java: graphics2d and rotation test

 

import java.awt.BasicStroke;

import java.awt.EventQueue;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.geom.AffineTransform;

import java.awt.image.BufferedImage;

import java.io.IOException;


import javax.imageio.ImageIO;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.border.EmptyBorder;


public class JFrameRotate extends JFrame {


    private static final long serialVersionUID = 1L;

    private JPanel contentPane;


    /**

     * Launch the application.

     */

    public static void main(String[] args) {

        EventQueue.invokeLater(new Runnable() {

            public void run() {

                try {

                    JFrameRotate frame = new JFrameRotate();

                    frame.setVisible(true);

                } catch (Exception e) {

                    e.printStackTrace();

                }

            }

        });

    }

    

    int panelWidth=600, panelHeight=600;


    /**

     * Create the frame.

     */

    public JFrameRotate() {

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        setBounds(0, 0, panelWidth, panelHeight);

        contentPane = new JPanel();

        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));


        setContentPane(contentPane);

        loadCard();

    }


    // JFrame: public void paint(Graphics g)

    // JPanel: protected void paintComponent(Graphics g)

    @Override

    public void paint(Graphics g) {

        if (bImg!=null) {

            //g.drawImage(bImg, xCenter, yCenter, this);

            // draw the image

            Graphics2D g2d = (Graphics2D) g;

            g2d.drawImage(bImg, rotate(10), contentPane);

            g2d.drawImage(bImg, rotate(45), contentPane);

            g2d.drawImage(bImg, rotate(90), contentPane);

            g2d.drawImage(bImg, rotate90(), contentPane);

        }

    }

    

    int strokeImg =1, widthImg=100, heightImg=150;

    int xCenter=200, yCenter=300;

    BufferedImage bImg;

    

    private void loadCard() {

        bImg = new BufferedImage(widthImg,

                heightImg, BufferedImage.TYPE_INT_BGR);

        

        Graphics2D g2d = bImg.createGraphics();

        g2d.setStroke(new BasicStroke(1)); // 1 pixel

        

        // https://stackoverflow.com/questions/31152233/opening-image-asset-java-jdk-8

        String sFName = "/images/KC.png";  // See here to setup image resources

        BufferedImage img;

        try {

            img = ImageIO.read(getClass().getResource(sFName));

            g2d.drawImage(img, strokeImg, strokeImg, widthImg-(2*strokeImg),

                    heightImg-(2*strokeImg), this);

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }           

    }

    

    private AffineTransform rotate(int degree) {


        double rotationAngle=degree*Math.PI/180;

        AffineTransform transform = new AffineTransform();

        transform.rotate(rotationAngle, xCenter, yCenter);

        //transform.rotate(rotationAngle);

        transform.translate(xCenter, yCenter);

        return transform;

    }

    

    /*

     * 90 degree only, keep on position top left

     */

    private AffineTransform rotate90() {


        double rotationAngle=90*Math.PI/180;

        AffineTransform transform = new AffineTransform();

        transform.rotate(rotationAngle, xCenter, yCenter);

        

        // yCenter-heightImg = horizontal position

        // xCenter: vertical position

        transform.translate(xCenter, yCenter-heightImg);

        return transform;

    }

}