jdk/src/java.desktop/share/classes/sun/java2d/marlin/DRenderer.java
changeset 47126 188ef162f019
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.desktop/share/classes/sun/java2d/marlin/DRenderer.java	Wed May 17 22:05:11 2017 +0200
@@ -0,0 +1,1526 @@
+/*
+ * Copyright (c) 2007, 2017, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package sun.java2d.marlin;
+
+import static sun.java2d.marlin.OffHeapArray.SIZE_INT;
+import jdk.internal.misc.Unsafe;
+
+final class DRenderer implements DPathConsumer2D, MarlinRenderer {
+
+    static final boolean DISABLE_RENDER = false;
+
+    static final boolean ENABLE_BLOCK_FLAGS = MarlinProperties.isUseTileFlags();
+    static final boolean ENABLE_BLOCK_FLAGS_HEURISTICS = MarlinProperties.isUseTileFlagsWithHeuristics();
+
+    private static final int ALL_BUT_LSB = 0xFFFFFFFE;
+    private static final int ERR_STEP_MAX = 0x7FFFFFFF; // = 2^31 - 1
+
+    private static final double POWER_2_TO_32 = 0x1.0p32d;
+
+    // use double to make tosubpix methods faster (no int to double conversion)
+    static final double SUBPIXEL_SCALE_X = SUBPIXEL_POSITIONS_X;
+    static final double SUBPIXEL_SCALE_Y = SUBPIXEL_POSITIONS_Y;
+    static final int SUBPIXEL_MASK_X = SUBPIXEL_POSITIONS_X - 1;
+    static final int SUBPIXEL_MASK_Y = SUBPIXEL_POSITIONS_Y - 1;
+
+    // number of subpixels corresponding to a tile line
+    private static final int SUBPIXEL_TILE
+        = TILE_H << SUBPIXEL_LG_POSITIONS_Y;
+
+    // 2048 (pixelSize) pixels (height) x 8 subpixels = 64K
+    static final int INITIAL_BUCKET_ARRAY
+        = INITIAL_PIXEL_DIM * SUBPIXEL_POSITIONS_Y;
+
+    // crossing capacity = edges count / 4 ~ 1024
+    static final int INITIAL_CROSSING_COUNT = INITIAL_EDGES_COUNT >> 2;
+
+    public static final int WIND_EVEN_ODD = 0;
+    public static final int WIND_NON_ZERO = 1;
+
+    // common to all types of input path segments.
+    // OFFSET as bytes
+    // only integer values:
+    public static final long OFF_CURX_OR  = 0;
+    public static final long OFF_ERROR    = OFF_CURX_OR  + SIZE_INT;
+    public static final long OFF_BUMP_X   = OFF_ERROR    + SIZE_INT;
+    public static final long OFF_BUMP_ERR = OFF_BUMP_X   + SIZE_INT;
+    public static final long OFF_NEXT     = OFF_BUMP_ERR + SIZE_INT;
+    public static final long OFF_YMAX     = OFF_NEXT     + SIZE_INT;
+
+    // size of one edge in bytes
+    public static final int SIZEOF_EDGE_BYTES = (int)(OFF_YMAX + SIZE_INT);
+
+    // curve break into lines
+    // cubic error in subpixels to decrement step
+    private static final double CUB_DEC_ERR_SUBPIX
+        = MarlinProperties.getCubicDecD2() * (NORM_SUBPIXELS / 8.0d); // 1 pixel
+    // cubic error in subpixels to increment step
+    private static final double CUB_INC_ERR_SUBPIX
+        = MarlinProperties.getCubicIncD1() * (NORM_SUBPIXELS / 8.0d); // 0.4 pixel
+
+    // TestNonAARasterization (JDK-8170879): cubics
+    // bad paths (59294/100000 == 59,29%, 94335 bad pixels (avg = 1,59), 3966 warnings (avg = 0,07)
+
+    // cubic bind length to decrement step
+    public static final double CUB_DEC_BND
+        = 8.0d * CUB_DEC_ERR_SUBPIX;
+    // cubic bind length to increment step
+    public static final double CUB_INC_BND
+        = 8.0d * CUB_INC_ERR_SUBPIX;
+
+    // cubic countlg
+    public static final int CUB_COUNT_LG = 2;
+    // cubic count = 2^countlg
+    private static final int CUB_COUNT = 1 << CUB_COUNT_LG;
+    // cubic count^2 = 4^countlg
+    private static final int CUB_COUNT_2 = 1 << (2 * CUB_COUNT_LG);
+    // cubic count^3 = 8^countlg
+    private static final int CUB_COUNT_3 = 1 << (3 * CUB_COUNT_LG);
+    // cubic dt = 1 / count
+    private static final double CUB_INV_COUNT = 1.0d / CUB_COUNT;
+    // cubic dt^2 = 1 / count^2 = 1 / 4^countlg
+    private static final double CUB_INV_COUNT_2 = 1.0d / CUB_COUNT_2;
+    // cubic dt^3 = 1 / count^3 = 1 / 8^countlg
+    private static final double CUB_INV_COUNT_3 = 1.0d / CUB_COUNT_3;
+
+    // quad break into lines
+    // quadratic error in subpixels
+    private static final double QUAD_DEC_ERR_SUBPIX
+        = MarlinProperties.getQuadDecD2() * (NORM_SUBPIXELS / 8.0d); // 0.5 pixel
+
+    // TestNonAARasterization (JDK-8170879): quads
+    // bad paths (62916/100000 == 62,92%, 103818 bad pixels (avg = 1,65), 6514 warnings (avg = 0,10)
+
+    // quadratic bind length to decrement step
+    public static final double QUAD_DEC_BND
+        = 8.0d * QUAD_DEC_ERR_SUBPIX;
+
+//////////////////////////////////////////////////////////////////////////////
+//  SCAN LINE
+//////////////////////////////////////////////////////////////////////////////
+    // crossings ie subpixel edge x coordinates
+    private int[] crossings;
+    // auxiliary storage for crossings (merge sort)
+    private int[] aux_crossings;
+
+    // indices into the segment pointer lists. They indicate the "active"
+    // sublist in the segment lists (the portion of the list that contains
+    // all the segments that cross the next scan line).
+    private int edgeCount;
+    private int[] edgePtrs;
+    // auxiliary storage for edge pointers (merge sort)
+    private int[] aux_edgePtrs;
+
+    // max used for both edgePtrs and crossings (stats only)
+    private int activeEdgeMaxUsed;
+
+    // crossings ref (dirty)
+    private final IntArrayCache.Reference crossings_ref;
+    // edgePtrs ref (dirty)
+    private final IntArrayCache.Reference edgePtrs_ref;
+    // merge sort initial arrays (large enough to satisfy most usages) (1024)
+    // aux_crossings ref (dirty)
+    private final IntArrayCache.Reference aux_crossings_ref;
+    // aux_edgePtrs ref (dirty)
+    private final IntArrayCache.Reference aux_edgePtrs_ref;
+
+//////////////////////////////////////////////////////////////////////////////
+//  EDGE LIST
+//////////////////////////////////////////////////////////////////////////////
+    private int edgeMinY = Integer.MAX_VALUE;
+    private int edgeMaxY = Integer.MIN_VALUE;
+    private double edgeMinX = Double.POSITIVE_INFINITY;
+    private double edgeMaxX = Double.NEGATIVE_INFINITY;
+
+    // edges [ints] stored in off-heap memory
+    private final OffHeapArray edges;
+
+    private int[] edgeBuckets;
+    private int[] edgeBucketCounts; // 2*newedges + (1 if pruning needed)
+    // used range for edgeBuckets / edgeBucketCounts
+    private int buckets_minY;
+    private int buckets_maxY;
+
+    // edgeBuckets ref (clean)
+    private final IntArrayCache.Reference edgeBuckets_ref;
+    // edgeBucketCounts ref (clean)
+    private final IntArrayCache.Reference edgeBucketCounts_ref;
+
+    // Flattens using adaptive forward differencing. This only carries out
+    // one iteration of the AFD loop. All it does is update AFD variables (i.e.
