Java Polygon tutorial

[Turk4n]

Hello and welcome to a CodeCall Java tutorial. Today I will talk about Pentagons in Java and how you can draw one also using it for fun with javas buildin GUI set; swing.
Firstly we all no what a Pentagons is, however for those unfamiliar with what a pentagons is here is an example of a pentagon.


So mainly a pentagon is a five edged figure. So how do I draw a pentagon with swing?
Well let's get going and do the thing.

Step #1
Make the pentagon(Object !)

Import the needed packages

Packages

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

Create the object

Class

public class Pent extends JPanel implements ActionListener {

Add up the needed variables

private int n,r;
	private double angle;
	private int[] x,y;
	private double dv = 5*2*Math.PI/360;
	private double turn = 0.0;
	private Timer tim = new Timer(100, this);

What are our variables for? Firstly we need two integers which represents the sum of every part and time. We need angle to deiced the angle of our pentagon you could do as you suit with it later on. We need two arrays to represent the 2-D figure. Dv will represent our edges and turn how much it will turn since I want to show one possibility with swing why not show off?
tim presents the time it will take to go around and around the world...

Build up functions

Pentagon

public Pent(int pieces, int radie) {
		n=pieces; r=radie;
		x = new int[n];
		y = new int[n];
		angle= 2*Math.PI/n;
	}

Our pentagon will take form soon, this is it's bones...

Start and Stop

	public void start() {
		tim.start();
	}
	public void stop() {
		tim.stop();
	}

Movement of our pentagon

	public void actionPerformed(ActionEvent E) {
		turn= turn+dv;
		if(turn>2*Math.PI)
			turn-= 2*Math.PI;
		repaint();
	}

Pentagon behavior

	public void paintComponent(Graphics G) {
		super.paintComponents(G);
		int x0 = getSize().width/2;
		int y0 = getSize().height/2;
		
		for(int i=0; i<n; i++) {
			double v = i*angle- turn;
		x[i] = x0 + (int)Math.round(r*Math.cos(v));
		y[i] = y0 + (int)Math.round(r*Math.sin(v));
		}
		G.fillPolygon(x, y, n);
	}
}

Here we are actually filling the figure in a component that will we later present up into a frame with a start and stop button. The math.round presents the rotation that will happen.
Lets work on the main class now.

Main packages

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

Main class

public class PentDemo extends JFrame implements ActionListener {

Main variables

private JButton On= new JButton("On");
	private JButton Off = new JButton("Off");
        private JPanel a = new JPanel();
	private Pent p = new Poly(5,50);

We are going to use a Frame as our container for the Panel which will contain the pentagram allowing us to have it in a fine motion without disturbance, you could do it on the frame if you like to instead of my way. As we do not extend from the Pentagon class(pent) instead we are creating a reference to it and adding values to the constructor.

The main constructor and GUI build...

	public PentDemo() {
		add(y,BorderLayout.CENTER);
		add(a,BorderLayout.SOUTH);
		a.add(On); a.add(Off); 
		On.addActionListener(this);
		Off.addActionListener(this);
		setSize(200,180);
		setVisible(true);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		setTitle("Pentagon");
	}

Simple frame build adding the components Panel and our Pent into the frame allowing us to use it for our own purpose I guess :X?(LOL).
Note as I told before you can add everything directly to the Frame we are extending from, instead of using a seperate Panel.(the variable called 'a')

Actions

	public void actionPerformed(ActionEvent e) {
		if(e.getSource() == On) {
			y.start();
		}
		else
			y.stop();
	}

As we using our reference from pent we can use methods inside from pent to our main, which is start and stop...

The main application...

	public static void main(String[] arg) {
		PentDemo pd = new PentDemo();
	}
}

And that's about it hope you enjoy this vague tutorial and hopefully you will do something more creative than I did...
Cheers !

Output

[WingedPanther]

+rep for nice code

[Turk4n]

Originally Posted by WingedPanther

+rep for nice code

Thank you

[BlaineSch]

How gewey!

I need to try this, I have never done GUI with Java before.
/me opens eclipse


+Rep!
Edit:

You must spread some Reputation around before giving it to Turk4n again.

[amrosama]

+rep!
love it!

[Turk4n]

Originally Posted by BlaineSch

How gewey!

I need to try this, I have never done GUI with Java before.
/me opens eclipse


+Rep!
Edit:

Lol, Good luck hope you will do something really cool

Originally Posted by amrosama

+rep!
love it!

Thank you my friend

[marwex89]

Nice work! +rep!

[Turk4n]

Originally Posted by marwex89

Nice work! +rep!

Thanks

[Jordan]

Awesome!!! +rep

[Turk4n]

Originally Posted by Jordan

Awesome!!! +rep

Glad you liked it :>