arrow.java

用java实现的画图程序

package com.sunking.tp.framework;
import java.beans.*;
import java.awt.*;
/**
 *
 * <p>Title: </p>
 * <p>Description: 箭头</p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: </p>
 * @author <a href="mailto:[e-mail]">SunKing</a>
 * @version 1.0
 * @see LineRenderer
 */
public class Arrow  implements LineRenderer {
    /**
     *所属连线
     */
    protected AssoicatorLine line;
    /**
     *箭头的绘画范围
     */
    transient protected Polygon polygon;
    /**
     * @param line 所属连线
     */
    public Arrow(AssoicatorLine line) {
        this.line = line;
    }
    /**
     *取得箭头的绘画范围
     */
    public Rectangle getBounds() {
        return getPolygon().getBounds();
    }
    /**
     *绘制箭头
     */
    public void paint(java.awt.Graphics g) {
        if(line.getAssociateType() == 1){
            return;
        }
        Color oldC= g.getColor();
        g.setColor(javax.swing.UIManager.getColor("Desktop.background"));
        g.fillPolygon(getPolygon());
        g.setColor(Color.black);
        if(line.getAssociateType() == 3){
            g.fillPolygon(getPolygon());
        }else{
            g.drawPolygon(getPolygon());
        }
        g.setColor(oldC);
    }
    /**
     *取得默认的绘画范围
     * @return
     */
    protected Polygon getPolygon(){
        if(polygon == null){
            polygon = getDefaultPolygon();
        }
        return polygon;
    }
    /**
     *根据所属连线的位置定位三个点的偏移点.
     */
    private Polygon getDefaultPolygon(){
        Locator locs[] = new Locator[] {
            new PolarCoordinate( 10, 0.5 + Math.PI ),
            new PolarCoordinate( 0, 0.0 ),
            new PolarCoordinate( 10, -0.5 + Math.PI )
        };
        int xArray[] = new int[locs.length];
        int yArray[] = new int[locs.length];
        for ( int i = 0; i < locs.length; i++ ) {
            xArray[i] = getArrowLocator( locs[i] ).x();
            yArray[i] = getArrowLocator( locs[i] ).y();
        }
        return new Polygon(
                xArray,
                yArray,
                locs.length);
    }
    protected Locator getArrowLocator( Locator loc ) {
        Locator source = new DrawingPoint((int)line.getX1(),(int)line.getY1());
        Locator dest = new DrawingPoint((int)line.getX2(),(int)line.getY2());
        Locator relative = new DrawingPoint(dest.x()-source.x(), dest.y()-source.y());
        PolarCoordinate coord = new PolarCoordinate( loc.r(), loc.theta() + relative.theta() );
        return new DrawingPoint( dest.x() + coord.x(), dest.y() + coord.y() );
    }
}
/**
 *
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: </p>
 * @author <a href="mailto:[e-mail]">SunKing</a>
 * @version 1.0
 */
interface Locator {
    public abstract int r();
    public abstract double theta();
    public abstract int x();
    public abstract int y();
}
/**
 *
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: </p>
 * @author <a href="mailto:[e-mail]">SunKing</a>
 * @version 1.0
 */
class PolarCoordinate implements Locator {
    protected int r;
    protected double theta;
    public PolarCoordinate(int r, double theta) {
        this.r = r;
        this.theta = theta;
    }
    public int r() {
        return r;
    }
    public double theta() {
        return theta;
    }
    public int x()  {
        return (int)( r * Math.cos( theta ) );
    }
    public int y()  {
        return (int)( r * Math.sin( theta ) );
    }
}
/**
 *
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: </p>
 * @author <a href="mailto:[e-mail]">SunKing</a>
 * @version 1.0
 */
class DrawingPoint implements Locator{
    protected int x;
    protected int y;
    public DrawingPoint(int x, int y) {
        this.x = x;
        this.y = y;
    }
    public int x()  {
        return x;
    }
    public int y()  {
        return y;
    }
    public int r() {
        int myX = x();
        int myY = y();
        return (int)Math.sqrt((myX * myX) + (myY * myY));
    }
    public double theta() {
        double theta = Math.atan((double)y()/(double)x());
        if (x() < 0)
            theta = theta + Math.PI;
        return theta;
    }
}