/*
 * Copyright (c) 2007, 2016, 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 java.awt.BasicStroke;
import java.awt.Shape;
import java.awt.geom.AffineTransform;
import java.awt.geom.Path2D;
import java.awt.geom.PathIterator;
import java.security.AccessController;
import static sun.java2d.marlin.MarlinUtils.logInfo;
import sun.awt.geom.PathConsumer2D;
import sun.java2d.ReentrantContextProvider;
import sun.java2d.ReentrantContextProviderCLQ;
import sun.java2d.ReentrantContextProviderTL;
import sun.java2d.pipe.AATileGenerator;
import sun.java2d.pipe.Region;
import sun.java2d.pipe.RenderingEngine;
import sun.security.action.GetPropertyAction;

Marlin RendererEngine implementation (derived from Pisces)
/**
 * Marlin RendererEngine implementation (derived from Pisces)
 */
public class MarlinRenderingEngine extends RenderingEngine
                                   implements MarlinConst
{
    private static enum NormMode {ON_WITH_AA, ON_NO_AA, OFF}

    private static final float MIN_PEN_SIZE = 1f / NORM_SUBPIXELS;

    
Public constructor
/**
     * Public constructor
     */
    public MarlinRenderingEngine() {
        super();
        logSettings(MarlinRenderingEngine.class.getName());
    }

    
Create a widened path as specified by the parameters.
 The specified src Shape is widened according to the specified attribute parameters as per the BasicStroke specification. 
Params:
src – the source path to be widened
width – the width of the widened path as per BasicStroke
caps – the end cap decorations as per BasicStroke
join – the segment join decorations as per BasicStroke
miterlimit – the miter limit as per BasicStroke
dashes – the dash length array as per BasicStroke
dashphase – the initial dash phase as per BasicStroke
Returns:
the widened path stored in a new Shape object
Since:
1.7/**
     * Create a widened path as specified by the parameters.
     * <p>
     * The specified {@code src} {@link Shape} is widened according
     * to the specified attribute parameters as per the
     * {@link BasicStroke} specification.
     *
     * @param src the source path to be widened
     * @param width the width of the widened path as per {@code BasicStroke}
     * @param caps the end cap decorations as per {@code BasicStroke}
     * @param join the segment join decorations as per {@code BasicStroke}
     * @param miterlimit the miter limit as per {@code BasicStroke}
     * @param dashes the dash length array as per {@code BasicStroke}
     * @param dashphase the initial dash phase as per {@code BasicStroke}
     * @return the widened path stored in a new {@code Shape} object
     * @since 1.7
     */
    @Override
    public Shape createStrokedShape(Shape src,
                                    float width,
                                    int caps,
                                    int join,
                                    float miterlimit,
                                    float dashes[],
                                    float dashphase)
    {
        final RendererContext rdrCtx = getRendererContext();
        try {
            // initialize a large copyable Path2D to avoid a lot of array growing:
            final Path2D.Float p2d =
                    (rdrCtx.p2d == null) ?
                    (rdrCtx.p2d = new Path2D.Float(Path2D.WIND_NON_ZERO,
                                                   INITIAL_MEDIUM_ARRAY))
                    : rdrCtx.p2d;
            // reset
            p2d.reset();

            strokeTo(rdrCtx,
                     src,
                     null,
                     width,
                     NormMode.OFF,
                     caps,
                     join,
                     miterlimit,
                     dashes,
                     dashphase,
                     rdrCtx.transformerPC2D.wrapPath2d(p2d)
                    );

            // Use Path2D copy constructor (trim)
            return new Path2D.Float(p2d);

        } finally {
            // recycle the RendererContext instance
            returnRendererContext(rdrCtx);
        }
    }

