| /* CubicSegment.java -- Cubic 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.CubicCurve2D; |
| import java.awt.geom.Point2D; |
| |
| /** |
| * Cubic Bezier curve segment |
| */ |
| public class CubicSegment extends Segment |
| { |
| public Point2D cp1; // control points |
| public Point2D cp2; // control points |
| |
| /** |
| * Constructor - takes coordinates of the starting point, |
| * first control point, second control point and end point, |
| * respecively. |
| */ |
| public CubicSegment(double x1, double y1, double c1x, double c1y, |
| double c2x, double c2y, double x2, double y2) |
| { |
| super(); |
| P1 = new Point2D.Double(x1, y1); |
| P2 = new Point2D.Double(x2, y2); |
| cp1 = new Point2D.Double(c1x, c1y); |
| cp2 = new Point2D.Double(c2x, c2y); |
| } |
| |
| public CubicSegment(Point2D p1, Point2D cp1, Point2D cp2, Point2D p2) |
| { |
| super(); |
| P1 = p1; |
| P2 = p2; |
| this.cp1 = cp1; |
| this.cp2 = cp2; |
| } |
| |
| /** |
| * Clones this segment |
| */ |
| public Object clone() |
| { |
| CubicSegment segment = null; |
| |
| try |
| { |
| segment = (CubicSegment) super.clone(); |
| |
| segment.P1 = (Point2D) P1.clone(); |
| segment.P2 = (Point2D) P2.clone(); |
| segment.cp1 = (Point2D) cp1.clone(); |
| segment.cp2 = (Point2D) cp2.clone(); |
| } |
| catch (CloneNotSupportedException cnse) |
| { |
| InternalError ie = new InternalError(); |
| ie.initCause(cnse); |
| throw ie; |
| } |
| |
| return segment; |
| } |
| |
| /** |
| * Get the "top" and "bottom" segments of this segment. First array element is |
| * p0 + normal, second is p0 - normal. |
| */ |
| public Segment[] getDisplacedSegments(double radius) |
| { |
| // It is, apparently, impossible to derive a curve parallel to a bezier |
| // curve (unless it's a straight line), so we have no choice but to |
| // approximate the displaced segments. Similar to FlattenPathIterator. |
| |
| Segment segmentTop = null; |
| Segment segmentBottom = null; |
| this.radius = radius; |
| |
| CubicCurve2D[] curves = new CubicCurve2D[10]; |
| curves[0] = new CubicCurve2D.Double(P1.getX(), P1.getY(), cp1.getX(), |
| cp1.getY(), cp2.getX(), cp2.getY(), |
| P2.getX(), P2.getY()); |
| int numCurves = 1; |
| |
| // Hard-coded a recursion limit of 10 and flatness of 1... should we make |
| // this an option somewhere? |
| while (numCurves > 0) |
| { |
| // The curve is flat enough, or we've reached our recursion limit, |
| // so take the current start/end points and add it as a line segment |
| // to our final approximated curves |
| if (curves[numCurves - 1].getFlatnessSq() <= (radius / 3) || numCurves == 10) |
| { |
| Segment[] displaced = new LineSegment( |
| curves[numCurves - 1].getP1(), |
| curves[numCurves - 1].getP2()).getDisplacedSegments(radius); |
| if (segmentTop == null) |
| { |
| segmentTop = displaced[0]; |
| segmentBottom = displaced[1]; |
| } |
| else |
| { |
| segmentTop.add(displaced[0]); |
| segmentBottom.add(displaced[1]); |
| } |
| numCurves--; |
| } |
| |
| // Otherwise, subdivide again and continue |
| else |
| { |
| CubicCurve2D left = new CubicCurve2D.Double(); |
| CubicCurve2D right = new CubicCurve2D.Double(); |
| curves[numCurves - 1].subdivide(left, right); |
| curves[numCurves - 1] = right; |
| curves[numCurves] = left; |
| curves[numCurves - 1] = right; |
| curves[numCurves] = left; |
| numCurves++; |
| } |
| } |
| |
| return new Segment[] { segmentTop, segmentBottom }; |
| } |
| |
| public void reverse() |
| { |
| Point2D temp = P1; |
| P1 = P2; |
| P2 = temp; |
| temp = cp1; |
| cp1 = cp2; |
| cp2 = temp; |
| } |
| |
| public double[] cp1() |
| { |
| return new double[]{cp1.getX(), cp1.getY()}; |
| } |
| |
| public double[] cp2() |
| { |
| return new double[]{cp2.getX(), cp2.getY()}; |
| } |
| } // class CubicSegment |