高分求救生成高质量缩略图！

Question

大家帮帮忙，我做的生成图片的缩略图质量挺差的。呵呵！

Answer 1

你好像是在求算法吧。我用swt的2Ddraw生成过效果还可以。

Answer 2

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.WritableRaster;
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.io.InputStream;
import java.io.File;
import java.io.FileOutputStream;public class test {
    public static BufferedImage resize(BufferedImage source, int targetW, int targetH) {
           // targetW，targetH分别表示目标长和宽
            int type = source.getType();
            BufferedImage target = null;
            double sx = (double) targetW / source.getWidth();
            double sy = (double) targetH / source.getHeight();
            //这里想实现在targetW，targetH范围内实现等比缩放。如果不需要等比缩放
                  //则将下面的if else语句注释即可
            if(sx>sy)
            {
                sx = sy;
                targetW = (int)(sx * source.getWidth());
            }else{
                sy = sx;
                targetH = (int)(sy * source.getHeight());
            }
            if (type == BufferedImage.TYPE_CUSTOM) { //handmade
                ColorModel cm = source.getColorModel();
                WritableRaster raster = cm.createCompatibleWritableRaster(targetW, targetH);
                boolean alphaPremultiplied = cm.isAlphaPremultiplied();
                target = new BufferedImage(cm, raster, alphaPremultiplied, null);
            } else
             target = new BufferedImage(targetW, targetH, type);
            Graphics2D g = target.createGraphics();
            //smoother than exlax:
            g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY );
            g.drawRenderedImage(source, AffineTransform.getScaleInstance(sx, sy));
            g.dispose();
            return target;
        }
    public static void saveImageAsJpg (String fromFileStr,String saveToFileStr,int width,int hight)
                throws Exception {
            BufferedImage srcImage;
            File saveFile=new File(saveToFileStr);
            File fromFile=new File(fromFileStr);
            srcImage = ImageIO.read(fromFile);
            if(width > 0 || hight > 0)
            {
                 srcImage = resize(srcImage, width, hight);
            }
            ImageIO.write(srcImage, "JPEG", saveFile);        }
    public static void main (String argv[]) {
        System.err.println("xxxxxx");
        try{
            //参数1(from),参数2(to),参数3(宽),参数4(高)
              test.saveImageAsJpg("c:/2.jpg","c:/3.jpg",400,400);
        }  catch(Exception e)
        {
            e.printStackTrace();
        }    }
}
//我现在写的！看看有没有更好的！

Answer 3

BufferedImage.getScaledInstance() 效果不好吗？

Answer 4

能否在说的细一些！或者给各demo！先谢了！！！！！