/* * Copyright (c) 2007, 2011, 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.pisces; import sun.awt.geom.PathConsumer2D; /** * The <code>Dasher</code> class takes a series of linear commands * (<code>moveTo</code>, <code>lineTo</code>, <code>close</code> and * <code>end</code>) and breaks them into smaller segments according to a * dash pattern array and a starting dash phase. * * <p> Issues: in J2Se, a zero length dash segment as drawn as a very * short dash, whereas Pisces does not draw anything.  The PostScript * semantics are unclear. * */final class Dasher implements sun.awt.geom.PathConsumer2D {     private final PathConsumer2D out;    private final float[] dash;    private final float startPhase;    private final boolean startDashOn;    private final int startIdx;     private boolean starting;    private boolean needsMoveTo;     private int idx;    private boolean dashOn;    private float phase;     private float sx, sy;    private float x0, y0;     // temporary storage for the current curve    private float[] curCurvepts;     /**     * Constructs a <code>Dasher</code>.     *     * @param out an output <code>PathConsumer2D</code>.     * @param dash an array of <code>float</code>s containing the dash pattern     * @param phase a <code>float</code> containing the dash phase     */    public Dasher(PathConsumer2D out, float[] dash, float phase) {        if (phase < 0) {            throw new IllegalArgumentException("phase < 0 !");        }         this.out = out;         // Normalize so 0 <= phase < dash[0]        int idx = 0;        dashOn = true;        float d;        while (phase >= (d = dash[idx])) {            phase -= d;            idx = (idx + 1) % dash.length;            dashOn = !dashOn;        }         this.dash = dash;        this.startPhase = this.phase = phase;        this.startDashOn = dashOn;        this.startIdx = idx;        this.starting = true;         // we need curCurvepts to be able to contain 2 curves because when        // dashing curves, we need to subdivide it        curCurvepts = new float[8 * 2];    }     public void moveTo(float x0, float y0) {        if (firstSegidx > 0) {            out.moveTo(sx, sy);            emitFirstSegments();        }        needsMoveTo = true;        this.idx = startIdx;        this.dashOn = this.startDashOn;        this.phase = this.startPhase;        this.sx = this.x0 = x0;        this.sy = this.y0 = y0;        this.starting = true;    }     private void emitSeg(float[] buf, int off, int type) {        switch (type) {        case 8:            out.curveTo(buf[off+0], buf[off+1],                        buf[off+2], buf[off+3],                        buf[off+4], buf[off+5]);            break;        case 6:            out.quadTo(buf[off+0], buf[off+1],                       buf[off+2], buf[off+3]);            break;        case 4:            out.lineTo(buf[off], buf[off+1]);        }    }     private void emitFirstSegments() {        for (int i = 0; i < firstSegidx; ) {            emitSeg(firstSegmentsBuffer, i+1, (int)firstSegmentsBuffer[i]);            i += (((int)firstSegmentsBuffer[i]) - 1);        }        firstSegidx = 0;    }     // We don't emit the first dash right away. If we did, caps would be    // drawn on it, but we need joins to be drawn if there's a closePath()    // So, we store the path elements that make up the first dash in the    // buffer below.    private float[] firstSegmentsBuffer = new float[7];    private int firstSegidx = 0;    // precondition: pts must be in relative coordinates (relative to x0,y0)    // fullCurve is true iff the curve in pts has not been split.    private void goTo(float[] pts, int off, final int type) {        float x = pts[off + type - 4];        float y = pts[off + type - 3];        if (dashOn) {            if (starting) {                firstSegmentsBuffer = Helpers.widenArray(firstSegmentsBuffer,                                      firstSegidx, type - 2);                firstSegmentsBuffer[firstSegidx++] = type;                System.arraycopy(pts, off, firstSegmentsBuffer, firstSegidx, type - 2);                firstSegidx += type - 2;            } else {                if (needsMoveTo) {                    out.moveTo(x0, y0);                    needsMoveTo = false;                }                emitSeg(pts, off, type);            }        } else {            starting = false;            needsMoveTo = true;        }        this.x0 = x;        this.y0 = y;    }     public void lineTo(float x1, float y1) {        float dx = x1 - x0;        float dy = y1 - y0;         float len = (float) Math.sqrt(dx*dx + dy*dy);         if (len == 0) {            return;        }         // The scaling factors needed to get the dx and dy of the        // transformed dash segments.        