1 /*
   2  * Copyright (c) 2007, 2017, 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 sun.java2d.marlin;
  27 
  28 import java.util.Arrays;
  29 
  30 /**
  31  * The <code>DDasher</code> class takes a series of linear commands
  32  * (<code>moveTo</code>, <code>lineTo</code>, <code>close</code> and
  33  * <code>end</code>) and breaks them into smaller segments according to a
  34  * dash pattern array and a starting dash phase.
  35  *
  36  * <p> Issues: in J2Se, a zero length dash segment as drawn as a very
  37  * short dash, whereas Pisces does not draw anything.  The PostScript
  38  * semantics are unclear.
  39  *
  40  */
  41 final class DDasher implements DPathConsumer2D, MarlinConst {
  42 
  43     static final int REC_LIMIT = 4;
  44     static final double ERR = 0.01d;
  45     static final double MIN_T_INC = 1.0d / (1 << REC_LIMIT);
  46 
  47     // More than 24 bits of mantissa means we can no longer accurately
  48     // measure the number of times cycled through the dash array so we
  49     // punt and override the phase to just be 0 past that point.
  50     static final double MAX_CYCLES = 16000000.0d;
  51 
  52     private DPathConsumer2D out;
  53     private double[] dash;
  54     private int dashLen;
  55     private double startPhase;
  56     private boolean startDashOn;
  57     private int startIdx;
  58 
  59     private boolean starting;
  60     private boolean needsMoveTo;
  61 
  62     private int idx;
  63     private boolean dashOn;
  64     private double phase;
  65 
  66     private double sx, sy;
  67     private double x0, y0;
  68 
  69     // temporary storage for the current curve
  70     private final double[] curCurvepts;
  71 
  72     // per-thread renderer context
  73     final DRendererContext rdrCtx;
  74 
  75     // flag to recycle dash array copy
  76     boolean recycleDashes;
  77 
  78     // dashes ref (dirty)
  79     final DoubleArrayCache.Reference dashes_ref;
  80     // firstSegmentsBuffer ref (dirty)
  81     final DoubleArrayCache.Reference firstSegmentsBuffer_ref;
  82 
  83     /**
  84      * Constructs a <code>DDasher</code>.
  85      * @param rdrCtx per-thread renderer context
  86      */
  87     DDasher(final DRendererContext rdrCtx) {
  88         this.rdrCtx = rdrCtx;
  89 
  90         dashes_ref = rdrCtx.newDirtyDoubleArrayRef(INITIAL_ARRAY); // 1K
  91 
  92         firstSegmentsBuffer_ref = rdrCtx.newDirtyDoubleArrayRef(INITIAL_ARRAY); // 1K
  93         firstSegmentsBuffer     = firstSegmentsBuffer_ref.initial;
  94 
  95         // we need curCurvepts to be able to contain 2 curves because when
  96         // dashing curves, we need to subdivide it
  97         curCurvepts = new double[8 * 2];
  98     }
  99 
 100     /**
 101      * Initialize the <code>DDasher</code>.
 102      *
 103      * @param out an output <code>DPathConsumer2D</code>.
