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package bezier; import model.gis.LineString; import model.gis.Point; /* * (C) 2004 - Geotechnical Software Services * * This code is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This code 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 Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this program; if not, write to the Free * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, * MA 02111-1307, USA. */ /** * A Bezier spline object. Use the SplineFactory class to create splines of this type. * * @author diffmension */ public class BezierSpline { private LineString controlPoints; private static int mult = 2; private int nParts;// 計算した後の1セットのポイント数 private int PartCount;// 計算前の1セットのポイント数 private boolean isPolygon = false; static int[][] coefficient; static boolean coeffFlag = true;;// 一回しか計算しない /** * Construct a bezier spline. Package local; Use the SplineFactory to create splines of this type. The control points are used according to the * definition of Bezier splines. * * @param controlPoints * Control points of spline (x0,y0,z0,x1,y1,z1,...) * @param nParts * Number of parts in generated spline. */ public BezierSpline(LineString line) { if (controlPoints == null) { controlPoints = new LineString(); } for (int i = 0; i < line.size(); i++) { controlPoints.add(line.get(i)); // center point if (i < line.size() - 1 && line.size() > 2) { Point point1 = line.get(i); Point point2 = line.get(i + 1); Point center = new Point(); center.setLatitude((point1.getLatitude() + point2.getLatitude()) / 2d); center.setLongitude((point1.getLongitude() + point2.getLongitude()) / 2d); controlPoints.add(center); } } // polygon 判断 if (line.get(line.size() - 1).getLongitude() == line.get(0).getLongitude() && line.get(line.size() - 1).getLatitude() == line.get(0).getLatitude() && line.size() > 2) { isPolygon = true; controlPoints.add(controlPoints.get(1));// polygonの場合は第二点を追加し、円を丸くにする } } /** * Generate this spline. * * @return Coordinates of the spline (x0,y0,z0,x1,y1,z1,...) */ public LineString generate() { if (controlPoints.size() < 3) { // LineString copy = new LineString(); // System.arraycopy(controlPoints, 0, copy, 0, controlPoints.size()); LineString line = new LineString(); for (int i = 0; i < controlPoints.size(); i++) { Point point = new Point(); point.setLatitude(controlPoints.get(i).getLatitude()); point.setLongitude(controlPoints.get(i).getLongitude()); line.add(point); } return line; } int n = controlPoints.size(); int remainder = 0; PartCount = 2;// if (coeffFlag) { createPascalsTriangle(PartCount); coeffFlag = false; } // PartCount = controlPoints.size() - 1; if (PartCount >= controlPoints.size()-1) { PartCount = controlPoints.size() - 2; } else { remainder = (controlPoints.size()) % PartCount; } nParts = PartCount * mult;// 1点 分4点 LineString spline = new LineString(); if (!isPolygon) { process(PartCount, 0, 0, spline, controlPoints); } process(PartCount, 1, 0, spline, controlPoints);// 第一曲線点 for (int i = 1; i < n - PartCount; i += PartCount) { for (int j = 1; j <= nParts; j++) { process(PartCount, i, j / (double) nParts, spline, controlPoints); } } if (remainder > 0) { LineString remainderLine = new LineString(); for (int i = remainder; i > 0; i--) { Point point = new Point(); point.setLatitude(controlPoints.get(controlPoints.size() - i).getLatitude()); point.setLongitude(controlPoints.get(controlPoints.size() - i).getLongitude()); remainderLine.add(point); } if (remainder >= 4) { int subPartCount = remainder - 1; int subnParts = mult * remainder; process(subPartCount, 0, 0, spline, remainderLine); for (int j = 1; j <= subnParts; j++) { process(subPartCount, 0, j / (double) subnParts, spline, remainderLine); } } else { spline.addAll(remainderLine); } } return spline; } /** * * @param nPow * 几次方 * @param i * 第几组 * @param t * 每一组里的第几个数 * @param line * @param spline */ private void process(int nPow, int i, double t, LineString spline, LineString motoLine) { double x = 0.0; double y = 0.0; int k = i; for (int j = 0; j <= nPow; j++) { // double b = blend(j, t); double b = blendn(nPow, j, t); x += b * motoLine.get(k).getLongitude(); y += b * motoLine.get(k).getLatitude(); k++; } Point point = new Point(); point.setLongitude(x); point.setLatitude(y); spline.add(point); } /** * n次方 n+1点 * * @param nPow * @param j * @param t * @return */ private double blendn(int nPow, int j, double t) {// 3次方 return coefficient[nPow][j] * Math.pow(t, j) * Math.pow((1 - t), nPow - j); } /** * PascalsTriangleを求め bezier のcoefficientを求める */ private void createPascalsTriangle(int PartCount) { int coeffCount = PartCount + 1; coefficient = null; coefficient = new int[coeffCount][];// Triangle for (int i = 0; i < coefficient.length; i++) { coefficient[i] = new int[i + 1]; for (int j = 0; j <= i; j++) { if (i == 0 || j == 0 || j == i) { coefficient[i][j] = 1; } else { coefficient[i][j] = coefficient[i - 1][j] + coefficient[i - 1][j - 1]; } // System.out.print(triangle[i][j]+"\t"); // 输出数组元素 } // System.out.println(); //换行 } } } |