SmoothMove.java Source code

Introduction

Here is the source code for SmoothMove.java

Source

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class SmoothMove extends JPanel implements MouseMotionListener {

    private int mX, mY;

    private Image mImage;

    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.getContentPane().add(new SmoothMove());
        f.setSize(200, 200);
        f.show();
    }

    public SmoothMove() {
        addMouseMotionListener(this);
        setVisible(true);
    }

    public void mouseMoved(MouseEvent me) {
        mX = (int) me.getPoint().getX();
        mY = (int) me.getPoint().getY();
        repaint();
    }

    public void mouseDragged(MouseEvent me) {
        mouseMoved(me);
    }

    public void update(Graphics g) {
        paint(g);
    }

    public void paint(Graphics g) {
        // Clear the offscreen image.
        Dimension d = getSize();
        checkOffscreenImage();
        Graphics offG = mImage.getGraphics();
        offG.setColor(getBackground());
        offG.fillRect(0, 0, d.width, d.height);
        // Draw into the offscreen image.
        paintOffscreen(mImage.getGraphics());
        // Put the offscreen image on the screen.
        g.drawImage(mImage, 0, 0, null);
    }

    private void checkOffscreenImage() {
        Dimension d = getSize();
        if (mImage == null || mImage.getWidth(null) != d.width || mImage.getHeight(null) != d.height) {
            mImage = createImage(d.width, d.height);
        }
    }

    public void paintOffscreen(Graphics g) {
        int s = 100;
        g.setColor(Color.blue);
        g.fillRect(mX - s / 2, mY - s / 2, s, s);
    }
}