 104      * @param dash an array of <code>double</code>s containing the dash pattern
 105      * @param dashLen length of the given dash array
 106      * @param phase a <code>double</code> containing the dash phase
 107      * @param recycleDashes true to indicate to recycle the given dash array
 108      * @return this instance
 109      */
 110     DDasher init(final DPathConsumer2D out, double[] dash, int dashLen,
 111                 double phase, boolean recycleDashes)
 112     {
 113         this.out = out;
 114 
 115         // Normalize so 0 <= phase < dash[0]
 116         int sidx = 0;
 117         dashOn = true;
 118         double sum = 0.0d;
 119         for (double d : dash) {
 120             sum += d;
 121         }
 122         double cycles = phase / sum;
 123         if (phase < 0.0d) {
 124             if (-cycles >= MAX_CYCLES) {
 125                 phase = 0.0d;
 126             } else {
 127                 int fullcycles = FloatMath.floor_int(-cycles);
 128                 if ((fullcycles & dash.length & 1) != 0) {
 129                     dashOn = !dashOn;
 130                 }
 131                 phase += fullcycles * sum;
 132                 while (phase < 0.0d) {
 133                     if (--sidx < 0) {
 134                         sidx = dash.length - 1;
 135                     }
 136                     phase += dash[sidx];
 137                     dashOn = !dashOn;
 138                 }
 139             }
 140         } else if (phase > 0.0d) {
 141             if (cycles >= MAX_CYCLES) {
 142                 phase = 0.0d;
 143             } else {
 144                 int fullcycles = FloatMath.floor_int(cycles);
 145                 if ((fullcycles & dash.length & 1) != 0) {
 146                     dashOn = !dashOn;
 147                 }
 148                 phase -= fullcycles * sum;
 149                 double d;
 150                 while (phase >= (d = dash[sidx])) {
 151                     phase -= d;
 152                     sidx = (sidx + 1) % dash.length;
 153                     dashOn = !dashOn;
 154                 }
 155             }
 156         }
 157 
 158         this.dash = dash;
 159         this.dashLen = dashLen;
 160         this.phase = phase;
 161         this.startPhase = phase;
 162         this.startDashOn = dashOn;
 163         this.startIdx = sidx;
 164         this.starting = true;
 165         this.needsMoveTo = false;
 166         this.firstSegidx = 0;
 167 
 168         this.recycleDashes = recycleDashes;
 169 
 170         return this; // fluent API
 171     }
 172 
 173     /**
 174      * Disposes this dasher:
 175      * clean up before reusing this instance
 176      */
 177     void dispose() {
 178         if (DO_CLEAN_DIRTY) {
 179             // Force zero-fill dirty arrays:
 180             Arrays.fill(curCurvepts, 0.0d);
 181         }
 182         // Return arrays:
 183         if (recycleDashes) {
 184             dash = dashes_ref.putArray(dash);
 185         }
 186         firstSegmentsBuffer = firstSegmentsBuffer_ref.putArray(firstSegmentsBuffer);
 187     }
 188 
 189     double[] copyDashArray(final float[] dashes) {
 190         final int len = dashes.length;
 191         final double[] newDashes;
 192         if (len <= MarlinConst.INITIAL_ARRAY) {
 193             newDashes = dashes_ref.initial;
 194         } else {
 195             if (DO_STATS) {
 196                 rdrCtx.stats.stat_array_dasher_dasher.add(len);
 197             }
 198             newDashes = dashes_ref.getArray(len);
 199         }
 200         for (int i = 0; i < len; i++) { newDashes[i] = dashes[i]; }
 201         return newDashes;
 202     }
 203 
 204     @Override
 205     public void moveTo(final double x0, final double y0) {
 206         if (firstSegidx != 0) {
 207             out.moveTo(sx, sy);
 208             emitFirstSegments();
 209         }
 210         needsMoveTo = true;
 211         this.idx = startIdx;
 212         this.dashOn = this.startDashOn;
 213         this.phase = this.startPhase;
 214         this.sx = x0;
 215         this.sy = y0;
 216         this.x0 = x0;
 217         this.y0 = y0;
 218         this.starting = true;
 219     }
 220 
 221     private void emitSeg(double[] buf, int off, int type) {
 222         switch (type) {
 223         case 8:
 224             out.curveTo(buf[off+0], buf[off+1],
 225                         buf[off+2], buf[off+3],
 226                         buf[off+4], buf[off+5]);
 227             return;
 228         case 6:
 229             out.quadTo(buf[off+0], buf[off+1],
 230                        buf[off+2], buf[off+3]);
 231             return;
 232         case 4:
 233             out.lineTo(buf[off], buf[off+1]);
 234             return;
 235         default:
 236         }
 237     }
 238 
 239     private void emitFirstSegments() {
 240         final double[] fSegBuf = firstSegmentsBuffer;
 241 
 242         for (int i = 0, len = firstSegidx; i < len; ) {
 243             int type = (int)fSegBuf[i];
 244             emitSeg(fSegBuf, i + 1, type);
 245             i += (type - 1);
 246         }
 247         firstSegidx = 0;
 248     }
 249     // We don't emit the first dash right away. If we did, caps would be
 250     // drawn on it, but we need joins to be drawn if there's a closePath()
 251     // So, we store the path elements that make up the first dash in the
 252     // buffer below.
