1 /*
   2  * Copyright (c) 2007, 2016, 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 com.sun.marlin;
  27 
  28 import static com.sun.marlin.OffHeapArray.SIZE_INT;
  29 import jdk.internal.misc.Unsafe;
  30 
  31 public final class RendererNoAA implements MarlinRenderer, MarlinConst {
  32 
  33     static final boolean DISABLE_RENDER = false;
  34 
  35     private static final int ALL_BUT_LSB = 0xfffffffe;
  36     private static final int ERR_STEP_MAX = 0x7fffffff; // = 2^31 - 1
  37 
  38     private static final double POWER_2_TO_32 = 0x1.0p32;
  39 
  40     // 2048 (pixelSize) pixels (height) x 8 subpixels = 64K
  41     static final int INITIAL_BUCKET_ARRAY = INITIAL_PIXEL_DIM;
  42 
  43     // crossing capacity = edges count / 4 ~ 1024
  44     static final int INITIAL_CROSSING_COUNT = INITIAL_EDGES_COUNT >> 2;
  45 
  46     // common to all types of input path segments.
  47     // OFFSET as bytes
  48     // only integer values:
  49     public static final long OFF_CURX_OR  = 0;
  50     public static final long OFF_ERROR    = OFF_CURX_OR  + SIZE_INT;
  51     public static final long OFF_BUMP_X   = OFF_ERROR    + SIZE_INT;
  52     public static final long OFF_BUMP_ERR = OFF_BUMP_X   + SIZE_INT;
  53     public static final long OFF_NEXT     = OFF_BUMP_ERR + SIZE_INT;
  54     public static final long OFF_YMAX     = OFF_NEXT     + SIZE_INT;
  55 
  56     // size of one edge in bytes
  57     public static final int SIZEOF_EDGE_BYTES = (int)(OFF_YMAX + SIZE_INT);
  58 
  59     // curve break into lines
  60     // cubic error in subpixels to decrement step
  61     private static final float CUB_DEC_ERR_SUBPIX
  62         = 1f * (1f / 8f); // 1 pixel for typical 1x1 subpixels
  63     // cubic error in subpixels to increment step
  64     private static final float CUB_INC_ERR_SUBPIX
  65         = 0.4f * (1f / 8f); // 0.4 pixel for typical 1x1 subpixels
  66 
  67     // cubic bind length to decrement step = 8 * error in subpixels
  68     // multiply by 8 = error scale factor:
  69     public static final float CUB_DEC_BND
  70         = 8f * CUB_DEC_ERR_SUBPIX;
  71     // cubic bind length to increment step = 8 * error in subpixels
  72     public static final float CUB_INC_BND
  73         = 8f * CUB_INC_ERR_SUBPIX;
  74 
  75     // cubic countlg
  76     public static final int CUB_COUNT_LG = 2;
  77     // cubic count = 2^countlg
  78     private static final int CUB_COUNT = 1 << CUB_COUNT_LG;
  79     // cubic count^2 = 4^countlg
  80     private static final int CUB_COUNT_2 = 1 << (2 * CUB_COUNT_LG);
  81     // cubic count^3 = 8^countlg
  82     private static final int CUB_COUNT_3 = 1 << (3 * CUB_COUNT_LG);
  83     // cubic dt = 1 / count
  84     private static final float CUB_INV_COUNT = 1f / CUB_COUNT;
  85     // cubic dt^2 = 1 / count^2 = 1 / 4^countlg
  86     private static final float CUB_INV_COUNT_2 = 1f / CUB_COUNT_2;
  87     // cubic dt^3 = 1 / count^3 = 1 / 8^countlg
  88     private static final float CUB_INV_COUNT_3 = 1f / CUB_COUNT_3;
  89 
  90     // quad break into lines
  91     // quadratic error in subpixels
  92     private static final float QUAD_DEC_ERR_SUBPIX
  93         = 1f * (1f / 8f); // 1 pixel for typical 1x1 subpixels
  94 
  95     // quadratic bind length to decrement step = 8 * error in subpixels
  96     public static final float QUAD_DEC_BND
  97         = 8f * QUAD_DEC_ERR_SUBPIX;
  98 
  99 //////////////////////////////////////////////////////////////////////////////
 100 //  SCAN LINE
 101 //////////////////////////////////////////////////////////////////////////////
 102     // crossings ie subpixel edge x coordinates
 103     private int[] crossings;
 104     // auxiliary storage for crossings (merge sort)
 105     private int[] aux_crossings;
 106 
 107     // indices into the segment pointer lists. They indicate the "active"
 108     // sublist in the segment lists (the portion of the list that contains
 109     // all the segments that cross the next scan line).
 110     private int edgeCount;
 111     private int[] edgePtrs;
 112     // auxiliary storage for edge pointers (merge sort)
 113     private int[] aux_edgePtrs;
 114 
 115     // max used for both edgePtrs and crossings (stats only)
 116     private int activeEdgeMaxUsed;
 117 
 118     // crossings ref (dirty)
 119     private final IntArrayCache.Reference crossings_ref;
 120     // edgePtrs ref (dirty)
 121     private final IntArrayCache.Reference edgePtrs_ref;
 122     // merge sort initial arrays (large enough to satisfy most usages) (1024)
 123     // aux_crossings ref (dirty)
 124     private final IntArrayCache.Reference aux_crossings_ref;
 125     // aux_edgePtrs ref (dirty)
 126     private final IntArrayCache.Reference aux_edgePtrs_ref;
 127 
 128 //////////////////////////////////////////////////////////////////////////////
 129 //  EDGE LIST
 130 //////////////////////////////////////////////////////////////////////////////
 131     private int edgeMinY = Integer.MAX_VALUE;
 132     private int edgeMaxY = Integer.MIN_VALUE;
 133     private float edgeMinX = Float.POSITIVE_INFINITY;
 134     private float edgeMaxX = Float.NEGATIVE_INFINITY;
 135 
 136     // edges [floats|ints] stored in off-heap memory
 137     private final OffHeapArray edges;
 138 
 139     private int[] edgeBuckets;
 140     private int[] edgeBucketCounts; // 2*newedges + (1 if pruning needed)
 141     // used range for edgeBuckets / edgeBucketCounts
 142     private int buckets_minY;
 143     private int buckets_maxY;
 144 
 145     // edgeBuckets ref (clean)
 146     private final IntArrayCache.Reference edgeBuckets_ref;
 147     // edgeBucketCounts ref (clean)
 148     private final IntArrayCache.Reference edgeBucketCounts_ref;
 149 
 150     boolean useRLE = false;
 151 
 152     // Flattens using adaptive forward differencing. This only carries out
 153     // one iteration of the AFD loop. All it does is update AFD variables (i.e.
 154     // X0, Y0, D*[X|Y], COUNT; not variables used for computing scanline crossings).
 155     private void quadBreakIntoLinesAndAdd(float x0, float y0,
 156                                           final Curve c,
 157                                           final float x2, final float y2)
 158     {
 159         int count = 1; // dt = 1 / count
 160 
 161         // maximum(ddX|Y) = norm(dbx, dby) * dt^2 (= 1)
 162         float maxDD = FloatMath.max(Math.abs(c.dbx), Math.abs(c.dby));
 163 
 164         final float _DEC_BND = QUAD_DEC_BND;
 165 
 166         while (maxDD >= _DEC_BND) {
 167             // divide step by half:
 168             maxDD /= 4f; // error divided by 2^2 = 4
 169 
 170             count <<= 1;
 171             if (DO_STATS) {
 172                 rdrCtx.stats.stat_rdr_quadBreak_dec.add(count);
 173             }
 174         }
 175 
 176         int nL = 0; // line count
 177         if (count > 1) {
 178             final float icount = 1f / count; // dt
 179             final float icount2 = icount * icount; // dt^2
 180 
 181             final float ddx = c.dbx * icount2;
 182             final float ddy = c.dby * icount2;
 183             float dx = c.bx * icount2 + c.cx * icount;
 184             float dy = c.by * icount2 + c.cy * icount;
 185 
 186             float x1, y1;
 187 
 188             while (--count > 0) {
 189                 x1 = x0 + dx;
 190                 dx += ddx;
 191                 y1 = y0 + dy;
 192                 dy += ddy;
 193 
 194                 addLine(x0, y0, x1, y1);
 195 
 196                 if (DO_STATS) { nL++; }
 197                 x0 = x1;
 198                 y0 = y1;
 199             }
 200         }
 201         addLine(x0, y0, x2, y2);
 202 
 203         if (DO_STATS) {
 204             rdrCtx.stats.stat_rdr_quadBreak.add(nL + 1);
 205         }
 206     }
 207 
 208     // x0, y0 and x3,y3 are the endpoints of the curve. We could compute these
 209     // using c.xat(0),c.yat(0) and c.xat(1),c.yat(1), but this might introduce
 210     // numerical errors, and our callers already have the exact values.
