Victor Menta Victor Menta - 7 months ago 18
Java Question

Adding axis labels and titles to a simple line graph/chart

I'm new to Java programming. I have a graph created in java but I want to add a title (e.g. "Variation of Distance with time")and also label the x-axis (e.g. "Time (s)") and y-axis (e.g. "Distance (m)"), with the y-axis rotated through 90 degrees.

How would I achieve that?

The code is given below.

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.Stroke;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

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;

public GraphPanel(List<Double> scores) {
this.scores = scores;
}

@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) / (scores.size() - 1);
double yScale = ((double) getHeight() - 2 * padding - labelPadding) / (getMaxScore() - getMinScore());

List<Point> graphPoints = new ArrayList<>();
for (int i = 0; i < scores.size(); i++) {
int x1 = (int) (i * xScale + padding + labelPadding);
int y1 = (int) ((getMaxScore() - scores.get(i)) * 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 (scores.size() > 0) {
g2.setColor(gridColor);
g2.drawLine(padding + labelPadding + 1 + pointWidth, y0, getWidth() - padding, y1);
g2.setColor(Color.BLACK);
String yLabel = ((int) ((getMinScore() + (getMaxScore() - getMinScore()) * ((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 < scores.size(); i++) {
if (scores.size() > 1) {
int x0 = i * (getWidth() - padding * 2 - labelPadding) / (scores.size() - 1) + padding + labelPadding;
int x1 = x0;
int y0 = getHeight() - padding - labelPadding;
int y1 = y0 - pointWidth;
if ((i % ((int) ((scores.size() / 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<>();
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(scores);
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();
}
});
}
}

Answer
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.Stroke;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class MainPanel extends JPanel {

public MainPanel(List<Double> scores) {

    setLayout(new BorderLayout());

    JLabel title = new JLabel("Variation of Distance with time");
    title.setFont(new Font("Arial", Font.BOLD, 25));
    title.setHorizontalAlignment(JLabel.CENTER);

    JPanel graphPanel = new GraphPanel(scores);

    MainPanel.VerticalPanel vertPanel = new MainPanel.VerticalPanel();

    MainPanel.HorizontalPanel horiPanel = new MainPanel.HorizontalPanel();

    add(title, BorderLayout.NORTH);
    add(horiPanel, BorderLayout.SOUTH);
    add(vertPanel, BorderLayout.WEST);
    add(graphPanel, BorderLayout.CENTER);
}

class VerticalPanel extends JPanel {

    public VerticalPanel() {
        setPreferredSize(new Dimension(25, 0));
    }

    @Override
    public void paintComponent(Graphics g) {

        super.paintComponent(g);

        Graphics2D gg = (Graphics2D) g;
        gg.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

        Font font = new Font("Arial", Font.PLAIN, 15);

        String string = "Time (s)";

        FontMetrics metrics = g.getFontMetrics(font);
        int width = metrics.stringWidth(string);
        int height = metrics.getHeight();

        gg.setFont(font);

        drawRotate(gg, getWidth(), (getHeight() + width) / 2, 270, string);
    }

    public void drawRotate(Graphics2D gg, double x, double y, int angle, String text) {
        gg.translate((float) x, (float) y);
        gg.rotate(Math.toRadians(angle));
        gg.drawString(text, 0, 0);
        gg.rotate(-Math.toRadians(angle));
        gg.translate(-(float) x, -(float) y);
    }

}

class HorizontalPanel extends JPanel {

    public HorizontalPanel() {
        setPreferredSize(new Dimension(0, 25));
    }

    @Override
    public void paintComponent(Graphics g) {

        super.paintComponent(g);

        Graphics2D gg = (Graphics2D) g;
        gg.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

        Font font = new Font("Arial", Font.PLAIN, 15);

        String string = "Distance (m)";

        FontMetrics metrics = g.getFontMetrics(font);
        int width = metrics.stringWidth(string);
        int height = metrics.getHeight();

        gg.setFont(font);

        gg.drawString(string, (getWidth() - width) / 2, 11);
    }

}

static class GraphPanel extends JPanel {
//    private List<Double> scores;

    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;

    public GraphPanel(List<Double> scores) {
        this.scores = scores;
    }

    @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) / (scores.size() - 1);
        double yScale = ((double) getHeight() - 2 * padding - labelPadding) / (getMaxScore() - getMinScore());

        List<Point> graphPoints = new ArrayList<>();
        for (int i = 0; i < scores.size(); i++) {
            int x1 = (int) (i * xScale + padding + labelPadding);
            int y1 = (int) ((getMaxScore() - scores.get(i)) * 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 (scores.size() > 0) {
                g2.setColor(gridColor);
                g2.drawLine(padding + labelPadding + 1 + pointWidth, y0, getWidth() - padding, y1);
                g2.setColor(Color.BLACK);
                String yLabel = ((int) ((getMinScore() + (getMaxScore() - getMinScore()) * ((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 < scores.size(); i++) {
            if (scores.size() > 1) {
                int x0 = i * (getWidth() - padding * 2 - labelPadding) / (scores.size() - 1) + padding + labelPadding;
                int x1 = x0;
                int y0 = getHeight() - padding - labelPadding;
                int y1 = y0 - pointWidth;
                if ((i % ((int) ((scores.size() / 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;
    }

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

    class VerticalPanel extends JPanel {

        public VerticalPanel() {
            setPreferredSize(new Dimension(25, 0));
        }

        @Override
        public void paintComponent(Graphics g) {

            super.paintComponent(g);

            Graphics2D gg = (Graphics2D) g;
            gg.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

            Font font = new Font("Arial", Font.PLAIN, 15);

            String string = "Time (s)";

            FontMetrics metrics = g.getFontMetrics(font);
            int width = metrics.stringWidth(string);
            int height = metrics.getHeight();

            gg.setFont(font);

            drawRotate(gg, getWidth(), (getHeight() + width) / 2, 270, string);
        }

        public void drawRotate(Graphics2D gg, double x, double y, int angle, String text) {
            gg.translate((float) x, (float) y);
            gg.rotate(Math.toRadians(angle));
            gg.drawString(text, 0, 0);
            gg.rotate(-Math.toRadians(angle));
            gg.translate(-(float) x, -(float) y);
        }

    }

    class HorizontalPanel extends JPanel {

        public HorizontalPanel() {
            setPreferredSize(new Dimension(0, 25));
        }

        @Override
        public void paintComponent(Graphics g) {

            super.paintComponent(g);

            Graphics2D gg = (Graphics2D) g;
            gg.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

            Font font = new Font("Arial", Font.PLAIN, 15);

            String string = "Distance (m)";

            FontMetrics metrics = g.getFontMetrics(font);
            int width = metrics.stringWidth(string);
            int height = metrics.getHeight();

            gg.setFont(font);

            gg.drawString(string, (getWidth() - width) / 2, 11);
        }

    }

}

}

The calling method will be something like:

public void btnPlotActionPerformed(java.awt.event.ActionEvent evt) {                                            
MainPanel daGraph = new MainPanel(plotValues);
    Object option[] = {" Exit "};
JOptionPane.showOptionDialog(this, daGraph, "Distance-Time Graph", JOptionPane.PLAIN_MESSAGE, JOptionPane.PLAIN_MESSAGE, null, option, null);
}