Java生成缩略图之Thumbnailator

Thumbnailator 是一个为Java界面更流畅的缩略图生成库。从API提供现有的图像文件和图像对象的缩略图中简化了缩略过程，两三行代码就能够从现有图片生成缩略图，且允许微调缩略图生成，同时保持了需要写入到最低限度的代码量。同时还支持根据一个目录批量生成缩略图。

http://code.google.com/p/thumbnailator/

版本：thumbnailator-0.4.2.jar

原图如下：

 1、指定大小进行缩放

//size(宽度, 高度)  
  
/*   
 * 若图片横比200小，高比300小，不变   
 * 若图片横比200小，高比300大，高缩小到300，图片比例不变   
 * 若图片横比200大，高比300小，横缩小到200，图片比例不变   
 * 若图片横比200大，高比300大，图片按比例缩小，横为200或高为300   
 */   
Thumbnails.of("images/a380_1280x1024.jpg")   
        .size(200, 300)  
        .toFile("c:/a380_200x300.jpg");  
  
Thumbnails.of("images/a380_1280x1024.jpg")   
        .size(2560, 2048)   
        .toFile("c:/a380_2560x2048.jpg");  

2、按照比例进行缩放

//scale(比例)  
Thumbnails.of("images/a380_1280x1024.jpg")   
        .scale(0.25f)  
        .toFile("c:/a380_25%.jpg");  
  
Thumbnails.of("images/a380_1280x1024.jpg")   
        .scale(1.10f)  
        .toFile("c:/a380_110%.jpg");  

3、不按照比例，指定大小进行缩放

//keepAspectRatio(false) 默认是按照比例缩放的  
Thumbnails.of("images/a380_1280x1024.jpg")   
        .size(200, 200)   
        .keepAspectRatio(false)   
        .toFile("c:/a380_200x200.jpg"); 

4、旋转

//rotate(角度),正数：顺时针 负数：逆时针  
Thumbnails.of("images/a380_1280x1024.jpg")   
        .size(1280, 1024)  
        .rotate(90)   
        .toFile("c:/a380_rotate+90.jpg");   
  
Thumbnails.of("images/a380_1280x1024.jpg")   
        .size(1280, 1024)  
        .rotate(-90)   
        .toFile("c:/a380_rotate-90.jpg");   

 

 5、水印

//watermark(位置，水印图，透明度)  
Thumbnails.of("images/a380_1280x1024.jpg")   
        .size(1280, 1024)  
        .watermark(Positions.BOTTOM_RIGHT, ImageIO.read(new File("images/watermark.png")), 0.5f)   
        .outputQuality(0.8f)   
        .toFile("c:/a380_watermark_bottom_right.jpg");  
  
Thumbnails.of("images/a380_1280x1024.jpg")   
        .size(1280, 1024)  
        .watermark(Positions.CENTER, ImageIO.read(new File("images/watermark.png")), 0.5f)   
        .outputQuality(0.8f)   
        .toFile("c:/a380_watermark_center.jpg");  

 

 6、裁剪

//sourceRegion()  
  
//图片中心400*400的区域  
Thumbnails.of("images/a380_1280x1024.jpg")  
        .sourceRegion(Positions.CENTER, 400,400)  
        .size(200, 200)  
        .keepAspectRatio(false)   
        .toFile("c:/a380_region_center.jpg");  
  
//图片右下400*400的区域  
Thumbnails.of("images/a380_1280x1024.jpg")  
        .sourceRegion(Positions.BOTTOM_RIGHT, 400,400)  
        .size(200, 200)  
        .keepAspectRatio(false)   
        .toFile("c:/a380_region_bootom_right.jpg");  
  
//指定坐标  
Thumbnails.of("images/a380_1280x1024.jpg")  
        .sourceRegion(600, 500, 400, 400)  
        .size(200, 200)  
        .keepAspectRatio(false)   
        .toFile("c:/a380_region_coord.jpg"); 

 7、转化图像格式

//outputFormat(图像格式)  
Thumbnails.of("images/a380_1280x1024.jpg")   
        .size(1280, 1024)  
        .outputFormat("png")   
        .toFile("c:/a380_1280x1024.png");   
  
Thumbnails.of("images/a380_1280x1024.jpg")   
        .size(1280, 1024)  
        .outputFormat("gif")   
        .toFile("c:/a380_1280x1024.gif"); 

8、输出到OutputStream

//toOutputStream(流对象)  
OutputStream os = new FileOutputStream("c:/a380_1280x1024_OutputStream.png");  
Thumbnails.of("images/a380_1280x1024.jpg")   
        .size(1280, 1024)  
        .toOutputStream(os);  

9、输出到BufferedImage

//asBufferedImage() 返回BufferedImage  
BufferedImage thumbnail = Thumbnails.of("images/a380_1280x1024.jpg")   
        .size(1280, 1024)  
        .asBufferedImage();  
ImageIO.write(thumbnail, "jpg", new File("c:/a380_1280x1024_BufferedImage.jpg"));

需要注意的是，对于CMYK模式的图像，由于JDK的Bug，目前还不能够处理，会出以下异常：

引用

javax.imageio.IIOException: Unsupported Image Type
at com.sun.imageio.plugins.jpeg.JPEGImageReader.readInternal(JPEGImageReader.java:1063)
at com.sun.imageio.plugins.jpeg.JPEGImageReader.read(JPEGImageReader.java:1034)
at javax.imageio.ImageReader.read(ImageReader.java:940)
at net.coobird.thumbnailator.tasks.io.FileImageSource.read(Unknown Source)

引用

 javax.imageio.IIOException: Incompatible color conversion
    at com.sun.imageio.plugins.jpeg.JPEGImageReader.checkColorConversion(JPEGImageReader.java:973)

ICC profile

引用

 java.lang.IllegalArgumentException: Numbers of source Raster bands and source color space components do not match
    at java.awt.image.ColorConvertOp.filter(ColorConvertOp.java:482)
    at com.sun.imageio.plugins.jpeg.JPEGImageReader.acceptPixels(JPEGImageReader.java:1268)
    at com.sun.imageio.plugins.jpeg.JPEGImageReader.readImage(Native Method)
    at com.sun.imageio.plugins.jpeg.JPEGImageReader.readInternal(JPEGImageReader.java:1236)
    at com.sun.imageio.plugins.jpeg.JPEGImageReader.read(JPEGImageReader.java:1039)
    at javax.imageio.ImageReader.read(ImageReader.java:939)

这些问题可以JAI.create()来代替ImageIO.read()解决。而高清图的内存溢出OOM问题只能使用ImageMagick转换了。

https://www.iteye.com/blog/rensanning-1545708

 demo:

package com.zhouhe.modules.api.wechat;

import net.coobird.thumbnailator.Thumbnails;
import java.io.*;

/**
 * @Author zhouhe
 * @Date 2019/11/21 13:26
 */
public class Test {

    @org.junit.Test
    public void test(){
        String folder = "E:/file/";
        String fileName = "111.jpg";
        thumbnails(folder,fileName);
    }

    /**
     * 生成缩略图并上传到原文件目录下
     * @param folder    文件夹
     * @param fileName  文件名
     */
    public static void thumbnails(String folder,String fileName){
        try {
            Thumbnails.of(folder+fileName)
                    .size(200, 300)
                    .toFile(folder+"Thumbnail_"+fileName);
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("缩略图生成失败！");
        }
    }

}