如下javabean代码缩略图象时严重失真,请问如何处理啊.

Question

代码如下:
代码运行正确,但在把800*600的图象处理成640*480时,图片严重失真. (注意:是等比缩放的)
如何更改啊?
//缩略图实现，将图片(jpg,gif,bmp等等)真实的变成想要的大小   
package org.yqing.yakcms.plugin.image.logic;import java.io.*;   
import java.util.*;   
import com.sun.image.codec.jpeg.*;   
import java.awt.image.*;   
import java.awt.*;   
import java.net.*;   
import java.applet.*;   
import java.sql.*;  
import javax.imageio.ImageIO; 
//缩略图类，   
//本java类能将jpg图片文件，进行等比或非等比的大小转换。   
//具体使用方法
//s_pic(大图片路径,生成小图片路径,大图片文件名,生成小图片文名,生成小图片宽度,生成小图片高度,是否等比缩放(默认为true))   
public class thumbs{   
  String InputDir; //输入图路径   
  String OutputDir; //输出图路径   
  String InputFileName; //输入图文件名   
  String OutputFileName; //输出图文件名   
  int OutputWidth = 80; //默认输出图片宽   
  int OutputHeight = 80; //默认输出图片高   
  int rate = 0;   
  boolean proportion = true; //是否等比缩放标记(默认为等比缩放)   
  boolean deleted=false;
  public thumbs() {   
    //初始化变量   
    InputDir = "";   
    OutputDir = "";   
    InputFileName = "";   
    OutputFileName = "";   
    OutputWidth = 80;   
    OutputHeight = 80;   
    rate = 0;   
  }   
    
  public void setInputDir(String InputDir) {   
    this.InputDir = InputDir;   
  }   
    
  public void setOutputDir(String OutputDir) {   
    this.OutputDir = OutputDir;   
  }   
    
  public void setInputFileName(String InputFileName) {   
    this.InputFileName = InputFileName;   
  }   
    
  public void setOutputFileName(String OutputFileName) {   
    this.OutputFileName = OutputFileName;   
  }   
    
  public void setOutputWidth(int OutputWidth) {   
    this.OutputWidth = OutputWidth;   
  }   
    
  public void setOutputHeight(int OutputHeight) {   
    this.OutputHeight = OutputHeight;   
  }   
    
  public void setW_H(int width, int height) {   
    this.OutputWidth = width;   
    this.OutputHeight = height;   
  }   
  public String s_pic() {   
    BufferedImage image;   
    String NewFileName;   
//建立输出文件对象   
    File file = new File(OutputDir + OutputFileName);   
    FileOutputStream tempout = null;   
    try {   
      tempout = new FileOutputStream(file);   
    }   
    catch (Exception ex) {   
      System.out.println(ex.toString());   
    }   
    Image img = null;   
    Toolkit tk = Toolkit.getDefaultToolkit();   
    Applet app = new Applet();   
    MediaTracker mt = new MediaTracker(app);   
    try {   
      img = tk.getImage(InputDir + InputFileName);   
      mt.addImage(img, 0);   
      mt.waitForID(0);   
    }   
    catch (Exception e) {   
      e.printStackTrace();   
    }   
    
    if ((img.getWidth(null) ==-1)||((img.getWidth(null)<this.OutputWidth) &&(img.getHeight(null)<this.OutputHeight))) {   
      System.out.println(" can't read,retry!" + "<BR>");   
      return "no";   
    }  
    else {   
      int new_w;   
      int new_h;   
      if (this.proportion == true) { //判断是否是等比缩放.   
//为等比缩放计算输出的图片宽度及高度   
        double rate1 = ( (double) img.getWidth(null)) / (double) OutputWidth +   
            0.1;   
        double rate2 = ( (double) img.getHeight(null)) / (double) OutputHeight +   
            0.1;   
        double rate = rate1 > rate2 ? rate1 : rate2;   
        new_w = (int) ( ( (double) img.getWidth(null)) / rate);   
        new_h = (int) ( ( (double) img.getHeight(null)) / rate);   
      }   
      else {   
        new_w = OutputWidth; //输出的图片宽度   
        new_h = OutputHeight; //输出的图片高度   
      }   
      BufferedImage buffImg = new BufferedImage(new_w, new_h,   
                                                BufferedImage.TYPE_INT_RGB);   
    