 211     // Another alternative would be to pass all the control points, and call
 212     // c.set here, but then too many numbers are passed around.
 213     private void curveBreakIntoLinesAndAdd(float x0, float y0,
 214                                            final Curve c,
 215                                            final float x3, final float y3)
 216     {
 217         int count           = CUB_COUNT;
 218         final float icount  = CUB_INV_COUNT;   // dt
 219         final float icount2 = CUB_INV_COUNT_2; // dt^2
 220         final float icount3 = CUB_INV_COUNT_3; // dt^3
 221 
 222         // the dx and dy refer to forward differencing variables, not the last
 223         // coefficients of the "points" polynomial
 224         float dddx, dddy, ddx, ddy, dx, dy;
 225         dddx = 2f * c.dax * icount3;
 226         dddy = 2f * c.day * icount3;
 227         ddx = dddx + c.dbx * icount2;
 228         ddy = dddy + c.dby * icount2;
 229         dx = c.ax * icount3 + c.bx * icount2 + c.cx * icount;
 230         dy = c.ay * icount3 + c.by * icount2 + c.cy * icount;
 231 
 232         // we use x0, y0 to walk the line
 233         float x1 = x0, y1 = y0;
 234         int nL = 0; // line count
 235 
 236         final float _DEC_BND = CUB_DEC_BND;
 237         final float _INC_BND = CUB_INC_BND;
 238 
 239         while (count > 0) {
 240             // divide step by half:
 241             while (Math.abs(ddx) >= _DEC_BND || Math.abs(ddy) >= _DEC_BND) {
 242                 dddx /= 8f;
 243                 dddy /= 8f;
 244                 ddx = ddx/4f - dddx;
 245                 ddy = ddy/4f - dddy;
 246                 dx = (dx - ddx) / 2f;
 247                 dy = (dy - ddy) / 2f;
 248 
 249                 count <<= 1;
 250                 if (DO_STATS) {
 251                     rdrCtx.stats.stat_rdr_curveBreak_dec.add(count);
 252                 }
 253             }
 254 
 255             // double step:
 256             // TODO: why use first derivative dX|Y instead of second ddX|Y ?
 257             // both scale changes should use speed or acceleration to have the same metric.
 258 
 259             // can only do this on even "count" values, because we must divide count by 2
 260             while (count % 2 == 0
 261                    && Math.abs(dx) <= _INC_BND && Math.abs(dy) <= _INC_BND)
 262             {
 263                 dx = 2f * dx + ddx;
 264                 dy = 2f * dy + ddy;
 265                 ddx = 4f * (ddx + dddx);
 266                 ddy = 4f * (ddy + dddy);
 267                 dddx *= 8f;
 268                 dddy *= 8f;
 269 
 270                 count >>= 1;
 271                 if (DO_STATS) {
 272                     rdrCtx.stats.stat_rdr_curveBreak_inc.add(count);
 273                 }
 274             }
 275             if (--count > 0) {
 276                 x1 += dx;
 277                 dx += ddx;
 278                 ddx += dddx;
 279                 y1 += dy;
 280                 dy += ddy;
 281                 ddy += dddy;
 282             } else {
 283                 x1 = x3;
 284                 y1 = y3;
 285             }
 286 
 287             addLine(x0, y0, x1, y1);
 288 
 289             if (DO_STATS) { nL++; }
 290             x0 = x1;
 291             y0 = y1;
 292         }
 293         if (DO_STATS) {
 294             rdrCtx.stats.stat_rdr_curveBreak.add(nL);
 295         }
 296     }
 297 
 298     private void addLine(float x1, float y1, float x2, float y2) {
 299         if (DO_MONITORS) {
 300             rdrCtx.stats.mon_rdr_addLine.start();
 301         }
 302         if (DO_STATS) {
 303             rdrCtx.stats.stat_rdr_addLine.add(1);
 304         }
 305         int or = 1; // orientation of the line. 1 if y increases, 0 otherwise.
 306         if (y2 < y1) {
 307             or = 0;
 308             float tmp = y2;
 309             y2 = y1;
 310             y1 = tmp;
 311             tmp = x2;
 312             x2 = x1;
 313             x1 = tmp;
 314         }
 315 
 316         // convert subpixel coordinates (float) into pixel positions (int)
 317 
 318         // The index of the pixel that holds the next HPC is at ceil(trueY - 0.5)
 319         // Since y1 and y2 are biased by -0.5 in tosubpixy(), this is simply
 320         // ceil(y1) or ceil(y2)
 321         // upper integer (inclusive)
 322         final int firstCrossing = FloatMath.max(FloatMath.ceil_int(y1), boundsMinY);
 323 
 324         // note: use boundsMaxY (last Y exclusive) to compute correct coverage
 325         // upper integer (exclusive)
 326         final int lastCrossing  = FloatMath.min(FloatMath.ceil_int(y2), boundsMaxY);
 327 
 328         /* skip horizontal lines in pixel space and clip edges
 329            out of y range [boundsMinY; boundsMaxY] */
 330         if (firstCrossing >= lastCrossing) {
 331             if (DO_MONITORS) {
 332                 rdrCtx.stats.mon_rdr_addLine.stop();
 333             }
 334             if (DO_STATS) {
 335                 rdrCtx.stats.stat_rdr_addLine_skip.add(1);
 336             }
 337             return;
 338         }
 339 
 340         // edge min/max X/Y are in subpixel space (inclusive) within bounds:
 341         // note: Use integer crossings to ensure consistent range within
 342         // edgeBuckets / edgeBucketCounts arrays in case of NaN values (int = 0)
 343         if (firstCrossing < edgeMinY) {
 344             edgeMinY = firstCrossing;
 345         }
 346         if (lastCrossing > edgeMaxY) {
 347             edgeMaxY = lastCrossing;
 348         }
 349 
 350         // Use double-precision for improved accuracy:
 351         final double x1d   = x1;
 352         final double y1d   = y1;
 353         final double slope = (x1d - x2) / (y1d - y2);
 354 
 355         if (slope >= 0.0) { // <==> x1 < x2
 356             if (x1 < edgeMinX) {
 357                 edgeMinX = x1;
 358             }
 359             if (x2 > edgeMaxX) {
 360                 edgeMaxX = x2;
 361             }
 362         } else {
 363             if (x2 < edgeMinX) {
 364                 edgeMinX = x2;
 365             }
 366             if (x1 > edgeMaxX) {
 367                 edgeMaxX = x1;
 368             }
 369         }
 370 
 371         // local variables for performance:
 372         final int _SIZEOF_EDGE_BYTES = SIZEOF_EDGE_BYTES;
 373 
 374         final OffHeapArray _edges = edges;
 375 
 376         // get free pointer (ie length in bytes)
 377         final int edgePtr = _edges.used;
 378 
 379         // use substraction to avoid integer overflow:
 380         if (_edges.length - edgePtr < _SIZEOF_EDGE_BYTES) {
 381             // suppose _edges.length > _SIZEOF_EDGE_BYTES
 382             // so doubling size is enough to add needed bytes
 383             // note: throw IOOB if neededSize > 2Gb:
 384             final long edgeNewSize = ArrayCacheConst.getNewLargeSize(
 385                                         _edges.length,
 386                                         edgePtr + _SIZEOF_EDGE_BYTES);
 387 
 388             if (DO_STATS) {
 389                 rdrCtx.stats.stat_rdr_edges_resizes.add(edgeNewSize);
 390             }
 391             _edges.resize(edgeNewSize);
 392         }
 393 
 394 
 395         final Unsafe _unsafe = OffHeapArray.UNSAFE;
 396         final long SIZE_INT = 4L;
 397         long addr   = _edges.address + edgePtr;
 398 
 399         // The x value must be bumped up to its position at the next HPC we will evaluate.
