); 84 } 85 public void closePath() { 86 p2d.closePath(); 87 } 88 public void pathDone() {} 89 public void curveTo(float x1, float y1, 90 float x2, float y2, 91 float x3, float y3) { 92 p2d.curveTo(x1, y1, x2, y2, x3, y3); 93 } 94 public void quadTo(float x1, float y1, float x2, float y2) { 95 p2d.quadTo(x1, y1, x2, y2); 96 } 97 public long getNativeConsumer() { 98 throw new InternalError("Not using a native peer"); 99 } 100 }); 101 return p2d; 102 } 103 104 /** 105 * Sends the geometry for a widened path as specified by the parameters 106 * to the specified consumer. 107 * <p> 108 * The specified {@code src} {@link Shape} is widened according 109 * to the parameters specified by the {@link BasicStroke} object. 110 * Adjustments are made to the path as appropriate for the 111 * {@link java.awt.RenderingHints#VALUE_STROKE_NORMALIZE} hint if the 112 * {@code normalize} boolean parameter is true. 113 * Adjustments are made to the path as appropriate for the 114 * {@link java.awt.RenderingHints#VALUE_ANTIALIAS_ON} hint if the 115 * {@code antialias} boolean parameter is true. 116 * <p> 117 * The geometry of the widened path is forwarded to the indicated 118 * {@link PathConsumer2D} object as it is calculated. 119 * 120 * @param src the source path to be widened 121 * @param bs the {@code BasicSroke} object specifying the 122 * decorations to be applied to the widened path 123 * @param normalize indicates whether stroke normalization should 124 * be applied 125 * @param antialias indicates whether or not adjustments appropriate 126 * to antialiased rendering should be applied 127 * @param consumer the {@code PathConsumer2D} instance to forward 128 * the widened geometry to 129 * @since 1.7 130 */ 131 public void strokeTo(Shape src, 132 AffineTransform at, 133 BasicStroke bs, 134 boolean thin, 135 boolean normalize, 136 boolean antialias, 137 final PathConsumer2D consumer) 138 { 139 NormMode norm = (normalize) ? 140 ((antialias) ? NormMode.ON_WITH_AA : NormMode.ON_NO_AA) 141 : NormMode.OFF; 142 strokeTo(src, at, bs, thin, norm, antialias, consumer); 143 } 144 145 void strokeTo(Shape src, 146 AffineTransform at, 147 BasicStroke bs, 148 boolean thin, 149 NormMode normalize, 150 boolean antialias, 151 PathConsumer2D pc2d) 152 { 153 float lw; 154 if (thin) { 155 if (antialias) { 156 lw = userSpaceLineWidth(at, 0.5f); 157 } else { 158 lw = userSpaceLineWidth(at, 1.0f); 159 } 160 } else { 161 lw = bs.getLineWidth(); 162 } 163 strokeTo(src, 164 at, 165 lw, 166 normalize, 167 bs.getEndCap(), 168 bs.getLineJoin(), 169 bs.getMiterLimit(), 170 bs.getDashArray(), 171 bs.getDashPhase(), 172 pc2d); 173 } 174 175 private float userSpaceLineWidth(AffineTransform at, float lw) { 176 177 double widthScale; 178 179 if ((at.getType() & (AffineTransform.TYPE_GENERAL_TRANSFORM | 180 AffineTransform.TYPE_GENERAL_SCALE)) != 0) { 181 widthScale = Math.sqrt(at.getDeterminant()); 182 } else { 183 /* First calculate the "maximum scale" of this transform. */ 184 double A = at.getScaleX(); // m00 185 double C = at.getShearX(); // m01 186 double B = at.getShearY(); // m10 187 double D = at.getScaleY(); // m11 188 189 /* 190 * Given a 2 x 2 affine matrix [ A B ] such that 191 * [ C D ] 192 * v' = [x' y'] = [Ax + Cy, Bx + Dy], we want to 193 * find the maximum magnitude (norm) of the vector v' 194 * with the constraint (x^2 + y^2 = 1). 195 * The equation to maximize is 196 * |v'| = sqrt((Ax+Cy)^2+(Bx+Dy)^2) 197 * or |v'| = sqrt((AA+BB)x^2 + 2(AC+BD)xy + (CC+DD)y^2). 198 * Since sqrt is monotonic we can maximize |v'|^2 199 * instead and plug in the substitution y = sqrt(1 - x^2). 200 * Trigonometric equalities can then be used to get 201 * rid of most of the sqrt terms. 