+    // X0, Y0, D*[X|Y], COUNT; not variables used for computing scanline crossings).
+    private void quadBreakIntoLinesAndAdd(double x0, double y0,
+                                          final DCurve c,
+                                          final double x2, final double y2)
+    {
+        int count = 1; // dt = 1 / count
+
+        // maximum(ddX|Y) = norm(dbx, dby) * dt^2 (= 1)
+        double maxDD = Math.abs(c.dbx) + Math.abs(c.dby);
+
+        final double _DEC_BND = QUAD_DEC_BND;
+
+        while (maxDD >= _DEC_BND) {
+            // divide step by half:
+            maxDD /= 4.0d; // error divided by 2^2 = 4
+
+            count <<= 1;
+            if (DO_STATS) {
+                rdrCtx.stats.stat_rdr_quadBreak_dec.add(count);
+            }
+        }
+
+        int nL = 0; // line count
+        if (count > 1) {
+            final double icount = 1.0d / count; // dt
+            final double icount2 = icount * icount; // dt^2
+
+            final double ddx = c.dbx * icount2;
+            final double ddy = c.dby * icount2;
+            double dx = c.bx * icount2 + c.cx * icount;
+            double dy = c.by * icount2 + c.cy * icount;
+
+            double x1, y1;
+
+            while (--count > 0) {
+                x1 = x0 + dx;
+                dx += ddx;
+                y1 = y0 + dy;
+                dy += ddy;
+
+                addLine(x0, y0, x1, y1);
+
+                if (DO_STATS) { nL++; }
+                x0 = x1;
+                y0 = y1;
+            }
+        }
+        addLine(x0, y0, x2, y2);
+
+        if (DO_STATS) {
+            rdrCtx.stats.stat_rdr_quadBreak.add(nL + 1);
+        }
+    }
+
+    // x0, y0 and x3,y3 are the endpoints of the curve. We could compute these
+    // using c.xat(0),c.yat(0) and c.xat(1),c.yat(1), but this might introduce
+    // numerical errors, and our callers already have the exact values.
+    // Another alternative would be to pass all the control points, and call
+    // c.set here, but then too many numbers are passed around.
+    private void curveBreakIntoLinesAndAdd(double x0, double y0,
+                                           final DCurve c,
+                                           final double x3, final double y3)
+    {
+        int count           = CUB_COUNT;
+        final double icount  = CUB_INV_COUNT;   // dt
+        final double icount2 = CUB_INV_COUNT_2; // dt^2
+        final double icount3 = CUB_INV_COUNT_3; // dt^3
+
+        // the dx and dy refer to forward differencing variables, not the last
+        // coefficients of the "points" polynomial
+        double dddx, dddy, ddx, ddy, dx, dy;
+        dddx = 2.0d * c.dax * icount3;
+        dddy = 2.0d * c.day * icount3;
+        ddx = dddx + c.dbx * icount2;
+        ddy = dddy + c.dby * icount2;
+        dx = c.ax * icount3 + c.bx * icount2 + c.cx * icount;
+        dy = c.ay * icount3 + c.by * icount2 + c.cy * icount;
+
+        // we use x0, y0 to walk the line
+        double x1 = x0, y1 = y0;
+        int nL = 0; // line count
+
+        final double _DEC_BND = CUB_DEC_BND;
+        final double _INC_BND = CUB_INC_BND;
+
+        while (count > 0) {
+            // divide step by half:
+            while (Math.abs(ddx) + Math.abs(ddy) >= _DEC_BND) {
+                dddx /= 8.0d;
+                dddy /= 8.0d;
+                ddx = ddx / 4.0d - dddx;
+                ddy = ddy / 4.0d - dddy;
+                dx = (dx - ddx) / 2.0d;
+                dy = (dy - ddy) / 2.0d;
+
+                count <<= 1;
+                if (DO_STATS) {
+                    rdrCtx.stats.stat_rdr_curveBreak_dec.add(count);
+                }
+            }
+
+            // double step:
+            // can only do this on even "count" values, because we must divide count by 2
+            while (count % 2 == 0
+                   && Math.abs(dx) + Math.abs(dy) <= _INC_BND)
+            {
+                dx = 2.0d * dx + ddx;
+                dy = 2.0d * dy + ddy;
+                ddx = 4.0d * (ddx + dddx);
+                ddy = 4.0d * (ddy + dddy);
+                dddx *= 8.0d;
+                dddy *= 8.0d;
+
+                count >>= 1;
+                if (DO_STATS) {
+                    rdrCtx.stats.stat_rdr_curveBreak_inc.add(count);
+                }
+            }
+            if (--count > 0) {
+                x1 += dx;
+                dx += ddx;
+                ddx += dddx;
+                y1 += dy;
+                dy += ddy;
+                ddy += dddy;
+            } else {
+                x1 = x3;
+                y1 = y3;
+            }
+
+            addLine(x0, y0, x1, y1);
+
+            if (DO_STATS) { nL++; }
+            x0 = x1;
+            y0 = y1;
+        }
+        if (DO_STATS) {
+            rdrCtx.stats.stat_rdr_curveBreak.add(nL);
+        }
+    }
+
+    private void addLine(double x1, double y1, double x2, double y2) {
+        if (DO_MONITORS) {
+            rdrCtx.stats.mon_rdr_addLine.start();
+        }
+        if (DO_STATS) {
+            rdrCtx.stats.stat_rdr_addLine.add(1);
+        }
+        int or = 1; // orientation of the line. 1 if y increases, 0 otherwise.
+        if (y2 < y1) {
+            or = 0;
+            double tmp = y2;
+            y2 = y1;
+            y1 = tmp;
+            tmp = x2;
+            x2 = x1;
+            x1 = tmp;
+        }
+
+        // convert subpixel coordinates [double] into pixel positions [int]
+
+        // The index of the pixel that holds the next HPC is at ceil(trueY - 0.5)
+        // Since y1 and y2 are biased by -0.5 in tosubpixy(), this is simply
+        // ceil(y1) or ceil(y2)
+        // upper integer (inclusive)
+        final int firstCrossing = FloatMath.max(FloatMath.ceil_int(y1), boundsMinY);
+
+        // note: use boundsMaxY (last Y exclusive) to compute correct coverage
+        // upper integer (exclusive)
+        final int lastCrossing  = FloatMath.min(FloatMath.ceil_int(y2), boundsMaxY);
+
+        /* skip horizontal lines in pixel space and clip edges
+           out of y range [boundsMinY; boundsMaxY] */
+        if (firstCrossing >= lastCrossing) {
+            if (DO_MONITORS) {
+                rdrCtx.stats.mon_rdr_addLine.stop();
+            }
+            if (DO_STATS) {
+                rdrCtx.stats.stat_rdr_addLine_skip.add(1);
+            }
+            return;
+        }
+
+        // edge min/max X/Y are in subpixel space (half-open interval):
+        // note: Use integer crossings to ensure consistent range within
+        // edgeBuckets / edgeBucketCounts arrays in case of NaN values (int = 0)
+        if (firstCrossing < edgeMinY) {
+            edgeMinY = firstCrossing;
+        }
+        if (lastCrossing > edgeMaxY) {
+            edgeMaxY = lastCrossing;
+        }
+
+        final double slope = (x1 - x2) / (y1 - y2);
+
+        if (slope >= 0.0d) { // <==> x1 < x2
+            if (x1 < edgeMinX) {
+                edgeMinX = x1;
+            }
+            if (x2 > edgeMaxX) {
+                edgeMaxX = x2;
+            }
+        } else {
+            if (x2 < edgeMinX) {
+                edgeMinX = x2;
+            }
+            if (x1 > edgeMaxX) {
+                edgeMaxX = x1;
+            }
+        }
+
+        // local variables for performance:
+        final int _SIZEOF_EDGE_BYTES = SIZEOF_EDGE_BYTES;
+
+        final OffHeapArray _edges = edges;
+
+        // get free pointer (ie length in bytes)
+        final int edgePtr = _edges.used;
+
+        // use substraction to avoid integer overflow:
+        if (_edges.length - edgePtr < _SIZEOF_EDGE_BYTES) {
+            // suppose _edges.length > _SIZEOF_EDGE_BYTES
+            // so doubling size is enough to add needed bytes
+            // note: throw IOOB if neededSize > 2Gb:
+            final long edgeNewSize = ArrayCacheConst.getNewLargeSize(
+                                        _edges.length,
+                                        edgePtr + _SIZEOF_EDGE_BYTES);
+
+            if (DO_STATS) {
+                rdrCtx.stats.stat_rdr_edges_resizes.add(edgeNewSize);
+            }
+            _edges.resize(edgeNewSize);
+        }
+
+
+        final Unsafe _unsafe = OffHeapArray.UNSAFE;
+        final long SIZE_INT = 4L;
+        long addr   = _edges.address + edgePtr;
+
+        // The x value must be bumped up to its position at the next HPC we will evaluate.
