一个图片缩放处理
package com.tjsoft.system;
import java.io.*;
import java.io.File;
import java.io.FileOutputStream;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
/**
* <p>Title:CImageZoom.java </p>
* <p>Description:图像缩放,支持JPG(JPEG)、GIF、PNG三种格式</p>
* 长，宽，比例，最少要设置一个
* <p>Copyright: Copyright 2002 Shenzhen Taiji SoftwareCorparation</p>
* <p>Company:Shenzhen Taiji SoftwareCorparation </p>
* @author 邹纪根
* @version 1.0 2003-10-05
*/
public class CImageZoom {
// 对象是否己经初始化
private boolean isInitFlag = false;
// 定义生成小图片的宽度和高度，给其一个就可以了
private int smallpicwidth = 0;
private int smallpicheight = 0;
// 定义小图片的相比原图片的比例
private double picscale = 0;
/**
* 构造函数
* @param 没有参数
*/
public CImageZoom() {
this.picscale = 0;
this.smallpicwidth = 0;
this.smallpicheight = 0;
this.isInitFlag = false;
}
/**
* @param scale 设置缩影图像相对于源图像的大小比例
*/
public void SetScale(double scale) {
if (scale <= 0) {
System.out.println(" 缩放比例不能为 0 和负数！ ");
}
this.picscale = scale;
this.isInitFlag = true;
}
/**
* @param smallpicwidth 设置缩影图像的宽度
*/
public void SetSmallWidth(int smallpicwidth) {
if (smallpicwidth <= 0) {
System.out.println(" 缩影图片的宽度不能为 0 和负数！ ");
}
this.smallpicwidth = smallpicwidth;
this.isInitFlag = true;
}
/**
* @param smallpicheight 设置缩影图像的高度
*/
public void SetSmallHeight(int smallpicheight) {
if (smallpicheight <= 0) {
System.out.println(" 缩影图片的高度不能为 0 和负数！ ");
}
this.smallpicheight = smallpicheight;
this.isInitFlag = true;
}
/**
* @description 生成源图像的缩影图像
* @param pic_big_pathfilename 源图像的完全路径
* @param pic_small_pathfilename 缩影图像的存放路径
*/
public boolean doZoom(String pic_big_pathfilename, String pic_small_pathfilename) {
if (!this.isInitFlag) {
System.out.println(" 对象参数没有初始化！ ");
return false;
}
if (pic_big_pathfilename == null || pic_small_pathfilename == null) {
System.out.println(" 包含文件名的路径为空！ ");
return false;
}
int smallw = 0;
int smallh = 0;
File fi = new File(pic_big_pathfilename);
Image src = null;
try {
src = javax.imageio.ImageIO.read(fi); //通过缓冲读入源图片文件，构造Image对象
}
catch (IOException ex) {
System.out.println(" 读取源图像文件出错！ ");
return false;
}
int srcw=src.getWidth(null); //得到源图宽
int srch=src.getHeight(null); //得到源图长
double scale = (double) srcw / srch; // 图像的长宽比例
//如果长宽都设置了
if(this.smallpicheight!=0&&this.smallpicwidth!=0){
double scalesmall=(double)this.smallpicwidth/this.smallpicheight;
if(scale>scalesmall){
smallw = this.smallpicwidth;
smallh=(int)((double)this.smallpicwidth/scale);
}else{
smallh = this.smallpicheight;
smallw=(int)((double)this.smallpicheight*scale);
}
}else{
// 只设置了宽
if (this.smallpicwidth != 0) {
smallw = this.smallpicwidth;
smallh = (smallw * srch) / srcw;
}
//只设置了长
else if (this.smallpicheight != 0) {
smallh = this.smallpicheight;
smallw = (smallh * srcw) / srch;
}
// 只设置的缩小比例
else if (this.picscale != 0) {
smallw = (int) ( (float) srcw * this.picscale);
smallh = (int) ( (float) srch * this.picscale);
}
else {
System.out.println(" 对象参数初始化不正确！ ");
return false;
}
}
try {
BufferedImage tag = new BufferedImage(smallw,smallh,BufferedImage.TYPE_INT_RGB);
tag.getGraphics().drawImage(src,0,0,smallw,smallh,null);
FileOutputStream out=new FileOutputStream(pic_small_pathfilename);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(tag);
out.close();
return true;
}
catch (IOException ex1) {
System.out.println(" 写入缩略图像文件出错！ ");
return false;
}
}
public static void main(String arg[]) throws Exception {
try{
CImageZoom CImageZoom = new CImageZoom();
CImageZoom.SetSmallWidth(600);
CImageZoom.SetSmallHeight(400);
CImageZoom.doZoom("D:\\uploadfile\\20060514154821562626-1.jpg","e:\\sm.jpg");
}catch(Exception e){
e.printStackTrace();
}
}
}
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