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Java example source code file (LayoutPathImpl.java)
The LayoutPathImpl.java Java example source code/* * Copyright (c) 2005, 2013, 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. */ /* * (C) Copyright IBM Corp. 2005, All Rights Reserved. */ package sun.font; // // This is the 'simple' mapping implementation. It does things the most // straightforward way even if that is a bit slow. It won't // handle complex paths efficiently, and doesn't handle closed paths. // import java.awt.Shape; import java.awt.font.LayoutPath; import java.awt.geom.AffineTransform; import java.awt.geom.GeneralPath; import java.awt.geom.NoninvertibleTransformException; import java.awt.geom.PathIterator; import java.awt.geom.Point2D; import java.util.Formatter; import java.util.ArrayList; import static java.awt.geom.PathIterator.*; import static java.lang.Math.abs; import static java.lang.Math.sqrt; public abstract class LayoutPathImpl extends LayoutPath { // // Convenience APIs // public Point2D pointToPath(double x, double y) { Point2D.Double pt = new Point2D.Double(x, y); pointToPath(pt, pt); return pt; } public Point2D pathToPoint(double a, double o, boolean preceding) { Point2D.Double pt = new Point2D.Double(a, o); pathToPoint(pt, preceding, pt); return pt; } public void pointToPath(double x, double y, Point2D pt) { pt.setLocation(x, y); pointToPath(pt, pt); } public void pathToPoint(double a, double o, boolean preceding, Point2D pt) { pt.setLocation(a, o); pathToPoint(pt, preceding, pt); } // // extra utility APIs // public abstract double start(); public abstract double end(); public abstract double length(); public abstract Shape mapShape(Shape s); // // debugging flags // private static final boolean LOGMAP = false; private static final Formatter LOG = new Formatter(System.out); /** * Indicate how positions past the start and limit of the * path are treated. PINNED adjusts these positions so * as to be within start and limit. EXTENDED ignores the * start and limit and effectively extends the first and * last segments of the path 'infinitely'. CLOSED wraps * positions around the ends of the path. */ public static enum EndType { PINNED, EXTENDED, CLOSED; public boolean isPinned() { return this == PINNED; } public boolean isExtended() { return this == EXTENDED; } public boolean isClosed() { return this == CLOSED; } }; // // Top level construction. // /** * Return a path representing the path from the origin through the points in order. */ public static LayoutPathImpl getPath(EndType etype, double ... coords) { if ((coords.length & 0x1) != 0) { throw new IllegalArgumentException("odd number of points not allowed"); } return SegmentPath.get(etype, coords); } /** * Use to build a SegmentPath. This takes the data and preanalyzes it for * information that the SegmentPath needs, then constructs a SegmentPath * from that. Mainly, this lets SegmentPath cache the lengths along * the path to each line segment, and so avoid calculating them over and over. */ public static final class SegmentPathBuilder { private double[] data; private int w; private double px; private double py; private double a; private boolean pconnect; /** * Construct a SegmentPathBuilder. */ public SegmentPathBuilder() { } /** * Reset the builder for a new path. Datalen is a hint of how many * points will be in the path, and the working buffer will be sized * to accommodate at least this number of points. If datalen is zero, * the working buffer is freed (it will be allocated on first use). */ public void reset(int datalen) { if (data == null || datalen > data.length) { data = new double[datalen]; } else if (datalen == 0) { data = null; } w = 0; px = py = 0; pconnect = false; } /** * Automatically build from a list of points represented by pairs of * doubles. Initial advance is zero. */ public SegmentPath build(EndType etype, double... pts) { assert(pts.length % 2 == 0); reset(pts.length / 2 * 3); for (int i = 0; i < pts.length; i += 2) { nextPoint(pts[i], pts[i+1], i != 0); } return complete(etype); } /** * Move to a new point. If there is no data, this will become the * first point. If there is data, and the previous call was a lineTo, this * point is checked against