+        // "firstcrossing" is the (sub)pixel number where the next crossing occurs
+        // thus, the actual coordinate of the next HPC is "firstcrossing + 0.5"
+        // so the Y distance we cover is "firstcrossing + 0.5 - trueY".
+        // Note that since y1 (and y2) are already biased by -0.5 in tosubpixy(), we have
+        // y1 = trueY - 0.5
+        // trueY = y1 + 0.5
+        // firstcrossing + 0.5 - trueY = firstcrossing + 0.5 - (y1 + 0.5)
+        //                             = firstcrossing - y1
+        // The x coordinate at that HPC is then:
+        // x1_intercept = x1 + (firstcrossing - y1) * slope
+        // The next VPC is then given by:
+        // VPC index = ceil(x1_intercept - 0.5), or alternately
+        // VPC index = floor(x1_intercept - 0.5 + 1 - epsilon)
+        // epsilon is hard to pin down in floating point, but easy in fixed point, so if
+        // we convert to fixed point then these operations get easier:
+        // long x1_fixed = x1_intercept * 2^32;  (fixed point 32.32 format)
+        // curx = next VPC = fixed_floor(x1_fixed - 2^31 + 2^32 - 1)
+        //                 = fixed_floor(x1_fixed + 2^31 - 1)
+        //                 = fixed_floor(x1_fixed + 0x7FFFFFFF)
+        // and error       = fixed_fract(x1_fixed + 0x7FFFFFFF)
+        final double x1_intercept = x1 + (firstCrossing - y1) * slope;
+
+        // inlined scalb(x1_intercept, 32):
+        final long x1_fixed_biased = ((long) (POWER_2_TO_32 * x1_intercept))
+                                     + 0x7FFFFFFFL;
+        // curx:
+        // last bit corresponds to the orientation
+        _unsafe.putInt(addr, (((int) (x1_fixed_biased >> 31L)) & ALL_BUT_LSB) | or);
+        addr += SIZE_INT;
+        _unsafe.putInt(addr,  ((int)  x1_fixed_biased) >>> 1);
+        addr += SIZE_INT;
+
+        // inlined scalb(slope, 32):
+        final long slope_fixed = (long) (POWER_2_TO_32 * slope);
+
+        // last bit set to 0 to keep orientation:
+        _unsafe.putInt(addr, (((int) (slope_fixed >> 31L)) & ALL_BUT_LSB));
+        addr += SIZE_INT;
+        _unsafe.putInt(addr,  ((int)  slope_fixed) >>> 1);
+        addr += SIZE_INT;
+
+        final int[] _edgeBuckets      = edgeBuckets;
+        final int[] _edgeBucketCounts = edgeBucketCounts;
+
+        final int _boundsMinY = boundsMinY;
+
+        // each bucket is a linked list. this method adds ptr to the
+        // start of the "bucket"th linked list.
+        final int bucketIdx = firstCrossing - _boundsMinY;
+
+        // pointer from bucket
+        _unsafe.putInt(addr, _edgeBuckets[bucketIdx]);
+        addr += SIZE_INT;
+        // y max (exclusive)
+        _unsafe.putInt(addr,  lastCrossing);
+
+        // Update buckets:
+        // directly the edge struct "pointer"
+        _edgeBuckets[bucketIdx]       = edgePtr;
+        _edgeBucketCounts[bucketIdx] += 2; // 1 << 1
+        // last bit means edge end
+        _edgeBucketCounts[lastCrossing - _boundsMinY] |= 0x1;
+
+        // update free pointer (ie length in bytes)
+        _edges.used += _SIZEOF_EDGE_BYTES;
+
+        if (DO_MONITORS) {
+            rdrCtx.stats.mon_rdr_addLine.stop();
+        }
+    }
+
+// END EDGE LIST
+//////////////////////////////////////////////////////////////////////////////
+
+    // Cache to store RLE-encoded coverage mask of the current primitive
+    final MarlinCache cache;
+
+    // Bounds of the drawing region, at subpixel precision.
+    private int boundsMinX, boundsMinY, boundsMaxX, boundsMaxY;
+
+    // Current winding rule
+    private int windingRule;
+
+    // Current drawing position, i.e., final point of last segment
+    private double x0, y0;
+
+    // Position of most recent 'moveTo' command
+    private double sx0, sy0;
+
+    // per-thread renderer context
+    final DRendererContext rdrCtx;
+    // dirty curve
+    private final DCurve curve;
+
+    // clean alpha array (zero filled)
+    private int[] alphaLine;
+
+    // alphaLine ref (clean)
+    private final IntArrayCache.Reference alphaLine_ref;
+
+    private boolean enableBlkFlags = false;
+    private boolean prevUseBlkFlags = false;
+
+    /* block flags (0|1) */
+    private int[] blkFlags;
+
+    // blkFlags ref (clean)
+    private final IntArrayCache.Reference blkFlags_ref;
+
+    DRenderer(final DRendererContext rdrCtx) {
+        this.rdrCtx = rdrCtx;
+
+        this.edges = rdrCtx.newOffHeapArray(INITIAL_EDGES_CAPACITY); // 96K
+
+        this.curve = rdrCtx.curve;
+
+        edgeBuckets_ref      = rdrCtx.newCleanIntArrayRef(INITIAL_BUCKET_ARRAY); // 64K
+        edgeBucketCounts_ref = rdrCtx.newCleanIntArrayRef(INITIAL_BUCKET_ARRAY); // 64K
+
+        edgeBuckets      = edgeBuckets_ref.initial;
+        edgeBucketCounts = edgeBucketCounts_ref.initial;
+
+        // 2048 (pixelsize) pixel large
+        alphaLine_ref = rdrCtx.newCleanIntArrayRef(INITIAL_AA_ARRAY); // 8K
+        alphaLine     = alphaLine_ref.initial;
+
+        this.cache = rdrCtx.cache;
+
+        crossings_ref     = rdrCtx.newDirtyIntArrayRef(INITIAL_CROSSING_COUNT); // 2K
+        aux_crossings_ref = rdrCtx.newDirtyIntArrayRef(INITIAL_CROSSING_COUNT); // 2K
+        edgePtrs_ref      = rdrCtx.newDirtyIntArrayRef(INITIAL_CROSSING_COUNT); // 2K
+        aux_edgePtrs_ref  = rdrCtx.newDirtyIntArrayRef(INITIAL_CROSSING_COUNT); // 2K
+
+        crossings     = crossings_ref.initial;
+        aux_crossings = aux_crossings_ref.initial;
+        edgePtrs      = edgePtrs_ref.initial;
+        aux_edgePtrs  = aux_edgePtrs_ref.initial;
+
+        blkFlags_ref = rdrCtx.newCleanIntArrayRef(INITIAL_ARRAY); // 1K = 1 tile line
+        blkFlags     = blkFlags_ref.initial;
+    }
+
+    DRenderer init(final int pix_boundsX, final int pix_boundsY,
+                  final int pix_boundsWidth, final int pix_boundsHeight,
+                  final int windingRule)
+    {
+        this.windingRule = windingRule;
+
+        // bounds as half-open intervals: minX <= x < maxX and minY <= y < maxY
+        this.boundsMinX =  pix_boundsX << SUBPIXEL_LG_POSITIONS_X;
+        this.boundsMaxX =
+            (pix_boundsX + pix_boundsWidth) << SUBPIXEL_LG_POSITIONS_X;
+        this.boundsMinY =  pix_boundsY << SUBPIXEL_LG_POSITIONS_Y;
+        this.boundsMaxY =
+            (pix_boundsY + pix_boundsHeight) << SUBPIXEL_LG_POSITIONS_Y;
+
+        if (DO_LOG_BOUNDS) {
+            MarlinUtils.logInfo("boundsXY = [" + boundsMinX + " ... "
+                                + boundsMaxX + "[ [" + boundsMinY + " ... "
+                                + boundsMaxY + "[");
+        }
+
+        // see addLine: ceil(boundsMaxY) => boundsMaxY + 1
+        // +1 for edgeBucketCounts
+        final int edgeBucketsLength = (boundsMaxY - boundsMinY) + 1;
+
+        if (edgeBucketsLength > INITIAL_BUCKET_ARRAY) {
+            if (DO_STATS) {
+                rdrCtx.stats.stat_array_renderer_edgeBuckets
+                    .add(edgeBucketsLength);
+                rdrCtx.stats.stat_array_renderer_edgeBucketCounts
+                    .add(edgeBucketsLength);
+            }
+            edgeBuckets = edgeBuckets_ref.getArray(edgeBucketsLength);
