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import java.awt.Color;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
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 java.awt.geom.GeneralPath;
public class BezLab extends Frame implements MouseListener, MouseMotionListener {
private int[] xs = { 75, 150, 300, 375 };
private int[] ys = { 250, 100, 350, 250 };
private int dragIndex = NOT_DRAGGING;
private final static int NEIGHBORHOOD = 15;
private final static int NOT_DRAGGING = -1;
public static void main(String[] args) {
(new BezLab()).setVisible(true);
}
BezLab() {
setSize(500, 450);
addMouseListener(this);
addMouseMotionListener(this);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
}
public void paint(Graphics g) {
for (int i = 0; i < 4; i++) {
if (i == 0 || i == 3)
g.setColor(Color.blue);
else
g.setColor(Color.cyan);
g.fillOval(xs[i] - 6, ys[i] - 6, 12, 12);
}
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(Color.black);
GeneralPath path = new GeneralPath();
path.moveTo(xs[0], ys[0]);
path.curveTo(xs[1], ys[1], xs[2], ys[2], xs[3], ys[3]);
g2d.draw(path);
}
public void mousePressed(MouseEvent e) {
dragIndex = NOT_DRAGGING;
int minDistance = Integer.MAX_VALUE;
int indexOfClosestPoint = -1;
for (int i = 0; i < 4; i++) {
int deltaX = xs[i] - e.getX();
int deltaY = ys[i] - e.getY();
int distance = (int) (Math.sqrt(deltaX * deltaX + deltaY * deltaY));
if (distance < minDistance) {
minDistance = distance;
indexOfClosestPoint = i;
}
}
if (minDistance > NEIGHBORHOOD)
return;
dragIndex = indexOfClosestPoint;
}
public void mouseReleased(MouseEvent e) {
if (dragIndex == NOT_DRAGGING)
return;
xs[dragIndex] = e.getX();
ys[dragIndex] = e.getY();
dragIndex = NOT_DRAGGING;
repaint();
}
public void mouseDragged(MouseEvent e) {
if (dragIndex == NOT_DRAGGING)
return;
xs[dragIndex] = e.getX();
ys[dragIndex] = e.getY();
repaint();
}
public void mouseClicked(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
public void mouseExited(MouseEvent e) {
}
public void mouseMoved(MouseEvent e) {
}
}
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