    
Sends the geometry for a widened path as specified by the parameters
to the specified consumer.
 The specified src Shape is widened according to the parameters specified by the BasicStroke object. Adjustments are made to the path as appropriate for the VALUE_STROKE_NORMALIZE hint if the normalize boolean parameter is true. Adjustments are made to the path as appropriate for the VALUE_ANTIALIAS_ON hint if the antialias boolean parameter is true. 
 The geometry of the widened path is forwarded to the indicated PathConsumer2D object as it is calculated. 
Params:
src – the source path to be widened
bs – the BasicSroke object specifying the decorations to be applied to the widened path
normalize – indicates whether stroke normalization should
                 be applied
antialias – indicates whether or not adjustments appropriate
                 to antialiased rendering should be applied
consumer – the PathConsumer2D instance to forward the widened geometry to
Since:
1.7/**
     * Sends the geometry for a widened path as specified by the parameters
     * to the specified consumer.
     * <p>
     * The specified {@code src} {@link Shape} is widened according
     * to the parameters specified by the {@link BasicStroke} object.
     * Adjustments are made to the path as appropriate for the
     * {@link VALUE_STROKE_NORMALIZE} hint if the {@code normalize}
     * boolean parameter is true.
     * Adjustments are made to the path as appropriate for the
     * {@link VALUE_ANTIALIAS_ON} hint if the {@code antialias}
     * boolean parameter is true.
     * <p>
     * The geometry of the widened path is forwarded to the indicated
     * {@link PathConsumer2D} object as it is calculated.
     *
     * @param src the source path to be widened
     * @param bs the {@code BasicSroke} object specifying the
     *           decorations to be applied to the widened path
     * @param normalize indicates whether stroke normalization should
     *                  be applied
     * @param antialias indicates whether or not adjustments appropriate
     *                  to antialiased rendering should be applied
     * @param consumer the {@code PathConsumer2D} instance to forward
     *                 the widened geometry to
     * @since 1.7
     */
    @Override
    public void strokeTo(Shape src,
                         AffineTransform at,
                         BasicStroke bs,
                         boolean thin,
                         boolean normalize,
                         boolean antialias,
                         final PathConsumer2D consumer)
    {
        final NormMode norm = (normalize) ?
                ((antialias) ? NormMode.ON_WITH_AA : NormMode.ON_NO_AA)
                : NormMode.OFF;

        final RendererContext rdrCtx = getRendererContext();
        try {
            strokeTo(rdrCtx, src, at, bs, thin, norm, antialias, consumer);
        } finally {
            // recycle the RendererContext instance
            returnRendererContext(rdrCtx);
        }
    }

    final void strokeTo(final RendererContext rdrCtx,
                        Shape src,
                        AffineTransform at,
                        BasicStroke bs,
                        boolean thin,
                        NormMode normalize,
                        boolean antialias,
                        PathConsumer2D pc2d)
    {
        float lw;
        if (thin) {
            if (antialias) {
                lw = userSpaceLineWidth(at, MIN_PEN_SIZE);
            } else {
                lw = userSpaceLineWidth(at, 1.0f);
            }
        } else {
            lw = bs.getLineWidth();
        }
        strokeTo(rdrCtx,
                 src,
                 at,
                 lw,
                 normalize,
                 bs.getEndCap(),
                 bs.getLineJoin(),
                 bs.getMiterLimit(),
                 bs.getDashArray(),
                 bs.getDashPhase(),
                 pc2d);
    }

    private final float userSpaceLineWidth(AffineTransform at, float lw) {

        float widthScale;

        if (at == null) {
            widthScale = 1.0f;
        } else if ((at.getType() & (AffineTransform.TYPE_GENERAL_TRANSFORM  |
                                    AffineTransform.TYPE_GENERAL_SCALE)) != 0) {
            widthScale = (float)Math.sqrt(at.getDeterminant());
        } else {
            // First calculate the "maximum scale" of this transform.
            double A = at.getScaleX();       // m00
            double C = at.getShearX();       // m01
            double B = at.getShearY();       // m10
            double D = at.getScaleY();       // m11

            /*
             * Given a 2 x 2 affine matrix [ A B ] such that
             *                             [ C D ]
             * v' = [x' y'] = [Ax + Cy, Bx + Dy], we want to
             * find the maximum magnitude (norm) of the vector v'
             * with the constraint (x^2 + y^2 = 1).
             * The equation to maximize is
             *     |v'| = sqrt((Ax+Cy)^2+(Bx+Dy)^2)
             * or  |v'| = sqrt((AA+BB)x^2 + 2(AC+BD)xy + (CC+DD)y^2).
             * Since sqrt is monotonic we can maximize |v'|^2
             * instead and plug in the substitution y = sqrt(1 - x^2).
             * Trigonometric equalities can then be used to get
             * rid of most of the sqrt terms.
             */

            double EA = A*A + B*B;          // x^2 coefficient
            double EB = 2.0*(A*C + B*D);    // xy coefficient
            double EC = C*C + D*D;          // y^2 coefficient

            /*
             * There is a lot of calculus omitted here.
             *
             * Conceptually, in the interests of understanding the
             * terms that the calculus produced we can consider
             * that EA and EC end up providing the lengths along
             * the major axes and the hypot term ends up being an
             * adjustment for the additional length along the off-axis
             * angle of rotated or sheared ellipses as well as an
             * adjustment for the fact that the equation below
             * averages the two major axis lengths.  (Notice that
             * the hypot term contains a part which resolves to the
             * difference of these two axis lengths in the absence
             * of rotation.)
             *
             * In the calculus, the ratio of the EB and (EA-EC) terms
             * ends up being the tangent of 2*theta where theta is
             * the angle that the long axis of the ellipse makes
             * with the horizontal axis.  Thus, this equation is
             * calculating the length of the hypotenuse of a triangle
             * along that axis.
             */