float cx = dx / len;        float cy = dy / len;         while (true) {            float leftInThisDashSegment = dash[idx] - phase;            if (len <= leftInThisDashSegment) {                curCurvepts[0] = x1;                curCurvepts[1] = y1;                goTo(curCurvepts, 0, 4);                // Advance phase within current dash segment                phase += len;                if (len == leftInThisDashSegment) {                    phase = 0f;                    idx = (idx + 1) % dash.length;                    dashOn = !dashOn;                }                return;            }             float dashdx = dash[idx] * cx;            float dashdy = dash[idx] * cy;            if (phase == 0) {                curCurvepts[0] = x0 + dashdx;                curCurvepts[1] = y0 + dashdy;            } else {                float p = leftInThisDashSegment / dash[idx];                curCurvepts[0] = x0 + p * dashdx;                curCurvepts[1] = y0 + p * dashdy;            }             goTo(curCurvepts, 0, 4);             len -= leftInThisDashSegment;            // Advance to next dash segment            idx = (idx + 1) % dash.length;            dashOn = !dashOn;            phase = 0;        }    }     private LengthIterator li = null;     // preconditions: curCurvepts must be an array of length at least 2 * type,    // that contains the curve we want to dash in the first type elements    private void somethingTo(int type) {        if (pointCurve(curCurvepts, type)) {            return;        }        if (li == null) {            li = new LengthIterator(4, 0.01f);        }        li.initializeIterationOnCurve(curCurvepts, type);         int curCurveoff = 0; // initially the current curve is at curCurvepts[0...type]        float lastSplitT = 0;        float t = 0;        float leftInThisDashSegment = dash[idx] - phase;        while ((t = li.next(leftInThisDashSegment)) < 1) {            if (t != 0) {                Helpers.subdivideAt((t - lastSplitT) / (1 - lastSplitT),                                    curCurvepts, curCurveoff,                                    curCurvepts, 0,                                    curCurvepts, type, type);                lastSplitT = t;                goTo(curCurvepts, 2, type);                curCurveoff = type;            }            // Advance to next dash segment            idx = (idx + 1) % dash.length;            dashOn = !dashOn;            phase = 0;            leftInThisDashSegment = dash[idx];        }        goTo(curCurvepts, curCurveoff+2, type);        phase += li.lastSegLen();        if (phase >= dash[idx]) {            phase = 0f;            idx = (idx + 1) % dash.length;            dashOn = !dashOn;        }    }     private static boolean pointCurve(float[] curve, int type) {        for (int i = 2; i < type; i++) {            if (curve[i] != curve[i-2]) {                return false;            }        }        return true;    }     // Objects of this class are used to iterate through curves. They return    // t values where the left side of the curve has a specified length.    // It does this by subdividing the input curve until a certain error    // condition has been met. A recursive subdivision procedure would    // return as many as 1<<limit curves, but this is an iterator and we    // don't need all the curves all at once, so what we carry out a    // lazy inorder traversal of the recursion tree (meaning we only move    // through the tree when we need the next subdivided curve). This saves    // us a lot of memory because at any one time we only need to store    // limit+1 curves - one for each level of the tree + 1.    // NOTE: the way we do things here is not enough to traverse a general    // tree; however, the trees we are interested in have the property that    // every non leaf node has exactly 2 children    private static class LengthIterator {        private enum Side {LEFT, RIGHT};        // Holds the curves at various levels of the recursion. The root        // (i.e. the original curve) is at recCurveStack[0] (but then it        // gets subdivided, the left half is put at 1, so most of the time        // only the right half of the original curve is at 0)        private float[][] recCurveStack;        // sides[i] indicates whether the node at level i+1 in the path from        // the root to the current leaf is a left or right child of its parent.        