org.mechio.api.interpolation.InterpolationHelper Maven / Gradle / Ivy

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/*
 * Copyright 2014 the MechIO Project.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.mechio.api.interpolation;

import java.awt.geom.Point2D;
import java.util.ArrayList;
import java.util.List;

/**
 * Utility methods to help Interpolators.
 * 
 * @author Matthew Stevenson 
 */
public class InterpolationHelper {
    /**
     * Splits a List of Points by those with a y-value of -1.
     * @param points List of points to split
     * @return A resulting List of sublists
     */
    public static List> splitList(List points){
        List> lists = new ArrayList();
        if(points == null){
            return lists;
        }
        int len = points.size();
        if(len < 2){
            lists.add(points);
            return lists;
        }
        List breaks = new ArrayList();
        if(points.get(0).getY() == -1.0){
            return splitList(points.subList(1, len));
        }
        if(points.get(len-1).getY() == -1.0){
            return splitList(points.subList(0, len-1));
        }
        for(int i=0; i< points.size(); i++){
            Point2D p = points.get(i);
            if(p.getY() == -1.0){
                breaks.add(i);
            }
        }
        if(breaks.isEmpty()){
            lists.add(points);
            return lists;
        }
        int prev = 0;
        for(int i : breaks){
            lists.add(points.subList(prev, i));
            prev = i+1;
        }
        lists.add(points.subList(prev, len));
        return lists;
    }
}