Scales an image to the requested width and height, assuming these are both >= 1; size given in pixels. - Java 2D Graphics

Java examples for 2D Graphics:BufferedImage Resize

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Description

Scales an image to the requested width and height, assuming these are both >= 1; size given in pixels.

Demo Code

/*// ww  w . java2  s.co m
 * {{{ header & license
 * Copyright (c) 2007 Patrick Wright
 *
 * This program 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 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 * }}}
 */
import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

public class Main{
    private static final Map qual;
    /**
     * Scales an image to the requested width and height, assuming these are both >= 1; size given in pixels.
     * If either width or height is <=0, the current image width or height will be used. This method assumes
     * that, at the moment the method is called, the width and height of the image are available; it won't wait for
     * them. Therefore, the method should be called once the image has completely loaded and not before.
     * <p/>
     * Override this method in a subclass to optimize image scaling operations; note that the legacy
     * {@link java.awt.Image#getScaledInstance(int,int,int)} is considered to perform poorly compared to more
     * recent developed techniques.
     * <p/>
     * For a discussion of the options from a member of the Java2D team, see
     * http://today.java.net/pub/a/today/2007/04/03/perils-of-image-getscaledinstance.html
     *
     * @param orgImage The image to scale
     * @return The scaled image instance.
     */
    public static BufferedImage getScaledInstance(ScalingOptions opt,
            BufferedImage orgImage) {
        int w = orgImage.getWidth(null);
        int h = orgImage.getHeight(null);

        if (opt.sizeMatches(w, h))
            return orgImage;

        w = (opt.getTargetWidth() <= 0 ? w : opt.getTargetWidth());
        h = (opt.getTargetHeight() <= 0 ? h : opt.getTargetHeight());

        Scaler scaler = (ImageUtil.Scaler) qual.get(opt
                .getDownscalingHint());
        BufferedImage tmp = scaler.getScaledInstance(orgImage, opt);

        return tmp;
    }
    /**
     * Scales an image to the requested width and height, assuming these are both >= 1; size given in pixels.
     * If either width or height is <=0, the current image width or height will be used. This method assumes       y
     * that, at the moment the method is called, the width and height of the image are available; it won't wait for
     * them. Therefore, the method should be called once the image has completely loaded and not before.
     * <p/>
     * Override this method in a subclass to optimize image scaling operations; note that the legacy
     * {@link java.awt.Image#getScaledInstance(int,int,int)} is considered to perform poorly compared to more
     * recent developed techniques.
     * <p/>
     * For a discussion of the options from a member of the Java2D team, see
     * http://today.java.net/pub/a/today/2007/04/03/perils-of-image-getscaledinstance.html
     *
     * @param orgImage    The image to scale
     * @param targetWidth  The target width in pixels
     * @param targetHeight The target height in pixels
     * @return The scaled image instance.
     */
    public static BufferedImage getScaledInstance(BufferedImage orgImage,
            int targetWidth, int targetHeight) {
        String downscaleQuality = Configuration.valueFor("xr.image.scale",
                DownscaleQuality.HIGH_QUALITY.asString());
        DownscaleQuality quality = DownscaleQuality.forString(
                downscaleQuality, DownscaleQuality.HIGH_QUALITY);

        Object hint = Configuration.valueFromClassConstant(
                "xr.image.render-quality",
                RenderingHints.VALUE_INTERPOLATION_BICUBIC);

        ScalingOptions opt = new ScalingOptions(targetWidth, targetHeight,
                BufferedImage.TYPE_INT_ARGB, quality, hint);

        return getScaledInstance(opt, orgImage);
    }
}

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