 253     private double[] firstSegmentsBuffer; // dynamic array
 254     private int firstSegidx;
 255 
 256     // precondition: pts must be in relative coordinates (relative to x0,y0)
 257     private void goTo(final double[] pts, final int off, final int type,
 258                       final boolean on)
 259     {
 260         final int index = off + type;
 261         final double x = pts[index - 4];
 262         final double y = pts[index - 3];
 263 
 264         if (on) {
 265             if (starting) {
 266                 goTo_starting(pts, off, type);

















 267             } else {
 268                 if (needsMoveTo) {

 269                     needsMoveTo = false;
 270                     out.moveTo(x0, y0);
 271                 }
 272                 emitSeg(pts, off, type);
 273             }
 274         } else {
 275             if (starting) {
 276                 // low probability test (hotspot)
 277                 starting = false;
 278             }
 279             needsMoveTo = true;
 280         }
 281         this.x0 = x;
 282         this.y0 = y;
 283     }
 284 
 285     private void goTo_starting(final double[] pts, final int off, final int type) {
 286         int len = type - 1; // - 2 + 1
 287         int segIdx = firstSegidx;
 288         double[] buf = firstSegmentsBuffer;
 289 
 290         if (segIdx + len  > buf.length) {
 291             if (DO_STATS) {
 292                 rdrCtx.stats.stat_array_dasher_firstSegmentsBuffer
 293                     .add(segIdx + len);
 294             }
 295             firstSegmentsBuffer = buf
 296                 = firstSegmentsBuffer_ref.widenArray(buf, segIdx,
 297                                                      segIdx + len);
 298         }
 299         buf[segIdx++] = type;
 300         len--;
 301         // small arraycopy (2, 4 or 6) but with offset:
 302         System.arraycopy(pts, off, buf, segIdx, len);
 303         firstSegidx = segIdx + len;
 304     }
 305 
 306     @Override
 307     public void lineTo(final double x1, final double y1) {
 308         final double dx = x1 - x0;
 309         final double dy = y1 - y0;
 310 
 311         double len = dx*dx + dy*dy;
 312         if (len == 0.0d) {
 313             return;
 314         }
 315         len = Math.sqrt(len);
 316 
 317         // The scaling factors needed to get the dx and dy of the
 318         // transformed dash segments.
 319         final double cx = dx / len;
 320         final double cy = dy / len;
 321 
 322         final double[] _curCurvepts = curCurvepts;
 323         final double[] _dash = dash;
 324         final int _dashLen = this.dashLen;
 325 
 326         int _idx = idx;
 327         boolean _dashOn = dashOn;
 328         double _phase = phase;
 329 
 330         double leftInThisDashSegment;
 331         double d, dashdx, dashdy, p;
 332 
 333         while (true) {
 334             d = _dash[_idx];
 335             leftInThisDashSegment = d - _phase;
 336 
 337             if (len <= leftInThisDashSegment) {
 338                 _curCurvepts[0] = x1;
 339                 _curCurvepts[1] = y1;
 340 
 341                 goTo(_curCurvepts, 0, 4, _dashOn);
 342 
 343                 // Advance phase within current dash segment
 344                 _phase += len;
 345 
 346                 // TODO: compare double values using epsilon:
 347                 if (len == leftInThisDashSegment) {
 348                     _phase = 0.0d;
 349                     _idx = (_idx + 1) % _dashLen;
 350                     _dashOn = !_dashOn;
 351                 }
 352 
 353                 // Save local state:
 354                 idx = _idx;
 355                 dashOn = _dashOn;
 356                 phase = _phase;
 357                 return;
 358             }
 359 
 360             dashdx = d * cx;
 361             dashdy = d * cy;
 362 
 363             if (_phase == 0.0d) {
 364                 _curCurvepts[0] = x0 + dashdx;
 365                 _curCurvepts[1] = y0 + dashdy;
 366             } else {
 367                 p = leftInThisDashSegment / d;
 368                 _curCurvepts[0] = x0 + p * dashdx;
 369                 _curCurvepts[1] = y0 + p * dashdy;
 370             }
 371 
 372             goTo(_curCurvepts, 0, 4, _dashOn);
 373 
 374             len -= leftInThisDashSegment;
 375             // Advance to next dash segment
 376             _idx = (_idx + 1) % _dashLen;
 377             _dashOn = !_dashOn;
 378             _phase = 0.0d;
 379         }
 380     }
 381 
 382     // shared instance in DDasher
 383     private final LengthIterator li = new LengthIterator();
 384 
 385     // preconditions: curCurvepts must be an array of length at least 2 * type,