      Graphics g = buffImg.createGraphics();   
    
      g.setColor(Color.white);   
      g.fillRect(0, 0, new_w, new_h);   
    
      g.drawImage(img, 0, 0, new_w, new_h, null);   
      g.dispose();   
    
     JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(tempout);
      try {   
        encoder.encode(buffImg);   
        tempout.close();   
      }   
      catch (IOException ex) {   
        System.out.println(ex.toString());   
      }   
    }   
   if(deleted)
     {
        File file1 = new File(OutputDir +OutputFileName);//删除原来的，并将文件重命名     File file2 = new File(InputDir + InputFileName);
      if(file2.exists() && file2.isFile())
       {     file2.delete(); }
        file1.renameTo(file2);
    }    return "ok";   
  }   
    
  public String s_pic(String InputDir, String OutputDir, String InputFileName,   
                      String OutputFileName) {   
//输入图路径   
    this.InputDir = InputDir;   
//输出图路径   
    this.OutputDir = OutputDir;   
//输入图文件名   
    this.InputFileName = InputFileName;   
//输出图文件名   
    this.OutputFileName = OutputFileName;   
    return s_pic();   
  }   
    
  public String s_pic(String InputDir, String OutputDir, String InputFileName,   
                      String OutputFileName, int  
                      width, int height, boolean gp,boolean isDeleted) {   
//输入图路径   
    this.InputDir = InputDir;   
//输出图路径   
    this.OutputDir = OutputDir;   
//输入图文件名   
    this.InputFileName = InputFileName;   
//输出图文件名   
    this.OutputFileName = OutputFileName;   
//设置图片长宽   
    setW_H(width, height);   
//是否是等比缩放 标记   
    this.proportion = gp;   
    this.deleted=isDeleted;
    return s_pic();   
  }   
 } 