 400         // "firstcrossing" is the (sub)pixel number where the next crossing occurs
 401         // thus, the actual coordinate of the next HPC is "firstcrossing + 0.5"
 402         // so the Y distance we cover is "firstcrossing + 0.5 - trueY".
 403         // Note that since y1 (and y2) are already biased by -0.5 in tosubpixy(), we have
 404         // y1 = trueY - 0.5
 405         // trueY = y1 + 0.5
 406         // firstcrossing + 0.5 - trueY = firstcrossing + 0.5 - (y1 + 0.5)
 407         //                             = firstcrossing - y1
 408         // The x coordinate at that HPC is then:
 409         // x1_intercept = x1 + (firstcrossing - y1) * slope
 410         // The next VPC is then given by:
 411         // VPC index = ceil(x1_intercept - 0.5), or alternately
 412         // VPC index = floor(x1_intercept - 0.5 + 1 - epsilon)
 413         // epsilon is hard to pin down in floating point, but easy in fixed point, so if
 414         // we convert to fixed point then these operations get easier:
 415         // long x1_fixed = x1_intercept * 2^32;  (fixed point 32.32 format)
 416         // curx = next VPC = fixed_floor(x1_fixed - 2^31 + 2^32 - 1)
 417         //                 = fixed_floor(x1_fixed + 2^31 - 1)
 418         //                 = fixed_floor(x1_fixed + 0x7fffffff)
 419         // and error       = fixed_fract(x1_fixed + 0x7fffffff)
 420         final double x1_intercept = x1d + (firstCrossing - y1d) * slope;
 421 
 422         // inlined scalb(x1_intercept, 32):
 423         final long x1_fixed_biased = ((long) (POWER_2_TO_32 * x1_intercept))
 424                                      + 0x7fffffffL;
 425         // curx:
 426         // last bit corresponds to the orientation
 427         _unsafe.putInt(addr, (((int) (x1_fixed_biased >> 31L)) & ALL_BUT_LSB) | or);
 428         addr += SIZE_INT;
 429         _unsafe.putInt(addr,  ((int)  x1_fixed_biased) >>> 1);
 430         addr += SIZE_INT;
 431 
 432         // inlined scalb(slope, 32):
 433         final long slope_fixed = (long) (POWER_2_TO_32 * slope);
 434 
 435         // last bit set to 0 to keep orientation:
 436         _unsafe.putInt(addr, (((int) (slope_fixed >> 31L)) & ALL_BUT_LSB));
 437         addr += SIZE_INT;
 438         _unsafe.putInt(addr,  ((int)  slope_fixed) >>> 1);
 439         addr += SIZE_INT;
 440 
 441         final int[] _edgeBuckets      = edgeBuckets;
 442         final int[] _edgeBucketCounts = edgeBucketCounts;
 443 
 444         final int _boundsMinY = boundsMinY;
 445 
 446         // each bucket is a linked list. this method adds ptr to the
 447         // start of the "bucket"th linked list.
 448         final int bucketIdx = firstCrossing - _boundsMinY;
 449 
 450         // pointer from bucket
 451         _unsafe.putInt(addr, _edgeBuckets[bucketIdx]);
 452         addr += SIZE_INT;
 453         // y max (inclusive)
 454         _unsafe.putInt(addr,  lastCrossing);
 455 
 456         // Update buckets:
 457         // directly the edge struct "pointer"
 458         _edgeBuckets[bucketIdx]       = edgePtr;
 459         _edgeBucketCounts[bucketIdx] += 2; // 1 << 1
 460         // last bit means edge end
 461         _edgeBucketCounts[lastCrossing - _boundsMinY] |= 0x1;
 462 
 463         // update free pointer (ie length in bytes)
 464         _edges.used += _SIZEOF_EDGE_BYTES;
 465 
 466         if (DO_MONITORS) {
 467             rdrCtx.stats.mon_rdr_addLine.stop();
 468         }
 469     }
 470 
 471 // END EDGE LIST
 472 //////////////////////////////////////////////////////////////////////////////
 473 
 474     // Bounds of the drawing region, at subpixel precision.
 475     private int boundsMinX, boundsMinY, boundsMaxX, boundsMaxY;
 476 
 477     // Current winding rule
 478     private int windingRule;
 479 
 480     // Current drawing position, i.e., final point of last segment
 481     private float x0, y0;
 482 
 483     // Position of most recent 'moveTo' command
 484     private float sx0, sy0;
 485 
 486     // per-thread renderer context
 487     final RendererContext rdrCtx;
 488     // dirty curve
 489     private final Curve curve;
 490 
 491     // clean alpha array (zero filled)
 492     private int[] alphaLine;
 493 
 494     // alphaLine ref (clean)
 495     private final IntArrayCache.Reference alphaLine_ref;
 496 
 497     private boolean enableBlkFlags = false;
 498     private boolean prevUseBlkFlags = false;
 499 
 500     /* block flags (0|1) */
 501     private int[] blkFlags;
 502 
 503     // blkFlags ref (clean)
 504     private final IntArrayCache.Reference blkFlags_ref;
 505 
 506     RendererNoAA(final RendererContext rdrCtx) {
 507         this.rdrCtx = rdrCtx;
 508 
 509         this.edges = rdrCtx.newOffHeapArray(INITIAL_EDGES_CAPACITY); // 96K
 510 
 511         this.curve = rdrCtx.curve;
 512 
 513         edgeBuckets_ref      = rdrCtx.newCleanIntArrayRef(INITIAL_BUCKET_ARRAY); // 64K
 514         edgeBucketCounts_ref = rdrCtx.newCleanIntArrayRef(INITIAL_BUCKET_ARRAY); // 64K
 515 
 516         edgeBuckets      = edgeBuckets_ref.initial;
 517         edgeBucketCounts = edgeBucketCounts_ref.initial;
 518 
 519         // 2048 (pixelsize) pixel large
 520         alphaLine_ref = rdrCtx.newCleanIntArrayRef(INITIAL_AA_ARRAY); // 8K
 521         alphaLine     = alphaLine_ref.initial;
 522 
 523         crossings_ref     = rdrCtx.newDirtyIntArrayRef(INITIAL_CROSSING_COUNT); // 2K
 524         aux_crossings_ref = rdrCtx.newDirtyIntArrayRef(INITIAL_CROSSING_COUNT); // 2K
 525         edgePtrs_ref      = rdrCtx.newDirtyIntArrayRef(INITIAL_CROSSING_COUNT); // 2K
 526         aux_edgePtrs_ref  = rdrCtx.newDirtyIntArrayRef(INITIAL_CROSSING_COUNT); // 2K
 527 
 528         crossings     = crossings_ref.initial;
 529         aux_crossings = aux_crossings_ref.initial;
 530         edgePtrs      = edgePtrs_ref.initial;
 531         aux_edgePtrs  = aux_edgePtrs_ref.initial;
 532 
 533         blkFlags_ref = rdrCtx.newCleanIntArrayRef(INITIAL_ARRAY); // 1K = 1 tile line
 534         blkFlags     = blkFlags_ref.initial;
 535     }
 536 
 537     public RendererNoAA init(final int pix_boundsX, final int pix_boundsY,
 538                   final int pix_boundsWidth, final int pix_boundsHeight,
 539                   final int windingRule)
 540     {
 541         this.windingRule = windingRule;
 542 
 543         // bounds as half-open intervals: minX <= x < maxX and minY <= y < maxY
 544         this.boundsMinX = pix_boundsX;
 545         this.boundsMaxX = pix_boundsX + pix_boundsWidth;
 546         this.boundsMinY = pix_boundsY;
 547         this.boundsMaxY = pix_boundsY + pix_boundsHeight;
 548 
 549         if (DO_LOG_BOUNDS) {
 550             MarlinUtils.logInfo("boundsXY = [" + boundsMinX + " ... "
 551                                 + boundsMaxX + "[ [" + boundsMinY + " ... "
 552                                 + boundsMaxY + "[");
 553         }
 554 
 555         // see addLine: ceil(boundsMaxY) => boundsMaxY + 1
 556         // +1 for edgeBucketCounts
 557         final int edgeBucketsLength = (boundsMaxY - boundsMinY) + 1;
 558 
 559         if (edgeBucketsLength > INITIAL_BUCKET_ARRAY) {
 560             if (DO_STATS) {
 561                 rdrCtx.stats.stat_array_renderer_edgeBuckets
 562                     .add(edgeBucketsLength);
 563                 rdrCtx.stats.stat_array_renderer_edgeBucketCounts
 564                     .add(edgeBucketsLength);
 565             }
