chartutilities.java

关于jfreechart的电子说明书,一种说明图型使用的介绍

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2.1 of the License, or 
 * (at your option) any later version.
 *
 * This library 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 Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
 * USA.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * -------------------
 * ChartUtilities.java
 * -------------------
 * (C) Copyright 2001-2005, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   Wolfgang Irler;
 *                   Richard Atkinson;
 *                   Xavier Poinsard;
 *
 * $Id: ChartUtilities.java,v 1.4.2.1 2005/10/25 16:50:20 mungady Exp $
 *
 * Changes
 * -------
 * 11-Dec-2001 : Version 1.  The JPEG method comes from Wolfgang Irler's 
 *               JFreeChartServletDemo class (DG);
 * 23-Jan-2002 : Changed saveChartAsXXX() methods to pass IOExceptions back to 
 *               caller (DG);
 * 26-Jun-2002 : Added image map methods (DG);
 * 05-Aug-2002 : Added writeBufferedImage methods
 *               Modified writeImageMap method to support flexible image 
 *               maps (RA);
 * 26-Aug-2002 : Added saveChartAsJPEG and writeChartAsJPEG methods with info 
 *               objects (RA);
 * 05-Sep-2002 : Added writeImageMap() method to support OverLIB
 *               - http://www.bosrup.com/web/overlib (RA);
 * 26-Sep-2002 : Fixed errors reported by Checkstyle (DG);
 * 17-Oct-2002 : Exposed JPEG quality setting and PNG compression level as 
 *               parameters (DG);
 * 25-Oct-2002 : Fixed writeChartAsJPEG() empty method bug (DG);
 * 13-Mar-2003 : Updated writeImageMap method as suggested by Xavier Poinsard 
 *               (see Feature Request 688079) (DG);
 * 12-Aug-2003 : Added support for custom image maps using 
 *               ToolTipTagFragmentGenerator and URLTagFragmentGenerator (RA);
 * 02-Sep-2003 : Separated PNG encoding from writing chart to an 
 *               OutputStream (RA);
 * 04-Dec-2003 : Chart draw() method modified to include anchor point (DG);
 * 20-Feb-2004 : Edited Javadocs and added argument checking (DG);
 * 05-Apr-2004 : Fixed problem with buffered image type (DG);
 * 01-Aug-2004 : Modified to use EncoderUtil for all image encoding (RA);
 * 02-Aug-2004 : Delegated image map related functionality to ImageMapUtil (RA);
 * 13-Jan-2005 : Renamed ImageMapUtil --> ImageMapUtilities, removed method
 *               writeImageMap(PrintWriter, String, ChartRenderingInfo) which 
 *               exists in ImageMapUtilities (DG);
 *
 */

package org.jfree.chart;

import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;

import org.jfree.chart.imagemap.ImageMapUtilities;
import org.jfree.chart.imagemap.OverLIBToolTipTagFragmentGenerator;
import org.jfree.chart.imagemap.StandardToolTipTagFragmentGenerator;
import org.jfree.chart.imagemap.StandardURLTagFragmentGenerator;
import org.jfree.chart.imagemap.ToolTipTagFragmentGenerator;
import org.jfree.chart.imagemap.URLTagFragmentGenerator;

import org.jfree.chart.encoders.EncoderUtil;
import org.jfree.chart.encoders.ImageFormat;

/**
 * A collection of utility methods for JFreeChart.  Includes methods for 
 * converting charts to image formats (PNG and JPEG) plus creating simple HTML 
 * image maps.
 */
public abstract class ChartUtilities {

    /**
     * Writes a chart to an output stream in PNG format.
     *
     * @param out  the output stream (<code>null</code> not permitted).
     * @param chart  the chart (<code>null</code> not permitted).
     * @param width  the image width.
     * @param height  the image height.
     *
     * @throws IOException if there are any I/O errors.
     */
    public static void writeChartAsPNG(OutputStream out,
                                       JFreeChart chart,
                                       int width,
                                       int height) throws IOException {

        // defer argument checking...
        writeChartAsPNG(out, chart, width, height, null);

