swtutils.java

jfreechart-1.0.12 开发包和文档等

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2007, 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.]
 *
 * -------------
 * SWTUtils.java
 * -------------
 * (C) Copyright 2006, 2007, by Henry Proudhon and Contributors.
 *
 * Original Author:  Henry Proudhon (henry.proudhon AT ensmp.fr);
 * Contributor(s):   Rainer Blessing;
 *                   David Gilbert ([e-mail]);
 *                   Christoph Beck.
 *
 * Changes
 * -------
 * 01-Aug-2006 : New class (HP);
 * 16-Jan-2007 : Use FontData.getHeight() instead of direct field access (RB);
 * 31-Jan-2007 : Moved the dummy JPanel from SWTGraphics2D.java,
 *               added a new convert method for mouse events (HP);
 * 12-Jul-2007 : Improved the mouse event conversion with buttons
 *               and modifiers handling, patch sent by Christoph Beck (HP);
 * 27-Aug-2007 : Modified toAwtMouseEvent signature (HP);
 * 27-Nov-2007 : Moved convertToSWT() method from SWTGraphics2D and added
 *               convertAWTImageToSWT() (DG);
 * 01-Jul-2008 : Simplify AWT/SWT font style conversions (HP);
 *
 */

package org.jfree.experimental.swt;

import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.InputEvent;
import java.awt.event.MouseEvent;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.awt.image.DirectColorModel;
import java.awt.image.IndexColorModel;
import java.awt.image.WritableRaster;

import javax.swing.JPanel;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Device;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.graphics.PaletteData;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.graphics.Rectangle;

/**
 * Utility class gathering some useful and general method.
 * Mainly convert forth and back graphical stuff between
 * awt and swt.
 */
public class SWTUtils {

    private final static String Az = "ABCpqr";

    /** A dummy JPanel used to provide font metrics. */
    protected static final JPanel DUMMY_PANEL = new JPanel();

    /**
     * Create a <code>FontData</code> object which encapsulate
     * the essential data to create a swt font. The data is taken
     * from the provided awt Font.
     * <p>Generally speaking, given a font size, the returned swt font
     * will display differently on the screen than the awt one.
     * Because the SWT toolkit use native graphical resources whenever
     * it is possible, this fact is platform dependent. To address
     * this issue, it is possible to enforce the method to return
     * a font with the same size (or at least as close as possible)
     * as the awt one.
     * <p>When the object is no more used, the user must explicitly
     * call the dispose method on the returned font to free the
     * operating system resources (the garbage collector won't do it).
     *
     * @param device The swt device to draw on (display or gc device).
     * @param font The awt font from which to get the data.
     * @param ensureSameSize A boolean used to enforce the same size
     * (in pixels) between the awt font and the newly created swt font.
     * @return a <code>FontData</code> object.
     */
    public static FontData toSwtFontData(Device device, java.awt.Font font,
            boolean ensureSameSize) {
        FontData fontData = new FontData();
        fontData.setName(font.getFamily());
        // SWT and AWT share the same style constants.
        fontData.setStyle(font.getStyle());
        // convert the font size (in pt for awt) to height in pixels for swt
        int height = (int) Math.round(font.getSize() * 72.0
                / device.getDPI().y);
        fontData.setHeight(height);
        // hack to ensure the newly created swt fonts will be rendered with the
        // same height as the awt one
        if (ensureSameSize) {
            GC tmpGC = new GC(device);
            Font tmpFont = new Font(device, fontData);
            tmpGC.setFont(tmpFont);
            if (tmpGC.textExtent(Az).x
                    > DUMMY_PANEL.getFontMetrics(font).stringWidth(Az)) {
                while (tmpGC.textExtent(Az).x
                        > DUMMY_PANEL.getFontMetrics(font).stringWidth(Az)) {
                    tmpFont.dispose();
                    height--;
                    fontData.setHeight(height);
                    tmpFont = new Font(device, fontData);
                    tmpGC.setFont(tmpFont);
                }
            }
            else if (tmpGC.textExtent(Az).x
                    < DUMMY_PANEL.getFontMetrics(font).stringWidth(Az)) {
                while (tmpGC.textExtent(Az).x
                        < DUMMY_PANEL.getFontMetrics(font).stringWidth(Az)) {
                    tmpFont.dispose();
                    height++;
                    fontData.setHeight(height);
                    tmpFont = new Font(device, fontData);
                    tmpGC.setFont(tmpFont);
                }
            }
            tmpFont.dispose();
            tmpGC.dispose();
        }
        return fontData;
    }

    /**
     * Create an awt font by converting as much information
     * as possible from the provided swt <code>FontData</code>.
     * <p>Generally speaking, given a font size, an swt font will
     * display differently on the screen than the corresponding awt
     * one. Because the SWT toolkit use native graphical ressources whenever
     * it is possible, this fact is platform dependent. To address
     * this issue, it is possible to enforce the method to return
     * an awt font with the same height as the swt one.
     *
     * @param device The swt device being drawn on (display or gc device).
     * @param fontData The swt font to convert.
     * @param ensureSameSize A boolean used to enforce the same size
     * (in pixels) between the swt font and the newly created awt font.
     * @return An awt font converted from the provided swt font.
     */
    public static java.awt.Font toAwtFont(Device device, FontData fontData,
            boolean ensureSameSize) {
        int height = (int) Math.round(fontData.getHeight() * device.getDPI().y
                / 72.0);
        // hack to ensure the newly created awt fonts will be rendered with the
        // same height as the swt one
        if (ensureSameSize) {
            GC tmpGC = new GC(device);
            Font tmpFont = new Font(device, fontData);
            tmpGC.setFont(tmpFont);
            JPanel DUMMY_PANEL = new JPanel();
            java.awt.Font tmpAwtFont = new java.awt.Font(fontData.getName(),
                    fontData.getStyle(), height);
            if (DUMMY_PANEL.getFontMetrics(tmpAwtFont).stringWidth(Az)
                    > tmpGC.textExtent(Az).x) {
                while (DUMMY_PANEL.getFontMetrics(tmpAwtFont).stringWidth(Az)
                        > tmpGC.textExtent(Az).x) {
                    height--;
                    tmpAwtFont = new java.awt.Font(fontData.getName(),
                            fontData.getStyle(), height);
                }
            }
            else if (DUMMY_PANEL.getFontMetrics(tmpAwtFont).stringWidth(Az)
                    < tmpGC.textExtent(Az).x) {
                while (DUMMY_PANEL.getFontMetrics(tmpAwtFont).stringWidth(Az)
                        < tmpGC.textExtent(Az).x) {
                    height++;
                    tmpAwtFont = new java.awt.Font(fontData.getName(),
                            fontData.getStyle(), height);
                }
            }
            tmpFont.dispose();
            tmpGC.dispose();
        }
        return new java.awt.Font(fontData.getName(), fontData.getStyle(),
                height);
    }

    /**
     * Create an awt font by converting as much information
     * as possible from the provided swt <code>Font</code>.
     *
     * @param device The swt device to draw on (display or gc device).
     * @param font The swt font to convert.
     * @return An awt font converted from the provided swt font.
     */
    public static java.awt.Font toAwtFont(Device device, Font font) {
        FontData fontData = font.getFontData()[0];
        return toAwtFont(device, fontData, true);
    }

    /**
     * Creates an awt color instance to match the rgb values
     * of the specified swt color.
     *
     * @param color The swt color to match.
     * @return an awt color abject.
     */
    public static java.awt.Color toAwtColor(Color color) {
        return new java.awt.Color(color.getRed(), color.getGreen(),