graphlayoutmanager.java

OpenJGraph是一个开源的Java库

package salvo.jesus.graph.visual.layout;

import java.awt.*;
import java.io.*;
import salvo.jesus.graph.visual.*;

/**
 * The layout manager interface responsible for visually laying out
 * the vertices in a graph.
 *
 * Implementations of this interface should be registered with an instance
 * of VisualGraph, via the setGraphLayoutManager() method.
 *
 * @author		Jesus M. Salvo Jr.
 */

public interface GraphLayoutManager extends Serializable {

  /**
   * Determines if the graph has been initially laid out.
   * This method should be called prior to any painting to be done by the
   * graph layout manager, as most internal variables are only
   * initialized during layout.
   *
   * @return  True if the graph has at least been laid out once.
   */
  public boolean isInitialized();

  /**
   * This method is called to layout the vertices in the graph, without
   * actually drawing the finished or intermediate layout.
   */
  public void layout();

  /**
   * Automatically called when a VisualVertex object has been added
   * to the VisualGraph object being laid out.
   *
   * @param vvertex   The newly added VisualVertex object.
   */
  public void addVertex( VisualVertex vvertex );

  /**
   * Automatically called when a VisualVertex object is about to be removed
   * from the VisualGraph object being laid out.
   *
   * @param vvertex   The VisualVertex object to be removed.
   */
  public void removeVertex( VisualVertex vvertex );

  /**
   * Automatically called when a VisualEdge object has been added
   * to the VisualGraph object being laid out.
   *
   * @param vedge   The newly added VisualEdge object.
   */
  public void addEdge( VisualEdge vedge );

  /**
   * Automatically called when a VisualEdge object is about to be removed
   * from the VisualGraph object being laid out.
   *
   * @param vedge   The VisualEdge object to be removed
   */
  public void removeEdge( VisualEdge vedge );

  /**
   * Automatically called when a VisualEdge object needs to be drawn. This method
   * is typically called from <tt>VisualEdgePainterImpl</tt> when the
   * <tt>VisualGraph</tt> encapsulating the <tt>VisualEdge</tt> has a
   * <tt>GraphLayoutManager</tt> set. Prior to calling this method, the
   * <tt>GeneralPath</tt> of the <tt>VisualEdge</tt> is reset.
   * <p>
   * Implementations of this method should set the segments of the <tt>VisualEdge</tt>'s
   * <tt>GeneralPath</tt> by calling the methods <tt>moveTo()</tt>, <tt>lineTo()</tt>,
   * <tt>curveTo()</tt>, and <tt>quadTo()</tt>.
   *
   * @param g2d     The Graphics2D object used for painting
   * @param vedge   The VisualEdge object to be drawn
   */
  public void routeEdge( Graphics2D g2d, VisualEdge vEdge );

  /**
   * This method is called to actually paint or draw the layout of the graph.
   * This method should only be called after at least one call to layout().
   */
  public void drawLayout();
}