Java by API/javax.swing/RepaintManager

RepaintManager: currentManager(JComponent c)

 

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.RepaintManager;
public class Main extends JComponent implements MouseMotionListener {
  static int imageWidth = 60, imageHeight = 60;
  int imageX, imageY;
  Image image;
  public Main(Image i) {
    image = i;
    addMouseMotionListener(this);
  }
  public void mouseDragged(MouseEvent e) {
    imageX = e.getX();
    imageY = e.getY();
    repaint();
  }
  public void mouseMoved(MouseEvent e) {
  }
  public void paint(Graphics g) {
    Graphics2D g2 = (Graphics2D) g;
    g2.drawImage(image, imageX, imageY, this);
  }
  public static void main(String[] args) {
    String imageFile = "A.jpg";
    RepaintManager.currentManager(null).setDoubleBufferingEnabled(false);
    Image image = Toolkit.getDefaultToolkit().getImage(Main.class.getResource(imageFile));
    image = image.getScaledInstance(imageWidth, imageHeight, Image.SCALE_DEFAULT);
    JFrame frame = new JFrame("DragImage");
    frame.getContentPane().add(new Main(image));
    frame.setSize(300, 300);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
}

RepaintManager: setDoubleBufferingEnabled(boolean aFlag)

 

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.RepaintManager;
public class Main extends JComponent implements MouseMotionListener {
  static int imageWidth = 60, imageHeight = 60;
  int imageX, imageY;
  Image image;
  public Main(Image i) {
    image = i;
    addMouseMotionListener(this);
  }
  public void mouseDragged(MouseEvent e) {
    imageX = e.getX();
    imageY = e.getY();
    repaint();
  }
  public void mouseMoved(MouseEvent e) {
  }
  public void paint(Graphics g) {
    Graphics2D g2 = (Graphics2D) g;
    g2.drawImage(image, imageX, imageY, this);
  }
  public static void main(String[] args) {
    String imageFile = "A.jpg";
    RepaintManager.currentManager(null).setDoubleBufferingEnabled(false);
    Image image = Toolkit.getDefaultToolkit().getImage(Main.class.getResource(imageFile));
    image = image.getScaledInstance(imageWidth, imageHeight, Image.SCALE_DEFAULT);
    JFrame frame = new JFrame("DragImage");
    frame.getContentPane().add(new Main(image));
    frame.setSize(300, 300);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
}