Move Shape with mouse
import java.applet.Applet;
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Label;
import java.awt.Rectangle;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JApplet;
//Use double buffering to remove rectangle flickers and make it repaint faster.
public class ShapeMover extends JApplet {
static protected Label label = new Label(
"Drag rectangle around within the area");
public void init() {
getContentPane().setLayout(new BorderLayout());
getContentPane().add(new MyCanvas());
getContentPane().add("South", label);
}
public static void main(String s[]) {
Frame f = new Frame("ShapeMover");
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
Applet applet = new ShapeMover();
f.add("Center", applet);
applet.init();
f.pack();
f.setSize(new Dimension(550, 250));
f.show();
}
}
class MyCanvas extends Canvas implements MouseListener, MouseMotionListener {
Rectangle rect = new Rectangle(0, 0, 100, 50);
Graphics2D g2;
int preX, preY;
boolean isFirstTime = true;
Rectangle area;
boolean pressOut = false;
public MyCanvas() {
setBackground(Color.white);
addMouseMotionListener(this);
addMouseListener(this);
}
public void mousePressed(MouseEvent e) {
preX = rect.x - e.getX();
preY = rect.y - e.getY();
if (rect.contains(e.getX(), e.getY()))
updateLocation(e);
else {
ShapeMover.label.setText("Drag it.");
pressOut = true;
}
}
public void mouseDragged(MouseEvent e) {
if (!pressOut)
updateLocation(e);
else
ShapeMover.label.setText("Drag it.");
}
public void mouseReleased(MouseEvent e) {
if (rect.contains(e.getX(), e.getY()))
updateLocation(e);
else {
ShapeMover.label.setText("Drag it.");
pressOut = false;
}
}
public void mouseMoved(MouseEvent e) {
}
public void mouseClicked(MouseEvent e) {
}
public void mouseExited(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
public void updateLocation(MouseEvent e) {
rect.setLocation(preX + e.getX(), preY + e.getY());
if (checkRect()) {
ShapeMover.label.setText(rect.getX() + ", " + rect.getY());
} else {
ShapeMover.label.setText("drag inside the area.");
}
repaint();
}
public void paint(Graphics g) {
update(g);
}
public void update(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
Dimension dim = getSize();
int w = (int) dim.getWidth();
int h = (int) dim.getHeight();
g2.setStroke(new BasicStroke(8.0f));
if (isFirstTime) {
area = new Rectangle(dim);
rect.setLocation(w / 2 - 50, h / 2 - 25);
isFirstTime = false;
}
// Clears the rectangle that was previously drawn.
g2.setPaint(Color.white);
g2.fillRect(0, 0, w, h);
g2.setColor(Color.red);
g2.draw(rect);
g2.setColor(Color.black);
g2.fill(rect);
}
boolean checkRect() {
if (area == null) {
return false;
}
if (area.contains(rect.x, rect.y, 100, 50)) {
return true;
}
int new_x = rect.x;
int new_y = rect.y;
if ((rect.x + 100) > area.getWidth()) {
new_x = (int) area.getWidth() - 99;
}
if (rect.x < 0) {
new_x = -1;
}
if ((rect.y + 50) > area.getHeight()) {
new_y = (int) area.getHeight() - 49;
}
if (rect.y < 0) {
new_y = -1;
}
rect.setLocation(new_x, new_y);
return false;
}
}
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