+            edgeBucketCounts = edgeBucketCounts_ref.getArray(edgeBucketsLength);
+        }
+
+        edgeMinY = Integer.MAX_VALUE;
+        edgeMaxY = Integer.MIN_VALUE;
+        edgeMinX = Double.POSITIVE_INFINITY;
+        edgeMaxX = Double.NEGATIVE_INFINITY;
+
+        // reset used mark:
+        edgeCount = 0;
+        activeEdgeMaxUsed = 0;
+        edges.used = 0;
+
+        return this; // fluent API
+    }
+
+    /**
+     * Disposes this renderer and recycle it clean up before reusing this instance
+     */
+    void dispose() {
+        if (DO_STATS) {
+            rdrCtx.stats.stat_rdr_activeEdges.add(activeEdgeMaxUsed);
+            rdrCtx.stats.stat_rdr_edges.add(edges.used);
+            rdrCtx.stats.stat_rdr_edges_count.add(edges.used / SIZEOF_EDGE_BYTES);
+            rdrCtx.stats.hist_rdr_edges_count.add(edges.used / SIZEOF_EDGE_BYTES);
+            rdrCtx.stats.totalOffHeap += edges.length;
+        }
+        // Return arrays:
+        crossings = crossings_ref.putArray(crossings);
+        aux_crossings = aux_crossings_ref.putArray(aux_crossings);
+
+        edgePtrs = edgePtrs_ref.putArray(edgePtrs);
+        aux_edgePtrs = aux_edgePtrs_ref.putArray(aux_edgePtrs);
+
+        alphaLine = alphaLine_ref.putArray(alphaLine, 0, 0); // already zero filled
+        blkFlags  = blkFlags_ref.putArray(blkFlags, 0, 0); // already zero filled
+
+        if (edgeMinY != Integer.MAX_VALUE) {
+            // if context is maked as DIRTY:
+            if (rdrCtx.dirty) {
+                // may happen if an exception if thrown in the pipeline processing:
+                // clear completely buckets arrays:
+                buckets_minY = 0;
+                buckets_maxY = boundsMaxY - boundsMinY;
+            }
+            // clear only used part
+            edgeBuckets = edgeBuckets_ref.putArray(edgeBuckets, buckets_minY,
+                                                                buckets_maxY);
+            edgeBucketCounts = edgeBucketCounts_ref.putArray(edgeBucketCounts,
+                                                             buckets_minY,
+                                                             buckets_maxY + 1);
+        } else {
+            // unused arrays
+            edgeBuckets = edgeBuckets_ref.putArray(edgeBuckets, 0, 0);
+            edgeBucketCounts = edgeBucketCounts_ref.putArray(edgeBucketCounts, 0, 0);
+        }
+
+        // At last: resize back off-heap edges to initial size
+        if (edges.length != INITIAL_EDGES_CAPACITY) {
+            // note: may throw OOME:
+            edges.resize(INITIAL_EDGES_CAPACITY);
+        }
+        if (DO_CLEAN_DIRTY) {
+            // Force zero-fill dirty arrays:
+            edges.fill(BYTE_0);
+        }
+        if (DO_MONITORS) {
+            rdrCtx.stats.mon_rdr_endRendering.stop();
+        }
+        // recycle the RendererContext instance
+        DMarlinRenderingEngine.returnRendererContext(rdrCtx);
+    }
+
+    private static double tosubpixx(final double pix_x) {
+        return SUBPIXEL_SCALE_X * pix_x;
+    }
+
+    private static double tosubpixy(final double pix_y) {
+        // shift y by -0.5 for fast ceil(y - 0.5):
+        return SUBPIXEL_SCALE_Y * pix_y - 0.5d;
+    }
+
+    @Override
+    public void moveTo(double pix_x0, double pix_y0) {
+        closePath();
+        final double sx = tosubpixx(pix_x0);
+        final double sy = tosubpixy(pix_y0);
+        this.sx0 = sx;
+        this.sy0 = sy;
+        this.x0 = sx;
+        this.y0 = sy;
+    }
+
+    @Override
+    public void lineTo(double pix_x1, double pix_y1) {
+        final double x1 = tosubpixx(pix_x1);
+        final double y1 = tosubpixy(pix_y1);
+        addLine(x0, y0, x1, y1);
+        x0 = x1;
+        y0 = y1;
+    }
+
+    @Override
+    public void curveTo(double x1, double y1,
+                        double x2, double y2,
+                        double x3, double y3)
+    {
+        final double xe = tosubpixx(x3);
+        final double ye = tosubpixy(y3);
+        curve.set(x0, y0, tosubpixx(x1), tosubpixy(y1),
+                          tosubpixx(x2), tosubpixy(y2), xe, ye);
+        curveBreakIntoLinesAndAdd(x0, y0, curve, xe, ye);
+        x0 = xe;
+        y0 = ye;
+    }
+
+    @Override
+    public void quadTo(double x1, double y1, double x2, double y2) {
+        final double xe = tosubpixx(x2);
+        final double ye = tosubpixy(y2);
+        curve.set(x0, y0, tosubpixx(x1), tosubpixy(y1), xe, ye);
+        quadBreakIntoLinesAndAdd(x0, y0, curve, xe, ye);
+        x0 = xe;
+        y0 = ye;
+    }
+
+    @Override
+    public void closePath() {
+        addLine(x0, y0, sx0, sy0);
+        x0 = sx0;
+        y0 = sy0;
+    }
+
+    @Override
+    public void pathDone() {
+        closePath();
+    }
+
+    @Override
+    public long getNativeConsumer() {
+        throw new InternalError("Renderer does not use a native consumer.");
+    }
+
+    private void _endRendering(final int ymin, final int ymax) {
+        if (DISABLE_RENDER) {
+            return;
+        }
+
+        // Get X bounds as true pixel boundaries to compute correct pixel coverage:
+        final int bboxx0 = bbox_spminX;
+        final int bboxx1 = bbox_spmaxX;
+
+        final boolean windingRuleEvenOdd = (windingRule == WIND_EVEN_ODD);
+
+        // Useful when processing tile line by tile line
+        final int[] _alpha = alphaLine;
+
+        // local vars (performance):
+        final MarlinCache _cache = cache;
+        final OffHeapArray _edges = edges;
+        final int[] _edgeBuckets = edgeBuckets;
+        final int[] _edgeBucketCounts = edgeBucketCounts;
+
+        int[] _crossings = this.crossings;
+        int[] _edgePtrs  = this.edgePtrs;
+
+        // merge sort auxiliary storage:
+        int[] _aux_crossings = this.aux_crossings;
+        int[] _aux_edgePtrs  = this.aux_edgePtrs;
+
+        // copy constants:
+        final long _OFF_ERROR    = OFF_ERROR;
+        final long _OFF_BUMP_X   = OFF_BUMP_X;
+        final long _OFF_BUMP_ERR = OFF_BUMP_ERR;
+
+        final long _OFF_NEXT     = OFF_NEXT;
+        final long _OFF_YMAX     = OFF_YMAX;
+
+        final int _ALL_BUT_LSB   = ALL_BUT_LSB;
+        final int _ERR_STEP_MAX  = ERR_STEP_MAX;
+
+        // unsafe I/O:
+        final Unsafe _unsafe = OffHeapArray.UNSAFE;
+        final long    addr0  = _edges.address;
+        long addr;
+        final int _SUBPIXEL_LG_POSITIONS_X = SUBPIXEL_LG_POSITIONS_X;
+        final int _SUBPIXEL_LG_POSITIONS_Y = SUBPIXEL_LG_POSITIONS_Y;
+        final int _SUBPIXEL_MASK_X = SUBPIXEL_MASK_X;
+        final int _SUBPIXEL_MASK_Y = SUBPIXEL_MASK_Y;
+        final int _SUBPIXEL_POSITIONS_X = SUBPIXEL_POSITIONS_X;
+
+        final int _MIN_VALUE = Integer.MIN_VALUE;
+        final int _MAX_VALUE = Integer.MAX_VALUE;
+
+        // Now we iterate through the scanlines. We must tell emitRow the coord
+        // of the first non-transparent pixel, so we must keep accumulators for
+        // the first and last pixels of the section of the current pixel row
+        // that we will emit.