private Side[] sides;        private int curveType;        private final int limit;        private final float ERR;        private final float minTincrement;        // lastT and nextT delimit the current leaf.        private float nextT;        private float lenAtNextT;        private float lastT;        private float lenAtLastT;        private float lenAtLastSplit;        private float lastSegLen;        // the current level in the recursion tree. 0 is the root. limit        // is the deepest possible leaf.        private int recLevel;        private boolean done;         // the lengths of the lines of the control polygon. Only its first        // curveType/2 - 1 elements are valid. This is an optimization. See        // next(float) for more detail.        private float[] curLeafCtrlPolyLengths = new float[3];         public LengthIterator(int reclimit, float err) {            this.limit = reclimit;            this.minTincrement = 1f / (1 << limit);            this.ERR = err;            this.recCurveStack = new float[reclimit+1][8];            this.sides = new Side[reclimit];            // if any methods are called without first initializing this object on            // a curve, we want it to fail ASAP.            this.nextT = Float.MAX_VALUE;            this.lenAtNextT = Float.MAX_VALUE;            this.lenAtLastSplit = Float.MIN_VALUE;            this.recLevel = Integer.MIN_VALUE;            this.lastSegLen = Float.MAX_VALUE;            this.done = true;        }         public void initializeIterationOnCurve(float[] pts, int type) {            System.arraycopy(pts, 0, recCurveStack[0], 0, type);            this.curveType = type;            this.recLevel = 0;            this.lastT = 0;            this.lenAtLastT = 0;            this.nextT = 0;            this.lenAtNextT = 0;            goLeft(); // initializes nextT and lenAtNextT properly            this.lenAtLastSplit = 0;            if (recLevel > 0) {                this.sides[0] = Side.LEFT;                this.done = false;            } else {                // the root of the tree is a leaf so we're done.                this.sides[0] = Side.RIGHT;                this.done = true;            }            this.lastSegLen = 0;        }         // 0 == false, 1 == true, -1 == invalid cached value.        private int cachedHaveLowAcceleration = -1;         private boolean haveLowAcceleration(float err) {            if (cachedHaveLowAcceleration == -1) {                final float len1 = curLeafCtrlPolyLengths[0];                final float len2 = curLeafCtrlPolyLengths[1];                // the test below is equivalent to !within(len1/len2, 1, err).                // It is using a multiplication instead of a division, so it                // should be a bit faster.                if (!Helpers.within(len1, len2, err*len2)) {                    cachedHaveLowAcceleration = 0;                    return false;                }                if (curveType == 8) {                    final float len3 = curLeafCtrlPolyLengths[2];                    // if len1 is close to 2 and 2 is close to 3, that probably                    // means 1 is close to 3 so the second part of this test might                    // not be needed, but it doesn't hurt to include it.                    if (!(Helpers.within(len2, len3, err*len3) &&                          Helpers.within(len1, len3, err*len3))) {                        cachedHaveLowAcceleration = 0;                        return false;                    }                }                cachedHaveLowAcceleration = 1;                return true;            }             return (cachedHaveLowAcceleration == 1);        }         // we want to avoid allocations/gc so we keep this array so we        // can put roots in it,        private float[] nextRoots = new float[4];         // caches the coefficients of the current leaf in its flattened        // form (see inside next() for what that means). The cache is        // invalid when it's third element is negative, since in any        // valid flattened curve, this would be >= 0.        private float[] flatLeafCoefCache = new float[] {0, 0, -1, 0};        // returns the t value where the remaining curve should be split in        // order for the left subdivided curve to have length len. If len        // is >= than the length of the uniterated curve, it returns 1.        