The directions of objects

Question

I am looking for the methods or classs that incorporate the directions of different object eg, polygons. I mean for instance polygon A lies North of the polygon B and so on. Other directions may include N;E;W;S etc.
Can you please give me suggestions and examples of how to find orientation of this. Thank you!

Answer 1

import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;
import java.awt.geom.*;
import javax.swing.*;
import javax.swing.event.MouseInputAdapter;
public class DirectionTest extends JPanel
    Shape[] shapes;
    int selectedIndex = -1;
    protected void paintComponent(Graphics g)
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        if(shapes == null)
            initShapes();
        for(int j = 0; j < shapes.length; j++)
            Color color = Color.blue;
            if(j == selectedIndex)
                color = Color.red;
            g2.setPaint(color);
            g2.draw(shapes[j]);
        if(selectedIndex > -1)
            Font font = g2.getFont().deriveFont(16f);
            g2.setFont(font);
            FontRenderContext frc = g2.getFontRenderContext();
            g2.setPaint(Color.green.darker());
            for(int j = 0; j < shapes.length; j++)
                if(j == selectedIndex)
                    continue;
                String s = getDirection(shapes[j]);
                float w = (float)font.getStringBounds(s, frc).getWidth();
                float h = font.getLineMetrics(s, frc).getAscent();
                Rectangle r = shapes[j].getBounds();
                float x = r.x + (r.width - w)/2;
                float y = r.y + (r.height + h)/2;
                g2.drawString(s, x, y);
    private String getDirection(Shape shape)
        Rectangle target = shapes[selectedIndex].getBounds();
        Rectangle r = shape.getBounds();
        int outcode = r.outcode(target.getCenterX(), target.getCenterY());
        String direction;
        switch(outcode)
            case Rectangle2D.OUT_TOP:
                direction = "NORTH";
                break;
            case Rectangle2D.OUT_TOP + Rectangle2D.OUT_RIGHT:
                direction = "NORTHEAST";
                break;
            case Rectangle2D.OUT_RIGHT:
                direction = "EAST";
                break;
            case Rectangle2D.OUT_RIGHT + Rectangle2D.OUT_BOTTOM:
                direction = "SOUTHEAST";
                break;
            case Rectangle2D.OUT_BOTTOM:
                direction = "SOUTH";
                break;
            case Rectangle2D.OUT_BOTTOM + Rectangle2D.OUT_LEFT:
                direction = "SOUTHWEST";
                break;
            case Rectangle2D.OUT_LEFT:
                direction = "WEST";
                break;
            case Rectangle2D.OUT_LEFT + Rectangle2D.OUT_TOP:
                direction = "NORTHWEST";
                break;
            default:
                direction = "CENTER";
        return direction;
    public void moveShape(int x, int y)
        AffineTransform at = AffineTransform.getTranslateInstance(x, y);
        shapes[selectedIndex] = at.createTransformedShape(shapes[selectedIndex]);
        repaint();
    public void setSelectedIndex(int index)
        selectedIndex = index;
        repaint();
    private void initShapes()
        shapes = new Shape[3];
        int w = getWidth();
        int h = getHeight();
        int R = Math.min(w, h)/6;
        int[][] xy = generateShapeArrays(w/4, h/4, R, 3);
        shapes[0] = new Polygon(xy[0], xy[1], 3);
        xy = generateShapeArrays(w/2, h/2, R, 5);
        shapes[1] = new Polygon(xy[0], xy[1], 5);
        xy = generateShapeArrays(w*3/4, h*3/4, R, 7);
        shapes[2] = new Polygon(xy[0], xy[1], 7);
    private int[][] generateShapeArrays(int cx, int cy, int R, int sides)
        int radInc = 0;
        if(sides % 2 == 0)
            radInc = 1;
        int[] x = new int[sides];
        int[] y = new int[sides];
        for(int i = 0; i < sides; i++)
            x[i] = cx + (int)(R * Math.sin(radInc*Math.PI/sides));
            y[i] = cy - (int)(R * Math.cos(radInc*Math.PI/sides));
            radInc += 2;
        // keep base of triangle level
        if(sides == 3)
            y[2] = y[1];
        return new int[][] { x, y };
    public static void main(String[] args)
        DirectionTest test = new DirectionTest();
        ShapeMover mover = new ShapeMover(test);
        test.addMouseListener(mover);
        test.addMouseMotionListener(mover);
        JFrame f = new JFrame("click and drag");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(test);
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
class ShapeMover extends MouseInputAdapter
    DirectionTest directionTest;
    int selectedIndex;
    Point start;
    boolean dragging;
    public ShapeMover(DirectionTest dt)
        directionTest = dt;
        dragging = false;
    public void mousePressed(MouseEvent e)
        Point p = e.getPoint();
        Shape[] shapes = directionTest.shapes;
        for(int j = 0; j < shapes.length; j++)
            if(shapes[j].contains(p))
                directionTest.setSelectedIndex(j);
                start = p;
                dragging = true;
                break;
    public void mouseReleased(MouseEvent e)
        dragging = false;
        directionTest.setSelectedIndex(-1);
    public void mouseDragged(MouseEvent e)
        if(dragging)
            Point end = e.getPoint();
            int dx = end.x - start.x;
            int dy = end.y - start.y;
            directionTest.moveShape(dx, dy);
            start = end;
}