java图片剪裁原理

java图片裁剪原理

总体思想：

1.前台网页用js得到裁剪图片的id及x,y，宽度和高度。

2.服务端根据id取出要裁剪的图片 。

3.根据这些参数来生成裁剪的图像。

后台代码如下：

package?com.wodexiangce;

import?java.awt.Rectangle;
import?java.awt.image.BufferedImage;
import?java.io.File;
import?java.io.FileInputStream;
import?java.io.IOException;
import?java.util.Iterator;

import?javax.imageio.ImageIO;
import?javax.imageio.ImageReadParam;
import?javax.imageio.ImageReader;
import?javax.imageio.stream.ImageInputStream;

/**?*//**
?*?
?*
?*?@author?<a?href="mailto:lqinglong@yahoo.cn">qinglong.lu</a>
?*
?*?2008-3-21
?*/
public?class?OperateImage?...{
???????
????//===源图片路径名称如:c:\1.jpg?
????private?String?srcpath?;
?????????
????//===剪切图片存放路径名称.如:c:\2.jpg
????private?String?subpath?;
????
????//===剪切点x坐标
????private?int?x?;
????
????private?int?y?;????
??????
????//===剪切点宽度
????private?int?width?;
?????
????private?int?height?;
????
????public?OperateImage()...{
????????????
????}??
????public?OperateImage(int?x,int?y,int?width,int?height)...{
?????????this.x?=?x?;
?????????this.y?=?y?;
?????????this.width?=?width?;???
?????????this.height?=?height?;
????}
????
????/**?*//**?
?????*?对图片裁剪，并把裁剪完蛋新图片保存?。
?????*/
????public?void?cut()?throws?IOException...{?
?????????
????????FileInputStream?is?=?null?;
????????ImageInputStream?iis?=null?;
?????
????????try...{???
????????????//读取图片文件
????????????is?=?new?FileInputStream(srcpath);?
????????????
????????????/**//*
?????????????*?返回包含所有当前已注册?ImageReader?的?Iterator，这些?ImageReader?
?????????????*?声称能够解码指定格式。?参数：formatName?-?包含非正式格式名称?.
?????????????*（例如?"jpeg"?或?"tiff"）等?。?
?????????????*/
????????????Iterator<ImageReader>?it?=?ImageIO.getImageReadersByFormatName("jpg");??
????????????ImageReader?reader?=?it.next();?
????????????//获取图片流?
????????????iis?=?ImageIO.createImageInputStream(is);
???????????????
????????????/**//*?
?????????????*?<p>iis:读取源.true:只向前搜索?</p>.将它标记为?‘只向前搜索’。
?????????????*?此设置意味着包含在输入源中的图像将只按顺序读取，可能允许?reader
?????????????*??避免缓存包含与以前已经读取的图像关联的数据的那些输入部分。
?????????????*/
????????????reader.setInput(iis,true)?;
????????????
????????????/**//*?
?????????????*?<p>描述如何对流进行解码的类<p>.用于指定如何在输入时从?Java?Image?I/O?
?????????????*?框架的上下文中的流转换一幅图像或一组图像。用于特定图像格式的插件
?????????????*?将从其?ImageReader?实现的?getDefaultReadParam?方法中返回?
?????????????*?ImageReadParam?的实例。??
?????????????*/
????????????ImageReadParam?param?=?reader.getDefaultReadParam();?
?????????????
????????????/**//*
?????????????*?图片裁剪区域。Rectangle?指定了坐标空间中的一个区域，通过?Rectangle?对象
?????????????*?的左上顶点的坐标（x，y）、宽度和高度可以定义这个区域。?
?????????????*/?
????????????Rectangle?rect?=?new?Rectangle(x,?y,?width,?height);?
????????????
??????????????
????????????//提供一个?BufferedImage，将其用作解码像素数据的目标。?
????????????param.setSourceRegion(rect);?

????????????/**//*
?????????????*?使用所提供的?ImageReadParam?读取通过索引?imageIndex?指定的对象，并将
?????????????*?它作为一个完整的?BufferedImage?返回。
?????????????*/
????????????BufferedImage?bi?=?reader.read(0,param);????????????????
??????
????????????//保存新图片?
????????????ImageIO.write(bi,?"jpg",?new?File(subpath));?????
????????}
????????
????????finally...{
????????????if(is!=null)
???????????????is.close()?;???????
????????????if(iis!=null)
???????????????iis.close();??
????????}?
????????
?????????
?????
????}

????public?int?getHeight()?...{
????????return?height;
????}

????public?void?setHeight(int?height)?...{
????????this.height?=?height;
????}

????public?String?getSrcpath()?...{
????????return?srcpath;
????}

????public?void?setSrcpath(String?srcpath)?...{
????????this.srcpath?=?srcpath;
????}

????public?String?getSubpath()?...{
????????return?subpath;
????}

????public?void?setSubpath(String?subpath)?...{
????????this.subpath?=?subpath;
????}

????public?int?getWidth()?...{
????????return?width;
????}

????public?void?setWidth(int?width)?...{
????????this.width?=?width;
????}

????public?int?getX()?...{
????????return?x;
????}

????public?void?setX(int?x)?...{
????????this.x?=?x;
????}

????public?int?getY()?...{
????????return?y;
????}

????public?void?setY(int?y)?...{
????????this.y?=?y;
????}?
????public?static?void?main(String[]?args)throws?Exception...{
????????
????????String?name?=?"d:\2005121210161588950.jpg";?
????????
????????OperateImage?o?=?new?OperateImage(100,100,100,100);
????????o.setSrcpath(name);??
????????o.setSubpath("D:\2.jpg");
????????o.cut()?;??
??????????
????}


}