arrowtip.java

开源（Open Source）项目JHotDraw的文档和源程序

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

package CH.ifa.draw.figures;

import java.io.*;
import java.awt.*;

import CH.ifa.draw.framework.*;
import CH.ifa.draw.standard.*;
import CH.ifa.draw.util.*;

/**
 * An arrow tip line decoration.
 * @see PolyLineFigure
 */
public  class ArrowTip extends AbstractLineDecoration {

    private double  fAngle;         // pointiness of arrow
    private double  fOuterRadius;
    private double  fInnerRadius;

    /*
     * Serialization support.
     */
    private static final long serialVersionUID = -3459171428373823638L;
    private int arrowTipSerializedDataVersion = 1;

	public ArrowTip() {
	    this(0.40, 8, 8);  // this(0.35, 15, 12);
	}

   /**
    * Constructs an arrow tip with the given angle and radius.
    */
	public ArrowTip(double angle, double outerRadius, double innerRadius) {
	    setAngle(angle);
	    setOuterRadius(outerRadius);
	    setInnerRadius(innerRadius);
	}
	
   /**
    * Calculates the outline of an arrow tip.
    */
    public Polygon outline(int x1, int y1, int x2, int y2) {
        double dir = Math.PI/2 - Math.atan2(x2-x1, y2-y1);
        return outline(x1, y1, dir);
    }

    private Polygon outline(int x, int y, double direction) {
        Polygon shape = new Polygon();

        shape.addPoint(x, y);
        addPointRelative(shape, x, y, getOuterRadius(), direction - getAngle());
        addPointRelative(shape, x, y, getInnerRadius(), direction);
        addPointRelative(shape, x, y, getOuterRadius(), direction + getAngle());
        shape.addPoint(x,y); // Closing the polygon (TEG 97-04-23)
        return shape;
    }

    private void addPointRelative(Polygon shape, int x, int y, double radius, double angle) {
        shape.addPoint(
            x + (int) (radius * Math.cos(angle)),
            y + (int) (radius * Math.sin(angle)));
    }

    /**
     * Stores the arrow tip to a StorableOutput.
     */
    public void write(StorableOutput dw) {
        dw.writeDouble(getAngle());
        dw.writeDouble(getOuterRadius());
        dw.writeDouble(getInnerRadius());
        super.write(dw);
    }

    /**
     * Reads the arrow tip from a StorableInput.
     */
    public void read(StorableInput dr) throws IOException {
        setAngle(dr.readDouble());
        setOuterRadius(dr.readDouble());
        setInnerRadius(dr.readDouble());
		super.read(dr);
    }

	/**
	 * Sets point angle of arrow. A smaller angle leads to a pointier arrow.
	 * The angle is measured between the arrow line and one of the points
	 * at the side of the arrow. Thus, the total angle at the arrow tip
	 * is the double of the angle specified.
 	 */
    protected void setAngle(double newAngle) {
        fAngle = newAngle;
    }
    
	/**
	 * Returns point angle of arrow. A smaller angle leads to a pointier arrow.
	 * The angle is measured between the arrow line and one of the points
	 * at the side of the arrow. Thus, the total angle at the arrow tip
	 * is the double of the angle specified.
 	 */
    protected double getAngle() {
    	return fAngle;
    }

	/**
	 * Sets the inner radius
	 */
    protected void setInnerRadius(double newInnerRadius) {
        fInnerRadius = newInnerRadius;
    }

	/**
	 * Returns the inner radius
	 */        
    protected double getInnerRadius() {
    	return fInnerRadius;
    }

	/**
	 * Sets the outer radius
	 */
    protected void setOuterRadius(double newOuterRadius) {
        fOuterRadius = newOuterRadius;
    }

	/**
	 * Returns the outer radius
	 */
    protected double getOuterRadius() {
    	return fOuterRadius;
    }
}