src/java.desktop/share/classes/sun/java2d/pisces/Dasher.java
changeset 47919 66350f079368
parent 47918 a82c9f231737
parent 47880 bbd692ad4fa3
child 47920 52c9e8d2f8d9
child 48093 2cb07c3778e1
--- a/src/java.desktop/share/classes/sun/java2d/pisces/Dasher.java	Tue Nov 21 11:27:46 2017 +0530
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,575 +0,0 @@
-/*
- * 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} class takes a series of linear commands
- * ({@code moveTo}, {@code lineTo}, {@code close} and
- * {@code end}) 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}.
-     *
-     * @param out an output {@code PathConsumer2D}.
-     * @param dash an array of {@code float}s containing the dash pattern
-     * @param phase a {@code float} 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 + 1);
-                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);
-                sides[recLevel] = Side.LEFT;
-                recLevel++;
-                goLeft();
-            }
-        }
-
-        // this is a bit of a hack. It returns -1 if we're not on a leaf, and
-        // the length of the leaf if we are on a leaf.
-        private float onLeaf() {
-            float[] curve = recCurveStack[recLevel];
-            float polyLen = 0;
-
-            float x0 = curve[0], y0 = curve[1];
-            for (int i = 2; i < curveType; i += 2) {
-                final float x1 = curve[i], y1 = curve[i+1];
-                final float len = Helpers.linelen(x0, y0, x1, y1);
-                polyLen += len;
-                curLeafCtrlPolyLengths[i/2 - 1] = len;
-                x0 = x1;
-                y0 = y1;
-            }
-
-            final float lineLen = Helpers.linelen(curve[0], curve[1], curve[curveType-2], curve[curveType-1]);
-            if (polyLen - lineLen < ERR || recLevel == limit) {
-                return (polyLen + lineLen)/2;
-            }
-            return -1;
-        }
-    }
-
-    @Override
-    public void curveTo(float x1, float y1,
-                        float x2, float y2,
-                        float x3, float y3)
-    {
-        curCurvepts[0] = x0;        curCurvepts[1] = y0;
-        curCurvepts[2] = x1;        curCurvepts[3] = y1;
-        curCurvepts[4] = x2;        curCurvepts[5] = y2;
-        curCurvepts[6] = x3;        curCurvepts[7] = y3;
-        somethingTo(8);
-    }
-
-    @Override
-    public void quadTo(float x1, float y1, float x2, float y2) {
-        curCurvepts[0] = x0;        curCurvepts[1] = y0;
-        curCurvepts[2] = x1;        curCurvepts[3] = y1;
-        curCurvepts[4] = x2;        curCurvepts[5] = y2;
-        somethingTo(6);
-    }
-
-    public void closePath() {
-        lineTo(sx, sy);
-        if (firstSegidx > 0) {
-            if (!dashOn || needsMoveTo) {
-                out.moveTo(sx, sy);
-            }
-            emitFirstSegments();
-        }
-        moveTo(sx, sy);
-    }
-
-    public void pathDone() {
-        if (firstSegidx > 0) {
-            out.moveTo(sx, sy);
-            emitFirstSegments();
-        }
-        out.pathDone();
-    }
-
-    @Override
-    public long getNativeConsumer() {
-        throw new InternalError("Dasher does not use a native consumer");
-    }
-}
-