function graphs

import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;

public class Graph extends JPanel {
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        Graph graph = new Graph(800, 600);
        graph.setPreferredSize(new Dimension(800, 600));
        frame.add(graph);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }

    private final BufferedImage image;

    public static Func func = power(2);

    public Graph(int width, int height) {
        setPreferredSize(new Dimension(width, height));
        image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

        Func easeInCubic = power(3);
        Func easeOutCubic = easeInCubic.flipXY();
        Func easeInOutCubic = easeInCubic.inOut();
        Func easeInCirc = circ;
        Func easeOutCirc = easeInCirc.flipXY();
        Func easeInOutCirc = easeInCirc.inOut();
        Func easeOutSine = sine;
        Func easeInSine = easeOutSine.flipXY();
        Func easeInOutSine = easeInSine.inOut();
        func = easeInOutSine;
    }

    public static Func power(final double e) {
        return new Func() {
            public double apply(double x) {
                return Math.pow(x, e);
            }
        };
    }

    public static Func circ = new Func() {
        public double apply(double x) {
            return 1-Math.sqrt(1-x*x);
        }
    };

    public static Func sine = new Func() {
        public double apply(double x) {
            return Math.sin(x*Math.PI/2);
        }
    };

    public void setFunc(Func func) {
        this.func = func;
    }

    @Override
    public void paint(Graphics _g) {
        Graphics2D g = (Graphics2D)_g;
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, getWidth(), getHeight());
        g.setColor(Color.BLACK);
        int lastX = 0, lastY = 0;
        for(int ix = 0; ix < getWidth(); ix++) {
            double x = ((double)ix)/getWidth();
            double y = func.apply(x);
            int iy = getHeight() - (int)(y*getHeight());
            g.drawLine(lastX, lastY, ix, iy);
            lastX = ix; lastY = iy;
        }
    }
}