202 */ 203 204 double EA = A*A + B*B; // x^2 coefficient 205 double EB = 2*(A*C + B*D); // xy coefficient 206 double EC = C*C + D*D; // y^2 coefficient 207 208 /* 209 * There is a lot of calculus omitted here. 210 * 211 * Conceptually, in the interests of understanding the 212 * terms that the calculus produced we can consider 213 * that EA and EC end up providing the lengths along 214 * the major axes and the hypot term ends up being an 215 * adjustment for the additional length along the off-axis 216 * angle of rotated or sheared ellipses as well as an 217 * adjustment for the fact that the equation below 218 * averages the two major axis lengths. (Notice that 219 * the hypot term contains a part which resolves to the 220 * difference of these two axis lengths in the absence 221 * of rotation.) 222 * 223 * In the calculus, the ratio of the EB and (EA-EC) terms 224 * ends up being the tangent of 2*theta where theta is 225 * the angle that the long axis of the ellipse makes 226 * with the horizontal axis. Thus, this equation is 227 * calculating the length of the hypotenuse of a triangle 228 * along that axis. 229 */ 230 231 double hypot = Math.sqrt(EB*EB + (EA-EC)*(EA-EC)); 232 /* sqrt omitted, compare to squared limits below. */ 233 double widthsquared = ((EA + EC + hypot)/2.0); 234 235 widthScale = Math.sqrt(widthsquared); 236 } 237 238 return (float) (lw / widthScale); 239 } 240 241 void strokeTo(Shape src, 242 AffineTransform at, 243 float width, 244 NormMode normalize, 245 int caps, 246 int join, 247 float miterlimit, 248 float dashes[], 249 float dashphase, 250 PathConsumer2D pc2d) 251 { 252 // We use strokerat and outat so that in Stroker and Dasher we can work only 253 // with the pre-transformation coordinates. This will repeat a lot of 254 // computations done in the path iterator, but the alternative is to 255 // work with transformed paths and compute untransformed coordinates 256 // as needed. This would be faster but I do not think the complexity 257 // of working with both untransformed and transformed coordinates in 258 // the same code is worth it. 259 // However, if a path's width is constant after a transformation, 260 // we can skip all this untransforming. 261 262 // If normalization is off we save some transformations by not 263 // transforming the input to pisces. Instead, we apply the 264 // transformation after the path processing has been done. 265 // We can't do this if normalization is on, because it isn't a good 266 // idea to normalize before the transformation is applied. 267 AffineTransform strokerat = null; 268 AffineTransform outat = null; 269 270 PathIterator pi = null; 271 272 if (at != null && !at.isIdentity()) { 273 final double a = at.getScaleX(); 274 final double b = at.getShearX(); 275 final double c = at.getShearY(); 276 final double d = at.getScaleY(); 277 final double det = a * d - c * b; 278 if (Math.abs(det) <= 2 * Float.MIN_VALUE) { 279 // this rendering engine takes one dimensional curves and turns 280 // them into 2D shapes by giving them width. 281 // However, if everything is to be passed through a singular 282 // transformation, these 2D shapes will be squashed down to 1D 283 // again so, nothing can be drawn. 284 285 // Every path needs an initial moveTo and a pathDone. If these 286 // are not there this causes a SIGSEGV in libawt.so (at the time 287 // of writing of this comment (September 16, 2010)). Actually, 288 // I am not sure if the moveTo is necessary to avoid the SIGSEGV 289 // but the pathDone is definitely needed. 290 pc2d.moveTo(0, 0); 291 pc2d.pathDone(); 292 return; 293 } 294 295 // If the transform is a constant multiple of an orthogonal transformation 296 // then every length is just multiplied by a constant, so we just 297 // need to transform input paths to stroker and tell stroker 298 // the scaled width. This condition is satisfied if 299 // a*b == -c*d && a*a+c*c == b*b+d*d. In the actual check below, we 300 // leave a bit of room for error. 