source: src/main/java/weka/gui/visualize/JPEGWriter.java @ 14

 /*
  *    This program is free software; you can redistribute it and/or modify
  *    it under the terms of the GNU General Public License as published by
  *    the Free Software Foundation; either version 2 of the License, or
  *    (at your option) any later version.
  *
  *    This program is distributed in the hope that it will be useful,
  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *    GNU General Public License for more details.
  *
  *    You should have received a copy of the GNU General Public License
  *    along with this program; if not, write to the Free Software
  *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */

 /*
  *    JPEGWriter.java
  *    Copyright (C) 2005 University of Waikato, Hamilton, New Zealand
  *
  */

package weka.gui.visualize;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.util.Iterator;
import java.util.Locale;

import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.plugins.jpeg.JPEGImageWriteParam;
import javax.imageio.stream.ImageOutputStream;
import javax.swing.JComponent;

/** 
 * This class takes any JComponent and outputs it to a JPEG-file.
 * Scaling is by default disabled, since we always take a screenshot.
 *
 * @author FracPete (fracpete at waikato dot ac dot nz)
 * @version $Revision: 5920 $
 */
public class JPEGWriter
  extends JComponentWriter {
  
  /** the quality of the image. */
  protected float m_Quality;
  
  /** the background color. */
  protected Color m_Background;
  
  /**
   * initializes the object.
   */
  public JPEGWriter() {
    super();
  }

  /**
   * initializes the object with the given Component.
   * 
   * @param c         the component to print in the output format
   */
  public JPEGWriter(JComponent c) {
    super(c);
  }

  /**
   * initializes the object with the given Component and filename.
   * 
   * @param c         the component to print in the output format
   * @param f         the file to store the output in
   */
  public JPEGWriter(JComponent c, File f) {
    super(c, f);
    
    m_Quality    = 1.0f;
    m_Background = Color.WHITE;
  }
  
  /**
   * further initialization.
   */
  public void initialize() {
    super.initialize();
    
    m_Quality    = 1.0f;
    m_Background = Color.WHITE;
    setScalingEnabled(false);
  }

  /**
   * returns the name of the writer, to display in the FileChooser.
   * must be overridden in the derived class.
   * 
   * @return the name of the writer
   */
  public String getDescription() {
    return "JPEG-Image";
  }
  
  /**
   * returns the extension (incl. ".") of the output format, to use in the
   * FileChooser. 
   * must be overridden in the derived class.
   * 
   * @return the file extension
   */
  public String getExtension() {
    return ".jpg";
  }
  
  /**
   * returns the current background color.
   * 
   * @return the current background color
   */
  public Color getBackground() {
    return m_Background;
  }
  
  /**
   * sets the background color to use in creating the JPEG.
   * 
   * @param c the color to use for background
   */
  public void setBackground(Color c) {
    m_Background = c;
  }
  
  /**
   * returns the quality the JPEG will be stored in.
   * 
   * @return the quality
   */
  public float getQuality() {
    return m_Quality;
  }
  
  /**
   * sets the quality the JPEG is saved in.
   * 
   * @param q the quality to use
   */
  public void setQuality(float q) {
    m_Quality = q;
  }
  
  /**
   * generates the actual output.
   * 
   * @throws Exception  if something goes wrong
   */
  public void generateOutput() throws Exception {
    BufferedImage       bi;
    Graphics            g;
    ImageWriter         writer;
    Iterator            iter;
    ImageOutputStream   ios;
    ImageWriteParam     param;

    // render image
    bi = new BufferedImage(getComponent().getWidth(), getComponent().getHeight(), BufferedImage.TYPE_INT_RGB);
    g  = bi.getGraphics();
    g.setPaintMode();
    g.setColor(getBackground());
    if (g instanceof Graphics2D)
      ((Graphics2D) g).scale(getXScale(), getYScale());
    g.fillRect(0, 0, getComponent().getWidth(), getComponent().getHeight());
    getComponent().printAll(g);
    
    // get jpeg writer
    writer = null;
    iter   = ImageIO.getImageWritersByFormatName(getExtension().replace(".", ""));
    if (iter.hasNext())
      writer = (ImageWriter) iter.next();
    else
      throw new Exception("No writer available for " + getDescription() + "!");

    // prepare output file
    ios = ImageIO.createImageOutputStream(getFile());
    writer.setOutput(ios);

    // set the quality
    param = new JPEGImageWriteParam(Locale.getDefault());
    param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT) ;
    param.setCompressionQuality(getQuality());

    // write the image
    writer.write(null, new IIOImage(bi, null, null), param);

    // cleanup
    ios.flush();
    writer.dispose();
    ios.close();    
  }
  
  /**
   * for testing only.
   * 
   * @param args the commandline arguments
   * @throws Exception if something goes wrong
   */
  public static void main(String[] args) throws Exception {
    System.out.println("building TreeVisualizer...");
    weka.gui.treevisualizer.TreeBuild builder = new weka.gui.treevisualizer.TreeBuild();
    weka.gui.treevisualizer.NodePlace arrange = new weka.gui.treevisualizer.PlaceNode2();
    weka.gui.treevisualizer.Node top = builder.create(new java.io.StringReader("digraph atree { top [label=\"the top\"] a [label=\"the first node\"] b [label=\"the second nodes\"] c [label=\"comes off of first\"] top->a top->b b->c }"));
    weka.gui.treevisualizer.TreeVisualizer tv = new weka.gui.treevisualizer.TreeVisualizer(null, top, arrange);
    tv.setSize(800 ,600);
    
    String filename = System.getProperty("java.io.tmpdir") + File.separator + "test.jpg";
    System.out.println("outputting to '" + filename + "'...");
    toOutput(new JPEGWriter(), tv, new File(filename));

    System.out.println("done!");
  }
}