JavaでSVGを出力

　Batik SVG Toolkitを使うと、Java2Dで描画した画像を簡単にSVGで出力できる。

　■準備
　　Batik SVG Toolkitからライブラリをダウンロードしてクラスパスを設定する。
　■ソースコード
　　次のようなサンプルコードを書いてみる。

package test;

import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.Line2D;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import org.apache.batik.dom.GenericDOMImplementation;
import org.apache.batik.svggen.SVGGraphics2D;
import org.apache.batik.svggen.SVGGraphics2DIOException;
import org.w3c.dom.DOMImplementation;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class SVGTest extends JPanel{

	private static final long serialVersionUID = 1L;
	private List<Shape> sp;
	private boolean isPress=false;
	private Point pos0=null;
	private Point pos1=null;
	private BasicStroke stroke=new BasicStroke(2.0f);
	
	public SVGTest() {
		super();
		super.setOpaque(false);
		sp=new ArrayList<Shape>();
		MouseAdapter ma=new MouseAdapter(){
			@Override
			public void mouseDragged(MouseEvent e) {
				if(isPress){
					pos1=e.getPoint();
					updateUI();
				}
			}
			@Override
			public void mousePressed(MouseEvent e) {
				isPress=true;
				pos0=e.getPoint();
			}
			@Override
			public void mouseReleased(MouseEvent e) {
				isPress=false;
				if(pos0!=null&&pos1!=null){
					sp.add(new Line2D.Double(pos0.x,pos0.y,pos1.x,pos1.y));
				}
				pos0=null;
				pos1=null;
			}
			
		};
		addMouseListener(ma);
		addMouseMotionListener(ma);
	}

	@Override
	protected void paintComponent(Graphics g) {
		super.paintComponent(g);
		Graphics2D g2=(Graphics2D)g;
		g2.setStroke(stroke);
		g2.setColor(Color.RED);
		for(int i=0;i<sp.size();i++){
			g2.draw(sp.get(i));
		}
		if(pos0!=null&&pos1!=null){
			g2.drawLine(pos0.x, pos0.y, pos1.x, pos1.y);
		}
	}
	
	void outputSVG(File f){
		Rectangle r=getBounds();
		DOMImplementation domImpl=GenericDOMImplementation.getDOMImplementation();
		Document document=domImpl.createDocument(null, "svg", null);
		SVGGraphics2D svg2d=new SVGGraphics2D(document);
		svg2d.setBackground(new Color(255,255,255,0));
		svg2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
		this.paintComponent(svg2d);
		Element sv=svg2d.getRoot();
		sv.setAttribute("xml:space", "preserve");
		sv.setAttribute("width", Integer.toString((int)r.getWidth()));
		sv.setAttribute("height", Integer.toString((int)r.getHeight()));
		sv.setAttribute("viewBox", 
				Integer.toString((int)r.getX())+" "+
				Integer.toString((int)r.getY())+" "+
				Integer.toString((int)r.getWidth())+" "+
				Integer.toString((int)r.getHeight())	
		);
		try {
    		OutputStream os = new FileOutputStream(f);
    	    BufferedOutputStream bos = new BufferedOutputStream(os);
    	    Writer out = new OutputStreamWriter(bos, "UTF-8");
    	    svg2d.stream(sv,out);
		} catch (UnsupportedEncodingException ue){
    		ue.printStackTrace();
    	} catch (SVGGraphics2DIOException se){
    		se.printStackTrace();
    	} catch (IOException ioe){
    		ioe.printStackTrace();
    	}
	}
	
	public static void main(String[] args){
		JFrame f=new JFrame();
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		f.getContentPane().setBackground(Color.WHITE);
		f.getContentPane().setLayout(new BorderLayout());
		final SVGTest wt=new SVGTest();
		f.getContentPane().add(wt,BorderLayout.CENTER);
		JMenuBar bar=new JMenuBar();
		JMenu menu=new JMenu("File");
		bar.add(menu);
		JMenuItem out=new JMenuItem("Output SVG");
		menu.add(out);
		out.addActionListener(new ActionListener(){
			@Override
			public void actionPerformed(ActionEvent arg0) {
				JFileChooser chooser=new JFileChooser();
				int ret = chooser.showDialog(null, "ファイル選択");
				if (ret != JFileChooser.APPROVE_OPTION) {return;}
				File file=chooser.getSelectedFile();
				wt.outputSVG(file);
			}
		});
		f.setJMenuBar(bar);
		f.setSize(800, 600);
		f.setVisible(true);
	}
}

　■結果
　　SVGが出力できました。