SampleStreamResource.java

package org.vaadin.jcrop;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;

import javax.imageio.ImageIO;

import com.vaadin.server.StreamResource.StreamSource;

public class SampleStreamResource implements StreamSource {
	ByteArrayOutputStream imagebuffer = null;
	int reloads = 0;

	/*
	 * We need to implement this method that returns the resource as a stream.
	 */
	@Override
	public InputStream getStream() {
		/* Create an image and draw something on it. */
		BufferedImage image = new BufferedImage(750, 500, BufferedImage.TYPE_INT_RGB);
		Graphics drawable = image.getGraphics();
		drawable.setColor(Color.lightGray);
		drawable.fillRect(0, 0, 750, 500);
		drawable.setColor(Color.yellow);
		drawable.fillOval(150, 25, 450, 450);
		drawable.setColor(Color.black);
		drawable.drawString("drawn=" + new Date().toString(), 280, 240);

		try {
			/* Write the image to a buffer. */
			this.imagebuffer = new ByteArrayOutputStream();
			ImageIO.write(image, "png", this.imagebuffer);

			/* Return a stream from the buffer. */
			return new ByteArrayInputStream(this.imagebuffer.toByteArray());
		} catch (IOException e) {
			return null;
		}
	}
}