Painting rectangle at an angle?

Question

Hi,
There are 2 points, (x1,y1) and (x2,y2), a line is drawn before then using the drawline method, what I want to do it have a rectangle which will go from point (x1,y1) to (x2,y2).
However, fillrect do not support any angle parameter and I can't find a method to the rotation.
See the orange rectangle in the image:
http://img207.imageshack.us/img207/7584/javamh1.jpg
Any help will be very much appreciated.

Answer 1

import java.awt.*;
import java.awt.font.*;
import java.awt.geom.*;
import javax.swing.*;
public class InLineRectangle extends JPanel {
    Point p1 = new Point(100,300);
    Point p2 = new Point(300,100);
    Rectangle rect = new Rectangle(75,25);
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setPaint(Color.blue);
        g2.draw(new Line2D.Double(p1, p2));
        g2.setPaint(Color.red);
        mark(p1, g2);
        mark(p2, g2);
        // Locate rect at 1/4 the length of the line from p1 to p2.
        double theta = Math.atan2(p2.y-p1.y, p2.x-p1.x);
        double length = p1.distance(p2);
        double x = p1.x + (length/4.0)*Math.cos(theta);
        double y = p1.y + (length/4.0)*Math.sin(theta);
        // Locate rect on the line.
        AffineTransform at = AffineTransform.getTranslateInstance(x, y-rect.height/2);
        // Rotate rect about x, y on the line.
        at.rotate(theta, 0, rect.height/2);
        g2.setPaint(Color.orange);
        g2.fill(at.createTransformedShape(rect));
        // Show x, y for confirmation.
        g2.setPaint(Color.green.darker());
        mark(new Point2D.Double(x, y), g2);
        // Draw text.
        String s = "aligned";
        Font font = g2.getFont().deriveFont(16f);
        g2.setFont(font);
        FontRenderContext frc = g2.getFontRenderContext();
        float sw = (float)font.getStringBounds(s, frc).getWidth();
        LineMetrics lm = font.getLineMetrics(s, frc);
        float sh = lm.getAscent() + lm.getDescent();
        x = (rect.width - sw)/2;
        y = (rect.height + sh)/2 - lm.getDescent();
        // Position the text relative to rect.
        AffineTransform xf = AffineTransform.getTranslateInstance(x, y);
        xf.preConcatenate(at);
        g2.setFont(font.deriveFont(xf));
        g2.setPaint(Color.blue);
        g2.drawString(s, 0, 0);
    private void mark(Point2D p, Graphics2D g2) {
        g2.fill(new Ellipse2D.Double(p.getX()-2, p.getY()-2, 4, 4));
    public Dimension getPreferredSize() {
        return new Dimension(400,400);
    public static void main(String[] args) {
        JOptionPane.showMessageDialog(null, new InLineRectangle(), "", -1);
}