public float next(final float len) {            final float targetLength = lenAtLastSplit + len;            while(lenAtNextT < targetLength) {                if (done) {                    lastSegLen = lenAtNextT - lenAtLastSplit;                    return 1;                }                goToNextLeaf();            }            lenAtLastSplit = targetLength;            final float leaflen = lenAtNextT - lenAtLastT;            float t = (targetLength - lenAtLastT) / leaflen;             // cubicRootsInAB is a fairly expensive call, so we just don't do it            // if the acceleration in this section of the curve is small enough.            if (!haveLowAcceleration(0.05f)) {                // We flatten the current leaf along the x axis, so that we're                // left with a, b, c which define a 1D Bezier curve. We then                // solve this to get the parameter of the original leaf that                // gives us the desired length.                 if (flatLeafCoefCache[2] < 0) {                    float x = 0+curLeafCtrlPolyLengths[0],                          y = x+curLeafCtrlPolyLengths[1];                    if (curveType == 8) {                        float z = y + curLeafCtrlPolyLengths[2];                        flatLeafCoefCache[0] = 3*(x - y) + z;                        flatLeafCoefCache[1] = 3*(y - 2*x);                        flatLeafCoefCache[2] = 3*x;                        flatLeafCoefCache[3] = -z;                    } else if (curveType == 6) {                        flatLeafCoefCache[0] = 0f;                        flatLeafCoefCache[1] = y - 2*x;                        flatLeafCoefCache[2] = 2*x;                        flatLeafCoefCache[3] = -y;                    }                }                float a = flatLeafCoefCache[0];                float b = flatLeafCoefCache[1];                float c = flatLeafCoefCache[2];                float d = t*flatLeafCoefCache[3];                 // we use cubicRootsInAB here, because we want only roots in 0, 1,                // and our quadratic root finder doesn't filter, so it's just a                // matter of convenience.                int n = Helpers.cubicRootsInAB(a, b, c, d, nextRoots, 0, 0, 1);                if (n == 1 && !Float.isNaN(nextRoots[0])) {                    t = nextRoots[0];                }            }            // t is relative to the current leaf, so we must make it a valid parameter            // of the original curve.            t = t * (nextT - lastT) + lastT;            if (t >= 1) {                t = 1;                done = true;            }            // even if done = true, if we're here, that means targetLength            // is equal to, or very, very close to the total length of the            // curve, so lastSegLen won't be too high. In cases where len            // overshoots the curve, this method will exit in the while            // loop, and lastSegLen will still be set to the right value.            lastSegLen = len;            return t;        }         public float lastSegLen() {            return lastSegLen;        }         // go to the next leaf (in an inorder traversal) in the recursion tree        // preconditions: must be on a leaf, and that leaf must not be the root.        private void goToNextLeaf() {            // We must go to the first ancestor node that has an unvisited            // right child.            recLevel--;            while(sides[recLevel] == Side.RIGHT) {                if (recLevel == 0) {                    done = true;                    return;                }                recLevel--;            }             sides[recLevel] = Side.RIGHT;            System.arraycopy(recCurveStack[recLevel], 0, recCurveStack[recLevel+1], 0, curveType);            recLevel++;            goLeft();        }         // go to the leftmost node from the current node. Return its length.        private void goLeft() {            float len = onLeaf();            if (len >= 0) {                lastT = nextT;                lenAtLastT = lenAtNextT;                nextT += (1 << (limit - recLevel)) * minTincrement;                lenAtNextT += len;                // invalidate caches                flatLeafCoefCache[2] = -1;                cachedHaveLowAcceleration = -1;            } else {                Helpers.subdivide(recCurveStack[recLevel], 0,                                  recCurveStack[recLevel+1], 0,                                  recCurveStack[recLevel], 0, curveType);

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