 566             edgeBuckets = edgeBuckets_ref.getArray(edgeBucketsLength);
 567             edgeBucketCounts = edgeBucketCounts_ref.getArray(edgeBucketsLength);
 568         }
 569 
 570         edgeMinY = Integer.MAX_VALUE;
 571         edgeMaxY = Integer.MIN_VALUE;
 572         edgeMinX = Float.POSITIVE_INFINITY;
 573         edgeMaxX = Float.NEGATIVE_INFINITY;
 574 
 575         // reset used mark:
 576         edgeCount = 0;
 577         activeEdgeMaxUsed = 0;
 578         edges.used = 0;
 579 
 580         // reset bbox:
 581         bboxX0 = 0;
 582         bboxX1 = 0;
 583 
 584         return this; // fluent API
 585     }
 586 
 587     /**
 588      * Disposes this renderer and recycle it clean up before reusing this instance
 589      */
 590     public void dispose() {
 591         if (DO_STATS) {
 592             rdrCtx.stats.stat_rdr_activeEdges.add(activeEdgeMaxUsed);
 593             rdrCtx.stats.stat_rdr_edges.add(edges.used);
 594             rdrCtx.stats.stat_rdr_edges_count.add(edges.used / SIZEOF_EDGE_BYTES);
 595             rdrCtx.stats.hist_rdr_edges_count.add(edges.used / SIZEOF_EDGE_BYTES);
 596             rdrCtx.stats.totalOffHeap += edges.length;
 597         }
 598         // Return arrays:
 599         crossings = crossings_ref.putArray(crossings);
 600         aux_crossings = aux_crossings_ref.putArray(aux_crossings);
 601 
 602         edgePtrs = edgePtrs_ref.putArray(edgePtrs);
 603         aux_edgePtrs = aux_edgePtrs_ref.putArray(aux_edgePtrs);
 604 
 605         alphaLine = alphaLine_ref.putArray(alphaLine, 0, 0); // already zero filled
 606         blkFlags  = blkFlags_ref.putArray(blkFlags, 0, 0); // already zero filled
 607 
 608         if (edgeMinY != Integer.MAX_VALUE) {
 609             // if context is maked as DIRTY:
 610             if (rdrCtx.dirty) {
 611                 // may happen if an exception if thrown in the pipeline processing:
 612                 // clear completely buckets arrays:
 613                 buckets_minY = 0;
 614                 buckets_maxY = boundsMaxY - boundsMinY;
 615             }
 616             // clear only used part
 617             edgeBuckets = edgeBuckets_ref.putArray(edgeBuckets, buckets_minY,
 618                                                                 buckets_maxY);
 619             edgeBucketCounts = edgeBucketCounts_ref.putArray(edgeBucketCounts,
 620                                                              buckets_minY,
 621                                                              buckets_maxY + 1);
 622         } else {
 623             // unused arrays
 624             edgeBuckets = edgeBuckets_ref.putArray(edgeBuckets, 0, 0);
 625             edgeBucketCounts = edgeBucketCounts_ref.putArray(edgeBucketCounts, 0, 0);
 626         }
 627 
 628         // At last: resize back off-heap edges to initial size
 629         if (edges.length != INITIAL_EDGES_CAPACITY) {
 630             // note: may throw OOME:
 631             edges.resize(INITIAL_EDGES_CAPACITY);
 632         }
 633         if (DO_CLEAN_DIRTY) {
 634             // Force zero-fill dirty arrays:
 635             edges.fill(BYTE_0);
 636         }
 637         if (DO_MONITORS) {
 638             rdrCtx.stats.mon_rdr_endRendering.stop();
 639         }
 640     }
 641 
 642     private static float tosubpixx(final float pix_x) {
 643         return pix_x;
 644     }
 645 
 646     private static float tosubpixy(final float pix_y) {
 647         // shift y by -0.5 for fast ceil(y - 0.5):
 648         return pix_y - 0.5f;
 649     }
 650 
 651     @Override
 652     public void moveTo(float pix_x0, float pix_y0) {
 653         closePath();
 654         final float sx = tosubpixx(pix_x0);
 655         final float sy = tosubpixy(pix_y0);
 656         this.sx0 = sx;
 657         this.sy0 = sy;
 658         this.x0 = sx;
 659         this.y0 = sy;
 660     }
 661 
 662     @Override
 663     public void lineTo(float pix_x1, float pix_y1) {
 664         final float x1 = tosubpixx(pix_x1);
 665         final float y1 = tosubpixy(pix_y1);
 666         addLine(x0, y0, x1, y1);
 667         x0 = x1;
 668         y0 = y1;
 669     }
 670 
 671     @Override
 672     public void curveTo(float x1, float y1,
 673             float x2, float y2,
 674             float x3, float y3)
 675     {
 676         final float xe = tosubpixx(x3);
 677         final float ye = tosubpixy(y3);
 678         curve.set(x0, y0, tosubpixx(x1), tosubpixy(y1),
 679                           tosubpixx(x2), tosubpixy(y2), xe, ye);
 680         curveBreakIntoLinesAndAdd(x0, y0, curve, xe, ye);
 681         x0 = xe;
 682         y0 = ye;
 683     }
 684 
 685     @Override
 686     public void quadTo(float x1, float y1, float x2, float y2) {
 687         final float xe = tosubpixx(x2);
 688         final float ye = tosubpixy(y2);
 689         curve.set(x0, y0, tosubpixx(x1), tosubpixy(y1), xe, ye);
 690         quadBreakIntoLinesAndAdd(x0, y0, curve, xe, ye);
 691         x0 = xe;
 692         y0 = ye;
 693     }
 694 
 695     @Override
 696     public void closePath() {
 697         addLine(x0, y0, sx0, sy0);
 698         x0 = sx0;
 699         y0 = sy0;
 700     }
 701 
 702     @Override
 703     public void pathDone() {
 704         closePath();
 705 
 706         // call endRendering() to determine the boundaries:
 707         endRendering();
 708     }
 709 
 710     private void _endRendering(final int ymin, final int ymax,
 711                                final MarlinAlphaConsumer ac)
 712     {
 713         if (DISABLE_RENDER) {
 714             return;
 715         }
 716 
 717         // Get X bounds as true pixel boundaries to compute correct pixel coverage:
 718         final int bboxx0 = bbox_spminX;
 719         final int bboxx1 = bbox_spmaxX;
 720 
 721         final boolean windingRuleEvenOdd = (windingRule == WIND_EVEN_ODD);
 722 
 723         // Useful when processing tile line by tile line
 724         final int[] _alpha = alphaLine;
 725 
 726         // local vars (performance):
 727         final OffHeapArray _edges = edges;
 728         final int[] _edgeBuckets = edgeBuckets;
 729         final int[] _edgeBucketCounts = edgeBucketCounts;
 730 
 731         int[] _crossings = this.crossings;
 732         int[] _edgePtrs  = this.edgePtrs;
 733 
 734         // merge sort auxiliary storage:
 735         int[] _aux_crossings = this.aux_crossings;
 736         int[] _aux_edgePtrs  = this.aux_edgePtrs;
 737 
 738         // copy constants:
 739         final long _OFF_ERROR    = OFF_ERROR;
 740         final long _OFF_BUMP_X   = OFF_BUMP_X;
 741         final long _OFF_BUMP_ERR = OFF_BUMP_ERR;
 742 
 743         final long _OFF_NEXT     = OFF_NEXT;
 744         final long _OFF_YMAX     = OFF_YMAX;
 745 
 746         final int _ALL_BUT_LSB   = ALL_BUT_LSB;
 747         final int _ERR_STEP_MAX  = ERR_STEP_MAX;
 748 
 749         // unsafe I/O:
 750         final Unsafe _unsafe = OffHeapArray.UNSAFE;
 751         final long    addr0  = _edges.address;
 752         long addr;
 753 
 754         final int _MIN_VALUE = Integer.MIN_VALUE;
 755         final int _MAX_VALUE = Integer.MAX_VALUE;
 756 
 757         // Now we iterate through the scanlines. We must tell emitRow the coord
 758         // of the first non-transparent pixel, so we must keep accumulators for
 759         // the first and last pixels of the section of the current pixel row
 760         // that we will emit.