301 if (nearZero(a*b + c*d, 2) && nearZero(a*a+c*c - (b*b+d*d), 2)) { 302 double scale = Math.sqrt(a*a + c*c); 303 if (dashes != null) { 304 dashes = java.util.Arrays.copyOf(dashes, dashes.length); 305 for (int i = 0; i < dashes.length; i++) { 306 dashes[i] = (float)(scale * dashes[i]); 307 } 308 dashphase = (float)(scale * dashphase); 309 } 310 width = (float)(scale * width); 311 pi = src.getPathIterator(at); 312 if (normalize != NormMode.OFF) { 313 pi = new NormalizingPathIterator(pi, normalize); 314 } 315 // by now strokerat == null && outat == null. Input paths to 316 // stroker (and maybe dasher) will have the full transform at 317 // applied to them and nothing will happen to the output paths. 318 } else { 319 if (normalize != NormMode.OFF) { 320 strokerat = at; 321 pi = src.getPathIterator(at); 322 pi = new NormalizingPathIterator(pi, normalize); 323 // by now strokerat == at && outat == null. Input paths to 324 // stroker (and maybe dasher) will have the full transform at 325 // applied to them, then they will be normalized, and then 326 // the inverse of *only the non translation part of at* will 327 // be applied to the normalized paths. This won't cause problems 328 // in stroker, because, suppose at = T*A, where T is just the 329 // translation part of at, and A is the rest. T*A has already 330 // been applied to Stroker/Dasher's input. Then Ainv will be 331 // applied. Ainv*T*A is not equal to T, but it is a translation, 332 // which means that none of stroker's assumptions about its 333 // input will be violated. After all this, A will be applied 334 // to stroker's output. 335 } else { 336 outat = at; 337 pi = src.getPathIterator(null); 338 // outat == at && strokerat == null. This is because if no 339 // normalization is done, we can just apply all our 340 // transformations to stroker's output. 341 } 342 } 343 } else { 344 // either at is null or it's the identity. In either case 345 // we don't transform the path. 346 pi = src.getPathIterator(null); 347 if (normalize != NormMode.OFF) { 348 pi = new NormalizingPathIterator(pi, normalize); 349 } 350 } 351 352 // by now, at least one of outat and strokerat will be null. Unless at is not 353 // a constant multiple of an orthogonal transformation, they will both be 354 // null. In other cases, outat == at if normalization is off, and if 355 // normalization is on, strokerat == at. 356 pc2d = TransformingPathConsumer2D.transformConsumer(pc2d, outat); 357 pc2d = TransformingPathConsumer2D.deltaTransformConsumer(pc2d, strokerat); 358 pc2d = new Stroker(pc2d, width, caps, join, miterlimit); 359 if (dashes != null) { 360 pc2d = new Dasher(pc2d, dashes, dashphase); 361 } 362 pc2d = TransformingPathConsumer2D.inverseDeltaTransformConsumer(pc2d, strokerat); 363 pathTo(pi, pc2d); 364 } 365 366 private static boolean nearZero(double num, int nulps) { 367 return Math.abs(num) < nulps * Math.ulp(num); 368 } 369 370 private static class NormalizingPathIterator implements PathIterator { 371 372 private final PathIterator src; 373 374 // the adjustment applied to the current position. 375 private float curx_adjust, cury_adjust; 376 // the adjustment applied to the last moveTo position. 377 private float movx_adjust, movy_adjust; 378 379 // constants used in normalization computations 380 private final float lval, rval; 381 382 NormalizingPathIterator(PathIterator src, NormMode mode) { 383 this.src = src; 384 switch (mode) { 385 case ON_NO_AA: 386 // round to nearest (0.25, 0.25) pixel 387 lval = rval = 0.25f; 388 break; 389 case ON_WITH_AA: 390 // round to nearest pixel center 391 lval = 0f; 392 rval = 0.5f; 393 break; 394 case OFF: 395 throw new InternalError("A NormalizingPathIterator should " + 396 "not be created if no normalization is being done"); 397 default: 398 throw new InternalError("Unrecognized normalization mode"); 399 } 400 } 401 402 public int currentSegment(float[] coords) { 