Example usage for org.apache.commons.math3.geometry.euclidean.twod.hull MonotoneChain MonotoneChain

Introduction

In this page you can find the example usage for org.apache.commons.math3.geometry.euclidean.twod.hull MonotoneChain MonotoneChain.

Prototype

public MonotoneChain() 

Source Link

Document

Create a new MonotoneChain instance.

Usage

From source file:gdsc.core.utils.ConvexHull.java

/**
 * Create a new convex hull from the given coordinates.
 *
 * @param xbase/* w  ww.j  a v  a2  s .c o  m*/
 *            the x base coordinate (origin)
 * @param ybase
 *            the y base coordinate (origin)
 * @param xCoordinates
 *            the x coordinates
 * @param yCoordinates
 *            the y coordinates
 * @param n
 *            the number of coordinates
 * @return the convex hull
 * @throws NullPointerException
 *             if the inputs are null
 * @throws ArrayIndexOutOfBoundsException
 *             if the yCoordinates are smaller than the xCoordinates
 */
public static ConvexHull create(float xbase, float ybase, float[] xCoordinates, float[] yCoordinates, int n) {
    // This algorithm is not suitable for floating point coords
    //return createGiftWrap(xbase, ybase, xCoordinates, yCoordinates, n);

    // Use Apache Math to do this
    MonotoneChain chain = new MonotoneChain();
    TurboList<Vector2D> points = new TurboList<Vector2D>(n);
    for (int i = 0; i < n; i++)
        points.add(new Vector2D(xbase + xCoordinates[i], ybase + yCoordinates[i]));
    ConvexHull2D hull = null;
    try {
        hull = chain.generate(points);
    } catch (ConvergenceException e) {
    }

    if (hull == null)
        return null;

    Vector2D[] v = hull.getVertices();
    if (v.length == 0)
        return null;

    int size = v.length;
    float[] xx = new float[size];
    float[] yy = new float[size];
    int n2 = 0;
    for (int i = 0; i < size; i++) {
        xx[n2] = (float) v[i].getX();
        yy[n2] = (float) v[i].getY();
        n2++;
    }
    return new ConvexHull(0, 0, xx, yy);
}

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