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

Java代码

//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");

//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

Java代码

//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");

//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

Java代码

//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");

//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

Java代码

//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");

//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

Java代码

//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");

//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

Java代码

//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");

//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

Java代码

//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");

//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

Java代码

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

//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

Java代码

//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"));

//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"));

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