/**
 * File: FFTGraph.java
 * Author: Brian Borowski
 * Date created: October 2000
 * Date last modified: June 30, 2011
 */
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;

import javax.swing.JPanel;

public class FFTGraph extends JPanel implements ComponentListener {
    private static final long serialVersionUID = 1L;
    private int[] xi, yi, yffti;
    private double[] x, y, yfft;
    private double xMin, xMax, yMin, yMax;
    private int width, height;
    private boolean overlay, showFFT, showNormal;

    public FFTGraph() {
        addComponentListener(this);
    }

    public Dimension getPreferredSize() {
        return new Dimension(350, 250);
    }

    private void findMinAndMax() {
        yMin = yMax = y[0];
        xMin = x[0];
        xMax = x[x.length - 1];
        for (int i = 1; i < y.length; ++i) {
            if (y[i] < yMin) yMin = y[i];
            if (yfft[i] < yMin) yMin = yfft[i];
            if (y[i] > yMax) yMax = y[i];
            if (yfft[i] > yMax) yMax = yfft[i];
        }
        yMin = yMin - 0.1 * Math.abs(yMin);
        yMax = yMax + 0.1 * Math.abs(yMax);
    }

    public void plot(final double x[], final double y[], final double yfft[],
        final boolean overlay, final boolean showFFT, final boolean showNormal) {

        if (x == null || y == null || yfft == null) return;

        this.x = x;
        this.y = y;
        this.yfft = yfft;
        this.overlay = overlay;
        this.showFFT = showFFT;
        this.showNormal = showNormal;
        xi = new int[x.length];
        yi = new int[y.length];
        yffti = new int[yfft.length];
        findMinAndMax();
        fitToScreen();
        repaint();
    }

    public void componentResized(final ComponentEvent e) {
        fitToScreen();
    }

    public void componentMoved(final ComponentEvent e) { }
    public void componentHidden(final ComponentEvent e) { }
    public void componentShown(final ComponentEvent e) { }

    private void fitToScreen() {
        if (x != null && y != null) {
            width = this.getSize().width;
            height = this.getSize().height;
            for (int i = 0; i < y.length; ++i) {
                xi[i] = changeXCoords(x[i]);
                if (!overlay) {
                    yi[i] = (changeYCoords(y[i]) + height) / 2;
                    yffti[i] = changeYCoords(yfft[i]) / 2;
                } else {
                    yi[i] = changeYCoords(y[i]);
                    yffti[i] = changeYCoords(yfft[i]);
                }
            }
        }
    }

    private int changeXCoords(final double x) {
        return (int)Math.round((width / (xMax - xMin)) * (x - xMax) + width - 1);
    }

    private int changeYCoords(final double y) {
        return (int)Math.round((height / (yMin - yMax)) * (y - yMin) + height - 1);
    }

    protected void paintComponent(final Graphics g) {
        g.setColor(Color.black);
        g.fillRect(0, 0, this.getSize().width, this.getSize().height);
        g.setColor(Color.darkGray);
        for (int i = 0; i < 8; i++) {
            final int x = i * width / 8;
            g.drawLine(x, 0, x, height);
        }
        if (xi != null) {
            if (!overlay) {
                final int y = height / 2;
                g.setColor(Color.darkGray);
                g.drawLine(0, y, width, y);
            }
            if (showNormal) {
                g.setColor(Color.white);
                g.drawPolyline(xi, yi, xi.length);
            }
            if (showFFT) {
                g.setColor(Color.green);
                g.drawPolyline(xi, yffti, xi.length);
            }
        }
    }
}