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576 lines
21 KiB
Java
576 lines
21 KiB
Java
/*
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* Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package sun.java2d.pisces;
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import sun.awt.geom.PathConsumer2D;
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/**
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* The {@code Dasher} class takes a series of linear commands
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* ({@code moveTo}, {@code lineTo}, {@code close} and
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* {@code end}) and breaks them into smaller segments according to a
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* dash pattern array and a starting dash phase.
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*
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* <p> Issues: in J2Se, a zero length dash segment as drawn as a very
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* short dash, whereas Pisces does not draw anything. The PostScript
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* semantics are unclear.
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*
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*/
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final class Dasher implements sun.awt.geom.PathConsumer2D {
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private final PathConsumer2D out;
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private final float[] dash;
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private final float startPhase;
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private final boolean startDashOn;
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private final int startIdx;
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private boolean starting;
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private boolean needsMoveTo;
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private int idx;
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private boolean dashOn;
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private float phase;
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private float sx, sy;
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private float x0, y0;
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// temporary storage for the current curve
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private float[] curCurvepts;
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/**
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* Constructs a {@code Dasher}.
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*
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* @param out an output {@code PathConsumer2D}.
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* @param dash an array of {@code float}s containing the dash pattern
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* @param phase a {@code float} containing the dash phase
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*/
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public Dasher(PathConsumer2D out, float[] dash, float phase) {
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if (phase < 0) {
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throw new IllegalArgumentException("phase < 0 !");
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}
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this.out = out;
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// Normalize so 0 <= phase < dash[0]
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int idx = 0;
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dashOn = true;
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float d;
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while (phase >= (d = dash[idx])) {
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phase -= d;
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idx = (idx + 1) % dash.length;
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dashOn = !dashOn;
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}
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this.dash = dash;
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this.startPhase = this.phase = phase;
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this.startDashOn = dashOn;
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this.startIdx = idx;
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this.starting = true;
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// we need curCurvepts to be able to contain 2 curves because when
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// dashing curves, we need to subdivide it
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curCurvepts = new float[8 * 2];
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}
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public void moveTo(float x0, float y0) {
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if (firstSegidx > 0) {
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out.moveTo(sx, sy);
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emitFirstSegments();
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}
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needsMoveTo = true;
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this.idx = startIdx;
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this.dashOn = this.startDashOn;
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this.phase = this.startPhase;
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this.sx = this.x0 = x0;
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this.sy = this.y0 = y0;
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this.starting = true;
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}
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private void emitSeg(float[] buf, int off, int type) {
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switch (type) {
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case 8:
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out.curveTo(buf[off+0], buf[off+1],
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buf[off+2], buf[off+3],
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buf[off+4], buf[off+5]);
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break;
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case 6:
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out.quadTo(buf[off+0], buf[off+1],
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buf[off+2], buf[off+3]);
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break;
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case 4:
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out.lineTo(buf[off], buf[off+1]);
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}
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}
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private void emitFirstSegments() {
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for (int i = 0; i < firstSegidx; ) {
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emitSeg(firstSegmentsBuffer, i+1, (int)firstSegmentsBuffer[i]);
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i += (((int)firstSegmentsBuffer[i]) - 1);
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}
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firstSegidx = 0;
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}
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// We don't emit the first dash right away. If we did, caps would be
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// drawn on it, but we need joins to be drawn if there's a closePath()
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// So, we store the path elements that make up the first dash in the
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// buffer below.
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private float[] firstSegmentsBuffer = new float[7];
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private int firstSegidx = 0;
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// precondition: pts must be in relative coordinates (relative to x0,y0)
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// fullCurve is true iff the curve in pts has not been split.