            double hypot = Math.sqrt(EB*EB + (EA-EC)*(EA-EC));
            // sqrt omitted, compare to squared limits below.
            double widthsquared = ((EA + EC + hypot)/2.0);

            widthScale = (float)Math.sqrt(widthsquared);
        }

        return (lw / widthScale);
    }

    final void strokeTo(final RendererContext rdrCtx,
                        Shape src,
                        AffineTransform at,
                        float width,
                        NormMode normalize,
                        int caps,
                        int join,
                        float miterlimit,
                        float dashes[],
                        float dashphase,
                        PathConsumer2D pc2d)
    {
        // We use strokerat and outat so that in Stroker and Dasher we can work only
        // with the pre-transformation coordinates. This will repeat a lot of
        // computations done in the path iterator, but the alternative is to
        // work with transformed paths and compute untransformed coordinates
        // as needed. This would be faster but I do not think the complexity
        // of working with both untransformed and transformed coordinates in
        // the same code is worth it.
        // However, if a path's width is constant after a transformation,
        // we can skip all this untransforming.

        // If normalization is off we save some transformations by not
        // transforming the input to pisces. Instead, we apply the
        // transformation after the path processing has been done.
        // We can't do this if normalization is on, because it isn't a good
        // idea to normalize before the transformation is applied.
        AffineTransform strokerat = null;
        AffineTransform outat = null;

        PathIterator pi;
        int dashLen = -1;
        boolean recycleDashes = false;

        if (at != null && !at.isIdentity()) {
            final double a = at.getScaleX();
            final double b = at.getShearX();
            final double c = at.getShearY();
            final double d = at.getScaleY();
            final double det = a * d - c * b;

            if (Math.abs(det) <= (2f * Float.MIN_VALUE)) {
                // this rendering engine takes one dimensional curves and turns
                // them into 2D shapes by giving them width.
                // However, if everything is to be passed through a singular
                // transformation, these 2D shapes will be squashed down to 1D
                // again so, nothing can be drawn.

                // Every path needs an initial moveTo and a pathDone. If these
                // are not there this causes a SIGSEGV in libawt.so (at the time
                // of writing of this comment (September 16, 2010)). Actually,
                // I am not sure if the moveTo is necessary to avoid the SIGSEGV
                // but the pathDone is definitely needed.
                pc2d.moveTo(0f, 0f);
                pc2d.pathDone();
                return;
            }

            // If the transform is a constant multiple of an orthogonal transformation
            // then every length is just multiplied by a constant, so we just
            // need to transform input paths to stroker and tell stroker
            // the scaled width. This condition is satisfied if
            // a*b == -c*d && a*a+c*c == b*b+d*d. In the actual check below, we
            // leave a bit of room for error.
            if (nearZero(a*b + c*d) && nearZero(a*a + c*c - (b*b + d*d))) {
                final float scale = (float) Math.sqrt(a*a + c*c);
                if (dashes != null) {
                    recycleDashes = true;
                    dashLen = dashes.length;
                    final float[] newDashes;
                    if (dashLen <= INITIAL_ARRAY) {
                        newDashes = rdrCtx.dasher.dashes_initial;
                    } else {
                        if (doStats) {
                            RendererContext.stats.stat_array_dasher_dasher
                                .add(dashLen);
                        }
                        newDashes = rdrCtx.getDirtyFloatArray(dashLen);
                    }
                    System.arraycopy(dashes, 0, newDashes, 0, dashLen);
                    dashes = newDashes;
                    for (int i = 0; i < dashLen; i++) {
                        dashes[i] = scale * dashes[i];
                    }
                    dashphase = scale * dashphase;
                }
                width = scale * width;
                pi = getNormalizingPathIterator(rdrCtx, normalize,
                                                src.getPathIterator(at));

                // by now strokerat == null && outat == null. Input paths to
                // stroker (and maybe dasher) will have the full transform at
                // applied to them and nothing will happen to the output paths.
            } else {
                if (normalize != NormMode.OFF) {
                    strokerat = at;
                    pi = getNormalizingPathIterator(rdrCtx, normalize,
                                                    src.getPathIterator(at));

                    // by now strokerat == at && outat == null. Input paths to
                    // stroker (and maybe dasher) will have the full transform at
                    // applied to them, then they will be normalized, and then
                    // the inverse of *only the non translation part of at* will
                    // be applied to the normalized paths. This won't cause problems
                    // in stroker, because, suppose at = T*A, where T is just the
                    // translation part of at, and A is the rest. T*A has already
                    // been applied to Stroker/Dasher's input. Then Ainv will be
                    // applied. Ainv*T*A is not equal to T, but it is a translation,
                    // which means that none of stroker's assumptions about its
                    // input will be violated. After all this, A will be applied
                    // to stroker's output.
                } else {
                    outat = at;
                    pi = src.getPathIterator(null);
                    // outat == at && strokerat == null. This is because if no
                    // normalization is done, we can just apply all our
                    // transformations to stroker's output.
                }
            }
        } else {
            // either at is null or it's the identity. In either case
            // we don't transform the path.
            pi = getNormalizingPathIterator(rdrCtx, normalize,
                                            src.getPathIterator(null));
        }

        if (useSimplifier) {
            // Use simplifier after stroker before Renderer
            // to remove collinear segments (notably due to cap square)
            pc2d = rdrCtx.simplifier.init(pc2d);
        }

