Area.subtract( Shape ) doesn't work on Shape Line2D.Double?

Question

Hi all,
I'm working on a method that will return a Shape from a BufferedImage that has transparent values, much like the one that dfgstg developed in [this thread|http://forums.sun.com/thread.jspa?messageID=9809317] . I'm having trouble understanding the difference between using this ( I'll call it line mode 1 ):Shape = Area.subtract( new Area( new Line2D().getBounds2D ) ) and this ( I'll call it line mode 2 ):Shape = Area.subtract( new Area( new Line2D().getBounds() ) ). When I use line mode 1, nothing gets subtracted when you use vertical or horizontal lines. When I use line mode 2, things show up, but I get the sense that it introduces artifacts into the resulting shape. Why is it necessary to turn a Line2D into a rectangle in order to subtract it from an Area? Line2D implements the Shape interface, so theoretically, it should be able to be subtracted from an Area. A program to demonstrate this problem ( between line mode 1 and line mode 2 ) is attached. Dfgstg uses line mode 2. Why is this necessary?
// ShapeTest2.java
// --- this code should compile ---
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
class ShapeTest2 extends JComponent
    public static final int LINE_MODE_1 = 1;
    public static final int LINE_MODE_2 = 2;
    Area _shape;   
    int _radius;
    int _diameter;
    Point2D.Double _center;
    ShapeTest2( int mode, int diameter )
        _diameter = diameter;
        _radius = _diameter/2;
        _center = new Point2D.Double( _diameter/2.0, _diameter/2.0 );
        setPreferredSize( new Dimension( _diameter, _diameter ) );
        _shape = new Area(
            new Ellipse2D.Double(
                0, 0, _diameter, _diameter 
        switch( mode )
            case LINE_MODE_1:lineMode1();break;
            case LINE_MODE_2:lineMode2();break;
            default: break;                          
    private void lineMode1()
        Point2D p1 = new Point2D.Double();
        Point2D p2 = new Point2D.Double();
        double random1, random2, random3;
        boolean inside;
        // make and subtract fifty lines
        for ( int i = 0; i < 50; i++ )
            inside = false;
            // search random points until you find two that are
            // less than the radius' distance from the center
            while( inside == false )
                random1 = Math.random()*_diameter;
                random2 = Math.random()*_diameter;
                random3 = Math.random()*_diameter;
                // make sure they are horizontally related
                // they have y in common
                p1 = new Point2D.Double( random1, random2 );
                p2 = new Point2D.Double( random3, random2 );
                if ( ( p1.distance( _center ) < _radius )
                        && ( p2.distance( _center ) < _radius ) )
                    inside = true;
            _shape.subtract(
                new Area(
                    // notice the getBounds2D - it returns a Rectangle2D
                    // it also doesn't show up for some reason
                    new Line2D.Double( p1, p2 ).getBounds2D()
    private void lineMode2()
        Point2D p1 = new Point2D.Double();
        Point2D p2 = new Point2D.Double();
        double random1, random2, random3;
        boolean inside;
        for ( int i = 0; i < 50; i++ )
            inside = false;
            while( inside == false )
                random1 = Math.random()*_diameter;
                random2 = Math.random()*_diameter;
                random3 = Math.random()*_diameter;
                // make sure they are horizontally related
                p1 = new Point2D.Double( random1, random2 );
                p2 = new Point2D.Double( random3, random2 );
                if ( ( p1.distance( _center ) < _radius )
                        && ( p2.distance( _center ) < _radius ) )
                    inside = true;
            _shape.subtract(
                new Area(
                    // getBounds() returns a rectangle
                    new Line2D.Double( p1, p2 ).getBounds()
    @Override
    protected void paintComponent( Graphics g )
        super.paintComponent( g );
        Graphics2D g2d = ( Graphics2D )g;
        g2d.setColor( Color.BLACK );
        g2d.draw( _shape );
    public static void main( String[] args )
        JFrame frame = new JFrame( "ShapeTest2" );
        int diameter = 300;
        ShapeTest2 lineMode1 =
            new ShapeTest2( ShapeTest2.LINE_MODE_1, diameter );
        ShapeTest2 lineMode2 =
            new ShapeTest2( ShapeTest2.LINE_MODE_2, diameter );
        frame.setLayout( new FlowLayout() );
        frame.add( lineMode1 );
        frame.add( lineMode2 );
        frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        frame.setLocation( 100, 100 );
        frame.pack();        
        frame.setVisible( true );
}

Answer 1

Keep all of your shapes right where they are! To make your text into hyperlinks then, just insert another shape...make it big or small enough to cover your text. Go ahead and drag it right over your text. Now attach the hyperlink to this shape. Now in the INspector,click over to the Graphics tab and change the opacity of this shape to 1%.
You have now created a "hotspot" hyperlink over your text! All without moving any of your other shapes around! Publish and see the results... Let me know if it works out for you!