the previous point, and if different, this * starts a new segment at the same advance as the end of the last * segment. If there is data, and the previous call was a moveTo, this * replaces the point used for that previous call. * * Calling this is optional, lineTo will suffice and the initial point * will be set to 0, 0. */ public void moveTo(double x, double y) { nextPoint(x, y, false); } /** * Connect to a new point. If there is no data, the previous point * is presumed to be 0, 0. This point is checked against * the previous point, and if different, this point is added to * the path and the advance extended. If this point is the same as the * previous point, the path remains unchanged. */ public void lineTo(double x, double y) { nextPoint(x, y, true); } /** * Add a new point, and increment advance if connect is true. * * This automatically rejects duplicate points and multiple disconnected points. */ private void nextPoint(double x, double y, boolean connect) { // if zero length move or line, ignore if (x == px && y == py) { return; } if (w == 0) { // this is the first point, make sure we have space if (data == null) { data = new double[6]; } if (connect) { w = 3; // default first point to 0, 0 } } // if multiple disconnected move, just update position, leave advance alone if (w != 0 && !connect && !pconnect) { data[w-3] = px = x; data[w-2] = py = y; return; } // grow data to deal with new point if (w == data.length) { double[] t = new double[w * 2]; System.arraycopy(data, 0, t, 0, w); data = t; } if (connect) { double dx = x - px; double dy = y - py; a += sqrt(dx * dx + dy * dy); } // update data data[w++] = x; data[w++] = y; data[w++] = a; // update state px = x; py = y; pconnect = connect; } public SegmentPath complete() { return complete(EndType.EXTENDED); } /** * Complete building a SegmentPath. Once this is called, the builder is restored * to its initial state and information about the previous path is released. The * end type indicates whether to treat the path as closed, extended, or pinned. */ public SegmentPath complete(EndType etype) { SegmentPath result; if (data == null || w < 6) { return null; } if (w == data.length) { result = new SegmentPath(data, etype); reset(0); // releases pointer to data } else { double[] dataToAdopt = new double[w]; System.arraycopy(data, 0, dataToAdopt, 0, w); result = new SegmentPath(dataToAdopt, etype); reset(2); // reuses data, since we held on to it } return result; } } /** * Represents a path built from segments. Each segment is * represented by a triple: x, y, and cumulative advance. * These represent the end point of the segment. The start * point of the first segment is represented by the triple * at position 0. * * The path might have breaks in it, e.g. it is not connected. * These will be represented by pairs of triplets that share the * same advance. * * The path might be extended, pinned, or closed. If extended, * the initial and final segments are considered to extend * 'indefinitely' past the bounds of the advance. If pinned, * they end at the bounds of the advance. If closed, * advances before the start or after the end 'wrap around' the * path. * * The start of the path is the initial triple. This provides * the nominal advance at the given x, y position (typically * zero). The end of the path is the final triple. This provides * the advance at the end, the total length of the path is * thus the ending advance minus the starting advance. * * Note: We might want to cache more auxiliary data than the * advance, but this seems adequate for now. */ public static final class SegmentPath extends LayoutPathImpl { private double[] data; // triplets x, y, a EndType etype; public static SegmentPath get(EndType etype, double... pts) { return new SegmentPathBuilder().build(etype, pts); } /** * Internal, use SegmentPathBuilder or one of the static * helper functions to construct a SegmentPath. */ SegmentPath(double[] data, EndType etype) { this.data = data; this.etype = etype; } // // LayoutPath API // public void pathToPoint(Point2D location, boolean preceding, Point2D point) { locateAndGetIndex(location, preceding, point); } // the path consists of line segments, which i'll call // 'path vectors'. call each run of path