        // by now, at least one of outat and strokerat will be null. Unless at is not
        // a constant multiple of an orthogonal transformation, they will both be
        // null. In other cases, outat == at if normalization is off, and if
        // normalization is on, strokerat == at.
        final TransformingPathConsumer2D transformerPC2D = rdrCtx.transformerPC2D;
        pc2d = transformerPC2D.transformConsumer(pc2d, outat);
        pc2d = transformerPC2D.deltaTransformConsumer(pc2d, strokerat);

        pc2d = rdrCtx.stroker.init(pc2d, width, caps, join, miterlimit);

        if (dashes != null) {
            if (!recycleDashes) {
                dashLen = dashes.length;
            }
            pc2d = rdrCtx.dasher.init(pc2d, dashes, dashLen, dashphase,
                                      recycleDashes);
        }
        pc2d = transformerPC2D.inverseDeltaTransformConsumer(pc2d, strokerat);
        pathTo(rdrCtx, pi, pc2d);

        /*
         * Pipeline seems to be:
         *    shape.getPathIterator
         * -> NormalizingPathIterator
         * -> inverseDeltaTransformConsumer
         * -> Dasher
         * -> Stroker
         * -> deltaTransformConsumer OR transformConsumer
         *
         * -> CollinearSimplifier to remove redundant segments
         *
         * -> pc2d = Renderer (bounding box)
         */
    }

    private static boolean nearZero(final double num) {
        return Math.abs(num) < 2.0 * Math.ulp(num);
    }

    PathIterator getNormalizingPathIterator(final RendererContext rdrCtx,
                                            final NormMode mode,
                                            final PathIterator src)
    {
        switch (mode) {
            case ON_WITH_AA:
                // NormalizingPathIterator NearestPixelCenter:
                return rdrCtx.nPCPathIterator.init(src);
            case ON_NO_AA:
                // NearestPixel NormalizingPathIterator:
                return rdrCtx.nPQPathIterator.init(src);
            case OFF:
                // return original path iterator if normalization is disabled:
                return src;
            default:
                throw new InternalError("Unrecognized normalization mode");
        }
    }

    abstract static class NormalizingPathIterator implements PathIterator {

        private PathIterator src;

        // the adjustment applied to the current position.
        private float curx_adjust, cury_adjust;
        // the adjustment applied to the last moveTo position.
        private float movx_adjust, movy_adjust;

        private final float[] tmp;

        NormalizingPathIterator(final float[] tmp) {
            this.tmp = tmp;
        }

        final NormalizingPathIterator init(final PathIterator src) {
            this.src = src;
            return this; // fluent API
        }

        
Disposes this path iterator:
clean up before reusing this instance
/**
         * Disposes this path iterator:
         * clean up before reusing this instance
         */
        final void dispose() {
            // free source PathIterator:
            this.src = null;
        }

        @Override
        public final int currentSegment(final float[] coords) {
            if (doMonitors) {
                RendererContext.stats.mon_npi_currentSegment.start();
            }
            int lastCoord;
            final int type = src.currentSegment(coords);

            switch(type) {
                case PathIterator.SEG_MOVETO:
                case PathIterator.SEG_LINETO:
                    lastCoord = 0;
                    break;
                case PathIterator.SEG_QUADTO:
                    lastCoord = 2;
                    break;
                case PathIterator.SEG_CUBICTO:
                    lastCoord = 4;
                    break;
                case PathIterator.SEG_CLOSE:
                    // we don't want to deal with this case later. We just exit now
                    curx_adjust = movx_adjust;
                    cury_adjust = movy_adjust;

                    if (doMonitors) {
                        RendererContext.stats.mon_npi_currentSegment.stop();
                    }
                    return type;
                default:
                    throw new InternalError("Unrecognized curve type");
            }

            // TODO: handle NaN, Inf and overflow

            // normalize endpoint
            float coord, x_adjust, y_adjust;

            coord = coords[lastCoord];
            x_adjust = normCoord(coord); // new coord
            coords[lastCoord] = x_adjust;
            x_adjust -= coord;

            coord = coords[lastCoord + 1];
            y_adjust = normCoord(coord); // new coord
            coords[lastCoord + 1] = y_adjust;
            y_adjust -= coord;