Answer 1

用java如何把图片处理到指定大小

Answer 2

缩略图大多数是用这种方法,不过我在网上查到另一种,据说是它个人写的.挺好的.你可以自定义高宽缩小.
[code=Java]
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;//生成等比例高质量缩略图
public class ScaleImage{    private int width;
    private int height;
    private int scaleWidth;
    double support=(double)3.0;
    double PI=(double)3.14159265358978;
    double[] contrib;
    double[] normContrib;
    double[] tmpContrib;
    int startContrib, stopContrib;
    int nDots;
    int nHalfDots;    /**
     * Start: Use Lanczos filter to replace the original algorithm for image
     * scaling. Lanczos improves quality of the scaled image modify by :blade
     */
    public static void main(String[] args){
        ScaleImage is=new ScaleImage();
        try{
            is.saveImageAsJpg("d:/008.jpg","d:/008bre.jpg",1024,768);
        }catch(Exception e){
            e.printStackTrace();
        }
    }    // fromFileStr原图片地址,saveToFileStr生成缩略图地址,formatWideth生成图片宽度,formatHeight高度
    public void saveImageAsJpg(String fromFileStr,String saveToFileStr,
            int formatWideth,int formatHeight) throws Exception{
        BufferedImage srcImage;
        File saveFile=new File(saveToFileStr);
        File fromFile=new File(fromFileStr);
        srcImage=javax.imageio.ImageIO.read(fromFile); // construct image
        int imageWideth=srcImage.getWidth(null);
        int imageHeight=srcImage.getHeight(null);
        int changeToWideth=0;
        int changeToHeight=0;
        if(imageWideth>0&&imageHeight>0){
            // flag=true;
            if(imageWideth/imageHeight>=formatWideth/formatHeight){
                if(imageWideth>formatWideth){
                    changeToWideth=formatWideth;
                    changeToHeight=(imageHeight*formatWideth)/imageWideth;
                }else{
                    changeToWideth=imageWideth;
                    changeToHeight=imageHeight;
                }
            }else{
                if(imageHeight>formatHeight){
                    changeToHeight=formatHeight;
                    changeToWideth=(imageWideth*formatHeight)/imageHeight;
                }else{
                    changeToWideth=imageWideth;
                    changeToHeight=imageHeight;
                }
            }
        }        srcImage=imageZoomOut(srcImage,changeToWideth,changeToHeight);
        ImageIO.write(srcImage,"JPEG",saveFile);
    }    public BufferedImage imageZoomOut(BufferedImage srcBufferImage,int w,int h){
        width=srcBufferImage.getWidth();
        height=srcBufferImage.getHeight();
        scaleWidth=w;        if(DetermineResultSize(w,h)==1){
            return srcBufferImage;
        }
        CalContrib();
        BufferedImage pbOut=HorizontalFiltering(srcBufferImage,w);
        BufferedImage pbFinalOut=VerticalFiltering(pbOut,h);
        return pbFinalOut;
    }    /**
     * 决定图像尺寸
     */
    private int DetermineResultSize(int w,int h){
        double scaleH, scaleV;
        scaleH=(double)w/(double)width;
        scaleV=(double)h/(double)height;
        // 需要判断一下scaleH，scaleV，不做放大操作
        if(scaleH>=1.0&&scaleV>=1.0){
            return 1;
        }
        return 0;    } // end of DetermineResultSize()    private double Lanczos(int i,int inWidth,int outWidth,double Support){
        double x;        x=(double)i*(double)outWidth/(double)inWidth;        return Math.sin(x*PI)/(x*PI)*Math.sin(x*PI/Support)/(x*PI/Support);    }    private void CalContrib(){
        nHalfDots=(int)((double)width*support/(double)scaleWidth);
        nDots=nHalfDots*2+1;
        try{
            contrib=new double[nDots];
            normContrib=new double[nDots];
            tmpContrib=new double[nDots];
        }catch(Exception e){
            System.out.println("init   contrib,normContrib,tmpContrib"+e);
        }        int center=nHalfDots;
        contrib[center]=1.0;        double weight=0.0;
        int i=0;
        for(i=1;i<=center;i++){
            contrib[center+i]=Lanczos(i,width,scaleWidth,support);
            weight+=contrib[center+i];
        }        for(i=center-1;i>=0;i--){
            contrib[i]=contrib[center*2-i];
        }        weight=weight*2+1.0;        for(i=0;i<=center;i++){
            normContrib[i]=contrib[i]/weight;
        }        for(i=center+1;i<nDots;i++){
            normContrib[i]=normContrib[center*2-i];
        }
    } // end of CalContrib()    // 处理边缘
    private void CalTempContrib(int start,int stop){
        double weight=0;        int i=0;
        for(i=start;i<=stop;i++){
            weight+=contrib[i];
        }        for(i=start;i<=stop;i++){
            tmpContrib[i]=contrib[i]/weight;
        }    } // end of CalTempContrib()    private int GetRedValue(int rgbValue){
        int temp=rgbValue&0x00ff0000;
        return temp>>16;
    }    private int GetGreenValue(int rgbValue){
        int temp=rgbValue&0x0000ff00;
        return temp>>8;
    }    private int GetBlueValue(int rgbValue){
        return rgbValue&0x000000ff;
    }    private int ComRGB(int redValue,int greenValue,int blueValue){        return (redValue<<16)+(greenValue<<8)+blueValue;
    }    