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private void goTo(float[] pts, int off, final int type) {
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float x = pts[off + type - 4];
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float y = pts[off + type - 3];
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if (dashOn) {
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if (starting) {
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firstSegmentsBuffer = Helpers.widenArray(firstSegmentsBuffer,
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firstSegidx, type - 2 + 1);
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firstSegmentsBuffer[firstSegidx++] = type;
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System.arraycopy(pts, off, firstSegmentsBuffer, firstSegidx, type - 2);
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firstSegidx += type - 2;
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} else {
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if (needsMoveTo) {
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out.moveTo(x0, y0);
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needsMoveTo = false;
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}
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emitSeg(pts, off, type);
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}
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} else {
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starting = false;
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needsMoveTo = true;
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}
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this.x0 = x;
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this.y0 = y;
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}
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public void lineTo(float x1, float y1) {
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float dx = x1 - x0;
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float dy = y1 - y0;
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float len = (float) Math.sqrt(dx*dx + dy*dy);
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if (len == 0) {
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return;
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}
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// The scaling factors needed to get the dx and dy of the
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// transformed dash segments.
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float cx = dx / len;
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float cy = dy / len;
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while (true) {
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float leftInThisDashSegment = dash[idx] - phase;
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if (len <= leftInThisDashSegment) {
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curCurvepts[0] = x1;
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curCurvepts[1] = y1;
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goTo(curCurvepts, 0, 4);
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// Advance phase within current dash segment
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phase += len;
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if (len == leftInThisDashSegment) {
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phase = 0f;
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idx = (idx + 1) % dash.length;
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dashOn = !dashOn;
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}
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return;
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}
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float dashdx = dash[idx] * cx;
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float dashdy = dash[idx] * cy;
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if (phase == 0) {
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curCurvepts[0] = x0 + dashdx;
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curCurvepts[1] = y0 + dashdy;
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} else {
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float p = leftInThisDashSegment / dash[idx];
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curCurvepts[0] = x0 + p * dashdx;
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curCurvepts[1] = y0 + p * dashdy;
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}
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goTo(curCurvepts, 0, 4);
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len -= leftInThisDashSegment;
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// Advance to next dash segment
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idx = (idx + 1) % dash.length;
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dashOn = !dashOn;
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phase = 0;
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}
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}
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private LengthIterator li = null;
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// preconditions: curCurvepts must be an array of length at least 2 * type,
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// that contains the curve we want to dash in the first type elements
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private void somethingTo(int type) {
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if (pointCurve(curCurvepts, type)) {
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return;
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}
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if (li == null) {
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li = new LengthIterator(4, 0.01f);
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}
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li.initializeIterationOnCurve(curCurvepts, type);
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int curCurveoff = 0; // initially the current curve is at curCurvepts[0...type]
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float lastSplitT = 0;
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float t = 0;
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float leftInThisDashSegment = dash[idx] - phase;
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while ((t = li.next(leftInThisDashSegment)) < 1) {
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if (t != 0) {
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Helpers.subdivideAt((t - lastSplitT) / (1 - lastSplitT),
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curCurvepts, curCurveoff,
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curCurvepts, 0,
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curCurvepts, type, type);
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lastSplitT = t;
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goTo(curCurvepts, 2, type);
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curCurveoff = type;
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}
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// Advance to next dash segment
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idx = (idx + 1) % dash.length;
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dashOn = !dashOn;
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phase = 0;
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leftInThisDashSegment = dash[idx];
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}
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goTo(curCurvepts, curCurveoff+2, type);
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phase += li.lastSegLen();
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if (phase >= dash[idx]) {
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phase = 0f;
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idx = (idx + 1) % dash.length;
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dashOn = !dashOn;
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}
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}
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private static boolean pointCurve(float[] curve, int type) {
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for (int i = 2; i < type; i++) {
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if (curve[i] != curve[i-2]) {
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return false;
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}
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}
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return true;
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}
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// Objects of this class are used to iterate through curves. They return
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// t values where the left side of the curve has a specified length.
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// It does this by subdividing the input curve until a certain error
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// condition has been met. A recursive subdivision procedure would
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// return as many as 1<<limit curves, but this is an iterator and we
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// don't need all the curves all at once, so what we carry out a
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// lazy inorder traversal of the recursion tree (meaning we only move
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// through the tree when we need the next subdivided curve). This saves
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// us a lot of memory because at any one time we only need to store
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// limit+1 curves - one for each level of the tree + 1.