+        // We also need to accumulate pix_bbox, but the iterator does it
+        // for us. We will just get the values from it once this loop is done
+        int minX = _MAX_VALUE;
+        int maxX = _MIN_VALUE;
+
+        int y = ymin;
+        int bucket = y - boundsMinY;
+
+        int numCrossings = this.edgeCount;
+        int edgePtrsLen = _edgePtrs.length;
+        int crossingsLen = _crossings.length;
+        int _arrayMaxUsed = activeEdgeMaxUsed;
+        int ptrLen = 0, newCount, ptrEnd;
+
+        int bucketcount, i, j, ecur;
+        int cross, lastCross;
+        int x0, x1, tmp, sum, prev, curx, curxo, crorientation, err;
+        int pix_x, pix_xmaxm1, pix_xmax;
+
+        int low, high, mid, prevNumCrossings;
+        boolean useBinarySearch;
+
+        final int[] _blkFlags = blkFlags;
+        final int _BLK_SIZE_LG = BLOCK_SIZE_LG;
+        final int _BLK_SIZE = BLOCK_SIZE;
+
+        final boolean _enableBlkFlagsHeuristics = ENABLE_BLOCK_FLAGS_HEURISTICS && this.enableBlkFlags;
+
+        // Use block flags if large pixel span and few crossings:
+        // ie mean(distance between crossings) is high
+        boolean useBlkFlags = this.prevUseBlkFlags;
+
+        final int stroking = rdrCtx.stroking;
+
+        int lastY = -1; // last emited row
+
+
+        // Iteration on scanlines
+        for (; y < ymax; y++, bucket++) {
+            // --- from former ScanLineIterator.next()
+            bucketcount = _edgeBucketCounts[bucket];
+
+            // marker on previously sorted edges:
+            prevNumCrossings = numCrossings;
+
+            // bucketCount indicates new edge / edge end:
+            if (bucketcount != 0) {
+                if (DO_STATS) {
+                    rdrCtx.stats.stat_rdr_activeEdges_updates.add(numCrossings);
+                }
+
+                // last bit set to 1 means that edges ends
+                if ((bucketcount & 0x1) != 0) {
+                    // eviction in active edge list
+                    // cache edges[] address + offset
+                    addr = addr0 + _OFF_YMAX;
+
+                    for (i = 0, newCount = 0; i < numCrossings; i++) {
+                        // get the pointer to the edge
+                        ecur = _edgePtrs[i];
+                        // random access so use unsafe:
+                        if (_unsafe.getInt(addr + ecur) > y) {
+                            _edgePtrs[newCount++] = ecur;
+                        }
+                    }
+                    // update marker on sorted edges minus removed edges:
+                    prevNumCrossings = numCrossings = newCount;
+                }
+
+                ptrLen = bucketcount >> 1; // number of new edge
+
+                if (ptrLen != 0) {
+                    if (DO_STATS) {
+                        rdrCtx.stats.stat_rdr_activeEdges_adds.add(ptrLen);
+                        if (ptrLen > 10) {
+                            rdrCtx.stats.stat_rdr_activeEdges_adds_high.add(ptrLen);
+                        }
+                    }
+                    ptrEnd = numCrossings + ptrLen;
+
+                    if (edgePtrsLen < ptrEnd) {
+                        if (DO_STATS) {
+                            rdrCtx.stats.stat_array_renderer_edgePtrs.add(ptrEnd);
+                        }
+                        this.edgePtrs = _edgePtrs
+                            = edgePtrs_ref.widenArray(_edgePtrs, numCrossings,
+                                                      ptrEnd);
+
+                        edgePtrsLen = _edgePtrs.length;
+                        // Get larger auxiliary storage:
+                        aux_edgePtrs_ref.putArray(_aux_edgePtrs);
+
+                        // use ArrayCache.getNewSize() to use the same growing
+                        // factor than widenArray():
+                        if (DO_STATS) {
+                            rdrCtx.stats.stat_array_renderer_aux_edgePtrs.add(ptrEnd);
+                        }
+                        this.aux_edgePtrs = _aux_edgePtrs
+                            = aux_edgePtrs_ref.getArray(
+                                ArrayCacheConst.getNewSize(numCrossings, ptrEnd)
+                            );
+                    }
+
+                    // cache edges[] address + offset
+                    addr = addr0 + _OFF_NEXT;
+
+                    // add new edges to active edge list:
+                    for (ecur = _edgeBuckets[bucket];
+                         numCrossings < ptrEnd; numCrossings++)
+                    {
+                        // store the pointer to the edge
+                        _edgePtrs[numCrossings] = ecur;
+                        // random access so use unsafe:
+                        ecur = _unsafe.getInt(addr + ecur);
+                    }
+
+                    if (crossingsLen < numCrossings) {
+                        // Get larger array:
+                        crossings_ref.putArray(_crossings);
+
+                        if (DO_STATS) {
+                            rdrCtx.stats.stat_array_renderer_crossings
+                                .add(numCrossings);
+                        }
+                        this.crossings = _crossings
+                            = crossings_ref.getArray(numCrossings);
+
+                        // Get larger auxiliary storage:
+                        aux_crossings_ref.putArray(_aux_crossings);
+
+                        if (DO_STATS) {
+                            rdrCtx.stats.stat_array_renderer_aux_crossings
+                                .add(numCrossings);
+                        }
+                        this.aux_crossings = _aux_crossings
+                            = aux_crossings_ref.getArray(numCrossings);
+
+                        crossingsLen = _crossings.length;
+                    }
+                    if (DO_STATS) {
+                        // update max used mark
+                        if (numCrossings > _arrayMaxUsed) {
+                            _arrayMaxUsed = numCrossings;
+                        }
+                    }
+                } // ptrLen != 0
+            } // bucketCount != 0
+
+
+            if (numCrossings != 0) {
+                /*
+                 * thresholds to switch to optimized merge sort
+                 * for newly added edges + final merge pass.
