楕円

TestMyEllipse01.java

ソースです。

import java.awt.Color;
import java.awt.Graphics2D;

import myMath.MyCurve;
import myMath.Tpl10;

public class TestMyEllipse01 extends Tpl10 {

	int t = 0;
	double a = 5.0;
	double b = 4.0;
	double c = 3.0;

	public void init() {
		tr.move(getWidth() / 2, getHeight() / 2);
		tr.set(1, 0, 0, -1);
		tr.scale(20);
		setTimer(10);
	}

	public void draw(Graphics2D g2) {
		double x;

		MyParaEllipse mp = new MyParaEllipse();

		x = Math.toRadians(t);

		// 軸
		g2.setColor(Color.black);
		g2.draw(tr.LineX());
		g2.draw(tr.LineY());
		// 焦点
		g2.setColor(Color.blue);
		g2.fill(tr.Point(c, 0));
		g2.fill(tr.Point(-c, 0));
		// 線
		g2.setColor(Color.green);
		mp.p(x);
		g2.draw(tr.Line(c, 0, mp.x, mp.y));
		g2.draw(tr.Line(-c, 0, mp.x, mp.y));
		// 点
		g2.setColor(Color.red);
		g2.fill(tr.Point(mp.x, mp.y));
		// 楕円
		draw(mp, 0, x);

		t++;
		if (t > 360) {
			t = 0;
		}
	}

	class MyParaEllipse extends MyCurve {
		public void p(double t) {
			x = a * Math.cos(t);
			y = b * Math.sin(t);
		}
	}

}

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