001/* =========================================================== 002 * JFreeChart : a free chart library for the Java(tm) platform 003 * =========================================================== 004 * 005 * (C) Copyright 2000-2014, by Object Refinery Limited and Contributors. 006 * 007 * Project Info: http://www.jfree.org/jfreechart/index.html 008 * 009 * This library is free software; you can redistribute it and/or modify it 010 * under the terms of the GNU Lesser General Public License as published by 011 * the Free Software Foundation; either version 2.1 of the License, or 012 * (at your option) any later version. 013 * 014 * This library is distributed in the hope that it will be useful, but 015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 017 * License for more details. 018 * 019 * You should have received a copy of the GNU Lesser General Public 020 * License along with this library; if not, write to the Free Software 021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 022 * USA. 023 * 024 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 025 * Other names may be trademarks of their respective owners.] 026 * 027 * ------------------ 028 * LineUtilities.java 029 * ------------------ 030 * (C) Copyright 2008, 2014, by Object Refinery Limited and Contributors. 031 * 032 * Original Author: David Gilbert (for Object Refinery Limited); 033 * Contributor(s): -; 034 * 035 * Changes 036 * ------- 037 * 05-Nov-2008 : Version 1 (DG); 038 * 28-Feb-2014 : Added extendLine() (DG); 039 * 040 */ 041 042package org.jfree.chart.util; 043 044import java.awt.geom.Line2D; 045import java.awt.geom.Rectangle2D; 046 047/** 048 * Some utility methods for {@link Line2D} objects. 049 * 050 * @since 1.0.12 051 */ 052public class LineUtilities { 053 054 /** 055 * Clips the specified line to the given rectangle. 056 * 057 * @param line the line (<code>null</code> not permitted). 058 * @param rect the clipping rectangle (<code>null</code> not permitted). 059 * 060 * @return <code>true</code> if the clipped line is visible, and 061 * <code>false</code> otherwise. 062 */ 063 public static boolean clipLine(Line2D line, Rectangle2D rect) { 064 065 double x1 = line.getX1(); 066 double y1 = line.getY1(); 067 double x2 = line.getX2(); 068 double y2 = line.getY2(); 069 070 double minX = rect.getMinX(); 071 double maxX = rect.getMaxX(); 072 double minY = rect.getMinY(); 073 double maxY = rect.getMaxY(); 074 075 int f1 = rect.outcode(x1, y1); 076 int f2 = rect.outcode(x2, y2); 077 078 while ((f1 | f2) != 0) { 079 if ((f1 & f2) != 0) { 080 return false; 081 } 082 double dx = (x2 - x1); 083 double dy = (y2 - y1); 084 // update (x1, y1), (x2, y2) and f1 and f2 using intersections 085 // then recheck 086 if (f1 != 0) { 087 // first point is outside, so we update it against one of the 088 // four sides then continue 089 if ((f1 & Rectangle2D.OUT_LEFT) == Rectangle2D.OUT_LEFT 090 && dx != 0.0) { 091 y1 = y1 + (minX - x1) * dy / dx; 092 x1 = minX; 093 } 094 else if ((f1 & Rectangle2D.OUT_RIGHT) == Rectangle2D.OUT_RIGHT 095 && dx != 0.0) { 096 y1 = y1 + (maxX - x1) * dy / dx; 097 x1 = maxX; 098 } 099 else if ((f1 & Rectangle2D.OUT_BOTTOM) == Rectangle2D.OUT_BOTTOM 100 && dy != 0.0) { 101 x1 = x1 + (maxY - y1) * dx / dy; 102 y1 = maxY; 103 } 104 else if ((f1 & Rectangle2D.OUT_TOP) == Rectangle2D.OUT_TOP 105 && dy != 0.0) { 106 x1 = x1 + (minY - y1) * dx / dy; 107 y1 = minY; 108 } 109 f1 = rect.outcode(x1, y1); 110 } 111 else if (f2 != 0) { 112 // second point is outside, so we update it against one of the 113 // four sides then continue 114 if ((f2 & Rectangle2D.OUT_LEFT) == Rectangle2D.OUT_LEFT 115 && dx != 0.0) { 116 y2 = y2 + (minX - x2) * dy / dx; 117 x2 = minX; 118 } 119 else if ((f2 & Rectangle2D.OUT_RIGHT) == Rectangle2D.OUT_RIGHT 120 && dx != 0.0) { 121 y2 = y2 + (maxX - x2) * dy / dx; 122 x2 = maxX; 123 } 124 else if ((f2 & Rectangle2D.OUT_BOTTOM) == Rectangle2D.OUT_BOTTOM 125 && dy != 0.0) { 126 x2 = x2 + (maxY - y2) * dx / dy; 127 y2 = maxY; 128 } 129 else if ((f2 & Rectangle2D.OUT_TOP) == Rectangle2D.OUT_TOP 130 && dy != 0.0) { 131 x2 = x2 + (minY - y2) * dx / dy; 132 y2 = minY; 133 } 134 f2 = rect.outcode(x2, y2); 135 } 136 } 137 138 line.setLine(x1, y1, x2, y2); 139 return true; // the line is visible - if it wasn't, we'd have 140 // returned false from within the while loop above 141 142 } 143 144 /** 145 * Creates a new line by extending an existing line. 146 * 147 * @param line the line (<code>null</code> not permitted). 148 * @param startPercent the amount to extend the line at the start point 149 * end. 150 * @param endPercent the amount to extend the line at the end point end. 151 * 152 * @return A new line. 153 * 154 * @since 1.0.18 155 */ 156 public static Line2D extendLine(Line2D line, double startPercent, 157 double endPercent) { 158 ParamChecks.nullNotPermitted(line, "line"); 159 double x1 = line.getX1(); 160 double x2 = line.getX2(); 161 double deltaX = x2 - x1; 162 double y1 = line.getY1(); 163 double y2 = line.getY2(); 164 double deltaY = y2 - y1; 165 x1 = x1 - (startPercent * deltaX); 166 y1 = y1 - (startPercent * deltaY); 167 x2 = x2 + (endPercent * deltaX); 168 y2 = y2 + (endPercent * deltaY); 169 return new Line2D.Double(x1, y1, x2, y2); 170 } 171 172}