import java.awt.Image;  

import java.awt.Rectangle;  

import java.awt.geom.AffineTransform;  

import java.awt.image.AffineTransformOp;  

import java.awt.image.BufferedImage;  

import java.io.File;  

import java.io.FileInputStream;  

import java.io.IOException;  

import java.io.InputStream;  

import java.util.Iterator;  

 

import javax.imageio.ImageIO;  

import javax.imageio.ImageReadParam;  

import javax.imageio.ImageReader;  

import javax.imageio.stream.ImageInputStream;  

 

public class ImageHelper {  

    public static void main(String[] args) throws Exception {

        try {

            ImageHelper.zoomImage("c:/test.jpg","c:\\7.png",400,400);

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

    }

    /*

     * 根据尺寸图片居中裁剪

     */  

     public static void cutCenterImage(String src,String dest,int w,int h) throws IOException{   

         Iterator iterator = ImageIO.getImageReadersByFormatName("jpg");   

         ImageReader reader = (ImageReader)iterator.next();   

         InputStream in=new FileInputStream(src);  

         ImageInputStream iis = ImageIO.createImageInputStream(in);   

         reader.setInput(iis, true);   

         ImageReadParam param = reader.getDefaultReadParam();   

         int imageIndex = 0;   

         Rectangle rect = new Rectangle((reader.getWidth(imageIndex)-w)/2, (reader.getHeight(imageIndex)-h)/2, w, h);    

         param.setSourceRegion(rect);   

         BufferedImage bi = reader.read(0,param);     

         ImageIO.write(bi, "jpg", new File(dest));             

    

     }  

    /*

     * 图片裁剪二分之一

     */  

     public static void cutHalfImage(String src,String dest) throws IOException{   

         Iterator iterator = ImageIO.getImageReadersByFormatName("jpg");   

         ImageReader reader = (ImageReader)iterator.next();   

         InputStream in=new FileInputStream(src);  

         ImageInputStream iis = ImageIO.createImageInputStream(in);   

         reader.setInput(iis, true);   

         ImageReadParam param = reader.getDefaultReadParam();   

         int imageIndex = 0;   

         int width = reader.getWidth(imageIndex)/2;   

         int height = reader.getHeight(imageIndex)/2;   

         Rectangle rect = new Rectangle(width/2, height/2, width, height);   

         param.setSourceRegion(rect);   

         BufferedImage bi = reader.read(0,param);     

         ImageIO.write(bi, "jpg", new File(dest));     

     }  

    

     /**

      * 图片裁剪通用接口

      * @param src   

      * @param dest

      * @param x

      * @param y

      * @param w

      * @param h

      * @throws IOException

      */

    public static void cutImage(String src,String dest,int x,int y,int w,int h) throws IOException{   

           Iterator iterator = ImageIO.getImageReadersByFormatName("jpg");   

           ImageReader reader = (ImageReader)iterator.next();   

           InputStream in=new FileInputStream(src);  

           ImageInputStream iis = ImageIO.createImageInputStream(in);   

           reader.setInput(iis, true);   

           ImageReadParam param = reader.getDefaultReadParam();   

           Rectangle rect = new Rectangle(x, y, w,h);    

           param.setSourceRegion(rect);   

           BufferedImage bi = reader.read(0,param);     

           ImageIO.write(bi, "jpg", new File(dest));             

 

    }   

    

    /**

     * 图片缩放

     * @param src  image path

     * @param dest target　Ｐ

     * @param w

     * @param h

     * @throws Exception

     */

    public static void zoomImage(String src,String dest,int w,int h) throws Exception {  

        double wr=0,hr=0;  

        File srcFile = new File(src);  

        File destFile = new File(dest);  

        BufferedImage bufImg = ImageIO.read(srcFile);  

        Image Itemp = bufImg.getScaledInstance(w, h, bufImg.SCALE_SMOOTH);  

        wr=w*1.0/bufImg.getWidth();  

        hr=h*1.0 / bufImg.getHeight();  

        // 如果是低于400的话 就不操作

        if(wr>1){

            wr=1;

        }

        if(hr>1){

            hr=1;

        }

        AffineTransformOp ato = new AffineTransformOp(AffineTransform.getScaleInstance(wr, hr), null);  

        Itemp = ato.filter(bufImg, null);  

        try {  

            ImageIO.write((BufferedImage) Itemp,dest.substring(dest.lastIndexOf(".")+1), destFile);  

        } catch (Exception ex) {  

            ex.printStackTrace();  

        }  

    }  

}