            // now that the end points are done, normalize the control points
            switch(type) {
                case PathIterator.SEG_MOVETO:
                    movx_adjust = x_adjust;
                    movy_adjust = y_adjust;
                    break;
                case PathIterator.SEG_LINETO:
                    break;
                case PathIterator.SEG_QUADTO:
                    coords[0] += (curx_adjust + x_adjust) / 2f;
                    coords[1] += (cury_adjust + y_adjust) / 2f;
                    break;
                case PathIterator.SEG_CUBICTO:
                    coords[0] += curx_adjust;
                    coords[1] += cury_adjust;
                    coords[2] += x_adjust;
                    coords[3] += y_adjust;
                    break;
                case PathIterator.SEG_CLOSE:
                    // handled earlier
                default:
            }
            curx_adjust = x_adjust;
            cury_adjust = y_adjust;

            if (doMonitors) {
                RendererContext.stats.mon_npi_currentSegment.stop();
            }
            return type;
        }

        abstract float normCoord(final float coord);

        @Override
        public final int currentSegment(final double[] coords) {
            final float[] _tmp = tmp; // dirty
            int type = this.currentSegment(_tmp);
            for (int i = 0; i < 6; i++) {
                coords[i] = _tmp[i];
            }
            return type;
        }

        @Override
        public final int getWindingRule() {
            return src.getWindingRule();
        }

        @Override
        public final boolean isDone() {
            if (src.isDone()) {
                // Dispose this instance:
                dispose();
                return true;
            }
            return false;
        }

        @Override
        public final void next() {
            src.next();
        }

        static final class NearestPixelCenter
                                extends NormalizingPathIterator
        {
            NearestPixelCenter(final float[] tmp) {
                super(tmp);
            }

            @Override
            float normCoord(final float coord) {
                // round to nearest pixel center
                return FloatMath.floor_f(coord) + 0.5f;
            }
        }

        static final class NearestPixelQuarter
                                extends NormalizingPathIterator
        {
            NearestPixelQuarter(final float[] tmp) {
                super(tmp);
            }

            @Override
            float normCoord(final float coord) {
                // round to nearest (0.25, 0.25) pixel quarter
                return FloatMath.floor_f(coord + 0.25f) + 0.25f;
            }
        }
    }

    private static void pathTo(final RendererContext rdrCtx, final PathIterator pi,
                               final PathConsumer2D pc2d)
    {
        // mark context as DIRTY:
        rdrCtx.dirty = true;

        final float[] coords = rdrCtx.float6;

        pathToLoop(coords, pi, pc2d);

        // mark context as CLEAN:
        rdrCtx.dirty = false;
    }

    private static void pathToLoop(final float[] coords, final PathIterator pi,
                                   final PathConsumer2D pc2d)
    {
        for (; !pi.isDone(); pi.next()) {
            switch (pi.currentSegment(coords)) {
                case PathIterator.SEG_MOVETO:
                    pc2d.moveTo(coords[0], coords[1]);
                    continue;
                case PathIterator.SEG_LINETO:
                    pc2d.lineTo(coords[0], coords[1]);
                    continue;
                case PathIterator.SEG_QUADTO:
                    pc2d.quadTo(coords[0], coords[1],
                                coords[2], coords[3]);
                    continue;
                case PathIterator.SEG_CUBICTO:
                    pc2d.curveTo(coords[0], coords[1],
                                 coords[2], coords[3],
                                 coords[4], coords[5]);
                    continue;
                case PathIterator.SEG_CLOSE:
                    pc2d.closePath();
                    continue;
                default:
            }
        }
        pc2d.pathDone();
    }

    
Construct an antialiased tile generator for the given shape with the given rendering attributes and store the bounds of the tile iteration in the bbox parameter. The at parameter specifies a transform that should affect both the shape and the BasicStroke attributes. The clip parameter specifies the current clip in effect in device coordinates and can be used to prune the data for the operation, but the renderer is not required to perform any clipping. If the BasicStroke parameter is null then the shape should be filled as is, otherwise the attributes of the BasicStroke should be used to specify a draw operation. The thin parameter indicates whether or not the transformed BasicStroke represents coordinates smaller than the minimum resolution of the antialiasing rasterizer as specified by the getMinimumAAPenWidth() method. 
 Upon returning, this method will fill the bbox parameter with 4 values indicating the bounds of the iteration of the tile generator. The iteration order of the tiles will be as specified by the pseudo-code: 
    for (y = bbox[1]; y < bbox[3]; y += tileheight) {
        for (x = bbox[0]; x < bbox[2]; x += tilewidth) {
        }
    }

