HTMLをGIFファイルに保存

html = new JEditorPane() {

  protected void paintComponent(Graphics g){

    super.paintComponent(g);

    hoge(g); // こんな感じに。

  }

};

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.Writer;
import java.net.URL;

import javax.imageio.ImageIO;
import javax.swing.Action;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
import javax.swing.text.AbstractDocument;
import javax.swing.text.BadLocationException;
import javax.swing.text.Caret;
import javax.swing.text.Document;
import javax.swing.text.EditorKit;
import javax.swing.text.ViewFactory;

/**
 * HTMLのレンダリングイメージをjpegで保存するサンプル
 * @author nagise
 */
public class HtmlCapture {
	public static void main(String[] args) throws Exception {
		String url = args[0];
		final String filename = args[1];
		if (url.indexOf("://") == -1) {
			url = "http://" + url;
		}
		HtmlCapture capture = new HtmlCapture(320,150, new URL(url));
		BufferedImage image = capture.getImage();
		ImageIO.write(image, "jpeg", new File(filename + System.currentTimeMillis() + ".jpeg"));
	}

	private URL url;
	private int width;
	private int height;

	HtmlCapture(int width, int height, URL url) {
		this.width = width;
		this.height = height;
		this.url = url;
	}

	public BufferedImage getImage() throws InterruptedException, IOException {
		JEditorPaneEx editorPane = new JEditorPaneEx();
		editorPane.setEditable(false);
		Listener listener = new Listener(editorPane);
		editorPane.addPropertyChangeListener(listener);
		editorPane.setPage(this.url);
		editorPane.setPreferredSize(new Dimension(this.width, this.height));
		final JFrame frame = new JFrame();
		frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
		frame.getContentPane().add(editorPane);

		SwingUtilities.invokeLater(new Runnable(){
			public void run() {
				frame.setVisible(true);
				frame.pack();
			}
		});
		try {
			listener.joinThread();
			return editorPane.getImage();
		} finally {
			SwingUtilities.invokeLater(new Runnable(){
				public void run() {
					frame.dispose();
				}
			});
		}
	}

	/**
	 * 画像をキャプチャするためのJEditorPaneの拡張
	 */
	public static class JEditorPaneEx extends JEditorPane {
		private Object lock = new Object();
		private boolean captureFlag;
		private BufferedImage captureImage;

		/** キャプチャのフラグ設定 */
		public void captureImage() {
			synchronized (this.lock) {
				this.captureFlag = true;
				this.repaint();
			}
		}
		/** キャプチャのフラグが立った時点で描画をジャックする */
		public void paint(Graphics g) {
			if (this.captureFlag) {
				this.captureFlag = false;
				Graphics g2 = null;
				BufferedImage image = new BufferedImage(
						this.getWidth(), this.getHeight(),
						BufferedImage.TYPE_INT_RGB);
				g2 = image.getGraphics();
				super.paint(g2);
				synchronized (this.lock) {
					this.captureImage = image;
					this.lock.notifyAll();
				}
				g.drawImage(image, 0, 0, null);
			} else {
				super.paint(g);
			}
		}
		public BufferedImage getImage() {
			synchronized (this.lock) {
				try {
					if (this.captureImage == null) {
						this.lock.wait();
					}
					return this.captureImage;
				} catch (InterruptedException e) {
					throw new RuntimeException(e);
				} finally {
					this.captureImage = null;
				}
			}
		}
		/** 非同期ロードをしないように設定 */
		protected EditorKit createDefaultEditorKit() {
			EditorKit kit = super.createDefaultEditorKit();
			AsynchronousProxyEditorKit ret = new AsynchronousProxyEditorKit(kit);
			return ret;
		}
	}
	/**
	 * JEditorPaneExが描画を行った際のプロパティ変更イベントを拾って
	 * キャプチャ可能となるタイミングまでwaitをかける
	 */
	public class Listener implements PropertyChangeListener, Runnable {
		private JEditorPaneEx editorPane;
		private Thread thread;
		private Object lock = new Object();
		public Listener(JEditorPaneEx editorPane) {
			this.editorPane = editorPane;
		}
		public void propertyChange(PropertyChangeEvent evt) {
			if ("page".equals(evt.getPropertyName())) {
				SwingUtilities.invokeLater(new Runnable(){
					public void run() {
						synchronized (Listener.this.lock) {
							Listener.this.thread = new Thread(Listener.this);
							Listener.this.thread.setDaemon(true);
							Listener.this.thread.start();
							Listener.this.lock.notifyAll();
						}
					}
				});
			}
		}
		public void run() {
			this.editorPane.captureImage();
		}
		public void joinThread() throws InterruptedException {
			synchronized (this.lock) {
				if (this.thread == null) {
					this.lock.wait();
				}
				this.thread.join();
			}
		}
	}
	/**
	 * EditorKitのcreateDefaultDocument()をオーバーライドして
	 * AbstractDocument.setAsynchronousLoadPriority(-1)を設定し
	 * Documentの非同期ロードを抑制する
	 */
	public static class AsynchronousProxyEditorKit extends EditorKit {
		private EditorKit target;
		AsynchronousProxyEditorKit(EditorKit target) {
			this.target = target;
		}
		public Document createDefaultDocument() {
			AbstractDocument doc = (AbstractDocument) this.target.createDefaultDocument();
			doc.setAsynchronousLoadPriority(-1);
			return doc;
		}
		public String getContentType() {
			return target.getContentType();
		}
		public ViewFactory getViewFactory() {
			return target.getViewFactory();
		}
		public Action[] getActions() {
			return target.getActions();
		}
		public Caret createCaret() {
			return target.createCaret();
		}
		public void read(InputStream arg0, Document arg1, int arg2) throws IOException, BadLocationException {
			target.read(arg0, arg1, arg2);
		}
		public void write(OutputStream arg0, Document arg1, int arg2, int arg3) throws IOException, BadLocationException {
			target.write(arg0, arg1, arg2, arg3);
		}
		public void read(Reader arg0, Document arg1, int arg2) throws IOException, BadLocationException {
			target.read(arg0, arg1, arg2);
		}
		public void write(Writer arg0, Document arg1, int arg2, int arg3) throws IOException, BadLocationException {
			target.write(arg0, arg1, arg2, arg3);
		}
	}
}