Answer 3

// 行水平滤波
    private int HorizontalFilter(BufferedImage bufImg,int startX,int stopX,
            int start,int stop,int y,double[] pContrib){
        double valueRed=0.0;
        double valueGreen=0.0;
        double valueBlue=0.0;
        int valueRGB=0;
        int i, j;        for(i=startX,j=start;i<=stopX;i++,j++) {
            valueRGB = bufImg.getRGB(i, y);            valueRed += GetRedValue(valueRGB) * pContrib[j];
            valueGreen += GetGreenValue(valueRGB) * pContrib[j];
            valueBlue += GetBlueValue(valueRGB) * pContrib[j];
        }        valueRGB = ComRGB(Clip((int) valueRed), Clip((int) valueGreen),
                Clip((int) valueBlue));
        return valueRGB;    } // end of HorizontalFilter()    // 图片水平滤波
    private BufferedImage HorizontalFiltering(BufferedImage bufImage, int iOutW) {
        int dwInW = bufImage.getWidth();
        int dwInH = bufImage.getHeight();
        int value = 0;
        BufferedImage pbOut=new BufferedImage(iOutW,dwInH,
                BufferedImage.TYPE_INT_RGB);        for(int x=0;x<iOutW;x++){            int startX;
            int start;
            int X=(int)(((double)x)*((double)dwInW)/((double)iOutW)+0.5);
            int y=0;            startX=X-nHalfDots;
            if(startX<0){
                startX=0;
                start=nHalfDots-X;
            }else{
                start=0;
            }            int stop;
            int stopX=X+nHalfDots;
            if(stopX>(dwInW-1)){
                stopX=dwInW-1;
                stop=nHalfDots+(dwInW-1-X);
            }else{
                stop=nHalfDots*2;
            }            if(start>0||stop<nDots-1){
                CalTempContrib(start,stop);
                for(y=0;y<dwInH;y++){
                    value=HorizontalFilter(bufImage,startX,stopX,start,
                            stop,y,tmpContrib);
                    pbOut.setRGB(x,y,value);
                }
            }else{
                for(y=0;y<dwInH;y++){
                    value=HorizontalFilter(bufImage,startX,stopX,start,
                            stop,y,normContrib);
                    pbOut.setRGB(x,y,value);
                }
            }
        }        return pbOut;    } // end of HorizontalFiltering()    private int VerticalFilter(BufferedImage pbInImage,int startY,int stopY,
            int start,int stop,int x,double[] pContrib){
        double valueRed=0.0;
        double valueGreen=0.0;
        double valueBlue=0.0;
        int valueRGB=0;
        int i, j;        for(i=startY,j=start;i<=stopY;i++,j++) {
            valueRGB = pbInImage.getRGB(x, i);            valueRed += GetRedValue(valueRGB) * pContrib[j];
            valueGreen += GetGreenValue(valueRGB) * pContrib[j];
            valueBlue += GetBlueValue(valueRGB) * pContrib[j];
            // System.out.println(valueRed+"->"+Clip((int)valueRed)+"<-");
            //   
            // System.out.println(valueGreen+"->"+Clip((int)valueGreen)+"<-");
            // System.out.println(valueBlue+"->"+Clip((int)valueBlue)+"<-"+"-->");
        }        valueRGB = ComRGB(Clip((int) valueRed), Clip((int) valueGreen),
                Clip((int) valueBlue));
        // System.out.println(valueRGB);
        return valueRGB;    } // end of VerticalFilter()    private BufferedImage VerticalFiltering(BufferedImage pbImage, int iOutH) {
        int iW = pbImage.getWidth();
        int iH = pbImage.getHeight();
        int value = 0;
        BufferedImage pbOut=new BufferedImage(iW,iOutH,
                BufferedImage.TYPE_INT_RGB);        for(int y=0;y<iOutH;y++){            int startY;
            int start;
            int Y=(int)(((double)y)*((double)iH)/((double)iOutH)+0.5);            startY=Y-nHalfDots;
            if(startY<0){
                startY=0;
                start=nHalfDots-Y;
            }else{
                start=0;
            }            int stop;
            int stopY=Y+nHalfDots;
            if(stopY>(int)(iH-1)){
                stopY=iH-1;
                stop=nHalfDots+(iH-1-Y);
            }else{
                stop=nHalfDots*2;
            }            if(start>0||stop<nDots-1){
                CalTempContrib(start,stop);
                for(int x=0;x<iW;x++){
                    value=VerticalFilter(pbImage,startY,stopY,start,stop,
                            x,tmpContrib);
                    pbOut.setRGB(x,y,value);
                }
            }else{
                for(int x=0;x<iW;x++){
                    value=VerticalFilter(pbImage,startY,stopY,start,stop,
                            x,normContrib);
                    pbOut.setRGB(x,y,value);
                }
            }        }        return pbOut;    } // end of VerticalFiltering()    int Clip(int x){
        if(x<0){
            return 0;
        }
        if(x>255){
            return 255;
        }
        return x;
    }}[/code]
换换试试,用SUN的那个包,没试过,不提供意见