vectors a 'path segment'. // no path vector in a path segment is zero length (in the // data, such vectors start a new path segment). // // for each path segment... // // for each path vector... // // we look at the dot product of the path vector and the vector from the // origin of the path vector to the test point. if <0 (case // A), the projection of the test point is before the start of // the path vector. if > the square of the length of the path vector // (case B), the projection is past the end point of the // path vector. otherwise (case C), it lies on the path vector. // determine the closeset point on the path vector. if case A, it // is the start of the path vector. if case B and this is the last // path vector in the path segment, it is the end of the path vector. If // case C, it is the projection onto the path vector. Otherwise // there is no closest point. // // if we have a closest point, compare the distance from it to // the test point against our current closest distance. // (culling should be fast, currently i am using distance // squared, but there's probably better ways). if we're // closer, save the new point as the current closest point, // and record the path vector index so we can determine the final // info if this turns out to be the closest point in the end. // // after we have processed all the segments we will have // tested each path vector and each endpoint. if our point is not on // an endpoint, we're done; we can compute the position and // offset again, or if we saved it off we can just use it. if // we're on an endpoint we need to see which path vector we should // associate with. if we're at the start or end of a path segment, // we're done-- the first or last vector of the segment is the // one we associate with. we project against that vector to // get the offset, and pin to that vector to get the length. // // otherwise, we compute the information as follows. if the // dot product (see above) with the following vector is zero, // we associate with that vector. otherwise, if the dot // product with the previous vector is zero, we associate with // that vector. otherwise we're beyond the end of the // previous vector and before the start of the current vector. // we project against both vectors and get the distance from // the test point to the projection (this will be the offset). // if they are the same, we take the following vector. // otherwise use the vector from which the test point is the // _farthest_ (this is because the point lies most clearly in // the half of the plane defined by extending that vector). // // the returned position is the path length to the (possibly // pinned) point, the offset is the projection onto the line // along the vector, and we have a boolean flag which if false // indicates that we associate with the previous vector at a // junction (which is necessary when projecting such a // location back to a point). public boolean pointToPath(Point2D pt, Point2D result) { double x = pt.getX(); // test point double y = pt.getY(); double bx = data[0]; // previous point double by = data[1]; double bl = data[2]; // start with defaults double cd2 = Double.MAX_VALUE; // current best distance from path, squared double cx = 0; // current best x double cy = 0; // current best y double cl = 0; // current best position along path int ci = 0; // current best index into data for (int i = 3; i < data.length; i += 3) { double nx = data[i]; // current end point double ny = data[i+1]; double nl = data[i+2]; double dx = nx - bx; // vector from previous to current double dy = ny - by; double dl = nl - bl; double px = x - bx; // vector from previous to test point double py = y - by; // determine sign of dot product of vectors from bx, by // if < 0, we're before the start of this vector double dot = dx * px + dy * py; // dot product double vcx, vcy, vcl; // hold closest point on vector as x, y, l int vi; // hold index of line, is data.length if last point on path do { // use break below, lets us avoid initializing vcx, vcy... if (dl == 0 || // moveto, or (dot < 0 && // before path vector and (!etype.isExtended() || i != 3))) { // closest point is start of vector vcx = bx; vcy = by; vcl = bl; vi = i; } else { double l2 = dl * dl; // aka dx * dx + dy * dy, square of length if (dot <= l2 || // closest point is not past end of vector, or (etype.isExtended() && // we're extended and at the last segment i == data.length - 3)) { double p = dot / l2; // get parametric along segment vcx = bx + p * dx; // compute closest point vcy = by + p * dy; vcl = bl + p * dl; vi = i; } else { if (i == data.length - 3) { vcx = nx; // special case, always test last point vcy = ny; vcl = nl; vi = data.length; } else { break; // typical case, skip point, we'll pick it up next iteration } } } double tdx = x - vcx; // compute distance from (usually pinned) projection to test point double tdy = y - vcy; double td2 = tdx * tdx + tdy * tdy; if (td2 <= cd2) { // new closest point, record info on it cd2 = td2; cx = vcx; cy = vcy; cl = vcl; ci = vi; } } while (false); bx = nx; by = ny; bl = nl; } // we have our closest point, get the info bx = data[ci-3]; by = data[ci-2]; if (cx != bx || cy != by) { // not on endpoint, no need to resolve double nx = data[ci]; double ny = data[ci+1]; double co = sqrt(cd2); // have a true perpendicular, so can use distance if ((x-cx)*(ny-by) > (y-cy)*(nx-bx)) { co = -co; // determine sign of offset } result.setLocation(cl, co); return false; } else { // on endpoint, we need to resolve which segment boolean havePrev = ci != 3 && data[ci-1] != data[ci-4]; boolean haveFoll = ci != data.length && data[ci-1] != data[ci+2]; boolean doExtend = etype.isExtended() && (ci == 3 || ci == data.length); if (havePrev && haveFoll) { Point2D.Double pp = new Point2D.Double(x, y); calcoffset(ci - 3, doExtend, pp); Point2D.Double fp = new Point2D.Double(x, y); calcoffset(ci, doExtend, fp); if (abs(pp.y) > abs(fp.y)) { result.setLocation(pp); return true; // associate with previous } else { result.setLocation(fp); return false; // associate with following } } else if (havePrev) { result.setLocation(x, y); calcoffset(ci - 3, doExtend, result); return true; } else { result.setLocation(x, y); calcoffset(ci, doExtend, result); return false; } } } /** * Return the location of the point passed in result as mapped to the * line indicated by index. If doExtend is true, extend the * x value without pinning to the ends of the line. * this assumes that index is valid and references a line that has * non-zero length. */ private void calcoffset(int index, boolean doExtend, Point2D result) { double bx = data[index-3]; double by = data[index-2]; double px = result.getX() - bx; double py = result.getY() - by; double dx = data[index] - bx; double dy = data[index+1] - by; double l = data[index+2] - data[index - 1]; // rx = A dot B / |B| // ry = A dot invB / |B| double rx = (px * dx + py * dy) / l; double ry = (px * -dy + py * dx) / l; if (!doExtend) { if (rx < 0) rx = 0; else if (rx > l) rx = l; } rx += data[index-1]; result.setLocation(rx, ry); } // // LayoutPathImpl API // public Shape mapShape(Shape s) { return new Mapper().mapShape(s); } public double start() { return data[2]; } public double end() { return data[data.length - 1]; } public double length() { return data[data.length-1] - data[2]; } // // Utilities // /** * Get the 'modulus' of an advance on a closed path. */ private double getClosedAdvance(double a, boolean preceding) { if (etype.isClosed()) { a -= data[2]; int count = (int)(a/length()); a -= count * length(); if (a < 0 || (a == 0 && preceding)) { a += length(); } a += data[2]; } return a; } /** * Return the index of the segment associated with advance. This * points to the start of the triple and is a multiple of 3 between * 3 and data.length-3 inclusive. It never points to a 'moveto' triple. * * If the path is closed, 'a' is mapped to * a value between the start and end of the path, inclusive. * If preceding is true, and 'a' lies on a segment boundary, * return the index of the preceding segment, else return the index * of the current segment (if it is not a moveto segment) otherwise * the following segment (which is never a moveto segment). * * Note: if the path is not closed, the advance might not actually * lie on the returned segment-- it might be before the first, or * after the last. The first or last segment (as appropriate) * will be returned in this case. */ private int getSegmentIndexForAdvance(double