If there is no output to be rendered, this method may return
null.
Params:
s – the shape to be rendered (fill or draw)
at – the transform to be applied to the shape and the
          stroke attributes
clip – the current clip in effect in device coordinates
bs – if non-null, a BasicStroke whose attributes should be applied to this operation
thin – true if the transformed stroke attributes are smaller
            than the minimum dropout pen width
normalize – true if the VALUE_STROKE_NORMALIZE RenderingHint is in effect
bbox – returns the bounds of the iteration
Returns:
the AATileGenerator instance to be consulted for tile coverages, or null if there is no output to render
Since:
1.7/**
     * Construct an antialiased tile generator for the given shape with
     * the given rendering attributes and store the bounds of the tile
     * iteration in the bbox parameter.
     * The {@code at} parameter specifies a transform that should affect
     * both the shape and the {@code BasicStroke} attributes.
     * The {@code clip} parameter specifies the current clip in effect
     * in device coordinates and can be used to prune the data for the
     * operation, but the renderer is not required to perform any
     * clipping.
     * If the {@code BasicStroke} parameter is null then the shape
     * should be filled as is, otherwise the attributes of the
     * {@code BasicStroke} should be used to specify a draw operation.
     * The {@code thin} parameter indicates whether or not the
     * transformed {@code BasicStroke} represents coordinates smaller
     * than the minimum resolution of the antialiasing rasterizer as
     * specified by the {@code getMinimumAAPenWidth()} method.
     * <p>
     * Upon returning, this method will fill the {@code bbox} parameter
     * with 4 values indicating the bounds of the iteration of the
     * tile generator.
     * The iteration order of the tiles will be as specified by the
     * pseudo-code:
     * <pre>
     *     for (y = bbox[1]; y < bbox[3]; y += tileheight) {
     *         for (x = bbox[0]; x < bbox[2]; x += tilewidth) {
     *         }
     *     }
     * </pre>
     * If there is no output to be rendered, this method may return
     * null.
     *
     * @param s the shape to be rendered (fill or draw)
     * @param at the transform to be applied to the shape and the
     *           stroke attributes
     * @param clip the current clip in effect in device coordinates
     * @param bs if non-null, a {@code BasicStroke} whose attributes
     *           should be applied to this operation
     * @param thin true if the transformed stroke attributes are smaller
     *             than the minimum dropout pen width
     * @param normalize true if the {@code VALUE_STROKE_NORMALIZE}
     *                  {@code RenderingHint} is in effect
     * @param bbox returns the bounds of the iteration
     * @return the {@code AATileGenerator} instance to be consulted
     *         for tile coverages, or null if there is no output to render
     * @since 1.7
     */
    @Override
    public AATileGenerator getAATileGenerator(Shape s,
                                              AffineTransform at,
                                              Region clip,
                                              BasicStroke bs,
                                              boolean thin,
                                              boolean normalize,
                                              int bbox[])
    {
        MarlinTileGenerator ptg = null;
        Renderer r = null;

        final RendererContext rdrCtx = getRendererContext();
        try {
            // Test if at is identity:
            final AffineTransform _at = (at != null && !at.isIdentity()) ? at
                                        : null;

            final NormMode norm = (normalize) ? NormMode.ON_WITH_AA : NormMode.OFF;

            if (bs == null) {
                // fill shape:
                final PathIterator pi = getNormalizingPathIterator(rdrCtx, norm,
                                            s.getPathIterator(_at));

                r = rdrCtx.renderer.init(clip.getLoX(), clip.getLoY(),
                                         clip.getWidth(), clip.getHeight(),
                                         pi.getWindingRule());

                // TODO: subdivide quad/cubic curves into monotonic curves ?
                pathTo(rdrCtx, pi, r);
            } else {
                // draw shape with given stroke:
                r = rdrCtx.renderer.init(clip.getLoX(), clip.getLoY(),
                                         clip.getWidth(), clip.getHeight(),
                                         PathIterator.WIND_NON_ZERO);

                strokeTo(rdrCtx, s, _at, bs, thin, norm, true, r);
            }
            if (r.endRendering()) {
                ptg = rdrCtx.ptg.init();
                ptg.getBbox(bbox);
                // note: do not returnRendererContext(rdrCtx)
                // as it will be called later by MarlinTileGenerator.dispose()
                r = null;
            }
        } finally {
            if (r != null) {
                // dispose renderer:
                r.dispose();
                // recycle the RendererContext instance
                MarlinRenderingEngine.returnRendererContext(rdrCtx);
            }
        }

        // Return null to cancel AA tile generation (nothing to render)
        return ptg;
    }

    @Override
    public final AATileGenerator getAATileGenerator(double x, double y,
                                                    double dx1, double dy1,
                                                    double dx2, double dy2,
                                                    double lw1, double lw2,
                                                    Region clip,
                                                    int bbox[])
    {
        // REMIND: Deal with large coordinates!
        double ldx1, ldy1, ldx2, ldy2;
        boolean innerpgram = (lw1 > 0.0 && lw2 > 0.0);

        if (innerpgram) {
            ldx1 = dx1 * lw1;
            ldy1 = dy1 * lw1;
            ldx2 = dx2 * lw2;
            ldy2 = dy2 * lw2;
            x -= (ldx1 + ldx2) / 2.0;
            y -= (ldy1 + ldy2) / 2.0;
            dx1 += ldx1;
            dy1 += ldy1;
            dx2 += ldx2;
            dy2 += ldy2;
            if (lw1 > 1.0 && lw2 > 1.0) {
                // Inner parallelogram was entirely consumed by stroke...
                innerpgram = false;
            }
        } else {
            ldx1 = ldy1 = ldx2 = ldy2 = 0.0;
        }

