How to rotate this rectangle over Ox, Oy and Oz axis in java?

Question

I created a rectangle in java using graphics2D and I want to rotate it over all axis, Ox, Oy and Oz in origin (0,0). How to do that ?

Because it's 2D, z = 0. So can you help me to rotate this rectangle over all axis ?

Thank you!

This is my code, I created a rectangle and I want to save it as image.

import java.awt.Canvas;
import java.awt.Color;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferedImage;
import java.io.File;

import javax.imageio.ImageIO;

public class DrawShape_SaveAsImage extends Canvas {

    public static void main(String[] args) {
        Frame f=new Frame("Draw shape and text on Canvas");
        final Canvas canvas=new DrawShape_SaveAsImage();

        f.add(canvas);

        f.setSize(600,600);
        f.setVisible(true);
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent event) {
                saveCanvas(canvas);
                System.exit(0);
            }
        });

    }

    public void paint(Graphics g) {
        Graphics2D g2=(Graphics2D)g;
        g2.setBackground(Color.WHITE);
        g2.clearRect(0, 0, this.getWidth(), this.getHeight());
        g2.setColor(Color.BLACK);
        g2.fillRect(100, 100, 200, 200);
    }

    public static void saveCanvas(Canvas canvas) {

        BufferedImage image=new BufferedImage(canvas.getWidth(), canvas.getHeight(),BufferedImage.TYPE_INT_RGB);

        Graphics2D g2=(Graphics2D)image.getGraphics();


        canvas.paint(g2);
        try {
            ImageIO.write(image, "png", new File("canvas.png"));
        } catch (Exception e) {

        }
    }
}

Answer 1

This is 2D so you can rotate around OZ only. First of all you should use Vectors for any coordinates (it makes math easy ;) ) Here you have the example of Vector class and rotation. You can check demo coded by me here: http://ideone.com/ZZjm6l

import java.util.*;
import java.lang.*;
import java.io.*;
import static java.lang.Math.*;
class Vector
{
    double x;
    double y;

    Vector(double a, double b)
    {
        x = a;
        y = b;
    }

    void add(Vector v)
    {
        x += v.x;
        y += v.y;
    }


    //other useful methods like multiply should be here

    void rotate(double angle) //https://en.wikipedia.org/wiki/Rotation_(mathematics)
    {
        double s = sin(angle);
        double c = cos(angle);

        x = x * c - y * s;
        y = x * s + y * c;
    }

}




class Main
{
    public static void main (String[] args) throws java.lang.Exception
    {
        Vector v = new Vector(1,1);
        v.rotate(Math.PI / 2);
        System.out.println(v.x + " " + v.y);
    }
}

So your fillRect should look like this after all:

g2.fillRect(v.x, v.y, 200, 200);

Good luck!