 761         // We also need to accumulate pix_bbox, but the iterator does it
 762         // for us. We will just get the values from it once this loop is done
 763         int minX = _MAX_VALUE;
 764         int maxX = _MIN_VALUE;
 765 
 766         int y = ymin;
 767         int bucket = y - boundsMinY;
 768 
 769         int numCrossings = this.edgeCount;
 770         int edgePtrsLen = _edgePtrs.length;
 771         int crossingsLen = _crossings.length;
 772         int _arrayMaxUsed = activeEdgeMaxUsed;
 773         int ptrLen = 0, newCount, ptrEnd;
 774 
 775         int bucketcount, i, j, ecur;
 776         int cross, lastCross;
 777         int x0, x1, tmp, sum, prev, curx, curxo, crorientation, err;
 778 
 779         int low, high, mid, prevNumCrossings;
 780         boolean useBinarySearch;
 781 
 782         final int[] _blkFlags = blkFlags;
 783         final int _BLK_SIZE_LG = BLOCK_SIZE_LG;
 784         final int _BLK_SIZE = BLOCK_SIZE;
 785 
 786         final boolean _enableBlkFlagsHeuristics = ENABLE_BLOCK_FLAGS_HEURISTICS && this.enableBlkFlags;
 787 
 788         // Use block flags if large pixel span and few crossings:
 789         // ie mean(distance between crossings) is high
 790         boolean useBlkFlags = this.prevUseBlkFlags;
 791 
 792         final int stroking = rdrCtx.stroking;
 793 
 794         int lastY = -1; // last emited row
 795 
 796 
 797         // Iteration on scanlines
 798         for (; y < ymax; y++, bucket++) {
 799             // --- from former ScanLineIterator.next()
 800             bucketcount = _edgeBucketCounts[bucket];
 801 
 802             // marker on previously sorted edges:
 803             prevNumCrossings = numCrossings;
 804 
 805             // bucketCount indicates new edge / edge end:
 806             if (bucketcount != 0) {
 807                 if (DO_STATS) {
 808                     rdrCtx.stats.stat_rdr_activeEdges_updates.add(numCrossings);
 809                 }
 810 
 811                 // last bit set to 1 means that edges ends
 812                 if ((bucketcount & 0x1) != 0) {
 813                     // eviction in active edge list
 814                     // cache edges[] address + offset
 815                     addr = addr0 + _OFF_YMAX;
 816 
 817                     for (i = 0, newCount = 0; i < numCrossings; i++) {
 818                         // get the pointer to the edge
 819                         ecur = _edgePtrs[i];
 820                         // random access so use unsafe:
 821                         if (_unsafe.getInt(addr + ecur) > y) {
 822                             _edgePtrs[newCount++] = ecur;
 823                         }
 824                     }
 825                     // update marker on sorted edges minus removed edges:
 826                     prevNumCrossings = numCrossings = newCount;
 827                 }
 828 
 829                 ptrLen = bucketcount >> 1; // number of new edge
 830 
 831                 if (ptrLen != 0) {
 832                     if (DO_STATS) {
 833                         rdrCtx.stats.stat_rdr_activeEdges_adds.add(ptrLen);
 834                         if (ptrLen > 10) {
 835                             rdrCtx.stats.stat_rdr_activeEdges_adds_high.add(ptrLen);
 836                         }
 837                     }
 838                     ptrEnd = numCrossings + ptrLen;
 839 
 840                     if (edgePtrsLen < ptrEnd) {
 841                         if (DO_STATS) {
 842                             rdrCtx.stats.stat_array_renderer_edgePtrs.add(ptrEnd);
 843                         }
 844                         this.edgePtrs = _edgePtrs
 845                             = edgePtrs_ref.widenArray(_edgePtrs, numCrossings,
 846                                                       ptrEnd);
 847 
 848                         edgePtrsLen = _edgePtrs.length;
 849                         // Get larger auxiliary storage:
 850                         aux_edgePtrs_ref.putArray(_aux_edgePtrs);
 851 
 852                         // use ArrayCache.getNewSize() to use the same growing
 853                         // factor than widenArray():
 854                         if (DO_STATS) {
 855                             rdrCtx.stats.stat_array_renderer_aux_edgePtrs.add(ptrEnd);
 856                         }
 857                         this.aux_edgePtrs = _aux_edgePtrs
 858                             = aux_edgePtrs_ref.getArray(
 859                                 ArrayCacheConst.getNewSize(numCrossings, ptrEnd)
 860                             );
 861                     }
 862 
 863                     // cache edges[] address + offset
 864                     addr = addr0 + _OFF_NEXT;
 865 
 866                     // add new edges to active edge list:
 867                     for (ecur = _edgeBuckets[bucket];
 868                          numCrossings < ptrEnd; numCrossings++)
 869                     {
 870                         // store the pointer to the edge
 871                         _edgePtrs[numCrossings] = ecur;
 872                         // random access so use unsafe:
 873                         ecur = _unsafe.getInt(addr + ecur);
 874                     }
 875 
 876                     if (crossingsLen < numCrossings) {
 877                         // Get larger array:
 878                         crossings_ref.putArray(_crossings);
 879 
 880                         if (DO_STATS) {
 881                             rdrCtx.stats.stat_array_renderer_crossings
 882                                 .add(numCrossings);
 883                         }
 884                         this.crossings = _crossings
 885                             = crossings_ref.getArray(numCrossings);
 886 
 887                         // Get larger auxiliary storage:
 888                         aux_crossings_ref.putArray(_aux_crossings);
 889 
 890                         if (DO_STATS) {
 891                             rdrCtx.stats.stat_array_renderer_aux_crossings
 892                                 .add(numCrossings);
 893                         }
 894                         this.aux_crossings = _aux_crossings
 895                             = aux_crossings_ref.getArray(numCrossings);
 896 
 897                         crossingsLen = _crossings.length;
 898                     }
 899                     if (DO_STATS) {
 900                         // update max used mark
 901                         if (numCrossings > _arrayMaxUsed) {
 902                             _arrayMaxUsed = numCrossings;
 903                         }
 904                     }
 905                 } // ptrLen != 0
 906             } // bucketCount != 0
 907 
 908 
 909             if (numCrossings != 0) {
 910                 /*
 911                  * thresholds to switch to optimized merge sort
 912                  * for newly added edges + final merge pass.
