Ever run into the problem of wanting to write an image object to disk in a popular format for images ?
With Java 2 platform, image objects or any memory based image representation can be written to disk in the JPEG format. The example shows a simple image created in memory written to disk in the JPEG format. The example makes use of the com.sun.image.codec.jpeg classes to do the encoding. Though it is not a part of the feature set of the Java 2 platform, these classes are still available in the distributed runtime.
Code
/*
* This example is from javareference.com
* for more information visit,
* http://www.javareference.com
*/
import java.awt.*;
import java.awt.image.*;
import java.io.*;
import com.sun.image.codec.jpeg.*;
/*
* This class can take a variable number of parameters on the command
* line. Program execution begins with the main() method. The class
* constructor is not invoked unless an object of type 'Class1'
* created in the main() method.
*
* @author Anand Hariharan([email protected])
*/
public class EncodeJPEG
{
public static void encode(Image img,int x, int y, int w, int h,
String absoluteFileName) throws Exception
{
int[] pixels = new int[w * h];
PixelGrabber pg = new PixelGrabber(img, x, y, w, h, pixels, 0, w);
try
{
pg.grabPixels();
}
catch (InterruptedException e)
{
System.err.println("interrupted waiting for pixels!");
return;
}
if ((pg.getStatus() & ImageObserver.ABORT) != 0)
{
System.err.println("image fetch aborted or errored");
return;
}
BufferedImage bimg = new BufferedImage(w,h,BufferedImage.TYPE_INT_RGB);
for (int j = 0; j < h; j++)
{
for (int i = 0; i < w; i++)
{
bimg.setRGB(x+i, y+j, pixels[j * w + i]);
}
}
FileOutputStream fout = new FileOutputStream(absoluteFileName);
JPEGImageEncoder jencoder = JPEGCodec.createJPEGEncoder(fout);
JPEGEncodeParam enParam = jencoder.getDefaultJPEGEncodeParam(bimg);
enParam.setQuality(1.0F, true);
jencoder.setJPEGEncodeParam(enParam);
jencoder.encode(bimg);
fout.close();
}
public static void main(String [] args) throws Exception
{
Frame f = new Frame();
f.addNotify();
// CREATE an image in memory to draw on
Image img = f.createImage(100,100);
Graphics g = img.getGraphics();
g.setColor(Color.red);
// Draw whatever is needed.
g.fillRect(0, 0, 100,100);
g.setColor(Color.black);
g.setFont(new Font("Arial", Font.BOLD, 14));
g.drawString("Hello from,",10,25);
g.drawString("Java",30,55);
g.drawString("Reference",10,80);
g.setColor(Color.white);
g.drawString("Hello from,",8,22);
g.drawString("Java",28,52);
g.drawString("Reference",8,77);
// Encode into a JPEG
String homeDir = System.getProperty("user.home");
System.out.println("Output JPEG ..." + homeDir + File.separator + "jpg.jpg");
encode(img,0,0,100,100, homeDir + File.separator + "jpg.jpg");
f.removeNotify();
f.dispose();
System.exit(0);
}
}
Demonstration
Following JPEG image is created using above java code.
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