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JAVA实现图片等比缩放,图片截取功能--封装类

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import java.awt.Graphics2D;

import java.awt.Rectangle;

import java.awt.RenderingHints;

import java.awt.geom.AffineTransform;

import java.awt.image.BufferedImage;

import java.awt.image.ColorModel;

import java.awt.image.WritableRaster;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

 

import javax.imageio.ImageIO;

 

import com.gzdec.common.log.LoggerUtil;

 

/**  

 * 图片工具类,完成图片的截取  

 */  

public class ImageHelper {   

    /**  

     * 实现图像的等比缩放  

     * @param source  

     * @param targetW  

     * @param targetH  

     * @return  

     */  

    private 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_INTERPOLATION,   

                RenderingHints.VALUE_INTERPOLATION_BICUBIC);   

        g.drawRenderedImage(source, AffineTransform.getScaleInstance(sx, sy));   

        g.dispose();   

        return target;   

    }   

 

    /**  

     * 实现图像的等比缩放和缩放后的截取, 处理成功返回true, 否则返回false  

     * @param inFilePath 要截取文件的路径  

     * @param outFilePath 截取后输出的路径  

     * @param width 要截取宽度  

     * @param hight 要截取的高度  

     * @throws Exception  

     */  

    public static boolean compress(String inFilePath, String outFilePath,   

            int width, int hight) {

        boolean ret = false;

        File file = new File(inFilePath);

        File saveFile = new File(outFilePath);

        InputStream in = null;

        try {

            in = new FileInputStream(file);

            ret = compress(in, saveFile, width, hight);

        } catch (FileNotFoundException e) {

            e.printStackTrace();

            ret = false;

        } finally{

            if(null != in){

                try {

                    in.close();

                } catch (IOException e) {

                    e.printStackTrace();

                }

            }

        }

 

        return ret;

    } 

 

    /**  

     * 实现图像的等比缩放和缩放后的截取, 处理成功返回true, 否则返回false  

     * @param inFilePath 要截取文件的路径  

     * @param outFilePath 截取后输出的路径  

     * @param width 要截取宽度  

     * @param hight 要截取的高度  

     * @throws Exception  

     */  

    public static boolean compress(InputStream in, File saveFile,   

            int width, int hight) {

//     boolean ret = false;

        BufferedImage srcImage = null;

        try {

            srcImage = ImageIO.read(in);

        } catch (IOException e) {

            e.printStackTrace();

            return false;

        }

 

        if (width > 0 || hight > 0) {

            // 原图的大小

            int sw = srcImage.getWidth();

            int sh = srcImage.getHeight();

            // 如果原图像的大小小于要缩放的图像大小,直接将要缩放的图像复制过去

            if (sw > width && sh > hight) {

                srcImage = resize(srcImage, width, hight);

            } else {

                String fileName = saveFile.getName();

                String formatName = fileName.substring(fileName

                        .lastIndexOf('.') + 1);

                try {

                    ImageIO.write(srcImage, formatName, saveFile);

                } catch (IOException e) {

                    e.printStackTrace();

                    return false;

                }

                return true;

            }

        }

        // 缩放后的图像的宽和高

        int w = srcImage.getWidth();

        int h = srcImage.getHeight();

        // 如果缩放后的图像和要求的图像宽度一样,就对缩放的图像的高度进行截取

        if (w == width) {

            // 计算X轴坐标

            int x = 0;

            int y = h / 2 - hight / 2;

            try {

                saveSubImage(srcImage, new Rectangle(x, y, width, hight), saveFile);

            } catch (IOException e) {

                e.printStackTrace();

                return false;

            }

        }

        // 否则如果是缩放后的图像的高度和要求的图像高度一样,就对缩放后的图像的宽度进行截取

        else if (h == hight) {

            // 计算X轴坐标

            int x = w / 2 - width / 2;

            int y = 0;

            try {

                saveSubImage(srcImage, new Rectangle(x, y, width, hight), saveFile);

            } catch (IOException e) {

                e.printStackTrace();

                return false;                

            }

        }

 

        return true;

    }

 