 913                  */
 914                 if ((ptrLen < 10) || (numCrossings < 40)) {
 915                     if (DO_STATS) {
 916                         rdrCtx.stats.hist_rdr_crossings.add(numCrossings);
 917                         rdrCtx.stats.hist_rdr_crossings_adds.add(ptrLen);
 918                     }
 919 
 920                     /*
 921                      * threshold to use binary insertion sort instead of
 922                      * straight insertion sort (to reduce minimize comparisons).
 923                      */
 924                     useBinarySearch = (numCrossings >= 20);
 925 
 926                     // if small enough:
 927                     lastCross = _MIN_VALUE;
 928 
 929                     for (i = 0; i < numCrossings; i++) {
 930                         // get the pointer to the edge
 931                         ecur = _edgePtrs[i];
 932 
 933                         /* convert subpixel coordinates (float) into pixel
 934                             positions (int) for coming scanline */
 935                         /* note: it is faster to always update edges even
 936                            if it is removed from AEL for coming or last scanline */
 937 
 938                         // random access so use unsafe:
 939                         addr = addr0 + ecur; // ecur + OFF_F_CURX
 940 
 941                         // get current crossing:
 942                         curx = _unsafe.getInt(addr);
 943 
 944                         // update crossing with orientation at last bit:
 945                         cross = curx;
 946 
 947                         // Increment x using DDA (fixed point):
 948                         curx += _unsafe.getInt(addr + _OFF_BUMP_X);
 949 
 950                         // Increment error:
 951                         err  =  _unsafe.getInt(addr + _OFF_ERROR)
 952                               + _unsafe.getInt(addr + _OFF_BUMP_ERR);
 953 
 954                         // Manual carry handling:
 955                         // keep sign and carry bit only and ignore last bit (preserve orientation):
 956                         _unsafe.putInt(addr,               curx - ((err >> 30) & _ALL_BUT_LSB));
 957                         _unsafe.putInt(addr + _OFF_ERROR, (err & _ERR_STEP_MAX));
 958 
 959                         if (DO_STATS) {
 960                             rdrCtx.stats.stat_rdr_crossings_updates.add(numCrossings);
 961                         }
 962 
 963                         // insertion sort of crossings:
 964                         if (cross < lastCross) {
 965                             if (DO_STATS) {
 966                                 rdrCtx.stats.stat_rdr_crossings_sorts.add(i);
 967                             }
 968 
 969                             /* use binary search for newly added edges
 970                                in crossings if arrays are large enough */
 971                             if (useBinarySearch && (i >= prevNumCrossings)) {
 972                                 if (DO_STATS) {
 973                                     rdrCtx.stats.stat_rdr_crossings_bsearch.add(i);
 974                                 }
 975                                 low = 0;
 976                                 high = i - 1;
 977 
 978                                 do {
 979                                     // note: use signed shift (not >>>) for performance
 980                                     // as indices are small enough to exceed Integer.MAX_VALUE
 981                                     mid = (low + high) >> 1;
 982 
 983                                     if (_crossings[mid] < cross) {
 984                                         low = mid + 1;
 985                                     } else {
 986                                         high = mid - 1;
 987                                     }
 988                                 } while (low <= high);
 989 
 990                                 for (j = i - 1; j >= low; j--) {
 991                                     _crossings[j + 1] = _crossings[j];
 992                                     _edgePtrs [j + 1] = _edgePtrs[j];
 993                                 }
 994                                 _crossings[low] = cross;
 995                                 _edgePtrs [low] = ecur;
 996 
 997                             } else {
 998                                 j = i - 1;
 999                                 _crossings[i] = _crossings[j];
1000                                 _edgePtrs[i] = _edgePtrs[j];
1001 
1002                                 while ((--j >= 0) && (_crossings[j] > cross)) {
1003                                     _crossings[j + 1] = _crossings[j];
1004                                     _edgePtrs [j + 1] = _edgePtrs[j];
1005                                 }
1006                                 _crossings[j + 1] = cross;
1007                                 _edgePtrs [j + 1] = ecur;
1008                             }
1009 
1010                         } else {
1011                             _crossings[i] = lastCross = cross;
1012                         }
1013                     }
1014                 } else {
1015                     if (DO_STATS) {
1016                         rdrCtx.stats.stat_rdr_crossings_msorts.add(numCrossings);
1017                         rdrCtx.stats.hist_rdr_crossings_ratio
1018                             .add((1000 * ptrLen) / numCrossings);
1019                         rdrCtx.stats.hist_rdr_crossings_msorts.add(numCrossings);
1020                         rdrCtx.stats.hist_rdr_crossings_msorts_adds.add(ptrLen);
1021                     }
1022 
1023                     // Copy sorted data in auxiliary arrays
1024                     // and perform insertion sort on almost sorted data
1025                     // (ie i < prevNumCrossings):
1026 
1027                     lastCross = _MIN_VALUE;
1028 
1029                     for (i = 0; i < numCrossings; i++) {
1030                         // get the pointer to the edge
1031                         ecur = _edgePtrs[i];
1032 
1033                         /* convert subpixel coordinates (float) into pixel
1034                             positions (int) for coming scanline */
1035                         /* note: it is faster to always update edges even
1036                            if it is removed from AEL for coming or last scanline */
1037 
1038                         // random access so use unsafe:
1039                         addr = addr0 + ecur; // ecur + OFF_F_CURX
1040 
1041                         // get current crossing:
1042                         curx = _unsafe.getInt(addr);
1043 
1044                         // update crossing with orientation at last bit:
1045                         cross = curx;
1046 
1047                         // Increment x using DDA (fixed point):
1048                         curx += _unsafe.getInt(addr + _OFF_BUMP_X);
1049 
1050                         // Increment error:
1051                         err  =  _unsafe.getInt(addr + _OFF_ERROR)
1052                               + _unsafe.getInt(addr + _OFF_BUMP_ERR);
1053 
1054                         // Manual carry handling:
1055                         // keep sign and carry bit only and ignore last bit (preserve orientation):
1056                         _unsafe.putInt(addr,               curx - ((err >> 30) & _ALL_BUT_LSB));
1057                         _unsafe.putInt(addr + _OFF_ERROR, (err & _ERR_STEP_MAX));
1058 
1059                         if (DO_STATS) {
1060                             rdrCtx.stats.stat_rdr_crossings_updates.add(numCrossings);
1061                         }
1062 
1063                         if (i >= prevNumCrossings) {
1064                             // simply store crossing as edgePtrs is in-place:
1065                             // will be copied and sorted efficiently by mergesort later:
1066                             _crossings[i]     = cross;
1067 
1068                         } else if (cross < lastCross) {
1069                             if (DO_STATS) {
1070                                 rdrCtx.stats.stat_rdr_crossings_sorts.add(i);
1071                             }
1072 
1073                             // (straight) insertion sort of crossings:
1074                             j = i - 1;
1075                             _aux_crossings[i] = _aux_crossings[j];
1076                             _aux_edgePtrs[i] = _aux_edgePtrs[j];
1077 
1078                             while ((--j >= 0) && (_aux_crossings[j] > cross)) {
1079                                 _aux_crossings[j + 1] = _aux_crossings[j];
1080                                 _aux_edgePtrs [j + 1] = _aux_edgePtrs[j];
1081                             }
1082                             _aux_crossings[j + 1] = cross;
1083                             _aux_edgePtrs [j + 1] = ecur;
1084 
1085                         } else {
1086                             // auxiliary storage:
1087                             _aux_crossings[i] = lastCross = cross;
1088                             _aux_edgePtrs [i] = ecur;
1089                         }
1090                     }
1091 
1092                     // use Mergesort using auxiliary arrays (sort only right part)
1093                     MergeSort.mergeSortNoCopy(_crossings,     _edgePtrs,
1094                                               _aux_crossings, _aux_edgePtrs,
1095                                               numCrossings,   prevNumCrossings);
1096                 }
1097 
1098                 // reset ptrLen
1099                 ptrLen = 0;
1100                 // --- from former ScanLineIterator.next()
1101 
1102 
1103                 /* note: bboxx0 and bboxx1 must be pixel boundaries
1104                    to have correct coverage computation */
1105 
1106                 // right shift on crossings to get the x-coordinate:
1107                 curxo = _crossings[0];
1108                 x0    = curxo >> 1;
1109                 if (x0 < minX) {
1110                     minX = x0; // subpixel coordinate
1111                 }
1112 
1113                 x1 = _crossings[numCrossings - 1] >> 1;
1114                 if (x1 > maxX) {
1115                     maxX = x1; // subpixel coordinate
1116                 }
1117 
1118 
1119                 // compute pixel coverages
1120                 prev = curx = x0;
1121                 // to turn {0, 1} into {-1, 1}, multiply by 2 and subtract 1.