        MarlinTileGenerator ptg = null;
        Renderer r = null;

        final RendererContext rdrCtx = getRendererContext();
        try {
            r = rdrCtx.renderer.init(clip.getLoX(), clip.getLoY(),
                                         clip.getWidth(), clip.getHeight(),
                                         Renderer.WIND_EVEN_ODD);

            r.moveTo((float) x, (float) y);
            r.lineTo((float) (x+dx1), (float) (y+dy1));
            r.lineTo((float) (x+dx1+dx2), (float) (y+dy1+dy2));
            r.lineTo((float) (x+dx2), (float) (y+dy2));
            r.closePath();

            if (innerpgram) {
                x += ldx1 + ldx2;
                y += ldy1 + ldy2;
                dx1 -= 2.0 * ldx1;
                dy1 -= 2.0 * ldy1;
                dx2 -= 2.0 * ldx2;
                dy2 -= 2.0 * ldy2;
                r.moveTo((float) x, (float) y);
                r.lineTo((float) (x+dx1), (float) (y+dy1));
                r.lineTo((float) (x+dx1+dx2), (float) (y+dy1+dy2));
                r.lineTo((float) (x+dx2), (float) (y+dy2));
                r.closePath();
            }
            r.pathDone();

            if (r.endRendering()) {
                ptg = rdrCtx.ptg.init();
                ptg.getBbox(bbox);
                // note: do not returnRendererContext(rdrCtx)
                // as it will be called later by MarlinTileGenerator.dispose()
                r = null;
            }
        } finally {
            if (r != null) {
                // dispose renderer:
                r.dispose();
                // recycle the RendererContext instance
                MarlinRenderingEngine.returnRendererContext(rdrCtx);
            }
        }

        // Return null to cancel AA tile generation (nothing to render)
        return ptg;
    }

    
Returns the minimum pen width that the antialiasing rasterizer
can represent without dropouts occuring.
Since:
1.7/**
     * Returns the minimum pen width that the antialiasing rasterizer
     * can represent without dropouts occuring.
     * @since 1.7
     */
    @Override
    public float getMinimumAAPenSize() {
        return MIN_PEN_SIZE;
    }

    static {
        if (PathIterator.WIND_NON_ZERO != Renderer.WIND_NON_ZERO ||
            PathIterator.WIND_EVEN_ODD != Renderer.WIND_EVEN_ODD ||
            BasicStroke.JOIN_MITER != Stroker.JOIN_MITER ||
            BasicStroke.JOIN_ROUND != Stroker.JOIN_ROUND ||
            BasicStroke.JOIN_BEVEL != Stroker.JOIN_BEVEL ||
            BasicStroke.CAP_BUTT != Stroker.CAP_BUTT ||
            BasicStroke.CAP_ROUND != Stroker.CAP_ROUND ||
            BasicStroke.CAP_SQUARE != Stroker.CAP_SQUARE)
        {
            throw new InternalError("mismatched renderer constants");
        }
    }

    // --- RendererContext handling ---
    // use ThreadLocal or ConcurrentLinkedQueue to get one RendererContext
    private static final boolean useThreadLocal;

    // reference type stored in either TL or CLQ
    static final int REF_TYPE;

    // Per-thread RendererContext
    private static final ReentrantContextProvider<RendererContext> rdrCtxProvider;

    // Static initializer to use TL or CLQ mode
    static {
        useThreadLocal = MarlinProperties.isUseThreadLocal();

        // Soft reference by default:
        final String refType = AccessController.doPrivileged(
                            new GetPropertyAction("sun.java2d.renderer.useRef",
                            "soft"));
        switch (refType) {
            default:
            case "soft":
                REF_TYPE = ReentrantContextProvider.REF_SOFT;
                break;
            case "weak":
                REF_TYPE = ReentrantContextProvider.REF_WEAK;
                break;
            case "hard":
                REF_TYPE = ReentrantContextProvider.REF_HARD;
                break;
        }

        if (useThreadLocal) {
            rdrCtxProvider = new ReentrantContextProviderTL<RendererContext>(REF_TYPE)
                {
                    @Override
                    protected RendererContext newContext() {
                        return RendererContext.createContext();
                    }
                };
        } else {
            rdrCtxProvider = new ReentrantContextProviderCLQ<RendererContext>(REF_TYPE)
                {
                    @Override
                    protected RendererContext newContext() {
                        return RendererContext.createContext();
                    }
                };
        }
    }

    private static boolean settingsLogged = !enableLogs;

    private static void logSettings(final String reClass) {
        // log information at startup
        if (settingsLogged) {
            return;
        }
        settingsLogged = true;