+                 */
+                if ((ptrLen < 10) || (numCrossings < 40)) {
+                    if (DO_STATS) {
+                        rdrCtx.stats.hist_rdr_crossings.add(numCrossings);
+                        rdrCtx.stats.hist_rdr_crossings_adds.add(ptrLen);
+                    }
+
+                    /*
+                     * threshold to use binary insertion sort instead of
+                     * straight insertion sort (to reduce minimize comparisons).
+                     */
+                    useBinarySearch = (numCrossings >= 20);
+
+                    // if small enough:
+                    lastCross = _MIN_VALUE;
+
+                    for (i = 0; i < numCrossings; i++) {
+                        // get the pointer to the edge
+                        ecur = _edgePtrs[i];
+
+                        /* convert subpixel coordinates into pixel
+                            positions for coming scanline */
+                        /* note: it is faster to always update edges even
+                           if it is removed from AEL for coming or last scanline */
+
+                        // random access so use unsafe:
+                        addr = addr0 + ecur; // ecur + OFF_F_CURX
+
+                        // get current crossing:
+                        curx = _unsafe.getInt(addr);
+
+                        // update crossing with orientation at last bit:
+                        cross = curx;
+
+                        // Increment x using DDA (fixed point):
+                        curx += _unsafe.getInt(addr + _OFF_BUMP_X);
+
+                        // Increment error:
+                        err  =  _unsafe.getInt(addr + _OFF_ERROR)
+                              + _unsafe.getInt(addr + _OFF_BUMP_ERR);
+
+                        // Manual carry handling:
+                        // keep sign and carry bit only and ignore last bit (preserve orientation):
+                        _unsafe.putInt(addr,               curx - ((err >> 30) & _ALL_BUT_LSB));
+                        _unsafe.putInt(addr + _OFF_ERROR, (err & _ERR_STEP_MAX));
+
+                        if (DO_STATS) {
+                            rdrCtx.stats.stat_rdr_crossings_updates.add(numCrossings);
+                        }
+
+                        // insertion sort of crossings:
+                        if (cross < lastCross) {
+                            if (DO_STATS) {
+                                rdrCtx.stats.stat_rdr_crossings_sorts.add(i);
+                            }
+
+                            /* use binary search for newly added edges
+                               in crossings if arrays are large enough */
+                            if (useBinarySearch && (i >= prevNumCrossings)) {
+                                if (DO_STATS) {
+                                    rdrCtx.stats.stat_rdr_crossings_bsearch.add(i);
+                                }
+                                low = 0;
+                                high = i - 1;
+
+                                do {
+                                    // note: use signed shift (not >>>) for performance
+                                    // as indices are small enough to exceed Integer.MAX_VALUE
+                                    mid = (low + high) >> 1;
+
+                                    if (_crossings[mid] < cross) {
+                                        low = mid + 1;
+                                    } else {
+                                        high = mid - 1;
+                                    }
+                                } while (low <= high);
+
+                                for (j = i - 1; j >= low; j--) {
+                                    _crossings[j + 1] = _crossings[j];
+                                    _edgePtrs [j + 1] = _edgePtrs[j];
+                                }
+                                _crossings[low] = cross;
+                                _edgePtrs [low] = ecur;
+
+                            } else {
+                                j = i - 1;
+                                _crossings[i] = _crossings[j];
+                                _edgePtrs[i] = _edgePtrs[j];
+
+                                while ((--j >= 0) && (_crossings[j] > cross)) {
+                                    _crossings[j + 1] = _crossings[j];
+                                    _edgePtrs [j + 1] = _edgePtrs[j];
+                                }
+                                _crossings[j + 1] = cross;
+                                _edgePtrs [j + 1] = ecur;
+                            }
+
+                        } else {
+                            _crossings[i] = lastCross = cross;
+                        }
+                    }
+                } else {
+                    if (DO_STATS) {
+                        rdrCtx.stats.stat_rdr_crossings_msorts.add(numCrossings);
+                        rdrCtx.stats.hist_rdr_crossings_ratio
+                            .add((1000 * ptrLen) / numCrossings);
+                        rdrCtx.stats.hist_rdr_crossings_msorts.add(numCrossings);
+                        rdrCtx.stats.hist_rdr_crossings_msorts_adds.add(ptrLen);
+                    }
+
+                    // Copy sorted data in auxiliary arrays
+                    // and perform insertion sort on almost sorted data
+                    // (ie i < prevNumCrossings):
+
+                    lastCross = _MIN_VALUE;
+
+                    for (i = 0; i < numCrossings; i++) {
+                        // get the pointer to the edge
+                        ecur = _edgePtrs[i];
+
+                        /* convert subpixel coordinates into pixel
+                            positions for coming scanline */
+                        /* note: it is faster to always update edges even
+                           if it is removed from AEL for coming or last scanline */
+
+                        // random access so use unsafe:
+                        addr = addr0 + ecur; // ecur + OFF_F_CURX
+
+                        // get current crossing:
+                        curx = _unsafe.getInt(addr);
+
+                        // update crossing with orientation at last bit:
+                        cross = curx;
+
+                        // Increment x using DDA (fixed point):
+                        curx += _unsafe.getInt(addr + _OFF_BUMP_X);
+
+                        // Increment error:
+                        err  =  _unsafe.getInt(addr + _OFF_ERROR)
+                              + _unsafe.getInt(addr + _OFF_BUMP_ERR);
+
+                        // Manual carry handling:
+                        // keep sign and carry bit only and ignore last bit (preserve orientation):
+                        _unsafe.putInt(addr,               curx - ((err >> 30) & _ALL_BUT_LSB));
+                        _unsafe.putInt(addr + _OFF_ERROR, (err & _ERR_STEP_MAX));
+
+                        if (DO_STATS) {
+                            rdrCtx.stats.stat_rdr_crossings_updates.add(numCrossings);
+                        }
+
+                        if (i >= prevNumCrossings) {
+                            // simply store crossing as edgePtrs is in-place:
+                            // will be copied and sorted efficiently by mergesort later:
+                            _crossings[i]     = cross;
+
+                        } else if (cross < lastCross) {
+                            if (DO_STATS) {
+                                rdrCtx.stats.stat_rdr_crossings_sorts.add(i);
+                            }
+
+                            // (straight) insertion sort of crossings:
+                            j = i - 1;
+                            _aux_crossings[i] = _aux_crossings[j];
+                            _aux_edgePtrs[i] = _aux_edgePtrs[j];
+
+                            while ((--j >= 0) && (_aux_crossings[j] > cross)) {
+                                _aux_crossings[j + 1] = _aux_crossings[j];
+                                _aux_edgePtrs [j + 1] = _aux_edgePtrs[j];
+                            }
+                            _aux_crossings[j + 1] = cross;
+                            _aux_edgePtrs [j + 1] = ecur;
+
+                        } else {
+                            // auxiliary storage:
+                            _aux_crossings[i] = lastCross = cross;
+                            _aux_edgePtrs [i] = ecur;
+                        }
+                    }
+
+                    // use Mergesort using auxiliary arrays (sort only right part)
+                    MergeSort.mergeSortNoCopy(_crossings,     _edgePtrs,
+                                              _aux_crossings, _aux_edgePtrs,
+                                              numCrossings,   prevNumCrossings);
+                }
+
+                // reset ptrLen
+                ptrLen = 0;
+                // --- from former ScanLineIterator.next()
+
+
+                /* note: bboxx0 and bboxx1 must be pixel boundaries
+                   to have correct coverage computation */
+
+                // right shift on crossings to get the x-coordinate:
+                curxo = _crossings[0];
+                x0    = curxo >> 1;
+                if (x0 < minX) {
+                    minX = x0; // subpixel coordinate
+                }
+
+                x1 = _crossings[numCrossings - 1] >> 1;
+                if (x1 > maxX) {
+                    maxX = x1; // subpixel coordinate
+                }
+
+
+                // compute pixel coverages
+                prev = curx = x0;
+                // to turn {0, 1} into {-1, 1}, multiply by 2 and subtract 1.
