/*
 * AreaCalc.java
 * Calculate area of arbitrary polygone 
 *
 * (c) kewler
 * http://kewler.ru
 *
 */

import java.awt.geom.*;

public class AreaCalc {

	public static void main(String[] args) {

		Area a1 = new Area(new Rectangle2D.Float(50, 50, 200, 100));
		System.out.println("area: "+area(a1));

	}



	public static double area(Area area) {

		double res = 0.0;
		double res1 = res;
		float x0,x1,x2,x3;
		float y0,y1,y2,y3;

		float[] sc = new float[6];
		float[] cc = new float[6];
		float[] pc = new float[6];

		for (PathIterator i = area.getPathIterator(null); !i.isDone(); i.next()) {
			int type = i.currentSegment(cc);

			switch (type) {
			case PathIterator.SEG_MOVETO:
				sc[0] = pc[0] = cc[0];
				sc[1] = pc[1] = cc[1];
				break;
			case PathIterator.SEG_CUBICTO:
				// System.out.println("CUBE");

				x0 = pc[0];
				y0 = pc[1];

				x1 = cc[0];
				y1 = cc[1];

				x2 = cc[2];
				y2 = cc[3];

				x3 = cc[4];
				y3 = cc[5];

				res1 = 0.3 * y1 * x0 - 0.15 * y1 * x2 - 0.15 * y1 * x3
						- 0.3 * y0 * x1 - 0.15 * y0 * x2 - 0.05 * y0 * x3
						+ 0.15 * y2 * x0 + 0.15 * y2 * x1 - 0.3 * y2 * x3
						+ 0.05 * y3 * x0 + 0.15 * y3 * x1 + 0.3 * y3 * x2;

				res += res1;
				// System.out.println("cubeto> "+res1+" >> "+res);

				pc[0] = cc[4];
				pc[1] = cc[5];

				break;
			case PathIterator.SEG_QUADTO:
				x0 = pc[0];
				y0 = pc[1];

				x1 = cc[0];
				y1 = cc[1];

				x2 = cc[2];
				y2 = cc[3];

			        res1 = (-x0*y1 + y0*x1 - 0.5 * x0*y2 - x1*y2 + 0.5 *x2*y0 + x2*y1)/3.0;
				res += res1;

				pc[0] = cc[2];
				pc[1] = cc[3];
				// System.out.println("QUAD");
			case PathIterator.SEG_LINETO:
				// res += x(i)*y(i+1) - x(i+1)*y(i) old
				// x(i) = pc[0]
				// x(i+1) = cc[0]
				// y(i) = pc[1]
				// y(i+1) = cc[1]
				// x(0) = sc[0]
				// y(0) = sc[1]

				// res+=pc[0]*cc[1]-cc[0]*pc[1];

				res1 = (pc[1] + cc[1]) * (pc[0] - cc[0]) / 2.0;
				res += res1;
				// System.out.println("lineto> "+res1+" >> "+res);

				pc[0] = cc[0];
				pc[1] = cc[1];
				break;
			case PathIterator.SEG_CLOSE:
				// System.out.println(cc[0]+","+cc[1]+" -> "+sc[0]+","+sc[1]);
				res1 = (pc[1] + sc[1]) * (pc[0] - sc[0]) / 2.0;
				res += res1;
				// System.out.println("segclose> "+res1+" >> "+res);
				break;
			} // switch

		} // for

		// res/=2.0;
		return Math.abs(res);
	}

}