        String refType;
        switch (REF_TYPE) {
            default:
            case ReentrantContextProvider.REF_HARD:
                refType = "hard";
                break;
            case ReentrantContextProvider.REF_SOFT:
                refType = "soft";
                break;
            case ReentrantContextProvider.REF_WEAK:
                refType = "weak";
                break;
        }

        logInfo("=========================================================="
                + "=====================");

        logInfo("Marlin software rasterizer           = ENABLED");
        logInfo("Version                              = ["
                + Version.getVersion() + "]");
        logInfo("sun.java2d.renderer                  = "
                + reClass);
        logInfo("sun.java2d.renderer.useThreadLocal   = "
                + useThreadLocal);
        logInfo("sun.java2d.renderer.useRef           = "
                + refType);

        logInfo("sun.java2d.renderer.pixelsize        = "
                + MarlinConst.INITIAL_PIXEL_DIM);
        logInfo("sun.java2d.renderer.subPixel_log2_X  = "
                + MarlinConst.SUBPIXEL_LG_POSITIONS_X);
        logInfo("sun.java2d.renderer.subPixel_log2_Y  = "
                + MarlinConst.SUBPIXEL_LG_POSITIONS_Y);
        logInfo("sun.java2d.renderer.tileSize_log2    = "
                + MarlinConst.TILE_SIZE_LG);

        logInfo("sun.java2d.renderer.blockSize_log2   = "
                + MarlinConst.BLOCK_SIZE_LG);

        logInfo("sun.java2d.renderer.blockSize_log2   = "
                + MarlinConst.BLOCK_SIZE_LG);

        // RLE / blockFlags settings

        logInfo("sun.java2d.renderer.forceRLE         = "
                + MarlinProperties.isForceRLE());
        logInfo("sun.java2d.renderer.forceNoRLE       = "
                + MarlinProperties.isForceNoRLE());
        logInfo("sun.java2d.renderer.useTileFlags     = "
                + MarlinProperties.isUseTileFlags());
        logInfo("sun.java2d.renderer.useTileFlags.useHeuristics = "
                + MarlinProperties.isUseTileFlagsWithHeuristics());
        logInfo("sun.java2d.renderer.rleMinWidth      = "
                + MarlinCache.RLE_MIN_WIDTH);

        // optimisation parameters
        logInfo("sun.java2d.renderer.useSimplifier    = "
                + MarlinConst.useSimplifier);

        // debugging parameters
        logInfo("sun.java2d.renderer.doStats          = "
                + MarlinConst.doStats);
        logInfo("sun.java2d.renderer.doMonitors       = "
                + MarlinConst.doMonitors);
        logInfo("sun.java2d.renderer.doChecks         = "
                + MarlinConst.doChecks);

        // logging parameters
        logInfo("sun.java2d.renderer.useLogger        = "
                + MarlinConst.useLogger);
        logInfo("sun.java2d.renderer.logCreateContext = "
                + MarlinConst.logCreateContext);
        logInfo("sun.java2d.renderer.logUnsafeMalloc  = "
                + MarlinConst.logUnsafeMalloc);

        // quality settings
        logInfo("Renderer settings:");
        logInfo("CUB_COUNT_LG = " + Renderer.CUB_COUNT_LG);
        logInfo("CUB_DEC_BND  = " + Renderer.CUB_DEC_BND);
        logInfo("CUB_INC_BND  = " + Renderer.CUB_INC_BND);
        logInfo("QUAD_DEC_BND = " + Renderer.QUAD_DEC_BND);

        logInfo("=========================================================="
                + "=====================");
    }

    
Get the RendererContext instance dedicated to the current thread
Returns:
RendererContext instance/**
     * Get the RendererContext instance dedicated to the current thread
     * @return RendererContext instance
     */
    @SuppressWarnings({"unchecked"})
    static RendererContext getRendererContext() {
        final RendererContext rdrCtx = rdrCtxProvider.acquire();
        if (doMonitors) {
            RendererContext.stats.mon_pre_getAATileGenerator.start();
        }
        return rdrCtx;
    }

    
Reset and return the given RendererContext instance for reuse
Params:
rdrCtx – RendererContext instance/**
     * Reset and return the given RendererContext instance for reuse
     * @param rdrCtx RendererContext instance
     */
    static void returnRendererContext(final RendererContext rdrCtx) {
        rdrCtx.dispose();

        if (doMonitors) {
            RendererContext.stats.mon_pre_getAATileGenerator.stop();
        }
        rdrCtxProvider.release(rdrCtx);
    }
}