 386     // that contains the curve we want to dash in the first type elements
 387     private void somethingTo(int type) {
 388         if (pointCurve(curCurvepts, type)) {
 389             return;
 390         }
 391         final LengthIterator _li = li;
 392         final double[] _curCurvepts = curCurvepts;
 393         final double[] _dash = dash;
 394         final int _dashLen = this.dashLen;
 395 
 396         _li.initializeIterationOnCurve(_curCurvepts, type);
 397 
 398         int _idx = idx;
 399         boolean _dashOn = dashOn;
 400         double _phase = phase;
 401 
 402         // initially the current curve is at curCurvepts[0...type]
 403         int curCurveoff = 0;
 404         double lastSplitT = 0.0d;
 405         double t;
 406         double leftInThisDashSegment = _dash[_idx] - _phase;
 407 
 408         while ((t = _li.next(leftInThisDashSegment)) < 1.0d) {
 409             if (t != 0.0d) {
 410                 DHelpers.subdivideAt((t - lastSplitT) / (1.0d - lastSplitT),
 411                                     _curCurvepts, curCurveoff,
 412                                     _curCurvepts, 0,
 413                                     _curCurvepts, type, type);
 414                 lastSplitT = t;
 415                 goTo(_curCurvepts, 2, type, _dashOn);
 416                 curCurveoff = type;
 417             }
 418             // Advance to next dash segment
 419             _idx = (_idx + 1) % _dashLen;
 420             _dashOn = !_dashOn;
 421             _phase = 0.0d;
 422             leftInThisDashSegment = _dash[_idx];
 423         }
 424 
 425         goTo(_curCurvepts, curCurveoff + 2, type, _dashOn);
 426 
 427         _phase += _li.lastSegLen();
 428         if (_phase >= _dash[_idx]) {
 429             _phase = 0.0d;
 430             _idx = (_idx + 1) % _dashLen;
 431             _dashOn = !_dashOn;
 432         }
 433         // Save local state:
 434         idx = _idx;
 435         dashOn = _dashOn;
 436         phase = _phase;
 437 
 438         // reset LengthIterator:
 439         _li.reset();
 440     }
 441 
 442     private static boolean pointCurve(double[] curve, int type) {
 443         for (int i = 2; i < type; i++) {
 444             if (curve[i] != curve[i-2]) {
 445                 return false;
 446             }
 447         }
 448         return true;
 449     }
 450 
 451     // Objects of this class are used to iterate through curves. They return
 452     // t values where the left side of the curve has a specified length.
 453     // It does this by subdividing the input curve until a certain error
 454     // condition has been met. A recursive subdivision procedure would
 455     // return as many as 1<<limit curves, but this is an iterator and we
 456     // don't need all the curves all at once, so what we carry out a
 457     // lazy inorder traversal of the recursion tree (meaning we only move
 458     // through the tree when we need the next subdivided curve). This saves
 459     // us a lot of memory because at any one time we only need to store
 460     // limit+1 curves - one for each level of the tree + 1.
 461     // NOTE: the way we do things here is not enough to traverse a general
 462     // tree; however, the trees we are interested in have the property that
 463     // every non leaf node has exactly 2 children
 464     static final class LengthIterator {
 465         private enum Side {LEFT, RIGHT}
 466         // Holds the curves at various levels of the recursion. The root
 467         // (i.e. the original curve) is at recCurveStack[0] (but then it
 468         // gets subdivided, the left half is put at 1, so most of the time
 469         // only the right half of the original curve is at 0)
 470         private final double[][] recCurveStack; // dirty
 471         // sides[i] indicates whether the node at level i+1 in the path from
 472         // the root to the current leaf is a left or right child of its parent.
 473         private final Side[] sides; // dirty
 474         private int curveType;
 475         // lastT and nextT delimit the current leaf.
 476         private double nextT;
 477         private double lenAtNextT;
 478         private double lastT;
 479         private double lenAtLastT;
 480         private double lenAtLastSplit;
 481         private double lastSegLen;
 482         // the current level in the recursion tree. 0 is the root. limit
 483         // is the deepest possible leaf.
 484         private int recLevel;
 485         private boolean done;
 486 
 487         // the lengths of the lines of the control polygon. Only its first
 488         // curveType/2 - 1 elements are valid. This is an optimization. See
 489         // next() for more detail.
