1 /* 2 * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package sun.java2d.marlin; 27 28 29 final class DCollinearSimplifier implements DPathConsumer2D { 30 31 enum SimplifierState { 32 33 Empty, PreviousPoint, PreviousLine 34 }; 35 // slope precision threshold 36 static final double EPS = 1e-4d; // aaime proposed 1e-3d 37 38 DPathConsumer2D delegate; 39 SimplifierState state; 40 double px1, py1, px2, py2; 41 double pslope; 42 43 DCollinearSimplifier() { 44 } 45 46 public DCollinearSimplifier init(DPathConsumer2D delegate) { 47 this.delegate = delegate; 48 this.state = SimplifierState.Empty; 49 50 return this; // fluent API 51 } 52 53 @Override 54 public void pathDone() { 55 emitStashedLine(); 56 state = SimplifierState.Empty; 57 delegate.pathDone(); 58 } 59 60 @Override 61 public void closePath() { 62 emitStashedLine(); 63 state = SimplifierState.Empty; 64 delegate.closePath(); 65 } 66 67 @Override 68 public long getNativeConsumer() { 69 return 0; 70 } 71 72 @Override 73 public void quadTo(double x1, double y1, double x2, double y2) { 74 emitStashedLine(); 75 delegate.quadTo(x1, y1, x2, y2); 76 // final end point: 77 state = SimplifierState.PreviousPoint; 78 px1 = x2; 79 py1 = y2; 80 } 81 82 @Override 83 public void curveTo(double x1, double y1, double x2, double y2, 84 double x3, double y3) { 85 emitStashedLine(); 86 delegate.curveTo(x1, y1, x2, y2, x3, y3); 87 // final end point: 88 state = SimplifierState.PreviousPoint; 89 px1 = x3; 90 py1 = y3; 91 } 92 93 @Override 94 public void moveTo(double x, double y) { 95 emitStashedLine(); 96 delegate.moveTo(x, y); 97 state = SimplifierState.PreviousPoint; 98 px1 = x; 99 py1 = y; 100 } 101 102 @Override 103 public void lineTo(final double x, final double y) { 104 switch (state) { 105 case Empty: 106 delegate.lineTo(x, y); 107 state = SimplifierState.PreviousPoint; 108 px1 = x; 109 py1 = y; 110 return; 111 112 case PreviousPoint: 113 state = SimplifierState.PreviousLine; 114 px2 = x; 115 py2 = y; 116 pslope = getSlope(px1, py1, x, y); 117 return; 118 119 case PreviousLine: 120 final double slope = getSlope(px2, py2, x, y); 121 // test for collinearity 122 if ((slope == pslope) || (Math.abs(pslope - slope) < EPS)) { 123 // merge segments 124 px2 = x; 125 py2 = y; 126 return; 127 } 128 // emit previous segment 129 delegate.lineTo(px2, py2); 130 px1 = px2; 131 py1 = py2; 132 px2 = x; 133 py2 = y; 134 pslope = slope; 135 return; 136 default: 137 } 138 } 139 140 private void emitStashedLine() { 141 if (state == SimplifierState.PreviousLine) { 142 delegate.lineTo(px2, py2); 143 } 144 } 145 146 private static double getSlope(double x1, double y1, double x2, double y2) { 147 double dy = y2 - y1; 148 if (dy == 0.0d) { 149 return (x2 > x1) ? Double.POSITIVE_INFINITY 150 : Double.NEGATIVE_INFINITY; 151 } 152 return (x2 - x1) / dy; 153 } 154 }