Swing Hacks

Make Your Frame Dissolve #42

Chapter 6, Transparent and Animated Windows

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HACK

Create a Genie Effect

One of my favorite bits of eye candy from Mac OS X is the minimize dis-

solve. When you click on the minimize button in any application, the win-

dow will shrink and slide into the dock. This is called the genie effect, and it

not only looks cool, but it also gives you feedback about where a window

has gone. Example 6-3 is a subclass of

Dissolver that overrides the paint( )

method to create a spinning, shrinking window that somewhat mimics the

genie effect.

Example 6-2. A simple test class

public class DissolveHack {

public static void main(String[] args) {

final JFrame frame = new JFrame("Dissolve Hack");

JButton quit = new JButton("Quit");

quit.addActionListener(new ActionListener( ) {

public void actionPerformed(ActionEvent evt) {

new Dissolver( ).dissolveExit(frame);

}

});

frame.getContentPane( ).add(quit);

frame.pack( );

frame.setLocation(300,300);

frame.setSize(400,400);

frame.setVisible(true);

}

}

Example 6-3. Adding a genie effect to your toolbox

class SpinDissolver extends Dissolver {

public void paint(Graphics g) {

Graphics2D g2 = (Graphics2D)g;

// draw the screen, offset in case the window isn't at 0,0

g.drawImage(screen_buffer,-fullscreen.getX( ),

-fullscreen.getY( ),null);

// save the current transform

AffineTransform old_trans = g2.getTransform( );

// move to the upper-lefthand corner of the frame

g2.translate(frame.getX(), frame.getY( ));

// move the frame off toward the left

g2.translate(-((count+1) * (frame.getX()+frame.getWidth( ))/20),0);

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Chapter 6, Transparent and Animated Windows

#42 Make Your Frame Dissolve

HACK

This dissolver will shrink the window and spin it, while moving it toward

the left at the same time. This make the window look like it is spinning off

into oblivion, as in Figure 6-5.

This hack shows off just a few of the really cool effects you can accomplish

with just a bit of Java2D code in your Swing application. Because the parent

Dissolve class takes care of most of the tricky parts, you can easily create

your own subclasses that focus on just the animation itself. You might want

to try some other animations, such as the circle and linear wipes common to

old movies, or a better genie effect that works when you quit your applica-

tion. Java2D gives you the power to do virtually any linear transform (shear,

scale, rotate, etc.), plus composites and convolutions. For even more effects,

you could use Java3D or JOGL to create three-dimensional effects like spin-

ning cubes and perspective transforms.

// shrink the frame

float scale = 1f / ((float)count+1);

g2.scale(scale,scale);

// rotate around the center

g2.rotate(((float)count)/3.14/1.3,

frame.getWidth()/2, frame.getHeight( )/2);

// finally draw the frame

g2.drawImage(frame_buffer,0,0,null);

// restore the current transform

g2.setTransform(old_trans);

}

}

Figure 6-5. A spin dissolve

Example 6-3. Adding a genie effect to your toolbox (continued)