Swing Hacks

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Chapter 6, Transparent and Animated Windows

#42 Make Your Frame Dissolve

HACK

To keep this simple, I have created a special class that does a simple fade-to-

transparent animation. Once the class is built, you can create more compli-

cated animations by overriding the paint method, leaving the messy details

to the parent class. Here’s the basic skeleton:

class Dissolver extends JComponent implements Runnable {

Frame frame;

Window fullscreen;

int count;

BufferedImage frame_buffer;

BufferedImage screen_buffer;

public Dissolver( ) { }

Dissolver

is a

JComponent

that implements

Runnable

so that it can have an

animation loop. It has member variables for the application frame to dis-

solve (

frame), the window that covers up the screen (fullscreen), an anima-

tion counter (

count), and the two buffers for storing the frame and the

desktop background image (

frame_buffer and screen_buffer).

Prepare the Dissolve

Dissolver has one method to start the dissolve process called dissolveExit( ),

which takes the

JFrame you want to dissolve and generates everything else it

needs internally:

public void dissolveExit(JFrame frame) {

try {

this.frame = frame;

Robot robot = new Robot( );

// cap screen w/ frame to frame buffer

Rectangle frame_rect = frame.getBounds( );

frame_buffer = robot.createScreenCapture(frame_rect);

// hide frame

frame.setVisible(false);

// cap screen w/o frame

Dimension screensize = Toolkit.getDefaultToolkit( )

.getScreenSize( );

Rectangle screen_rect = new Rectangle(0,0,

screensize.width, screensize.height);

screen_buffer = robot.createScreenCapture(screen_rect);

// create big window w/o decorations

fullscreen = new Window(new JFrame( ));

fullscreen.setSize(screensize);

fullscreen.add(this);

this.setSize(screensize);

fullscreen.setVisible(true);