dsarrow.java

用JAVA编写的绘图程序 功能简介： 支持存储

package drawsmart.itsv.basic;

import java.awt.Graphics;
import drawsmart.itsv.framework.LineRenderer;
import java.awt.*;

/**
 * <p>Title: 绘制器</p>
 * <p>Description: 绘制直线的箭头</p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: </p>
 * @author not attributable
 * @version 2.0
 */

public abstract class DSArrow implements LineRenderer {
  /**
     *所属连线
     */
    protected DSLine line;
    /**
     *箭头的绘画范围
     */
    transient protected Polygon polygon;
    /**
     * @param line 所属连线
     */
    public DSArrow(DSLine 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) {
        Color oldC= g.getColor();
        g.setColor(javax.swing.UIManager.getColor("Desktop.background"));
        g.fillPolygon(getPolygon());
        g.setColor(Color.black);
        //
        g.drawPolygon(getPolygon());

        g.setColor(oldC);
    }
    /**
     *取得默认的绘画范围
     * @return
     */
    protected Polygon getPolygon(){
        //每次刷新都需要重新绘制箭头
        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());
        //System.out.println("X1="+line.getX1()+"  Y1="+line.getY1()+"  X2="+line.getX2()+"  Y2="+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
 * @version 2.0
 */
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>
 * @version 2.0
 */
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>
 * @version 2.0
 */
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;
    }


}