1 /* Segment.java -- Abstract segment used for BasicStroke
2 Copyright (C) 2006 Free Software Foundation, Inc.
4 This file is part of GNU Classpath.
6 GNU Classpath is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU Classpath is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU Classpath; see the file COPYING. If not, write to the
18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 Linking this library statically or dynamically with other modules is
22 making a combined work based on this library. Thus, the terms and
23 conditions of the GNU General Public License cover the whole
26 As a special exception, the copyright holders of this library give you
27 permission to link this library with independent modules to produce an
28 executable, regardless of the license terms of these independent
29 modules, and to copy and distribute the resulting executable under
30 terms of your choice, provided that you also meet, for each linked
31 independent module, the terms and conditions of the license of that
32 module. An independent module is a module which is not derived from
33 or based on this library. If you modify this library, you may extend
34 this exception to your version of the library, but you are not
35 obligated to do so. If you do not wish to do so, delete this
36 exception statement from your version. */
39 package gnu.java.awt.java2d;
41 import java.awt.geom.Point2D;
43 public abstract class Segment implements Cloneable
45 // Start and end points of THIS segment
49 // Segments can be linked together internally as a linked list
54 // Half the stroke width
55 protected double radius;
58 * Create a new, empty segment
69 * Add a segment to the polygon
70 * @param newsegment segment to add
72 public void add(Segment newsegment)
74 newsegment.first = first;
75 last.next = newsegment;
76 last = last.next.last;
80 * Reverses the orientation of the whole polygon
82 public void reverseAll()
87 Segment former = this;
94 Segment oldnext = v.next;
98 v = oldnext; // move to the next in list
102 public String toString()
104 return "Segment:"+P1+", "+P2;
108 * Get the normal vector to the slope of the line.
109 * @return vector of length radius, normal to the (x0,y0)-(x1,y1) vector)
111 protected double[] normal(double x0, double y0, double x1, double y1)
113 double dx = (x1 - x0);
114 double dy = (y1 - y0);
117 dy = radius * ((dx > 0)?1:-1);
122 dx = radius * ((dy > 0)?-1:1);
127 double N = Math.sqrt(dx * dx + dy * dy);
129 dx = -radius * dy / N;
130 dy = radius * odx / N;
132 return new double[]{ dx, dy };
136 * Reverse the current segment
138 public abstract void reverse();
141 * Get the "top" and "bottom" segments of a segment.
142 * First array element is p0 + normal, second is p0 - normal.
144 public abstract Segment[] getDisplacedSegments(double radius);
147 * Returns the coordinates of the first control point, or the start point
148 * for a line segment.
150 public abstract double[] cp1();
153 * Returns the coordinates of the second control point, or the end point
154 * for a line segment.
156 public abstract double[] cp2();