403 int type = src.currentSegment(coords); 404 405 int lastCoord; 406 switch(type) { 407 case PathIterator.SEG_CUBICTO: 408 lastCoord = 4; 409 break; 410 case PathIterator.SEG_QUADTO: 411 lastCoord = 2; 412 break; 413 case PathIterator.SEG_LINETO: 414 case PathIterator.SEG_MOVETO: 415 lastCoord = 0; 416 break; 417 case PathIterator.SEG_CLOSE: 418 // we don't want to deal with this case later. We just exit now 419 curx_adjust = movx_adjust; 420 cury_adjust = movy_adjust; 421 return type; 422 default: 423 throw new InternalError("Unrecognized curve type"); 424 } 425 426 // normalize endpoint 427 float x_adjust = (float)Math.floor(coords[lastCoord] + lval) + 428 rval - coords[lastCoord]; 429 float y_adjust = (float)Math.floor(coords[lastCoord+1] + lval) + 430 rval - coords[lastCoord + 1]; 431 432 coords[lastCoord ] += x_adjust; 433 coords[lastCoord + 1] += y_adjust; 434 435 // now that the end points are done, normalize the control points 436 switch(type) { 437 case PathIterator.SEG_CUBICTO: 438 coords[0] += curx_adjust; 439 coords[1] += cury_adjust; 440 coords[2] += x_adjust; 441 coords[3] += y_adjust; 442 break; 443 case PathIterator.SEG_QUADTO: 444 coords[0] += (curx_adjust + x_adjust) / 2; 445 coords[1] += (cury_adjust + y_adjust) / 2; 446 break; 447 case PathIterator.SEG_LINETO: 448 break; 449 case PathIterator.SEG_MOVETO: 450 movx_adjust = x_adjust; 451 movy_adjust = y_adjust; 452 break; 453 case PathIterator.SEG_CLOSE: 454 throw new InternalError("This should be handled earlier."); 455 } 456 curx_adjust = x_adjust; 457 cury_adjust = y_adjust; 458 return type; 459 } 460 461 public int currentSegment(double[] coords) { 462 float[] tmp = new float[6]; 463 int type = this.currentSegment(tmp); 464 for (int i = 0; i < 6; i++) { 465 coords[i] = tmp[i]; 466 } 467 return type; 468 } 469 470 public int getWindingRule() { 471 return src.getWindingRule(); 472 } 473 474 public boolean isDone() { 475 return src.isDone(); 476 } 477 478 public void next() { 479 src.next(); 480 } 481 } 482 483 static void pathTo(PathIterator pi, PathConsumer2D pc2d) { 484 RenderingEngine.feedConsumer(pi, pc2d); 485 pc2d.pathDone(); 486 } 487 488 /** 489 * Construct an antialiased tile generator for the given shape with 490 * the given rendering attributes and store the bounds of the tile 491 * iteration in the bbox parameter. 492 * The {@code at} parameter specifies a transform that should affect 493 * both the shape and the {@code BasicStroke} attributes. 494 * The {@code clip} parameter specifies the current clip in effect 495 * in device coordinates and can be used to prune the data for the 496 * operation, but the renderer is not required to perform any 497 * clipping. 498 * If the {@code BasicStroke} parameter is null then the shape 499 * should be filled as is, otherwise the attributes of the 500 * {@code BasicStroke} should be used to specify a draw operation. 501 * The {@code thin} parameter indicates whether or not the 502 * transformed {@code BasicStroke} represents coordinates smaller 503 * than the minimum resolution of the antialiasing rasterizer as 504 * specified by the {@code getMinimumAAPenWidth()} method. 505 * <p> 506 * Upon returning, this method will fill the {@code bbox} parameter 507 * with 4 values indicating the bounds of the iteration of the 508 * tile generator. 