GraphPanel.java

import java.awt.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.*;


/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
/**
 *
 * @author Nawal
 */
public class GraphPanel extends JPanel {

    private int width = 800;
    private int heigth = 400;
    private int padding = 25;
    private int labelPadding = 25;
    private Color lineColor = new Color(44, 102, 230, 180);
    private Color pointColor = new Color(100, 100, 100, 180);
    private Color gridColor = new Color(200, 200, 200, 200);
    private static final Stroke GRAPH_STROKE = new BasicStroke(2f);
    private int pointWidth = 4;
    private int numberYDivisions = 10;
    //private List<Double> scores;
    private double [][] frequencyGraph;
    Graph arrays = new Graph();

    public GraphPanel() {
         this.frequencyGraph = arrays.getFreq();
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

        double xScale = ((double) getWidth() - (2 * padding) - labelPadding) / (frequencyGraph.length - 1);
        double yScale = ((double) getHeight() - 2 * padding - labelPadding) / arrays.getMaxValue() - arrays.getMinValue();

        List<Point> graphPoints = new ArrayList<Point>();
        for (int i = 0; i < frequencyGraph.length; i++) {
             for (int j = 0; j < frequencyGraph[i].length; j++) {
                  int x1 = (int) (i * xScale + padding + labelPadding);
                  int y1 = (int) (j * yScale + padding);
                  graphPoints.add(new Point(x1, y1)); 
             }
        }

        // draw white background
        g2.setColor(Color.WHITE);
        g2.fillRect(padding + labelPadding, padding, getWidth() - (2 * padding) - labelPadding, getHeight() - 2 * padding - labelPadding);
        g2.setColor(Color.BLACK);

        // create hatch marks and grid lines for y axis.
        for (int i = 0; i < numberYDivisions + 1; i++) {
            int x0 = padding + labelPadding;
            int x1 = pointWidth + padding + labelPadding;
            int y0 = getHeight() - ((i * (getHeight() - padding * 2 - labelPadding)) / numberYDivisions + padding + labelPadding);
            int y1 = y0;
            if (frequencyGraph.length > 0) {
                g2.setColor(gridColor);
                g2.drawLine(padding + labelPadding + 1 + pointWidth, y0, getWidth() - padding, y1);
                g2.setColor(Color.BLACK);
                String yLabel = ((int) ((arrays.getMinValue() + (arrays.getMaxValue() - arrays.getMinValue()) * ((i * 1.0) / numberYDivisions)) * 100)) / 100.0 + "";
                FontMetrics metrics = g2.getFontMetrics();
                int labelWidth = metrics.stringWidth(yLabel);
                g2.drawString(yLabel, x0 - labelWidth - 5, y0 + (metrics.getHeight() / 2) - 3);
            }
            g2.drawLine(x0, y0, x1, y1);
        }

        // and for x axis
        for (int i = 0; i < frequencyGraph.length; i++) {
            if (frequencyGraph.length > 1) {
                int x0 = i * (getWidth() - padding * 2 - labelPadding) / (frequencyGraph.length - 1) + padding + labelPadding;
                int x1 = x0;
                int y0 = getHeight() - padding - labelPadding;
                int y1 = y0 - pointWidth;
                if ((i % ((int) ((frequencyGraph.length / 20.0)) + 1)) == 0) {
                    g2.setColor(gridColor);
                    g2.drawLine(x0, getHeight() - padding - labelPadding - 1 - pointWidth, x1, padding);
                    g2.setColor(Color.BLACK);
                    String xLabel = i + "";
                    FontMetrics metrics = g2.getFontMetrics();
                    int labelWidth = metrics.stringWidth(xLabel);
                    g2.drawString(xLabel, x0 - labelWidth / 2, y0 + metrics.getHeight() + 3);
                }
                g2.drawLine(x0, y0, x1, y1);
            }
        }

        // create x and y axes 
        g2.drawLine(padding + labelPadding, getHeight() - padding - labelPadding, padding + labelPadding, padding);
        g2.drawLine(padding + labelPadding, getHeight() - padding - labelPadding, getWidth() - padding, getHeight() - padding - labelPadding);

        Stroke oldStroke = g2.getStroke();
        g2.setColor(lineColor);
        g2.setStroke(GRAPH_STROKE);
        for (int i = 0; i < graphPoints.size() - 1; i++) {
            int x1 = graphPoints.get(i).x;
            int y1 = graphPoints.get(i).y;
            int x2 = graphPoints.get(i + 1).x;
            int y2 = graphPoints.get(i + 1).y;
            g2.drawLine(x1, y1, x2, y2);
        }

        g2.setStroke(oldStroke);
        g2.setColor(pointColor);
        for (int i = 0; i < graphPoints.size(); i++) {
            int x = graphPoints.get(i).x - pointWidth / 2;
            int y = graphPoints.get(i).y - pointWidth / 2;
            int ovalW = pointWidth;
            int ovalH = pointWidth;
            g2.fillOval(x, y, ovalW, ovalH);
        }
    }

//    @Override
//    public Dimension getPreferredSize() {
//        return new Dimension(width, heigth);
//    }

//    private double getMinScore() {
//        double minScore = Double.MAX_VALUE;
//        for (Double score : scores) {
//            minScore = Math.min(minScore, score);
//        }
//        return minScore;
//    }
//
//    private double getMaxScore() {
//        double maxScore = Double.MIN_VALUE;
//        for (Double score : scores) {
//            maxScore = Math.max(maxScore, score);
//        }
//        return maxScore;
//    }

//    public void setScores(List<Double> scores) {
//        this.scores = scores;
//        invalidate();
//        this.repaint();
//    }

//    public List<Double> getScores() {
//        return scores;
//    }
    
    private static void createAndShowGui() {
//         List<Double> scores = new ArrayList<Double>();
//         Random random = new Random();
//         int maxDataPoints = 40;
//         int maxScore = 10;
//         for (int i = 0; i < maxDataPoints; i++) {
//              scores.add((double) random.nextDouble() * maxScore);
//              scores.add((double) i);
//         }
         GraphPanel mainPanel = new GraphPanel();
         mainPanel.setPreferredSize(new Dimension(800, 600));
         JFrame frame = new JFrame("DrawGraph");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.getContentPane().add(mainPanel);
         frame.pack();
         frame.setLocationRelativeTo(null);
         frame.setVisible(true);
    }
   
    public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}