| /* Segment.java -- Abstract segment used for BasicStroke |
| Copyright (C) 2006 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.java.awt.java2d; |
| |
| import java.awt.geom.Point2D; |
| |
| public abstract class Segment implements Cloneable |
| { |
| // Start and end points of THIS segment |
| public Point2D P1; |
| public Point2D P2; |
| |
| // Segments can be linked together internally as a linked list |
| public Segment first; |
| public Segment next; |
| public Segment last; |
| |
| // Half the stroke width |
| protected double radius; |
| |
| /** |
| * Create a new, empty segment |
| */ |
| public Segment() |
| { |
| P1 = P2 = null; |
| first = this; |
| next = null; |
| last = this; |
| } |
| |
| /** |
| * Add a segment to the polygon |
| * @param newsegment segment to add |
| */ |
| public void add(Segment newsegment) |
| { |
| newsegment.first = first; |
| last.next = newsegment; |
| last = last.next.last; |
| } |
| |
| /** |
| * Reverses the orientation of the whole polygon |
| */ |
| public void reverseAll() |
| { |
| reverse(); |
| first = last; |
| Segment v = next; |
| Segment former = this; |
| next = null; |
| |
| while (v != null) |
| { |
| v.reverse(); |
| v.last = this; |
| Segment oldnext = v.next; |
| v.next = former; |
| |
| former = v; |
| v = oldnext; // move to the next in list |
| } |
| } |
| |
| public String toString() |
| { |
| return "Segment:"+P1+", "+P2; |
| } |
| |
| /** |
| * Get the normal vector to the slope of the line. |
| * @return vector of length radius, normal to the (x0,y0)-(x1,y1) vector) |
| */ |
| protected double[] normal(double x0, double y0, double x1, double y1) |
| { |
| double dx = (x1 - x0); |
| double dy = (y1 - y0); |
| if( dy == 0 ) |
| { |
| dy = radius * ((dx > 0)?1:-1); |
| dx = 0; |
| } |
| else if( dx == 0 ) |
| { |
| dx = radius * ((dy > 0)?-1:1); |
| dy = 0; |
| } |
| else |
| { |
| double N = Math.sqrt(dx * dx + dy * dy); |
| double odx = dx; |
| dx = -radius * dy / N; |
| dy = radius * odx / N; |
| } |
| return new double[]{ dx, dy }; |
| } |
| |
| /** |
| * Reverse the current segment |
| */ |
| public abstract void reverse(); |
| |
| /** |
| * Get the "top" and "bottom" segments of a segment. |
| * First array element is p0 + normal, second is p0 - normal. |
| */ |
| public abstract Segment[] getDisplacedSegments(double radius); |
| |
| /** |
| * Returns the coordinates of the first control point, or the start point |
| * for a line segment. |
| */ |
| public abstract double[] cp1(); |
| |
| /** |
| * Returns the coordinates of the second control point, or the end point |
| * for a line segment. |
| */ |
| public abstract double[] cp2(); |
| |
| } |