    }

    /**
     * Writes a chart to an output stream in PNG format.
     *
     * @param out  the output stream (<code>null</code> not permitted).
     * @param chart  the chart (<code>null</code> not permitted).
     * @param width  the image width.
     * @param height  the image height.
     * @param encodeAlpha  encode alpha?
     * @param compression  the compression level (0-9).
     *
     * @throws IOException if there are any I/O errors.
     */
    public static void writeChartAsPNG(OutputStream out,
                                       JFreeChart chart,
                                       int width,
                                       int height,
                                       boolean encodeAlpha,
                                       int compression) throws IOException {

        // defer argument checking...
        ChartUtilities.writeChartAsPNG(
            out, chart, width, height, null, encodeAlpha, compression
        );

    }

    /**
     * Writes a chart to an output stream in PNG format.  This method allows 
     * you to pass in a {@link ChartRenderingInfo} object, to collect 
     * information about the chart dimensions/entities.  You will need this 
     * info if you want to create an HTML image map.
     *
     * @param out  the output stream (<code>null</code> not permitted).
     * @param chart  the chart (<code>null</code> not permitted).
     * @param width  the image width.
     * @param height  the image height.
     * @param info  the chart rendering info (<code>null</code> permitted).
     *
     * @throws IOException if there are any I/O errors.
     */
    public static void writeChartAsPNG(OutputStream out,
                                       JFreeChart chart,
                                       int width,
                                       int height,
                                       ChartRenderingInfo info) 
        throws IOException {

        if (chart == null) {
            throw new IllegalArgumentException("Null 'chart' argument.");
        }
        BufferedImage bufferedImage 
            = chart.createBufferedImage(width, height, info);
        EncoderUtil.writeBufferedImage(bufferedImage, ImageFormat.PNG, out);
    }

    /**
     * Writes a chart to an output stream in PNG format.  This method allows 
     * you to pass in a {@link ChartRenderingInfo} object, to collect 
     * information about the chart dimensions/entities.  You will need this 
     * info if you want to create an HTML image map.
     *
     * @param out  the output stream (<code>null</code> not permitted).
     * @param chart  the chart (<code>null</code> not permitted).
     * @param width  the image width.
     * @param height  the image height.
     * @param info  carries back chart rendering info (<code>null</code> 
     *              permitted).
     * @param encodeAlpha  encode alpha?
     * @param compression  the PNG compression level (0-9).
     *
     * @throws IOException if there are any I/O errors.
     */
    public static void writeChartAsPNG(OutputStream out,
                                       JFreeChart chart,
                                       int width, int height,
                                       ChartRenderingInfo info,
                                       boolean encodeAlpha,
                                       int compression) throws IOException {

        if (out == null) {
            throw new IllegalArgumentException("Null 'out' argument.");
        }
        if (chart == null) {
            throw new IllegalArgumentException("Null 'chart' argument.");
        }
        BufferedImage chartImage = chart.createBufferedImage(
            width, height, BufferedImage.TYPE_INT_ARGB, info
        );
        ChartUtilities.writeBufferedImageAsPNG(
            out, chartImage, encodeAlpha, compression
        );

    }

    /**
     * Writes a scaled version of a chart to an output stream in PNG format.
     *
     * @param out  the output stream (<code>null</code> not permitted).
     * @param chart  the chart (<code>null</code> not permitted).
     * @param width  the unscaled chart width.
     * @param height  the unscaled chart height.
     * @param widthScaleFactor  the horizontal scale factor.
     * @param heightScaleFactor  the vertical scale factor.
     *
     * @throws IOException if there are any I/O problems.
     */
    public static void writeScaledChartAsPNG(OutputStream out,
                                             JFreeChart chart,
                                             int width,
                                             int height,
                                             int widthScaleFactor,
                                             int heightScaleFactor) 
        throws IOException {

        if (out == null) {
            throw new IllegalArgumentException("Null 'out' argument.");
        }
        if (chart == null) {
            throw new IllegalArgumentException("Null 'chart' argument.");
        }

        double desiredWidth = width * widthScaleFactor;
        double desiredHeight = height * heightScaleFactor;
        double defaultWidth = width;
        double defaultHeight = height;
        boolean scale = false;

        // get desired width and height from somewhere then...
        if ((widthScaleFactor != 1) || (heightScaleFactor != 1)) {
            scale = true;
        }

        double scaleX = desiredWidth / defaultWidth;
        double scaleY = desiredHeight / defaultHeight;

        BufferedImage image = new BufferedImage(
            (int) desiredWidth, (int) desiredHeight, BufferedImage.TYPE_INT_ARGB
        );
        Graphics2D g2 = image.createGraphics();