 490         private final double[] curLeafCtrlPolyLengths = new double[3];
 491 
 492         LengthIterator() {
 493             this.recCurveStack = new double[REC_LIMIT + 1][8];
 494             this.sides = new Side[REC_LIMIT];
 495             // if any methods are called without first initializing this object
 496             // on a curve, we want it to fail ASAP.
 497             this.nextT = Double.MAX_VALUE;
 498             this.lenAtNextT = Double.MAX_VALUE;
 499             this.lenAtLastSplit = Double.MIN_VALUE;
 500             this.recLevel = Integer.MIN_VALUE;
 501             this.lastSegLen = Double.MAX_VALUE;
 502             this.done = true;
 503         }
 504 
 505         /**
 506          * Reset this LengthIterator.
 507          */
 508         void reset() {
 509             // keep data dirty
 510             // as it appears not useful to reset data:
 511             if (DO_CLEAN_DIRTY) {
 512                 final int recLimit = recCurveStack.length - 1;
 513                 for (int i = recLimit; i >= 0; i--) {
 514                     Arrays.fill(recCurveStack[i], 0.0d);
 515                 }
 516                 Arrays.fill(sides, Side.LEFT);
 517                 Arrays.fill(curLeafCtrlPolyLengths, 0.0d);
 518                 Arrays.fill(nextRoots, 0.0d);
 519                 Arrays.fill(flatLeafCoefCache, 0.0d);
 520                 flatLeafCoefCache[2] = -1.0d;
 521             }
 522         }
 523 
 524         void initializeIterationOnCurve(double[] pts, int type) {
 525             // optimize arraycopy (8 values faster than 6 = type):
 526             System.arraycopy(pts, 0, recCurveStack[0], 0, 8);
 527             this.curveType = type;
 528             this.recLevel = 0;
 529             this.lastT = 0.0d;
 530             this.lenAtLastT = 0.0d;
 531             this.nextT = 0.0d;
 532             this.lenAtNextT = 0.0d;
 533             goLeft(); // initializes nextT and lenAtNextT properly
 534             this.lenAtLastSplit = 0.0d;
 535             if (recLevel > 0) {
 536                 this.sides[0] = Side.LEFT;
 537                 this.done = false;
 538             } else {
 539                 // the root of the tree is a leaf so we're done.
 540                 this.sides[0] = Side.RIGHT;
 541                 this.done = true;
 542             }
 543             this.lastSegLen = 0.0d;
 544         }
 545 
 546         // 0 == false, 1 == true, -1 == invalid cached value.
 547         private int cachedHaveLowAcceleration = -1;
 548 
 549         private boolean haveLowAcceleration(double err) {
 550             if (cachedHaveLowAcceleration == -1) {
 551                 final double len1 = curLeafCtrlPolyLengths[0];
 552                 final double len2 = curLeafCtrlPolyLengths[1];
 553                 // the test below is equivalent to !within(len1/len2, 1, err).
 554                 // It is using a multiplication instead of a division, so it
 555                 // should be a bit faster.
 556                 if (!DHelpers.within(len1, len2, err * len2)) {
 557                     cachedHaveLowAcceleration = 0;
 558                     return false;
 559                 }
 560                 if (curveType == 8) {
 561                     final double len3 = curLeafCtrlPolyLengths[2];
 562                     // if len1 is close to 2 and 2 is close to 3, that probably
 563                     // means 1 is close to 3 so the second part of this test might
 564                     // not be needed, but it doesn't hurt to include it.
 565                     final double errLen3 = err * len3;
 566                     if (!(DHelpers.within(len2, len3, errLen3) &&
 567                           DHelpers.within(len1, len3, errLen3))) {
 568                         cachedHaveLowAcceleration = 0;
 569                         return false;
 570                     }
 571                 }
 572                 cachedHaveLowAcceleration = 1;
 573                 return true;
 574             }
 575 
 576             return (cachedHaveLowAcceleration == 1);
 577         }
 578 
 579         // we want to avoid allocations/gc so we keep this array so we
 580         // can put roots in it,
 581         private final double[] nextRoots = new double[4];
 582 
 583         // caches the coefficients of the current leaf in its flattened
 584         // form (see inside next() for what that means). The cache is
 585         // invalid when it's third element is negative, since in any
 586         // valid flattened curve, this would be >= 0.
