package threadbook.ch09;

import java.awt.*;

import java.awt.font.*;

import java.awt.geom.*;

import java.awt.image.*;

import javax.swing.*;

public class ScrollText extends JComponent {

private BufferedImage image;

private Dimension imageSize;

private volatile int currOffset;

private Thread internalThread;

private volatile boolean noStopRequested;

public ScrollText(String text) {

currOffset = 0;

buildImage(text);

setMinimumSize(imageSize);

setPreferredSize(imageSize);

setMaximumSize(imageSize);

setSize(imageSize);

noStopRequested = true;

Runnable r = new Runnable() {

public void run() {

try {

runWork();

} catch ( Exception x ) {

x.printStackTrace();

}

}

};

internalThread = new Thread(r, "ScrollText");

internalThread.start();

}

private void buildImage(String text) {

// Request that the drawing be done with anti-aliasing

// turned on and the quality high.

RenderingHints renderHints = new RenderingHints(

RenderingHints.KEY_ANTIALIASING,

RenderingHints.VALUE_ANTIALIAS_ON);

renderHints.put(

RenderingHints.KEY_RENDERING,

RenderingHints.VALUE_RENDER_QUALITY);

// Create a scratch image for use in determining

// the text dimensions.

BufferedImage scratchImage = new BufferedImage(

1, 1, BufferedImage.TYPE_INT_RGB);

Graphics2D scratchG2 = scratchImage.createGraphics();

scratchG2.setRenderingHints(renderHints);

Font font =

new Font("Serif", Font.BOLD | Font.ITALIC, 24);

FontRenderContext frc = scratchG2.getFontRenderContext();

TextLayout tl = new TextLayout(text, font, frc);

Rectangle2D textBounds = tl.getBounds();

int textWidth = (int) Math.ceil(textBounds.getWidth());

int textHeight = (int) Math.ceil(textBounds.getHeight());

int horizontalPad = 10;

int verticalPad = 6;

imageSize = new Dimension(

textWidth + horizontalPad,

textHeight + verticalPad

);

// Create the properly-sized image

image = new BufferedImage(

imageSize.width,

imageSize.height,

BufferedImage.TYPE_INT_RGB);

Graphics2D g2 = image.createGraphics();

g2.setRenderingHints(renderHints);

int baselineOffset =

( verticalPad / 2 ) - ( (int) textBounds.getY());

g2.setColor(Color.white);

g2.fillRect(0, 0, imageSize.width, imageSize.height);

g2.setColor(Color.blue);

tl.draw(g2, 0, baselineOffset);

// Free-up resources right away, but keep "image" for

// animation.

scratchG2.dispose();

scratchImage.flush();

g2.dispose();

}

public void paint(Graphics g) {

// Make sure to clip the edges, regardless of curr size

g.setClip(0, 0, imageSize.width, imageSize.height);

int localOffset = currOffset; // in case it changes

g.drawImage(image, -localOffset, 0, this);

g.drawImage(

image, imageSize.width - localOffset, 0, this);

// draw outline

g.setColor(Color.black);

g.drawRect(

0, 0, imageSize.width - 1, imageSize.height - 1);

}

private void runWork() {

while ( noStopRequested ) {

try {

Thread.sleep(100); // 10 frames per second

// adjust the scroll position

currOffset =

( currOffset + 1 ) % imageSize.width;

// signal the event thread to call paint()

repaint();

} catch ( InterruptedException x ) {

Thread.currentThread().interrupt();

}

}

}

public void stopRequest() {

noStopRequested = false;

internalThread.interrupt();

}

public boolean isAlive() {

return internalThread.isAlive();

}

public static void main(String[] args) {

ScrollText st =

new ScrollText("Java can do animation!");

JPanel p = new JPanel(new FlowLayout());

p.add(st);

JFrame f = new JFrame("ScrollText Demo");

f.setContentPane(p);

f.setSize(400, 100);

f.setVisible(true);

}

}