elbowconnection.java

开源（Open Source）项目JHotDraw的文档和源程序

/*
 * @(#)ElbowConnection.java 5.2
 *
 */

package CH.ifa.draw.figures;

import java.awt.*;
import java.util.*;
import java.io.IOException;
import CH.ifa.draw.framework.*;
import CH.ifa.draw.standard.*;
import CH.ifa.draw.util.*;

/**
 * A LineConnection that constrains a connection to
 * orthogonal lines.
 */
public  class ElbowConnection extends LineConnection {

    /*
     * Serialization support.
     */
    private static final long serialVersionUID = 2193968743082078559L;
    private int elbowConnectionSerializedDataVersion = 1;

    public ElbowConnection() {
        super();
    }

    public void updateConnection() {
        super.updateConnection();
        updatePoints();
    }

    public void layoutConnection() {
    }

    /**
     * Gets the handles of the figure.
     */
    public Vector handles() {
        Vector handles = new Vector(fPoints.size()*2);
        handles.addElement(new ChangeConnectionStartHandle(this));
        for (int i = 1; i < fPoints.size()-1; i++)
            handles.addElement(new NullHandle(this, locator(i)));
        handles.addElement(new ChangeConnectionEndHandle(this));
        for (int i = 0; i < fPoints.size()-1; i++)
            handles.addElement(new ElbowHandle(this, i));
        return handles;
    }

    public Locator connectedTextLocator(Figure f) {
        return new ElbowTextLocator();
    }

    protected void updatePoints() {
        willChange();
        Point start = startPoint();
        Point end = endPoint();
        fPoints.removeAllElements();
        fPoints.addElement(start);

        if (start.x == end.x || start.y == end.y) {
            fPoints.addElement(end);
        }
        else {
            Rectangle r1 = start().owner().displayBox();
            Rectangle r2 = end().owner().displayBox();

            int x1, y1, x2, y2;
            int dir = Geom.direction(r1.x + r1.width/2, r1.y + r1.height/2,
                        r2.x + r2.width/2, r2.y + r2.height/2);
            if (dir == Geom.NORTH || dir == Geom.SOUTH) {
                fPoints.addElement(new Point(start.x, (start.y + end.y)/2));
                fPoints.addElement(new Point(end.x, (start.y + end.y)/2));
            }
            else {
                fPoints.addElement(new Point((start.x + end.x)/2, start.y));
                fPoints.addElement(new Point((start.x + end.x)/2, end.y));
            }
            fPoints.addElement(end);
        }
        changed();
    }
}

class ElbowTextLocator extends AbstractLocator {
    public Point locate(Figure owner) {
        Point p = owner.center();
        Rectangle r = owner.displayBox();
        return new Point(p.x, p.y-10); // hack
    }
}