1122                 // last bit contains orientation (0 or 1)
1123                 crorientation = ((curxo & 0x1) << 1) - 1;
1124 
1125                 if (windingRuleEvenOdd) {
1126                     sum = crorientation;
1127 
1128                     // Even Odd winding rule: take care of mask ie sum(orientations)
1129                     for (i = 1; i < numCrossings; i++) {
1130                         curxo = _crossings[i];
1131                         curx  =  curxo >> 1;
1132                         // to turn {0, 1} into {-1, 1}, multiply by 2 and subtract 1.
1133                         // last bit contains orientation (0 or 1)
1134                         crorientation = ((curxo & 0x1) << 1) - 1;
1135 
1136                         if ((sum & 0x1) != 0) {
1137                             // TODO: perform line clipping on left-right sides
1138                             // to avoid such bound checks:
1139                             x0 = (prev > bboxx0) ? prev : bboxx0;
1140 
1141                             if (curx < bboxx1) {
1142                                 x1 = curx;
1143                             } else {
1144                                 x1 = bboxx1;
1145                                 // skip right side (fast exit loop):
1146                                 i = numCrossings;
1147                             }
1148 
1149                             if (x0 < x1) {
1150                                 x0 -= bboxx0; // turn x0, x1 from coords to indices
1151                                 x1 -= bboxx0; // in the alpha array.
1152 
1153                                 _alpha[x0] += 1;
1154                                 _alpha[x1] -= 1;
1155 
1156                                 if (useBlkFlags) {
1157                                     // flag used blocks:
1158                                     _blkFlags[x0 >> _BLK_SIZE_LG] = 1;
1159                                     _blkFlags[x1 >> _BLK_SIZE_LG] = 1;
1160                                 }
1161                             }
1162                         }
1163 
1164                         sum += crorientation;
1165                         prev = curx;
1166                     }
1167                 } else {
1168                     // Non-zero winding rule: optimize that case (default)
1169                     // and avoid processing intermediate crossings
1170                     for (i = 1, sum = 0;; i++) {
1171                         sum += crorientation;
1172 
1173                         if (sum != 0) {
1174                             // prev = min(curx)
1175                             if (prev > curx) {
1176                                 prev = curx;
1177                             }
1178                         } else {
1179                             // TODO: perform line clipping on left-right sides
1180                             // to avoid such bound checks:
1181                             x0 = (prev > bboxx0) ? prev : bboxx0;
1182 
1183                             if (curx < bboxx1) {
1184                                 x1 = curx;
1185                             } else {
1186                                 x1 = bboxx1;
1187                                 // skip right side (fast exit loop):
1188                                 i = numCrossings;
1189                             }
1190 
1191                             if (x0 < x1) {
1192                                 x0 -= bboxx0; // turn x0, x1 from coords to indices
1193                                 x1 -= bboxx0; // in the alpha array.
1194 
1195                                 _alpha[x0] += 1;
1196                                 _alpha[x1] -= 1;
1197 
1198                                 if (useBlkFlags) {
1199                                     // flag used blocks:
1200                                     _blkFlags[x0 >> _BLK_SIZE_LG] = 1;
1201                                     _blkFlags[x1 >> _BLK_SIZE_LG] = 1;
1202                                 }
1203                             }
1204                             prev = _MAX_VALUE;
1205                         }
1206 
1207                         if (i == numCrossings) {
1208                             break;
1209                         }
1210 
1211                         curxo = _crossings[i];
1212                         curx  =  curxo >> 1;
1213                         // to turn {0, 1} into {-1, 1}, multiply by 2 and subtract 1.
1214                         // last bit contains orientation (0 or 1)
1215                         crorientation = ((curxo & 0x1) << 1) - 1;
1216                     }
1217                 }
1218             } // numCrossings > 0
1219 
1220             // even if this last row had no crossings, alpha will be zeroed
1221             // from the last emitRow call. But this doesn't matter because
1222             // maxX < minX, so no row will be emitted to the AlphaConsumer.
1223             if (true) {
1224                 lastY = y;
1225 
1226                 // convert subpixel to pixel coordinate within boundaries:
1227                 minX = FloatMath.max(minX, bboxx0);
1228                 maxX = FloatMath.min(maxX, bboxx1);
1229 
1230                 if (maxX >= minX) {
1231                     // note: alpha array will be zeroed by copyAARow()
1232                     // +1 because alpha [pix_minX; pix_maxX[
1233                     // fix range [x0; x1[
1234                     // note: if x1=bboxx1, then alpha is written up to bboxx1+1
1235                     // inclusive: alpha[bboxx1] ignored, alpha[bboxx1+1] == 0
1236                     // (normally so never cleared below)
1237                     copyAARow(_alpha, lastY, minX, maxX + 1, useBlkFlags, ac);
1238 
1239                     // speculative for next pixel row (scanline coherence):
1240                     if (_enableBlkFlagsHeuristics) {
1241                         // Use block flags if large pixel span and few crossings:
1242                         // ie mean(distance between crossings) is larger than
1243                         // 1 block size;
1244 
1245                         // fast check width:
1246                         maxX -= minX;
1247 
1248                         // if stroking: numCrossings /= 2
1249                         // => shift numCrossings by 1
1250                         // condition = (width / (numCrossings - 1)) > blockSize
1251                         useBlkFlags = (maxX > _BLK_SIZE) && (maxX >
1252                             (((numCrossings >> stroking) - 1) << _BLK_SIZE_LG));
1253 
1254                         if (DO_STATS) {
1255                             tmp = FloatMath.max(1,
1256                                     ((numCrossings >> stroking) - 1));
1257                             rdrCtx.stats.hist_tile_generator_encoding_dist
1258                                 .add(maxX / tmp);
1259                         }
1260                     }
1261                 } else {
1262                     ac.clearAlphas(lastY);
1263                 }
1264                 minX = _MAX_VALUE;
1265                 maxX = _MIN_VALUE;
1266             }
1267         } // scan line iterator
1268 
1269         // Emit final row
1270         y--;
1271 
1272         // convert subpixel to pixel coordinate within boundaries:
1273         minX = FloatMath.max(minX, bboxx0);
1274         maxX = FloatMath.min(maxX, bboxx1);
1275 
1276         if (maxX >= minX) {
1277             // note: alpha array will be zeroed by copyAARow()
1278             // +1 because alpha [pix_minX; pix_maxX[
1279             // fix range [x0; x1[
1280             // note: if x1=bboxx1, then alpha is written up to bboxx1+1
1281             // inclusive: alpha[bboxx1] ignored then cleared and
1282             // alpha[bboxx1+1] == 0 (normally so never cleared after)