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// NOTE: the way we do things here is not enough to traverse a general
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// tree; however, the trees we are interested in have the property that
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// every non leaf node has exactly 2 children
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private static class LengthIterator {
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private enum Side {LEFT, RIGHT};
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// Holds the curves at various levels of the recursion. The root
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// (i.e. the original curve) is at recCurveStack[0] (but then it
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// gets subdivided, the left half is put at 1, so most of the time
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// only the right half of the original curve is at 0)
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private float[][] recCurveStack;
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// sides[i] indicates whether the node at level i+1 in the path from
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// the root to the current leaf is a left or right child of its parent.
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private Side[] sides;
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private int curveType;
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private final int limit;
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private final float ERR;
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private final float minTincrement;
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// lastT and nextT delimit the current leaf.
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private float nextT;
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private float lenAtNextT;
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private float lastT;
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private float lenAtLastT;
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private float lenAtLastSplit;
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private float lastSegLen;
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// the current level in the recursion tree. 0 is the root. limit
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// is the deepest possible leaf.
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private int recLevel;
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private boolean done;
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// the lengths of the lines of the control polygon. Only its first
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// curveType/2 - 1 elements are valid. This is an optimization. See
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// next(float) for more detail.
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private float[] curLeafCtrlPolyLengths = new float[3];
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public LengthIterator(int reclimit, float err) {
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this.limit = reclimit;
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this.minTincrement = 1f / (1 << limit);
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this.ERR = err;
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this.recCurveStack = new float[reclimit+1][8];
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this.sides = new Side[reclimit];
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// if any methods are called without first initializing this object on
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// a curve, we want it to fail ASAP.
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this.nextT = Float.MAX_VALUE;
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this.lenAtNextT = Float.MAX_VALUE;
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this.lenAtLastSplit = Float.MIN_VALUE;
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this.recLevel = Integer.MIN_VALUE;
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this.lastSegLen = Float.MAX_VALUE;
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this.done = true;
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}
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public void initializeIterationOnCurve(float[] pts, int type) {
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System.arraycopy(pts, 0, recCurveStack[0], 0, type);
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this.curveType = type;
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this.recLevel = 0;
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this.lastT = 0;
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this.lenAtLastT = 0;
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this.nextT = 0;
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this.lenAtNextT = 0;
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goLeft(); // initializes nextT and lenAtNextT properly
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this.lenAtLastSplit = 0;
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if (recLevel > 0) {
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this.sides[0] = Side.LEFT;
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this.done = false;
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} else {
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// the root of the tree is a leaf so we're done.
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this.sides[0] = Side.RIGHT;
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this.done = true;
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}
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this.lastSegLen = 0;
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}
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// 0 == false, 1 == true, -1 == invalid cached value.
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private int cachedHaveLowAcceleration = -1;
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private boolean haveLowAcceleration(float err) {
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if (cachedHaveLowAcceleration == -1) {
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final float len1 = curLeafCtrlPolyLengths[0];
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final float len2 = curLeafCtrlPolyLengths[1];
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// the test below is equivalent to !within(len1/len2, 1, err).
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// It is using a multiplication instead of a division, so it
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// should be a bit faster.
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if (!Helpers.within(len1, len2, err*len2)) {
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cachedHaveLowAcceleration = 0;
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return false;
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}
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if (curveType == 8) {
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final float len3 = curLeafCtrlPolyLengths[2];
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// if len1 is close to 2 and 2 is close to 3, that probably
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// means 1 is close to 3 so the second part of this test might
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// not be needed, but it doesn't hurt to include it.
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if (!(Helpers.within(len2, len3, err*len3) &&
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Helpers.within(len1, len3, err*len3))) {
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cachedHaveLowAcceleration = 0;
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return false;
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}
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}
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cachedHaveLowAcceleration = 1;
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return true;
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}
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return (cachedHaveLowAcceleration == 1);
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}
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// we want to avoid allocations/gc so we keep this array so we
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// can put roots in it,
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private float[] nextRoots = new float[4];
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// caches the coefficients of the current leaf in its flattened
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// form (see inside next() for what that means). The cache is
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// invalid when it's third element is negative, since in any
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// valid flattened curve, this would be >= 0.
