edge.java

ALGAE是一个快速创建算法演示的框架。目前支持的算法实现语言包括java和c

package edu.odu.cs.zeil.AlgAE.Client.DataViewer.DataGraph;

import edu.odu.cs.zeil.AlgAE.Debug;
import edu.odu.cs.zeil.AlgAE.Direction;
import edu.odu.cs.zeil.AlgAE.Client.GraphicsInfo;
import edu.odu.cs.zeil.AlgAE.Client.DataViewer.DataGraph.Edgeable;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.Polygon;


  

public abstract class Edge
{
  public /* final */ Edgeable source;      // final causes intermittant
  public /* final */ Edgeable destination; //  compiler problems: JDK 1.1.2
  public /* final */ int dir;
  public /* final */ Color color;
  public /* final */ String label;


  Edge(Edgeable src, Edgeable dest, int direction, Color colour, String edgeLabel)
  {
    source = src;
    destination = dest;
    dir = direction;
    color = colour;
    label = edgeLabel;
  }
  

  Point exitPoint()
  {
    int d = dir;
    if (dir == Direction.ANYDIR)
      {
	if (destination != null)
	  d = source.directionTo(destination.center());
	else
	  d = Direction.SW;
      }
    return source.exitPoint(d);
  }
  

  protected void drawExitPoint (GraphicsInfo gi, Point p)
  {
    if (dir != Direction.ANYDIR) {
      gi.g.setColor (color);
      int diameter = 3*gi.getTextOffset().width / 3;
      gi.g.fillOval (p.x - diameter/2, p.y - diameter/2,
		     diameter, diameter);
    }
  }

  abstract Point entryPoint();

  abstract void draw(GraphicsInfo gi);

  abstract double length();

  abstract double positionScore(double targetLength);


  protected void drawArrowHead(Point tip, Point base, GraphicsInfo gi)
  {
    int dx = tip.x - base.x;
    int dy = tip.y - base.y;
    if (dx != 0 || dy != 0)
      {
	double len = Math.sqrt (((double)dx)*dx + ((double)dy)*dy);

	Point p1 = new Point();
	p1.x = tip.x - (int)(3 * gi.getTextOffset().width / 2 / len * dx);
	p1.y = tip.y - (int)(3 * gi.getTextOffset().width / 2 / len * dy);
	      
	Polygon triangle = new Polygon();
	triangle.addPoint (tip.x, tip.y);
	triangle.addPoint 
	  (p1.x + 2 * (tip.y - p1.y) / 3,
	   p1.y - 2 * (tip.x - p1.x) / 3
	    );
	triangle.addPoint 
	  (p1.x - 2 * (tip.y - p1.y) / 3,
	   p1.y + 2 * (tip.x - p1.x) / 3
	    );
	gi.g.setColor (color);
	gi.g.fillPolygon (triangle);
      }
  }


  static public final double one2 = 1.0/Math.sqrt(2.0);
  static public final double one5 = 1.0/Math.sqrt(5.0);
  static public final double two5 = 2.0/Math.sqrt(5.0);
  
  static public final double xNorm[] =
    {0.0, one5, one2, two5, 1.0, two5, one2, one5,
     0.0, -one5, -one2, -two5, -1.0, -two5, -one2, -one5};

  static public final double yNorm[] =
    {-1.0, -two5, -one2, -one5, 0.0, one5, one2, two5, 
     1.0, two5, one2, one5, 0.0, -one5, -one2, -two5};
     



}