a, boolean preceding) { // must have local advance a = getClosedAdvance(a, preceding); // note we must avoid 'moveto' segments. the first segment is // always a moveto segment, so we always skip it. int i, lim; for (i = 5, lim = data.length-1; i < lim; i += 3) { double v = data[i]; if (a < v || (a == v && preceding)) { break; } } return i-2; // adjust to start of segment } /** * Map a location based on the provided segment, returning in pt. * Seg must be a valid 'lineto' segment. Note: if the path is * closed, x must be within the start and end of the path. */ private void map(int seg, double a, double o, Point2D pt) { double dx = data[seg] - data[seg-3]; double dy = data[seg+1] - data[seg-2]; double dl = data[seg+2] - data[seg-1]; double ux = dx/dl; // could cache these, but is it worth it? double uy = dy/dl; a -= data[seg-1]; pt.setLocation(data[seg-3] + a * ux - o * uy, data[seg-2] + a * uy + o * ux); } /** * Map the point, and return the segment index. */ private int locateAndGetIndex(Point2D loc, boolean preceding, Point2D result) { double a = loc.getX(); double o = loc.getY(); int seg = getSegmentIndexForAdvance(a, preceding); map(seg, a, o, result); return seg; } // // Mapping classes. // Map the path onto each path segment. // Record points where the advance 'enters' and 'exits' the path segment, and connect successive // points when appropriate. // /** * This represents a line segment from the iterator. Each target segment will * interpret it, and since this process needs slope along the line * segment, this lets us compute it once and pass it around easily. */ class LineInfo { double sx, sy; // start double lx, ly; // limit double m; // slope dy/dx /** * Set the lineinfo to this line */ void set(double sx, double sy, double lx, double ly) { this.sx = sx; this.sy = sy; this.lx = lx; this.ly = ly; double dx = lx - sx; if (dx == 0) { m = 0; // we'll check for this elsewhere } else { double dy = ly - sy; m = dy / dx; } } void set(LineInfo rhs) { this.sx = rhs.sx; this.sy = rhs.sy; this.lx = rhs.lx; this.ly = rhs.ly; this.m = rhs.m; } /** * Return true if we intersect the infinitely tall rectangle with * lo <= x < hi. If we do, also return the pinned portion of ourselves in * result. */ boolean pin(double lo, double hi, LineInfo result) { result.set(this); if (lx >= sx) { if (sx < hi && lx >= lo) { if (sx < lo) { if (m != 0) result.sy = sy + m * (lo - sx); result.sx = lo; } if (lx > hi) { if (m != 0) result.ly = ly + m * (hi - lx); result.lx = hi; } return true; } } else { if (lx < hi && sx >= lo) { if (lx < lo) { if (m != 0) result.ly = ly + m * (lo - lx); result.lx = lo; } if (sx > hi) { if (m != 0) result.sy = sy + m * (hi - sx); result.sx = hi; } return true; } } return false; } /** * Return true if we intersect the segment at ix. This takes * the path end type into account and computes the relevant * parameters to pass to pin(double, double, LineInfo). */ boolean pin(int ix, LineInfo result) { double lo = data[ix-1]; double hi = data[ix+2]; switch (SegmentPath.this.etype) { case PINNED: break; case EXTENDED: if (ix == 3) lo = Double.NEGATIVE_INFINITY; if (ix == data.length - 3) hi = Double.POSITIVE_INFINITY; break; case CLOSED: // not implemented break; } return pin(lo, hi, result); } } /** * Each segment will construct its own general path, mapping the provided lines * into its own simple space. */ class Segment { final int ix; // index into data array for this segment final double ux, uy; // unit vector final LineInfo temp; // working line info boolean broken; // true if a moveto has occurred since we last added to our path double cx, cy; // last point in gp GeneralPath gp; // path built for this segment Segment(int ix) { this.ix = ix; double len = data[ix+2] - data[ix-1]; this.ux = (data[ix] - data[ix-3]) / len; this.uy = (data[ix+1] - data[ix-2]) / len; this.temp = new LineInfo(); } void init() { if (LOGMAP) LOG.format("s(%d) init\n", ix); broken = true; cx = cy = Double.MIN_VALUE; this.gp = new GeneralPath(); } void move() { if (LOGMAP) LOG.format("s(%d) move\n", ix); broken = true; } void close() { if (!broken) { if (LOGMAP) LOG.format("s(%d) close\n[cp]\n", ix); gp.closePath(); } } void line(LineInfo li) { if (LOGMAP) LOG.format("s(%d) line %g, %g to %g, %g\n", ix, li.sx, li.sy, li.lx, li.ly); if (li.pin(ix, temp)) { if (LOGMAP) LOG.format("pin: %g, %g to %g, %g\n", temp.sx, temp.sy, temp.lx, temp.ly); temp.sx -= data[ix-1]; double sx = data[ix-3] + temp.sx * ux - temp.sy * uy; double sy = data[ix-2] + temp.sx * uy + temp.sy * ux; temp.lx -= data[ix-1]; double lx = data[ix-3] + temp.lx * ux - temp.ly * uy; double ly = data[ix-2] + temp.lx * uy + temp.ly * ux; if (LOGMAP) LOG.format("points: %g, %g to %g, %g\n", sx, sy, lx, ly); if (sx != cx || sy != cy) { if (broken) { if (LOGMAP) LOG.format("[mt %g, %g]\n", sx, sy); gp.moveTo((float)sx, (float)sy); } else { if (LOGMAP) LOG.format("[lt %g, %g]\n", sx, sy); gp.lineTo((float)sx, (float)sy); } } if (LOGMAP) LOG.format("[lt %g, %g]\n", lx, ly); gp.lineTo((float)lx, (float)ly); broken = false; cx = lx; cy = ly; } } } class Mapper { final LineInfo li; // working line info final ArrayList<Segment> segments; // cache additional data on segments, working objects final Point2D.Double mpt; // last moveto source point final Point2D.Double cpt; // current source point boolean haveMT; // true when last op was a moveto Mapper() { li = new LineInfo(); segments = new ArrayList<Segment>(); for (int i = 3; i < data.length; i += 3) { if (data[i+2] != data[i-1]) { // a new segment segments.add(new Segment(i)); } } mpt = new Point2D.Double(); cpt = new Point2D.Double(); } void init() { if (LOGMAP) LOG.format("init\n"); haveMT = false; for (Segment s: segments) { s.init(); } } void moveTo(double x, double y) { if (LOGMAP) LOG.format("moveto %g, %g\n", x, y); mpt.x = x; mpt.y = y; haveMT = true; } void lineTo(double x, double y) { if (LOGMAP) LOG.format("lineto %g, %g\n", x, y); if (haveMT) { // prepare previous point for no-op check cpt.x = mpt.x; cpt.y = mpt.y; } if (x == cpt.x && y == cpt.y) { // lineto is a no-op return; } if (haveMT) { // current point is the most recent moveto point haveMT = false; for (Segment s: segments) { s.move(); } } li.set(cpt.x, cpt.y, x, y); for (Segment s: segments) { s.line(li); } cpt.x = x; cpt.y = y; } void close() { if (LOGMAP) LOG.format("close\n"); lineTo(mpt.x, mpt.y); for (Segment s: segments) { s.close(); } } public Shape mapShape(Shape s) { if (LOGMAP) LOG.format("mapshape on path: %s\n", LayoutPathImpl.SegmentPath.this); PathIterator pi = s.getPathIterator(null, 1); // cheap way to handle curves. if (LOGMAP) LOG.format("start\n"); init(); final double[] coords = new double[2]; while (!pi.isDone()) { switch (pi.currentSegment(coords)) { case SEG_CLOSE: close(); break; case SEG_MOVETO: moveTo(coords[0], coords[1]); break; case SEG_LINETO: lineTo(coords[0], coords[1]); break; default: break; } pi.next(); } if (LOGMAP) LOG.format("finish\n\n"); GeneralPath gp = new GeneralPath(); for (Segment seg: segments) { gp.append(seg.gp, false); } return gp; } } // // for debugging // public String toString() { StringBuilder b = new StringBuilder(); b.append("{"); b.append(etype.toString()); b.append(" "); for (int i = 0; i < data.length; i += 3) { if (i > 0) { b.append(","); } float x = ((int)(data[i] * 100))/100.0f; float y = ((int)(data[i+1] * 100))/100.0f; float l = ((int)(data[i+2] * 10))/10.0f; b.append("{"); b.append(x); b.append(","); b.append(y); b.append(","); b.append(l); b.append("}"); } b.append("}"); return b.toString(); } } public static class EmptyPath extends LayoutPathImpl { private AffineTransform tx; public EmptyPath(AffineTransform tx) { this.tx = tx; } public void pathToPoint(Point2D location, boolean preceding, Point2D point) { if (tx != null) { tx.transform(location, point); } else { point.setLocation(location); } } public boolean pointToPath(Point2D pt, Point2D result) { result.setLocation(pt); if (tx != null) { try { tx.inverseTransform(pt, result); } catch (NoninvertibleTransformException ex) { } } return result.getX() > 0; } public double start() { return 0; } public double end() { return 0; } public double length() { return 0; } public Shape mapShape(Shape s) { if (tx != null) { return tx.createTransformedShape(s); } return s; } } } Other Java examples (source code examples)Here is a short list of links related to this Java LayoutPathImpl.java source code file: |
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