1283             copyAARow(_alpha, y, minX, maxX + 1, useBlkFlags, ac);
1284         } else if (y != lastY) {
1285             ac.clearAlphas(y);
1286         }
1287 
1288         // update member:
1289         edgeCount = numCrossings;
1290         prevUseBlkFlags = useBlkFlags;
1291 
1292         if (DO_STATS) {
1293             // update max used mark
1294             activeEdgeMaxUsed = _arrayMaxUsed;
1295         }
1296     }
1297 
1298     void endRendering() {
1299         if (DO_MONITORS) {
1300             rdrCtx.stats.mon_rdr_endRendering.start();
1301         }
1302         if (edgeMinY == Integer.MAX_VALUE) {
1303             return; // undefined edges bounds
1304         }
1305 
1306         final int _boundsMinY = boundsMinY;
1307         final int _boundsMaxY = boundsMaxY;
1308 
1309         // bounds as inclusive intervals
1310         final int spminX = FloatMath.max(FloatMath.ceil_int(edgeMinX - 0.5f), boundsMinX);
1311         final int spmaxX = FloatMath.min(FloatMath.ceil_int(edgeMaxX - 0.5f), boundsMaxX - 1);
1312 
1313         // edge Min/Max Y are already rounded to subpixels within bounds:
1314         final int spminY = edgeMinY;
1315         final int spmaxY;
1316         int maxY = edgeMaxY;
1317 
1318         if (maxY <= _boundsMaxY - 1) {
1319             spmaxY = maxY;
1320         } else {
1321             spmaxY = _boundsMaxY - 1;
1322             maxY   = _boundsMaxY;
1323         }
1324         buckets_minY = spminY - _boundsMinY;
1325         buckets_maxY = maxY   - _boundsMinY;
1326 
1327         if (DO_LOG_BOUNDS) {
1328             MarlinUtils.logInfo("edgesXY = [" + edgeMinX + " ... " + edgeMaxX
1329                                 + "][" + edgeMinY + " ... " + edgeMaxY + "]");
1330             MarlinUtils.logInfo("spXY    = [" + spminX + " ... " + spmaxX
1331                                 + "][" + spminY + " ... " + spmaxY + "]");
1332         }
1333 
1334         // test clipping for shapes out of bounds
1335         if ((spminX > spmaxX) || (spminY > spmaxY)) {
1336             return;
1337         }
1338 
1339         // half open intervals
1340         // inclusive:
1341         final int pminX = spminX;
1342         // exclusive:
1343         final int pmaxX = spmaxX + 1; // +1 to ensure proper upper bound
1344         // inclusive:
1345         final int pminY = spminY;
1346         // exclusive:
1347         final int pmaxY = spmaxY + 1; // +1 to ensure proper upper bound
1348 
1349         // store BBox to answer ptg.getBBox():
1350         initConsumer(pminX, pminY, pmaxX, pmaxY);
1351 
1352         // Heuristics for using block flags:
1353         if (ENABLE_BLOCK_FLAGS) {
1354             enableBlkFlags = this.useRLE;
1355             prevUseBlkFlags = enableBlkFlags && !ENABLE_BLOCK_FLAGS_HEURISTICS;
1356 
1357             if (enableBlkFlags) {
1358                 // ensure blockFlags array is large enough:
1359                 // note: +2 to ensure enough space left at end
1360                 final int blkLen = ((pmaxX - pminX) >> BLOCK_SIZE_LG) + 2;
1361                 if (blkLen > INITIAL_ARRAY) {
1362                     blkFlags = blkFlags_ref.getArray(blkLen);
1363                 }
1364             }
1365         }
1366 
1367         // memorize the rendering bounding box:
1368         /* note: bbox_spminX and bbox_spmaxX must be pixel boundaries
1369            to have correct coverage computation */
1370         // inclusive:
1371         bbox_spminX = pminX;
1372         // exclusive:
1373         bbox_spmaxX = pmaxX;
1374         // inclusive:
1375         bbox_spminY = pminY;
1376         // exclusive:
1377         bbox_spmaxY = pmaxY;
1378 
1379         if (DO_LOG_BOUNDS) {
1380             MarlinUtils.logInfo("pXY       = [" + pminX + " ... " + pmaxX
1381                                 + "[ [" + pminY + " ... " + pmaxY + "[");
1382             MarlinUtils.logInfo("bbox_spXY = [" + bbox_spminX + " ... "
1383                                 + bbox_spmaxX + "[ [" + bbox_spminY + " ... "
1384                                 + bbox_spmaxY + "[");
1385         }
1386 
1387         // Prepare alpha line:
1388         // add 2 to better deal with the last pixel in a pixel row.
1389         final int width = (pmaxX - pminX) + 2;
1390 
1391         // Useful when processing tile line by tile line
1392         if (width > INITIAL_AA_ARRAY) {
1393             if (DO_STATS) {
1394                 rdrCtx.stats.stat_array_renderer_alphaline.add(width);
1395             }
1396             alphaLine = alphaLine_ref.getArray(width);
1397         }
1398     }
1399 
1400     void initConsumer(int minx, int miny, int maxx, int maxy)
1401     {
1402         // assert maxy >= miny && maxx >= minx;
1403         bboxX0 = minx;
1404         bboxX1 = maxx;
1405         bboxY0 = miny;
1406         bboxY1 = maxy;
1407 
1408         final int width = (maxx - minx);
1409 
1410         if (FORCE_NO_RLE) {
1411             useRLE = false;
1412         } else if (FORCE_RLE) {
1413             useRLE = true;
1414         } else {
1415             // heuristics: use both bbox area and complexity
1416             // ie number of primitives:
1417 
1418             // fast check min width:
1419             if (width <= RLE_MIN_WIDTH) {
1420                 useRLE = false;
1421             } else {
1422                 useRLE = true;
1423             }
1424         }
1425     }
1426 
1427     private int bbox_spminX, bbox_spmaxX, bbox_spminY, bbox_spmaxY;
1428 
1429     public void produceAlphas(final MarlinAlphaConsumer ac) {
1430         ac.setMaxAlpha(1);
1431 
1432         if (enableBlkFlags && !ac.supportBlockFlags()) {
1433             // consumer does not support block flag optimization:
1434             enableBlkFlags = false;
1435             prevUseBlkFlags = false;
1436         }
1437 
1438         if (DO_MONITORS) {
1439             rdrCtx.stats.mon_rdr_endRendering_Y.start();
1440         }
1441 
1442         // Process all scan lines:
1443         _endRendering(bbox_spminY, bbox_spmaxY, ac);
1444 
1445         if (DO_MONITORS) {
1446             rdrCtx.stats.mon_rdr_endRendering_Y.stop();
1447         }
1448     }
1449 
1450     void copyAARow(final int[] alphaRow,
1451                    final int pix_y, final int pix_from, final int pix_to,
1452                    final boolean useBlockFlags,
1453                    final MarlinAlphaConsumer ac)
1454     {
1455         if (DO_MONITORS) {
1456             rdrCtx.stats.mon_rdr_copyAARow.start();
1457         }
1458         if (DO_STATS) {
1459             rdrCtx.stats.stat_cache_rowAA.add(pix_to - pix_from);
1460         }
1461 
1462         if (useBlockFlags) {
1463             if (DO_STATS) {
1464                 rdrCtx.stats.hist_tile_generator_encoding.add(1);
1465             }
1466             ac.setAndClearRelativeAlphas(blkFlags, alphaRow, pix_y, pix_from, pix_to);
1467         } else {
1468             if (DO_STATS) {
1469                 rdrCtx.stats.hist_tile_generator_encoding.add(0);
1470             }
1471             ac.setAndClearRelativeAlphas(alphaRow, pix_y, pix_from, pix_to);
1472         }
1473         if (DO_MONITORS) {
1474             rdrCtx.stats.mon_rdr_copyAARow.stop();
1475         }
1476     }
1477 
1478     // output pixel bounding box:
1479     int bboxX0, bboxX1, bboxY0, bboxY1;
1480 
1481     @Override
1482     public int getOutpixMinX() {
1483         return bboxX0;
1484     }
1485 
1486     @Override
1487     public int getOutpixMaxX() {
1488         return bboxX1;
1489     }
1490 
1491     @Override
1492     public int getOutpixMinY() {
1493         return bboxY0;
1494     }
1495 
1496     @Override
1497     public int getOutpixMaxY() {
1498         return bboxY1;
1499     }
1500 }