Java: Move image towards mouse position
Solution 1:
The answer will depend on what you mean by "move towards"...
For example, if you want "bob" to act like a cat and chase the "mouse", then you will need some way to continuous evaluate the current mouse position and the image position. For this I would use a Swing Timer
, its simple and doesn't violate the single thread rules of Swing, for example...
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class ImageFollowingMouseTest {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
createAndShowGUI();
}
});
}
private static void createAndShowGUI() {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(new ImageFollowingMousePanel());
f.setSize(400, 400);
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}
class ImageFollowingMousePanel extends JPanel implements MouseMotionListener {
private final BufferedImage image;
private Point imagePosition = new Point(150, 150);
private Point mousePoint;
private double imageAngleRad = 0;
public ImageFollowingMousePanel() {
BufferedImage i = null;
try {
i = ImageIO.read(new File("6Wu0b.png"));
} catch (IOException e) {
e.printStackTrace();
}
image = i;
addMouseMotionListener(this);
Timer timer = new Timer(40, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if (mousePoint != null) {
int centerX = imagePosition.x + (image.getWidth() / 2);
int centerY = imagePosition.y + (image.getHeight() / 2);
if (mousePoint.x != centerX) {
imagePosition.x += mousePoint.x < centerX ? -1 : 1;
}
if (mousePoint.y != centerY) {
imagePosition.y += mousePoint.y < centerY ? -1 : 1;
}
repaint();
}
}
});
timer.start();
}
protected void paintComponent(Graphics gr) {
super.paintComponent(gr);
Graphics2D g = (Graphics2D) gr;
g.setRenderingHint(
RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
int cx = image.getWidth() / 2;
int cy = image.getHeight() / 2;
AffineTransform oldAT = g.getTransform();
g.translate(cx + imagePosition.x, cy + imagePosition.y);
g.rotate(imageAngleRad);
g.translate(-cx, -cy);
g.drawImage(image, 0, 0, null);
g.setTransform(oldAT);
}
@Override
public void mouseDragged(MouseEvent e) {
}
@Override
public void mouseMoved(MouseEvent e) {
mousePoint = e.getPoint();
double dx = e.getX() - imagePosition.getX();
double dy = e.getY() - imagePosition.getY();
imageAngleRad = Math.atan2(dy, dx);
repaint();
}
}