Java图片处理工具类

Thumbnailator 是一个优秀的图片处理的Google开源Java类库

支持的处理操作：图片缩放，区域裁剪，水印，旋转，保持比例。

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，宽缩小到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，宽为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 按比例缩放

//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 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");

4 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(newFile("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(newFile("images/watermark.png")),0.5f)  
    .outputQuality(0.8f)  
    .toFile("c:/a380_watermark_center.jpg");

5 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");

6 图像格式转换

//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");

7 输出

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

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

来源：https://my.oschina.net/jamescasta/blog/3129750

标签

Thumbnailator

java