Visual Studio Code - Coding a flag in Java

user25019520
May 13, 2024
234 views
0 votes
2 Answers

I need to figure out how to draw the Jamaica 🇯🇲 flag in Java on visual studio code.

I cannot figure out how to draw the flag. All I know is that I must used this header:

import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JComponent;

public class JamaicaComponent extends JComponent {
    public void paintComponent(Graphics g)

I have tried this code, but it doesn’t work as expected

import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JComponent;

public class JamaicaComponent extends JComponent 
{
    public void paintComponent(Graphics g)
    {
        //jamaica flat
        g.setColor(Color.GREEN);
        g.fillRect(10, 10, 180, 60);
        g.setColor(Color.YELLOW);
        g.fillRect(10, 70, 180, 60);
        g.setColor(Color.BLACK);
        g.fillRect(10, 130, 180, 60);
    }
    
}

What the code renders:

Tags: java swing

Answers

Fill with green. Draw two black triangles. Then two yellow lines of appropriate thickness.

public void paintComponent(Graphics graphics) {
    Graphics2D g = (Graphics2D)graphics;
    
    int width = getWidth();
    int height = getHeight();
    
    // Fill with green
    g.setColor(Color.GREEN);
    g.fillRect(0, 0, width, height);
    
    // 2 black triangles
    g.setColor(Color.BLACK);
    g.fillPolygon(new int[] { 0, width / 2, 0 }, new int[] { 0, height / 2, height }, 3);
    g.fillPolygon(new int[] { width, width / 2, width }, new int[] { 0, height / 2, height }, 3);

    // Note: you could draw the 2 triangles as a single sideways hourglass polygon:
    //g.fillPolygon(new int[] { 0, width, width, 0 }, new int[] { 0, height, 0, height }, 4);
    
    // 2 yellow lines
    int lineWidth = height / 9;  // Just a guess. Try different values.
    g.setColor(Color.YELLOW);
    g.setStroke(new BasicStroke(lineWidth));
    g.draw(new Line2D.Float(0, 0, width, height));
    g.draw(new Line2D.Float(width, 0, 0, height));
}

Rectangle-only solution.

Just draw the X and Y axes in yellow, and color the four quadrants of the plane alternatingly in black and green. With appropriate isometric projection, that is:

import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JComponent;
import javax.swing.SwingUtilities;
import static java.lang.Math.*;

public class JamaicaComponent extends JComponent 
{
    public void paintComponent(Graphics g)
    {
        int w = 800;
        int h = 400;
        Color green = new Color(0x009B3A);
        Color black = Color.BLACK;
        Color gold = new Color(0xFED100);
        for (int r = 0; r < h; r++) {
          for (int c = 0; c < w; c++) {
            double rx = c / (double) w - 0.5;
            double ry = r / (double) h - 0.5;
            double x = (rx - ry) / sqrt(2);
            double y = (rx + ry) / sqrt(2);
            double d = min(abs(x), abs(y));
            double stripeWidth = sqrt(17) / 24 / sqrt(5);
            g.setColor(
              d < stripeWidth ? gold : (x * y) < 0 ? green : black 
            );
            g.fillRect(c, r, 1, 1);
          }
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }

    private static void createAndShowGUI() {
        JFrame frame = new JFrame("Jamaica Flag");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new JamaicaComponent());
        frame.setSize(200, 200);
        frame.setVisible(true);
    }
}

Certainly a good way to memorize flags.

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Visual Studio Code – Coding a flag in Java

Answers