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private float[] flatLeafCoefCache = new float[] {0, 0, -1, 0};
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// returns the t value where the remaining curve should be split in
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// order for the left subdivided curve to have length len. If len
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// is >= than the length of the uniterated curve, it returns 1.
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public float next(final float len) {
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final float targetLength = lenAtLastSplit + len;
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while(lenAtNextT < targetLength) {
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if (done) {
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lastSegLen = lenAtNextT - lenAtLastSplit;
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return 1;
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}
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goToNextLeaf();
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}
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lenAtLastSplit = targetLength;
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final float leaflen = lenAtNextT - lenAtLastT;
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float t = (targetLength - lenAtLastT) / leaflen;
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// cubicRootsInAB is a fairly expensive call, so we just don't do it
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// if the acceleration in this section of the curve is small enough.
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if (!haveLowAcceleration(0.05f)) {
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// We flatten the current leaf along the x axis, so that we're
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// left with a, b, c which define a 1D Bezier curve. We then
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// solve this to get the parameter of the original leaf that
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// gives us the desired length.
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if (flatLeafCoefCache[2] < 0) {
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float x = 0+curLeafCtrlPolyLengths[0],
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y = x+curLeafCtrlPolyLengths[1];
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if (curveType == 8) {
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float z = y + curLeafCtrlPolyLengths[2];
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flatLeafCoefCache[0] = 3*(x - y) + z;
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flatLeafCoefCache[1] = 3*(y - 2*x);
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flatLeafCoefCache[2] = 3*x;
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flatLeafCoefCache[3] = -z;
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} else if (curveType == 6) {
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flatLeafCoefCache[0] = 0f;
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flatLeafCoefCache[1] = y - 2*x;
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flatLeafCoefCache[2] = 2*x;
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flatLeafCoefCache[3] = -y;
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}
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}
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float a = flatLeafCoefCache[0];
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float b = flatLeafCoefCache[1];
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float c = flatLeafCoefCache[2];
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float d = t*flatLeafCoefCache[3];
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// we use cubicRootsInAB here, because we want only roots in 0, 1,
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// and our quadratic root finder doesn't filter, so it's just a
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// matter of convenience.
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int n = Helpers.cubicRootsInAB(a, b, c, d, nextRoots, 0, 0, 1);
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if (n == 1 && !Float.isNaN(nextRoots[0])) {
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t = nextRoots[0];
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}
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}
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// t is relative to the current leaf, so we must make it a valid parameter
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// of the original curve.
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t = t * (nextT - lastT) + lastT;
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if (t >= 1) {
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t = 1;
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done = true;
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}
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// even if done = true, if we're here, that means targetLength
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// is equal to, or very, very close to the total length of the
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// curve, so lastSegLen won't be too high. In cases where len
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// overshoots the curve, this method will exit in the while
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// loop, and lastSegLen will still be set to the right value.
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lastSegLen = len;
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return t;
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}
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public float lastSegLen() {
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return lastSegLen;
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}
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// go to the next leaf (in an inorder traversal) in the recursion tree
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// preconditions: must be on a leaf, and that leaf must not be the root.
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private void goToNextLeaf() {
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// We must go to the first ancestor node that has an unvisited
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// right child.
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recLevel--;
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while(sides[recLevel] == Side.RIGHT) {
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if (recLevel == 0) {
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done = true;
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return;
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}
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recLevel--;
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}
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sides[recLevel] = Side.RIGHT;
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System.arraycopy(recCurveStack[recLevel], 0, recCurveStack[recLevel+1], 0, curveType);
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recLevel++;
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goLeft();
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}
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// go to the leftmost node from the current node. Return its length.
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private void goLeft() {
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float len = onLeaf();
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if (len >= 0) {
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lastT = nextT;
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lenAtLastT = lenAtNextT;
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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");
|
|
}
|
|
}
|
|
|