 587         private final double[] flatLeafCoefCache = new double[]{0.0d, 0.0d, -1.0d, 0.0d};
 588 
 589         // returns the t value where the remaining curve should be split in
 590         // order for the left subdivided curve to have length len. If len
 591         // is >= than the length of the uniterated curve, it returns 1.
 592         double next(final double len) {
 593             final double targetLength = lenAtLastSplit + len;
 594             while (lenAtNextT < targetLength) {
 595                 if (done) {
 596                     lastSegLen = lenAtNextT - lenAtLastSplit;
 597                     return 1.0d;
 598                 }
 599                 goToNextLeaf();
 600             }
 601             lenAtLastSplit = targetLength;
 602             final double leaflen = lenAtNextT - lenAtLastT;
 603             double t = (targetLength - lenAtLastT) / leaflen;
 604 
 605             // cubicRootsInAB is a fairly expensive call, so we just don't do it
 606             // if the acceleration in this section of the curve is small enough.
 607             if (!haveLowAcceleration(0.05d)) {
 608                 // We flatten the current leaf along the x axis, so that we're
 609                 // left with a, b, c which define a 1D Bezier curve. We then
 610                 // solve this to get the parameter of the original leaf that
 611                 // gives us the desired length.
 612                 final double[] _flatLeafCoefCache = flatLeafCoefCache;
 613 
 614                 if (_flatLeafCoefCache[2] < 0.0d) {
 615                     double x =     curLeafCtrlPolyLengths[0],
 616                           y = x + curLeafCtrlPolyLengths[1];
 617                     if (curveType == 8) {
 618                         double z = y + curLeafCtrlPolyLengths[2];
 619                         _flatLeafCoefCache[0] = 3.0d * (x - y) + z;
 620                         _flatLeafCoefCache[1] = 3.0d * (y - 2.0d * x);
 621                         _flatLeafCoefCache[2] = 3.0d * x;
 622                         _flatLeafCoefCache[3] = -z;
 623                     } else if (curveType == 6) {
 624                         _flatLeafCoefCache[0] = 0.0d;
 625                         _flatLeafCoefCache[1] = y - 2.0d * x;
 626                         _flatLeafCoefCache[2] = 2.0d * x;
 627                         _flatLeafCoefCache[3] = -y;
 628                     }
 629                 }
 630                 double a = _flatLeafCoefCache[0];
 631                 double b = _flatLeafCoefCache[1];
 632                 double c = _flatLeafCoefCache[2];
 633                 double d = t * _flatLeafCoefCache[3];
 634 
 635                 // we use cubicRootsInAB here, because we want only roots in 0, 1,
 636                 // and our quadratic root finder doesn't filter, so it's just a
 637                 // matter of convenience.
 638                 int n = DHelpers.cubicRootsInAB(a, b, c, d, nextRoots, 0, 0.0d, 1.0d);
 639                 if (n == 1 && !Double.isNaN(nextRoots[0])) {
 640                     t = nextRoots[0];
 641                 }
 642             }
 643             // t is relative to the current leaf, so we must make it a valid parameter
 644             // of the original curve.
 645             t = t * (nextT - lastT) + lastT;
 646             if (t >= 1.0d) {
 647                 t = 1.0d;
 648                 done = true;
 649             }
 650             // even if done = true, if we're here, that means targetLength
 651             // is equal to, or very, very close to the total length of the
 652             // curve, so lastSegLen won't be too high. In cases where len
 653             // overshoots the curve, this method will exit in the while
 654             // loop, and lastSegLen will still be set to the right value.
 655             lastSegLen = len;
 656             return t;
 657         }
 658 
 659         double lastSegLen() {
 660             return lastSegLen;
 661         }
 662 
 663         // go to the next leaf (in an inorder traversal) in the recursion tree
 664         // preconditions: must be on a leaf, and that leaf must not be the root.
 665         private void goToNextLeaf() {
 666             // We must go to the first ancestor node that has an unvisited
 667             // right child.