+                // last bit contains orientation (0 or 1)
+                crorientation = ((curxo & 0x1) << 1) - 1;
+
+                if (windingRuleEvenOdd) {
+                    sum = crorientation;
+
+                    // Even Odd winding rule: take care of mask ie sum(orientations)
+                    for (i = 1; i < numCrossings; i++) {
+                        curxo = _crossings[i];
+                        curx  =  curxo >> 1;
+                        // to turn {0, 1} into {-1, 1}, multiply by 2 and subtract 1.
+                        // last bit contains orientation (0 or 1)
+                        crorientation = ((curxo & 0x1) << 1) - 1;
+
+                        if ((sum & 0x1) != 0) {
+                            // TODO: perform line clipping on left-right sides
+                            // to avoid such bound checks:
+                            x0 = (prev > bboxx0) ? prev : bboxx0;
+
+                            if (curx < bboxx1) {
+                                x1 = curx;
+                            } else {
+                                x1 = bboxx1;
+                                // skip right side (fast exit loop):
+                                i = numCrossings;
+                            }
+
+                            if (x0 < x1) {
+                                x0 -= bboxx0; // turn x0, x1 from coords to indices
+                                x1 -= bboxx0; // in the alpha array.
+
+                                pix_x      =  x0      >> _SUBPIXEL_LG_POSITIONS_X;
+                                pix_xmaxm1 = (x1 - 1) >> _SUBPIXEL_LG_POSITIONS_X;
+
+                                if (pix_x == pix_xmaxm1) {
+                                    // Start and end in same pixel
+                                    tmp = (x1 - x0); // number of subpixels
+                                    _alpha[pix_x    ] += tmp;
+                                    _alpha[pix_x + 1] -= tmp;
+
+                                    if (useBlkFlags) {
+                                        // flag used blocks:
+                                        // note: block processing handles extra pixel:
+                                        _blkFlags[pix_x    >> _BLK_SIZE_LG] = 1;
+                                    }
+                                } else {
+                                    tmp = (x0 & _SUBPIXEL_MASK_X);
+                                    _alpha[pix_x    ]
+                                        += (_SUBPIXEL_POSITIONS_X - tmp);
+                                    _alpha[pix_x + 1]
+                                        += tmp;
+
+                                    pix_xmax = x1 >> _SUBPIXEL_LG_POSITIONS_X;
+
+                                    tmp = (x1 & _SUBPIXEL_MASK_X);
+                                    _alpha[pix_xmax    ]
+                                        -= (_SUBPIXEL_POSITIONS_X - tmp);
+                                    _alpha[pix_xmax + 1]
+                                        -= tmp;
+
+                                    if (useBlkFlags) {
+                                        // flag used blocks:
+                                        // note: block processing handles extra pixel:
+                                        _blkFlags[pix_x    >> _BLK_SIZE_LG] = 1;
+                                        _blkFlags[pix_xmax >> _BLK_SIZE_LG] = 1;
+                                    }
+                                }
+                            }
+                        }
+
+                        sum += crorientation;
+                        prev = curx;
+                    }
+                } else {
+                    // Non-zero winding rule: optimize that case (default)
+                    // and avoid processing intermediate crossings
+                    for (i = 1, sum = 0;; i++) {
+                        sum += crorientation;
+
+                        if (sum != 0) {
+                            // prev = min(curx)
+                            if (prev > curx) {
+                                prev = curx;
+                            }
+                        } else {
+                            // TODO: perform line clipping on left-right sides
+                            // to avoid such bound checks:
+                            x0 = (prev > bboxx0) ? prev : bboxx0;
+
+                            if (curx < bboxx1) {
+                                x1 = curx;
+                            } else {
+                                x1 = bboxx1;
+                                // skip right side (fast exit loop):
+                                i = numCrossings;
+                            }
+
+                            if (x0 < x1) {
+                                x0 -= bboxx0; // turn x0, x1 from coords to indices
+                                x1 -= bboxx0; // in the alpha array.
+
+                                pix_x      =  x0      >> _SUBPIXEL_LG_POSITIONS_X;
+                                pix_xmaxm1 = (x1 - 1) >> _SUBPIXEL_LG_POSITIONS_X;
+
+                                if (pix_x == pix_xmaxm1) {
+                                    // Start and end in same pixel
+                                    tmp = (x1 - x0); // number of subpixels
+                                    _alpha[pix_x    ] += tmp;
+                                    _alpha[pix_x + 1] -= tmp;
+
+                                    if (useBlkFlags) {
+                                        // flag used blocks:
+                                        // note: block processing handles extra pixel:
+                                        _blkFlags[pix_x    >> _BLK_SIZE_LG] = 1;
+                                    }
+                                } else {
+                                    tmp = (x0 & _SUBPIXEL_MASK_X);
+                                    _alpha[pix_x    ]
+                                        += (_SUBPIXEL_POSITIONS_X - tmp);
+                                    _alpha[pix_x + 1]
+                                        += tmp;
+
+                                    pix_xmax = x1 >> _SUBPIXEL_LG_POSITIONS_X;
+
+                                    tmp = (x1 & _SUBPIXEL_MASK_X);
+                                    _alpha[pix_xmax    ]
+                                        -= (_SUBPIXEL_POSITIONS_X - tmp);
+                                    _alpha[pix_xmax + 1]
+                                        -= tmp;
+
+                                    if (useBlkFlags) {
+                                        // flag used blocks:
+                                        // note: block processing handles extra pixel:
+                                        _blkFlags[pix_x    >> _BLK_SIZE_LG] = 1;
+                                        _blkFlags[pix_xmax >> _BLK_SIZE_LG] = 1;
+                                    }
+                                }
+                            }
+                            prev = _MAX_VALUE;
+                        }
+
+                        if (i == numCrossings) {
+                            break;
+                        }
+
+                        curxo = _crossings[i];
+                        curx  =  curxo >> 1;
+                        // to turn {0, 1} into {-1, 1}, multiply by 2 and subtract 1.
+                        // last bit contains orientation (0 or 1)
+                        crorientation = ((curxo & 0x1) << 1) - 1;
+                    }
+                }
+            } // numCrossings > 0
+
+            // even if this last row had no crossings, alpha will be zeroed
+            // from the last emitRow call. But this doesn't matter because
+            // maxX < minX, so no row will be emitted to the MarlinCache.
