magarena/src/magic/GraphicsUtilities.java

/*
 * $Id$
 *
 * Dual-licensed under LGPL (Sun and Romain Guy) and BSD (Romain Guy).
 *
 * Copyright 2005 Sun Microsystems, Inc., 4150 Network Circle,
 * Santa Clara, California 95054, U.S.A. All rights reserved.
 *
 * Copyright (c) 2006 Romain Guy <romain.guy@mac.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package magic;

import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsEnvironment;
import java.awt.RenderingHints;
import java.awt.Transparency;
import java.awt.image.BufferedImage;

/**
 * <p><code>GraphicsUtilities</code> contains a set of tools to perform
 * common graphics operations easily. 
 *
 * @author Romain Guy <romain.guy@mac.com>
 * @author rbair
 * @author Karl Schaefer
 */
public class GraphicsUtilities {
    
    public static BufferedImage scale(
            final BufferedImage img,
            final int targetWidth,
            final int targetHeight) {
        if (img.getWidth() == targetWidth && img.getHeight() == targetHeight) {
            return img;
        } else {
            return scale(
                    img, 
                    targetWidth, 
                    targetHeight, 
                    RenderingHints.VALUE_INTERPOLATION_BILINEAR, 
                    true);
        }
    }

    /**
     * Convenience method that returns a scaled instance of the
     * provided {@code BufferedImage}.
     *
     * @param img the original image to be scaled
     * @param targetWidth the desired width of the scaled instance,
     *    in pixels
     * @param targetHeight the desired height of the scaled instance,
     *    in pixels
     * @param hint one of the rendering hints that corresponds to
     *    {@code RenderingHints.KEY_INTERPOLATION} (e.g.
     *    {@code RenderingHints.VALUE_INTERPOLATION_NEAREST_NEIGHBOR},
     *    {@code RenderingHints.VALUE_INTERPOLATION_BILINEAR},
     *    {@code RenderingHints.VALUE_INTERPOLATION_BICUBIC})
     * @param higherQuality if true, this method will use a multi-step
     *    scaling technique that provides higher quality than the usual
     *    one-step technique (only useful in downscaling cases, where
     *    {@code targetWidth} or {@code targetHeight} is
     *    smaller than the original dimensions, and generally only when
     *    the {@code BILINEAR} hint is specified)
     * @return a scaled version of the original {@code BufferedImage}
     */
    private static BufferedImage scale(final BufferedImage img,
                               final int targetWidth,
                               final int targetHeight,
                               final Object hint,
                               final boolean higherQuality) {
        final int type = (img.getTransparency() == Transparency.OPAQUE) ?
            BufferedImage.TYPE_INT_RGB : BufferedImage.TYPE_INT_ARGB;
        BufferedImage ret = img;
        int w, h;
        if (higherQuality && (img.getWidth() > targetWidth && img.getHeight() > targetHeight)) {
            // Use multi-step technique: start with original size, then
            // scale down in multiple passes with drawImage()
            // until the target size is reached
            w = img.getWidth();
            h = img.getHeight();
        } else {
            // Use one-step technique: scale directly from original
            // size to target size with a single drawImage() call
            w = targetWidth;
            h = targetHeight;
        }
        
        do {
            if (higherQuality && w > targetWidth) {
                w /= 2;
                if (w < targetWidth) {
                    w = targetWidth;
                }
            }

            if (higherQuality && h > targetHeight) {
                h /= 2;
                if (h < targetHeight) {
                    h = targetHeight;
                }
            }

            final BufferedImage tmp = new BufferedImage(w, h, type);
            final Graphics2D g2 = tmp.createGraphics();
            g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, hint);
            g2.drawImage(ret, 0, 0, w, h, null);
            g2.dispose();

            ret = tmp;
        } while (w != targetWidth || h != targetHeight);

        return ret;
    }

    // Returns the graphics configuration for the primary screen
    private static GraphicsConfiguration getGraphicsConfiguration() {
        return GraphicsEnvironment.getLocalGraphicsEnvironment().
                    getDefaultScreenDevice().getDefaultConfiguration();
    }

    private static boolean isHeadless() {
        return GraphicsEnvironment.isHeadless();
    }
}