 668             int _recLevel = recLevel;
 669             final Side[] _sides = sides;
 670 
 671             _recLevel--;
 672             while(_sides[_recLevel] == Side.RIGHT) {
 673                 if (_recLevel == 0) {
 674                     recLevel = 0;
 675                     done = true;
 676                     return;
 677                 }
 678                 _recLevel--;
 679             }
 680 
 681             _sides[_recLevel] = Side.RIGHT;
 682             // optimize arraycopy (8 values faster than 6 = type):
 683             System.arraycopy(recCurveStack[_recLevel], 0,
 684                              recCurveStack[_recLevel+1], 0, 8);
 685             _recLevel++;
 686 
 687             recLevel = _recLevel;
 688             goLeft();
 689         }
 690 
 691         // go to the leftmost node from the current node. Return its length.
 692         private void goLeft() {
 693             double len = onLeaf();
 694             if (len >= 0.0d) {
 695                 lastT = nextT;
 696                 lenAtLastT = lenAtNextT;
 697                 nextT += (1 << (REC_LIMIT - recLevel)) * MIN_T_INC;
 698                 lenAtNextT += len;
 699                 // invalidate caches
 700                 flatLeafCoefCache[2] = -1.0d;
 701                 cachedHaveLowAcceleration = -1;
 702             } else {
 703                 DHelpers.subdivide(recCurveStack[recLevel], 0,
 704                                   recCurveStack[recLevel+1], 0,
 705                                   recCurveStack[recLevel], 0, curveType);
 706                 sides[recLevel] = Side.LEFT;
 707                 recLevel++;
 708                 goLeft();
 709             }
 710         }
 711 
 712         // this is a bit of a hack. It returns -1 if we're not on a leaf, and
 713         // the length of the leaf if we are on a leaf.
 714         private double onLeaf() {
 715             final double[] curve = recCurveStack[recLevel];
 716             final int _curveType = curveType;
 717             double polyLen = 0.0d;
 718 
 719             double x0 = curve[0], y0 = curve[1];
 720             for (int i = 2; i < _curveType; i += 2) {
 721                 final double x1 = curve[i], y1 = curve[i+1];
 722                 final double len = DHelpers.linelen(x0, y0, x1, y1);
 723                 polyLen += len;
 724                 curLeafCtrlPolyLengths[i/2 - 1] = len;
 725                 x0 = x1;
 726                 y0 = y1;
 727             }
 728 
 729             final double lineLen = DHelpers.linelen(curve[0], curve[1],
 730                                                     curve[_curveType-2],
 731                                                     curve[_curveType-1]);
 732             if ((polyLen - lineLen) < ERR || recLevel == REC_LIMIT) {
 733                 return (polyLen + lineLen) / 2.0d;
 734             }
 735             return -1.0d;
 736         }
 737     }
 738 
 739     @Override
 740     public void curveTo(final double x1, final double y1,
 741                         final double x2, final double y2,
 742                         final double x3, final double y3)
 743     {
 744         final double[] _curCurvepts = curCurvepts;
 745         _curCurvepts[0] = x0;        _curCurvepts[1] = y0;
 746         _curCurvepts[2] = x1;        _curCurvepts[3] = y1;
 747         _curCurvepts[4] = x2;        _curCurvepts[5] = y2;
 748         _curCurvepts[6] = x3;        _curCurvepts[7] = y3;
 749         somethingTo(8);
 750     }
 751 
 752     @Override
 753     public void quadTo(final double x1, final double y1,
 754                        final double x2, final double y2)
 755     {
 756         final double[] _curCurvepts = curCurvepts;
 757         _curCurvepts[0] = x0;        _curCurvepts[1] = y0;
 758         _curCurvepts[2] = x1;        _curCurvepts[3] = y1;
 759         _curCurvepts[4] = x2;        _curCurvepts[5] = y2;
 760         somethingTo(6);
 761     }
 762 
 763     @Override
 764     public void closePath() {
 765         lineTo(sx, sy);
 766         if (firstSegidx != 0) {
 767             if (!dashOn || needsMoveTo) {
 768                 out.moveTo(sx, sy);
 769             }
 770             emitFirstSegments();
 771         }
 772         moveTo(sx, sy);
 773     }
 774 
 775     @Override
 776     public void pathDone() {
 777         if (firstSegidx != 0) {
 778             out.moveTo(sx, sy);
 779             emitFirstSegments();
 780         }
 781         out.pathDone();
 782 
 783         // Dispose this instance:
 784         dispose();
 785     }
 786 
 787     @Override
 788     public long getNativeConsumer() {
 789         throw new InternalError("DDasher does not use a native consumer");
 790     }
 791 }
 792 
--- EOF ---