rescale Icon If Needed

Description

Demo Code

/*//from   ww  w .  j a  v  a2s.c  o  m
 * Copyright (C) 2011 Thedeath<www.fseek.org>
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.swing.Icon;
import javax.swing.ImageIcon;

public class Main{
    public static Icon rescaleIconIfNeeded(Icon systemIcon, int height,
            int width) {
        BufferedImage scaledInstance = null;
        if (systemIcon.getIconHeight() > height) {
            if (systemIcon instanceof ImageIcon) {
                ImageIcon tempImg = (ImageIcon) systemIcon;
                BufferedImage img = null;
                if (scaledInstance != null) {
                    img = scaledInstance;
                } else {
                    img = imageToBufferedImage(tempImg.getImage());
                }
                scaledInstance = getScaledInstance(img,
                        img.getWidth(), height, null, false);
            }
        }
        if (systemIcon.getIconWidth() > width) {
            if (systemIcon instanceof ImageIcon) {
                ImageIcon tempImg = (ImageIcon) systemIcon;
                BufferedImage img = null;
                if (scaledInstance != null) {
                    img = scaledInstance;
                } else {
                    img = imageToBufferedImage(tempImg.getImage());
                }
                scaledInstance = getScaledInstance(img, width,
                        img.getHeight(), null, false);
            }
        }
        if (scaledInstance == null) {
            return systemIcon;
        }
        return new ImageIcon(scaledInstance);
    }
    public static BufferedImage imageToBufferedImage(Image img) {
        int width = img.getWidth(null); // es muss keinen ImageObserver geben
        int height = img.getHeight(null);
        BufferedImage bufImg = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_ARGB);
        Graphics g = bufImg.createGraphics();
        g.drawImage(img, 0, 0, null);
        g.dispose();
        return bufImg;
    }
    /**
     * 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 down scaling 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}
     */
    public static BufferedImage getScaledInstance(BufferedImage img,
            int targetWidth, int targetHeight, Object hint,
            boolean higherQuality) {
        int type = (img.getTransparency() == Transparency.OPAQUE) ? BufferedImage.TYPE_INT_RGB
                : BufferedImage.TYPE_INT_ARGB;
        BufferedImage ret = (BufferedImage) img;
        int w, h;
        if (higherQuality) {
            // 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;
                }
            }

            BufferedImage tmp = new BufferedImage(w, h, type);
            Graphics2D g2 = tmp.createGraphics();
            if (hint == null)
                hint = RenderingHints.VALUE_INTERPOLATION_BILINEAR;
            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;
    }
}
rescale Icon If Needed - Java Swing

Description

Demo Code

Related Tutorials
