A basic panel that displays a small up or down arrow. : JPanel « Swing « Java Tutorial






/* 
 * JCommon : a free general purpose class library for the Java(tm) platform
 * 
 *
 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
 * 
 * Project Info:  http://www.jfree.org/jcommon/index.html
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2.1 of the License, or 
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
 * USA.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 * 
 * ---------------
 * ArrowPanel.java
 * ---------------
 * (C) Copyright 2002-2004, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: ArrowPanel.java,v 1.6 2007/11/02 17:50:36 taqua Exp $
 *
 * Changes
 * -------
 * 25-Sep-2002 : Version 1 (DG);
 * 13-Oct-2002 : Added Javadocs (DG);
 *
 */

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.Polygon;
import java.awt.Shape;
import java.awt.geom.Rectangle2D;

import javax.swing.JPanel;

/**
 * A basic panel that displays a small up or down arrow.
 * 
 * @author David Gilbert
 */
public class ArrowPanel extends JPanel {

  /** A constant for the up arrow. */
  public static final int UP = 0;

  /** A constant for the down arrow. */
  public static final int DOWN = 1;

  /** The arrow type. */
  private int type = UP;

  /** The available area. */
  private Rectangle2D available = new Rectangle2D.Float();

  /**
   * Creates a new arrow panel.
   * 
   * @param type
   *          the arrow type.
   */
  public ArrowPanel(final int type) {
    this.type = type;
    setPreferredSize(new Dimension(14, 9));
  }

  /**
   * Paints the arrow panel.
   * 
   * @param g
   *          the graphics device for drawing on.
   */
  public void paintComponent(final Graphics g) {

    super.paintComponent(g);
    final Graphics2D g2 = (Graphics2D) g;

    // first determine the size of the drawing area...
    final Dimension size = getSize();
    final Insets insets = getInsets();
    this.available.setRect(insets.left, insets.top, size.getWidth() - insets.left - insets.right,
        size.getHeight() - insets.top - insets.bottom);
    g2.translate(insets.left, insets.top);
    g2.fill(getArrow(this.type));

  }

  /**
   * Returns a shape for the arrow.
   * 
   * @param t
   *          the arrow type.
   * 
   * @return the arrow shape.
   */
  private Shape getArrow(final int t) {
    switch (t) {
    case UP:
      return getUpArrow();
    case DOWN:
      return getDownArrow();
    default:
      return getUpArrow();
    }
  }

  /**
   * Returns an up arrow.
   * 
   * @return an up arrow.
   */
  private Shape getUpArrow() {
    final Polygon result = new Polygon();
    result.addPoint(7, 2);
    result.addPoint(2, 7);
    result.addPoint(12, 7);
    return result;
  }

  /**
   * Returns a down arrow.
   * 
   * @return a down arrow.
   */
  private Shape getDownArrow() {
    final Polygon result = new Polygon();
    result.addPoint(7, 7);
    result.addPoint(2, 2);
    result.addPoint(12, 2);
    return result;
  }

}








14.45.JPanel
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14.45.2.Using JPanel as a canvasUsing JPanel as a canvas
14.45.3.Subclass JPanelSubclass JPanel
14.45.4.Customizing JPanel Look and Feel
14.45.5.A basic panel that displays a small up or down arrow.
14.45.6.A panel that allows the user to select a date.
14.45.7.A JPanel with a textured background.
14.45.8.Gradient Panel