Coordinate trabalhar com coordenadas

/*
 * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * -Redistribution of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 *
 * -Redistribution in binary form must reproduce the above copyright notice,
 *  this list of conditions and the following disclaimer in the documentation
 *  and/or other materials provided with the distribution.
 *
 * Neither the name of Sun Microsystems, Inc. or the names of contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility.
 */
/* CoordinatesDemo.java is a 1.4 application that requires no other files. */

import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.Point;
import java.awt.event.MouseEvent;

import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.event.MouseInputListener;

/*
 * This displays a framed area. As the user moves the cursor over the area, a
 * label displays the cursor's location. When the user clicks, the area displays
 * a 7x7 dot at the click location.
 */
public class CoordinatesDemo {
  private JLabel label;

  private Point clickPoint, cursorPoint;

  private void buildUI(Container container) {
    container.setLayout(new BoxLayout(container, BoxLayout.PAGE_AXIS));

    CoordinateArea coordinateArea = new CoordinateArea(this);
    container.add(coordinateArea);

    label = new JLabel();
    resetLabel();
    container.add(label);

    //Align the left edges of the components.
    coordinateArea.setAlignmentX(Component.LEFT_ALIGNMENT);
    label.setAlignmentX(Component.LEFT_ALIGNMENT); //redundant
  }

  public void updateCursorLocation(int x, int y) {
    if (x < 0 || y < 0) {
      cursorPoint = null;
      updateLabel();
      return;
    }

    if (cursorPoint == null) {
      cursorPoint = new Point();
    }

    cursorPoint.x = x;
    cursorPoint.y = y;
    updateLabel();
  }

  public void updateClickPoint(Point p) {
    clickPoint = p;
    updateLabel();
  }

  public void resetLabel() {
    cursorPoint = null;
    updateLabel();
  }

  protected void updateLabel() {
    String text = "";

    if ((clickPoint == null) && (cursorPoint == null)) {
      text = "Click or move the cursor within the framed area.";
    } else {

      if (clickPoint != null) {
        text += "The last click was at (" + clickPoint.x + ", "
            + clickPoint.y + "). ";
      }

      if (cursorPoint != null) {
        text += "The cursor is at (" + cursorPoint.x + ", "
            + cursorPoint.y + "). ";
      }
    }

    label.setText(text);
  }

  /**
   * Create the GUI and show it. For thread safety, this method should be
   * invoked from the event-dispatching thread.
   */
  private static void createAndShowGUI() {
    //Make sure we have nice window decorations.
    JFrame.setDefaultLookAndFeelDecorated(true);

    //Create and set up the window.
    JFrame frame = new JFrame("CoordinatesDemo");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    //Set up the content pane.
    CoordinatesDemo controller = new CoordinatesDemo();
    controller.buildUI(frame.getContentPane());

    //Display the window.
    frame.pack();
    frame.setVisible(true);
  }

  public static void main(String[] args) {
    //Schedule a job for the event-dispatching thread:
    //creating and showing this application's GUI.
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        createAndShowGUI();
      }
    });
  }

  public static class CoordinateArea extends JComponent implements
      MouseInputListener {
    Point point = null;

    CoordinatesDemo controller;

    Dimension preferredSize = new Dimension(400, 75);

    Color gridColor;

    public CoordinateArea(CoordinatesDemo controller) {
      this.controller = controller;

      //Add a border of 5 pixels at the left and bottom,
      //and 1 pixel at the top and right.
      setBorder(BorderFactory.createMatteBorder(1, 5, 5, 1, Color.RED));

      addMouseListener(this);
      addMouseMotionListener(this);
      setBackground(Color.WHITE);
      setOpaque(true);
    }

    public Dimension getPreferredSize() {
      return preferredSize;
    }

    protected void paintComponent(Graphics g) {
      //Paint background if we're opaque.
      if (isOpaque()) {
        g.setColor(getBackground());
        g.fillRect(0, 0, getWidth(), getHeight());
      }

      //Paint 20x20 grid.
      g.setColor(Color.GRAY);
      drawGrid(g, 20);

      //If user has chosen a point, paint a small dot on top.
      if (point != null) {
        g.setColor(getForeground());
        g.fillRect(point.x - 3, point.y - 3, 7, 7);
      }
    }

    //Draws a 20x20 grid using the current color.
    private void drawGrid(Graphics g, int gridSpace) {
      Insets insets = getInsets();
      int firstX = insets.left;
      int firstY = insets.top;
      int lastX = getWidth() - insets.right;
      int lastY = getHeight() - insets.bottom;

      //Draw vertical lines.
      int x = firstX;
      while (x < lastX) {
        g.drawLine(x, firstY, x, lastY);
        x += gridSpace;
      }

      //Draw horizontal lines.
      int y = firstY;
      while (y < lastY) {
        g.drawLine(firstX, y, lastX, y);
        y += gridSpace;
      }
    }

    //Methods required by the MouseInputListener interface.
    public void mouseClicked(MouseEvent e) {
      int x = e.getX();
      int y = e.getY();
      if (point == null) {
        point = new Point(x, y);
      } else {
        point.x = x;
        point.y = y;
      }
      controller.updateClickPoint(point);
      repaint();
    }

    public void mouseMoved(MouseEvent e) {
      controller.updateCursorLocation(e.getX(), e.getY());
    }

    public void mouseExited(MouseEvent e) {
      controller.resetLabel();
    }

    public void mouseReleased(MouseEvent e) {
    }

    public void mouseEntered(MouseEvent e) {
    }

    public void mousePressed(MouseEvent e) {
    }

    public void mouseDragged(MouseEvent e) {
    }
  }
}