plotcanvas.java

jacckit的说明文档,介绍了使用说明,各种接口的使用,是个好的帮助文章

/*
 * Copyright 2003-2004, Franz-Josef Elmer, All rights reserved
 *
 * 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 program 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
 * (http://www.gnu.org/copyleft/lesser.html).
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package jcckit.plot;

import jcckit.data.DataPlot;
import jcckit.graphic.Anchor;
import jcckit.graphic.ClippingRectangle;
import jcckit.util.ConfigParameters;

/**
 * An abstract canvas containg a single {@link Plot}.
 * The canvas is specified by a {@link ClippingRectangle}, called 
 * <em>paper</em>. A horizontal and vertical {@link Anchor} determine
 * the position of the paper on the actual device.
 * 
 * @author Franz-Josef Elmer
 */
public class PlotCanvas implements PlotListener {
  /** Configuration parameter key. */
  public static final String PAPER_KEY = "paper",
                             HORIZONTAL_ANCHOR_KEY = "horizontalAnchor",
                             VERTICAL_ANCHOR_KEY = "verticalAnchor",
                             PLOT_KEY = "plot";
  private final ClippingRectangle _paper;
  private final Anchor _horizontalAnchor;
  private final Anchor _verticalAnchor;
  private final Plot _plot;

  /**
   * Creates an instance from the specified configuration parameters.
   * <table border=1 cellpadding=5>
   * <tr><th>Key &amp; Default Value</th><th>Type</th><th>Mandatory</th>
   *     <th>Description</th></tr>
   * <tr><td><tt>horizontalAnchor = center</tt></td>
   *     <td><tt>String</tt></td><td>no</td>
   *     <td>Horizontal position of the paper relative to the device
   *         border. Possible values are <tt>left</tt>, <tt>center</tt>,
   *         and <tt>right</tt>.</td></tr>
   * <tr><td><tt>paper = 0,&nbsp;0,&nbsp;1,&nbsp;0.6</tt></td>
   *     <td><tt>double[]</tt></td><td>no</td>
   *     <td>Rectangle defining the paper. The first two values determine
   *         the x- and y- coordinates (in device-independent units) 
   *         of the lower-left corner. The last two values determine the 
   *         upper-right corner.</td></tr>
   * <tr><td><tt>plot = </tt>default values of {@link Plot}</td>
   *     <td><tt>ConfigParameters</tt></td><td>no</td>
   *     <td>Definition of the {@link Plot}.</td></tr>
   * <tr><td><tt>verticalAnchor = center</tt></td>
   *     <td><tt>String</tt></td><td>no</td>
   *     <td>Vertical position of the paper relative to the device
   *         border. Possible values are <tt>top</tt>, <tt>center</tt>,
   *         and <tt>bottom</tt>.</td></tr>
   * </table>
   * <p>
   * Note, that this instance registers itself at the  
   * wrapped {@link Plot} instance.
   */
  public PlotCanvas(ConfigParameters config) {
    double[] paper = config.getDoubleArray(PAPER_KEY,
                                           new double[] {0, 0, 1, 0.6});
    _paper = new ClippingRectangle(paper[0], paper[1], paper[2], paper[3]);
    _horizontalAnchor = Anchor.getHorizontalAnchor(config,
                                  HORIZONTAL_ANCHOR_KEY, Anchor.CENTER);
    _verticalAnchor = Anchor.getVerticalAnchor(config,
                                  VERTICAL_ANCHOR_KEY, Anchor.CENTER);
    _plot = new Plot(config.getNode(PLOT_KEY));
    _plot.addPlotListener(this);
  }

  /** Returns the paper definition. */
  public ClippingRectangle getPaper() {
    return _paper;
  }

  /** Returns the horizontal anchor. */
  public Anchor getHorizontalAnchor() {
    return _horizontalAnchor;
  }

  /** Returns the vertical anchor. */
  public Anchor getVerticalAnchor() {
    return _verticalAnchor;
  }

  /** Returns the plot. */
  public Plot getPlot() {
    return _plot;
  }
  
  /** 
   * Connects the wrapped {@link Plot} instance with the specified
   * {@link DataPlot}.
   * @param dataPlot Data to be connected with this plot canvas.
   *        Can be <tt>null</tt> in order to disconnect this instance from
   *        a <tt>DataPlot</tt>.
   */
  public void connect(DataPlot dataPlot) {
    _plot.connect(dataPlot);
  }

  /**
   * Handles the spcified event. Here nothing is done. But
   * subclass may override this method.
   */
  public void plotChanged(PlotEvent event) {}
}