+            if ((y & _SUBPIXEL_MASK_Y) == _SUBPIXEL_MASK_Y) {
+                lastY = y >> _SUBPIXEL_LG_POSITIONS_Y;
+
+                // convert subpixel to pixel coordinate within boundaries:
+                minX = FloatMath.max(minX, bboxx0) >> _SUBPIXEL_LG_POSITIONS_X;
+                maxX = FloatMath.min(maxX, bboxx1) >> _SUBPIXEL_LG_POSITIONS_X;
+
+                if (maxX >= minX) {
+                    // note: alpha array will be zeroed by copyAARow()
+                    // +1 because alpha [pix_minX; pix_maxX[
+                    // fix range [x0; x1[
+                    // note: if x1=bboxx1, then alpha is written up to bboxx1+1
+                    // inclusive: alpha[bboxx1] ignored, alpha[bboxx1+1] == 0
+                    // (normally so never cleared below)
+                    copyAARow(_alpha, lastY, minX, maxX + 1, useBlkFlags);
+
+                    // speculative for next pixel row (scanline coherence):
+                    if (_enableBlkFlagsHeuristics) {
+                        // Use block flags if large pixel span and few crossings:
+                        // ie mean(distance between crossings) is larger than
+                        // 1 block size;
+
+                        // fast check width:
+                        maxX -= minX;
+
+                        // if stroking: numCrossings /= 2
+                        // => shift numCrossings by 1
+                        // condition = (width / (numCrossings - 1)) > blockSize
+                        useBlkFlags = (maxX > _BLK_SIZE) && (maxX >
+                            (((numCrossings >> stroking) - 1) << _BLK_SIZE_LG));
+
+                        if (DO_STATS) {
+                            tmp = FloatMath.max(1,
+                                    ((numCrossings >> stroking) - 1));
+                            rdrCtx.stats.hist_tile_generator_encoding_dist
+                                .add(maxX / tmp);
+                        }
+                    }
+                } else {
+                    _cache.clearAARow(lastY);
+                }
+                minX = _MAX_VALUE;
+                maxX = _MIN_VALUE;
+            }
+        } // scan line iterator
+
+        // Emit final row
+        y--;
+        y >>= _SUBPIXEL_LG_POSITIONS_Y;
+
+        // convert subpixel to pixel coordinate within boundaries:
+        minX = FloatMath.max(minX, bboxx0) >> _SUBPIXEL_LG_POSITIONS_X;
+        maxX = FloatMath.min(maxX, bboxx1) >> _SUBPIXEL_LG_POSITIONS_X;
+
+        if (maxX >= minX) {
+            // note: alpha array will be zeroed by copyAARow()
+            // +1 because alpha [pix_minX; pix_maxX[
+            // fix range [x0; x1[
+            // note: if x1=bboxx1, then alpha is written up to bboxx1+1
+            // inclusive: alpha[bboxx1] ignored then cleared and
+            // alpha[bboxx1+1] == 0 (normally so never cleared after)
+            copyAARow(_alpha, y, minX, maxX + 1, useBlkFlags);
+        } else if (y != lastY) {
+            _cache.clearAARow(y);
+        }
+
+        // update member:
+        edgeCount = numCrossings;
+        prevUseBlkFlags = useBlkFlags;
+
+        if (DO_STATS) {
+            // update max used mark
+            activeEdgeMaxUsed = _arrayMaxUsed;
+        }
+    }
+
+    boolean endRendering() {
+        if (DO_MONITORS) {
+            rdrCtx.stats.mon_rdr_endRendering.start();
+        }
+        if (edgeMinY == Integer.MAX_VALUE) {
+            return false; // undefined edges bounds
+        }
+
+        // bounds as half-open intervals
+        final int spminX = FloatMath.max(FloatMath.ceil_int(edgeMinX - 0.5d), boundsMinX);
+        final int spmaxX = FloatMath.min(FloatMath.ceil_int(edgeMaxX - 0.5d), boundsMaxX);
+
+        // edge Min/Max Y are already rounded to subpixels within bounds:
+        final int spminY = edgeMinY;
+        final int spmaxY = edgeMaxY;
+
+        buckets_minY = spminY - boundsMinY;
+        buckets_maxY = spmaxY - boundsMinY;
+
+        if (DO_LOG_BOUNDS) {
+            MarlinUtils.logInfo("edgesXY = [" + edgeMinX + " ... " + edgeMaxX
+                                + "[ [" + edgeMinY + " ... " + edgeMaxY + "[");
+            MarlinUtils.logInfo("spXY    = [" + spminX + " ... " + spmaxX
+                                + "[ [" + spminY + " ... " + spmaxY + "[");
+        }
+
+        // test clipping for shapes out of bounds
+        if ((spminX >= spmaxX) || (spminY >= spmaxY)) {
+            return false;
+        }
+
+        // half open intervals
+        // inclusive:
+        final int pminX =  spminX                    >> SUBPIXEL_LG_POSITIONS_X;
+        // exclusive:
+        final int pmaxX = (spmaxX + SUBPIXEL_MASK_X) >> SUBPIXEL_LG_POSITIONS_X;
+        // inclusive:
+        final int pminY =  spminY                    >> SUBPIXEL_LG_POSITIONS_Y;
+        // exclusive:
+        final int pmaxY = (spmaxY + SUBPIXEL_MASK_Y) >> SUBPIXEL_LG_POSITIONS_Y;
+
+        // store BBox to answer ptg.getBBox():
+        this.cache.init(pminX, pminY, pmaxX, pmaxY);
+
+        // Heuristics for using block flags:
+        if (ENABLE_BLOCK_FLAGS) {
+            enableBlkFlags = this.cache.useRLE;
+            prevUseBlkFlags = enableBlkFlags && !ENABLE_BLOCK_FLAGS_HEURISTICS;
+
+            if (enableBlkFlags) {
+                // ensure blockFlags array is large enough:
+                // note: +2 to ensure enough space left at end
+                final int blkLen = ((pmaxX - pminX) >> BLOCK_SIZE_LG) + 2;
+                if (blkLen > INITIAL_ARRAY) {
+                    blkFlags = blkFlags_ref.getArray(blkLen);
+                }
+            }
+        }
+
+        // memorize the rendering bounding box:
+        /* note: bbox_spminX and bbox_spmaxX must be pixel boundaries
+           to have correct coverage computation */
+        // inclusive:
+        bbox_spminX = pminX << SUBPIXEL_LG_POSITIONS_X;
+        // exclusive:
+        bbox_spmaxX = pmaxX << SUBPIXEL_LG_POSITIONS_X;
+        // inclusive:
+        bbox_spminY = spminY;
+        // exclusive:
+        bbox_spmaxY = spmaxY;
+
+        if (DO_LOG_BOUNDS) {
+            MarlinUtils.logInfo("pXY       = [" + pminX + " ... " + pmaxX
+                                + "[ [" + pminY + " ... " + pmaxY + "[");
+            MarlinUtils.logInfo("bbox_spXY = [" + bbox_spminX + " ... "
+                                + bbox_spmaxX + "[ [" + bbox_spminY + " ... "
+                                + bbox_spmaxY + "[");
+        }
+
+        // Prepare alpha line:
+        // add 2 to better deal with the last pixel in a pixel row.
+        final int width = (pmaxX - pminX) + 2;
+
+        // Useful when processing tile line by tile line
+        if (width > INITIAL_AA_ARRAY) {
+            if (DO_STATS) {
+                rdrCtx.stats.stat_array_renderer_alphaline.add(width);
+            }
+            alphaLine = alphaLine_ref.getArray(width);
+        }
+
+        // process first tile line:
+        endRendering(pminY);
+
+        return true;
+    }
+
+    private int bbox_spminX, bbox_spmaxX, bbox_spminY, bbox_spmaxY;
+
+    void endRendering(final int pminY) {
+        if (DO_MONITORS) {
+            rdrCtx.stats.mon_rdr_endRendering_Y.start();
+        }
+
+        final int spminY       = pminY << SUBPIXEL_LG_POSITIONS_Y;
+        final int fixed_spminY = FloatMath.max(bbox_spminY, spminY);
+
+        // avoid rendering for last call to nextTile()
+        if (fixed_spminY < bbox_spmaxY) {
+            // process a complete tile line ie scanlines for 32 rows
+            final int spmaxY = FloatMath.min(bbox_spmaxY, spminY + SUBPIXEL_TILE);
+
+            // process tile line [0 - 32]
+            cache.resetTileLine(pminY);
+
+            // Process only one tile line:
+            _endRendering(fixed_spminY, spmaxY);
+        }
+        if (DO_MONITORS) {
+            rdrCtx.stats.mon_rdr_endRendering_Y.stop();
+        }
+    }
+
+    void copyAARow(final int[] alphaRow,
+                   final int pix_y, final int pix_from, final int pix_to,
+                   final boolean useBlockFlags)
+    {
+        if (DO_MONITORS) {
+            rdrCtx.stats.mon_rdr_copyAARow.start();
+        }
+        if (useBlockFlags) {
+            if (DO_STATS) {
+                rdrCtx.stats.hist_tile_generator_encoding.add(1);
+            }
+            cache.copyAARowRLE_WithBlockFlags(blkFlags, alphaRow, pix_y, pix_from, pix_to);
+        } else {
+            if (DO_STATS) {
+                rdrCtx.stats.hist_tile_generator_encoding.add(0);
+            }
+            cache.copyAARowNoRLE(alphaRow, pix_y, pix_from, pix_to);
+        }
+        if (DO_MONITORS) {
+            rdrCtx.stats.mon_rdr_copyAARow.stop();
+        }
+    }
+}