    /**

     * 实现图像的等比缩放和缩放后的截取, 处理成功返回true, 否则返回false

     * @param in 图片输入流

     * @param saveFile 压缩后的图片输出流

     * @param proportion 压缩比

     * @throws Exception

     * author: cxg 2009-5-24 下午12:05:05

     */

    public static boolean compress(InputStream in, File saveFile, int proportion) {

        if(null == in

                ||null == saveFile

                ||proportion < 1){// 检查参数有效性

            LoggerUtil.error(ImageHelper.class, "--invalid parameter, do nothing!");

            return false;

        }

 

        BufferedImage srcImage = null;

        try {

            srcImage = ImageIO.read(in);

        } catch (IOException e) {

            e.printStackTrace();

            return false;

        }

        // 原图的大小

        int width = srcImage.getWidth() / proportion;

        int hight = srcImage.getHeight() / proportion;

 

        srcImage = resize(srcImage, width, hight);

 

        // 缩放后的图像的宽和高

        int w = srcImage.getWidth();

        int h = srcImage.getHeight();

        // 如果缩放后的图像和要求的图像宽度一样,就对缩放的图像的高度进行截取

        if (w == width) {

            // 计算X轴坐标

            int x = 0;

            int y = h / 2 - hight / 2;

            try {

                saveSubImage(srcImage, new Rectangle(x, y, width, hight), saveFile);

            } catch (IOException e) {

                e.printStackTrace();

                return false;

            }

        }

        // 否则如果是缩放后的图像的高度和要求的图像高度一样,就对缩放后的图像的宽度进行截取

        else if (h == hight) {

            // 计算X轴坐标

            int x = w / 2 - width / 2;

            int y = 0;

            try {

                saveSubImage(srcImage, new Rectangle(x, y, width, hight), saveFile);

            } catch (IOException e) {

                e.printStackTrace();

                return false;

            }

        }

 

        return true;

    }

 

    /**

     * 实现缩放后的截图

     * @param image 缩放后的图像

     * @param subImageBounds 要截取的子图的范围

     * @param subImageFile 要保存的文件

     * @throws IOException 

     */  

    private static void saveSubImage(BufferedImage image,   

            Rectangle subImageBounds, File subImageFile) throws IOException {   

        if (subImageBounds.x < 0 || subImageBounds.y < 0  

                || subImageBounds.width - subImageBounds.x > image.getWidth()   

                || subImageBounds.height - subImageBounds.y > image.getHeight()) {   

            LoggerUtil.error(ImageHelper.class, "Bad subimage bounds");   

            return;   

        }   

        BufferedImage subImage = image.getSubimage(subImageBounds.x,subImageBounds.y, subImageBounds.width, subImageBounds.height);   

        String fileName = subImageFile.getName();   

        String formatName = fileName.substring(fileName.lastIndexOf('.') + 1);   

        ImageIO.write(subImage, formatName, subImageFile);

    }   

 

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

 

       /**

        * saveSubImage 截图类的使用

        * srcImage 为BufferedImage对象

        * Rectangle    为需要截图的长方形坐标

        * saveFile 需要保存的路径及名称

        * **/

        //需要截图的长方形坐标

        /*Rectangle rect =new Rectangle();

        rect.x=40;

        rect.y=40;

        rect.height=160;

        rect.width=160;

 

        InputStream in = null;

        //需要保存的路径及名称

        File saveFile = new File("d:\\kec3.jpg");

        //需要进行处理的图片的路径

        in = new FileInputStream(new File("d:\\kec.jpg"));

        BufferedImage srcImage = null;

        //将输入的数据转为BufferedImage对象

        srcImage = ImageIO.read(in);

 

        ImageHelper img=new ImageHelper();

        img.saveSubImage(srcImage, rect, saveFile);*/

 

       /**

        * compress 图片缩放类的使用(缩略图)

        * srcImage 为InputStream对象

        * Rectangle    为需要截图的长方形坐标

        * proportion 为压缩比例

        * **/

        /*InputStream in = null;

        //缩放后需要保存的路径

        File saveFile = new File("d:\\kec2.jpg");

        try {

            //原图片的路径

            in = new FileInputStream(new File("d:\\kec.jpg"));

            compress(in, saveFile, 5);

        } catch (Exception e) {

            e.printStackTrace();

        } finally {

            in.close();

        }*/

    }

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