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|
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;
public class Resizing extends JPanel {
Rectangle rect = new Rectangle(100,100,150,150);
Rectangle rect2 = new Rectangle(100,250,150,100);
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
g2.setColor(new Color(0, 0, 200));
g2.fill(rect);
g2.setColor(new Color(0, 0, 100));
g2.fill(rect2);
}
public static void main(String[] args) {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Resizing test = new Resizing();
Resizer resizer = new Resizer(test);
test.addMouseListener(resizer);
test.addMouseMotionListener(resizer);
f.add(test);
f.setSize(400,400);
f.setLocation(100,100);
f.setVisible(true);
}
}
class Resizer extends MouseAdapter {
Resizing component;
boolean dragging = false;
// Give user some leeway for selections.
final int PROX_DIST = 3;
public Resizer(Resizing r) {
component = r;
}
public void mousePressed(MouseEvent e) {
if(component.getCursor() != Cursor.getDefaultCursor()) {
// If cursor is set for resizing, allow dragging.
dragging = true;
}
}
public void mouseReleased(MouseEvent e) {
dragging = false;
}
public void mouseDragged(MouseEvent e) {
if(dragging){
Point p = e.getPoint();
Rectangle r = component.rect;
int type = component.getCursor().getType();
int dx = p.x - r.x;
int dy = p.y - r.y;
switch(type) {
case Cursor.N_RESIZE_CURSOR:
int height = r.height - dy;
r.setRect(r.x, r.y+dy, r.width, height);
break;
case Cursor.S_RESIZE_CURSOR:
height = dy;
r.setRect(r.x, r.y, r.width, height);
break;
default:
System.out.println("unexpected type: " + type);
}
component.repaint();
}
}
public void mouseMoved(MouseEvent e) {
Point p = e.getPoint();
if(!isOverRect(p)) {
if(component.getCursor() != Cursor.getDefaultCursor()) {
// If cursor is not over rect reset it to the default.
component.setCursor(Cursor.getDefaultCursor());
}
return;
}
// Locate cursor relative to center of rect.
int outcode = getOutcode(p);
Rectangle r = component.rect;
switch(outcode) {
case Rectangle.OUT_TOP:
if(Math.abs(p.y - r.y) < PROX_DIST) {
component.setCursor(Cursor.getPredefinedCursor(
Cursor.N_RESIZE_CURSOR));
}
break;
case Rectangle.OUT_BOTTOM:
if(Math.abs(p.y - (r.y+r.height)) < PROX_DIST) {
component.setCursor(Cursor.getPredefinedCursor(
Cursor.S_RESIZE_CURSOR));
}
break;
default: // center
component.setCursor(Cursor.getDefaultCursor());
}
}
/**
* Make a smaller Rectangle and use it to locate the
* cursor relative to the Rectangle center.
*/
private int getOutcode(Point p) {
Rectangle r = (Rectangle)component.rect.clone();
r.grow(-PROX_DIST, -PROX_DIST);
return r.outcode(p.x, p.y);
}
/**
* Make a larger Rectangle and check to see if the
* cursor is over it.
*/
private boolean isOverRect(Point p) {
Rectangle r = (Rectangle)component.rect.clone();
r.grow(PROX_DIST, PROX_DIST);
return r.contains(p);
}
} |
