|
/*
Java Media APIs: Cross-Platform Imaging, Media and Visualization
Alejandro Terrazas
Sams, Published November 2002,
ISBN 0672320940
*/
import java.applet.Applet;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.MemoryImageSource;
import java.awt.image.PixelGrabber;
import java.net.MalformedURLException;
import java.net.URL;
import javax.swing.JFrame;
/**
* GrabandFade.java -- displays provided image and then slowly fades to black
*/
public class GrabandFade extends Applet {
private Image originalImage;
private Image newImage;
private MemoryImageSource mis;
private int width;
private int height;
private int index = 10;
private int[] originalPixelArray;
private boolean imageLoaded = false;
private String imageURLString = "file:peppers.png";
public void init() {
URL url;
try {
// set imageURLString here
url = new URL(imageURLString);
originalImage = getImage(url);
} catch (MalformedURLException me) {
showStatus("Malformed URL: " + me.getMessage());
}
/*
* Create PixelGrabber and use it to fill originalPixelArray with image
* pixel data. This array will then by used by the MemoryImageSource.
*/
try {
PixelGrabber grabber = new PixelGrabber(originalImage, 0, 0, -1,
-1, true);
if (grabber.grabPixels()) {
width = grabber.getWidth();
height = grabber.getHeight();
originalPixelArray = (int[]) grabber.getPixels();
mis = new MemoryImageSource(width, height, originalPixelArray,
0, width);
mis.setAnimated(true);
newImage = createImage(mis);
} else {
System.err.println("Grabbing Failed");
}
} catch (InterruptedException ie) {
System.err.println("Pixel Grabbing Interrupted");
}
}
/**
* overwrite update method to avoid clearing of drawing area
*/
public void update(Graphics g) {
paint(g);
}
/**
* continually draw image, then decrease color components of all pixels
* contained in the originalPixelArray array until color components are all
* 0
*/
public void paint(Graphics g) {
int value;
int alpha, sourceRed, sourceGreen, sourceBlue;
if (newImage != null) {
g.drawImage(newImage, 0, 0, this); // redraw image
// if image isn't faded to black, continue
if (imageLoaded == false) {
imageLoaded = true;
for (int x = 0; x < width; x += 1)
for (int y = 0; y < height; y += 1) {
// find the color components
value = originalPixelArray[x * height + y];
alpha = (value >> 24) & 0x000000ff;
sourceRed = (value >> 16) & 0x000000ff;
sourceGreen = (value >> 8) & 0x000000ff;
sourceBlue = value & 0x000000ff;
// subtract index from each red component
if (sourceRed > index) {
sourceRed -= index;
imageLoaded = false;
} else
sourceRed = 0;
// subtract index from each green component
if (sourceGreen > index) {
sourceGreen -= index;
imageLoaded = false;
} else
sourceGreen = 0;
// subtract index from each blue component
if (sourceBlue > index) {
sourceBlue -= index;
imageLoaded = false;
} else
sourceBlue = 0;
/*
* when we pack new color components into integer we
* make sure the alpha (transparency) value represents
* opaque
*/
value = (alpha << 24);
value += (sourceRed << 16);
value += (sourceGreen << 8);
value += sourceBlue;
// fill pixel array
originalPixelArray[x * height + y] = value;
}
mis.newPixels(); //send pixels to ImageConsumer
}
}
}
public static void main(String[] argv) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GrabandFade a = new GrabandFade();
frame.getContentPane().add(a);
frame.setSize(300, 300);
a.init();
a.start();
frame.setVisible(true);
}
}
|