509 * The iteration order of the tiles will be as specified by the 510 * pseudo-code: 511 * <pre> 512 * for (y = bbox[1]; y < bbox[3]; y += tileheight) { 513 * for (x = bbox[0]; x < bbox[2]; x += tilewidth) { 514 * } 515 * } 516 * </pre> 517 * If there is no output to be rendered, this method may return 518 * null. 519 * 520 * @param s the shape to be rendered (fill or draw) 521 * @param at the transform to be applied to the shape and the 522 * stroke attributes 523 * @param clip the current clip in effect in device coordinates 524 * @param bs if non-null, a {@code BasicStroke} whose attributes 525 * should be applied to this operation 526 * @param thin true if the transformed stroke attributes are smaller 527 * than the minimum dropout pen width 528 * @param normalize true if the {@code VALUE_STROKE_NORMALIZE} 529 * {@code RenderingHint} is in effect 530 * @param bbox returns the bounds of the iteration 531 * @return the {@code AATileGenerator} instance to be consulted 532 * for tile coverages, or null if there is no output to render 533 * @since 1.7 534 */ 535 public AATileGenerator getAATileGenerator(Shape s, 536 AffineTransform at, 537 Region clip, 538 BasicStroke bs, 539 boolean thin, 540 boolean normalize, 541 int bbox[]) 542 { 543 Renderer r; 544 NormMode norm = (normalize) ? NormMode.ON_WITH_AA : NormMode.OFF; 545 if (bs == null) { 546 PathIterator pi; 547 if (normalize) { 548 pi = new NormalizingPathIterator(s.getPathIterator(at), norm); 549 } else { 550 pi = s.getPathIterator(at); 551 } 552 r = new Renderer(3, 3, 553 clip.getLoX(), clip.getLoY(), 554 clip.getWidth(), clip.getHeight(), 555 pi.getWindingRule()); 556 pathTo(pi, r); 557 } else { 558 r = new Renderer(3, 3, 559 clip.getLoX(), clip.getLoY(), 560 clip.getWidth(), clip.getHeight(), 561 PathIterator.WIND_NON_ZERO); 562 strokeTo(s, at, bs, thin, norm, true, r); 563 } 564 r.endRendering(); 565 PiscesTileGenerator ptg = new PiscesTileGenerator(r, r.MAX_AA_ALPHA); 566 ptg.getBbox(bbox); 567 return ptg; 568 } 569 570 public AATileGenerator getAATileGenerator(double x, double y, 571 double dx1, double dy1, 572 double dx2, double dy2, 573 double lw1, double lw2, 574 Region clip, 575 int bbox[]) 576 { 577 // REMIND: Deal with large coordinates! 578 double ldx1, ldy1, ldx2, ldy2; 579 boolean innerpgram = (lw1 > 0 && lw2 > 0); 580 581 if (innerpgram) { 582 ldx1 = dx1 * lw1; 583 ldy1 = dy1 * lw1; 584 ldx2 = dx2 * lw2; 585 ldy2 = dy2 * lw2; 586 x -= (ldx1 + ldx2) / 2.0; 587 y -= (ldy1 + ldy2) / 2.0; 588 dx1 += ldx1; 589 dy1 += ldy1; 590 dx2 += ldx2; 591 dy2 += ldy2; 592 if (lw1 > 1 && lw2 > 1) { 593 // Inner parallelogram was entirely consumed by stroke... 594 innerpgram = false; 595 } 596 } else { 597 ldx1 = ldy1 = ldx2 = ldy2 = 0; 598 } 599 600 Renderer r = new Renderer(3, 3, 601 clip.getLoX(), clip.getLoY(), 602 clip.getWidth(), clip.getHeight(), 603 PathIterator.WIND_EVEN_ODD); 604 605 r.moveTo((float) x, (float) y); 606 r.lineTo((float) (x+dx1), (float) (y+dy1)); 607 r.lineTo((float) (x+dx1+dx2), (float) (y+dy1+dy2)); 608 r.lineTo((float) (x+dx2), (float) (y+dy2)); 609 r.closePath(); 610 611 if (innerpgram) { 612 x += ldx1 + ldx2; 613 y += ldy1 + ldy2; 614 dx1 -= 2.0 * ldx1; 615 dy1 -= 2.0 * ldy1; 616 dx2 -= 2.0 * ldx2; 617 dy2 -= 2.0 * ldy2; 618 r.moveTo((float) x, (float) y); 619 r.lineTo((float) (x+dx1), (float) (y+dy1)); 620 r.lineTo((float) (x+dx1+dx2), (float) (y+dy1+dy2)); 621 r.lineTo((float) (x+dx2), (float) (y+dy2)); 622 r.closePath(); 623 } 624 625 r.pathDone(); 626 627 r.endRendering(); 628 PiscesTileGenerator ptg = new PiscesTileGenerator(r, r.MAX_AA_ALPHA); 629 ptg.getBbox(bbox); 630 return ptg; 631 } 632 633 /** 634 * Returns the minimum pen width that the antialiasing rasterizer 635 * can represent without dropouts occurring. 636 * @since 1.7 637 */ 638 public float getMinimumAAPenSize() { 639 return 0.5f; 640 } 641 642 static { 643 if (PathIterator.WIND_NON_ZERO != Renderer.WIND_NON_ZERO || 644 PathIterator.WIND_EVEN_ODD != Renderer.WIND_EVEN_ODD || 645 BasicStroke.JOIN_MITER != Stroker.JOIN_MITER || 646 BasicStroke.JOIN_ROUND != Stroker.JOIN_ROUND || 647 BasicStroke.JOIN_BEVEL != Stroker.JOIN_BEVEL || 648 BasicStroke.CAP_BUTT != Stroker.CAP_BUTT || 649 BasicStroke.CAP_ROUND != Stroker.CAP_ROUND || 650 BasicStroke.CAP_SQUARE != Stroker.CAP_SQUARE) 651 { 652 throw new InternalError("mismatched renderer constants"); 653 } 654 } 655} 656 657