thumbnailator 例子

Examples
Create a thumbnail from an image file
Thumbnails.of(new File("original.jpg"))
        .size(160, 160)
        .toFile(new File("thumbnail.jpg"));
In this example, the image from original.jpg is resized, and then saved to thumbnail.jpg.

Alternatively, Thumbnailator will accept file names as a String. Using File objects to specify image files is not required:

Thumbnails.of("original.jpg")
        .size(160, 160)
        .toFile("thumbnail.jpg");
This form can be useful when writing quick prototype code, or when Thumbnailator is being used from scripting languages.

Create a thumbnail with rotation and a watermark
Thumbnails.of(new File("original.jpg"))
        .size(160, 160)
        .rotate(90)
        .watermark(Positions.BOTTOM_RIGHT, ImageIO.read(new File("watermark.png")), 0.5f)
        .outputQuality(0.8f)
        .toFile(new File("image-with-watermark.jpg"));
In this example, the image from original.jpg is resized, then rotated to clockwise by 90 degrees, then a watermark is placed at the bottom right-hand corner which is half transparent, then is saved to image-with-watermark.jpg with 80% compression quality settings.

Create a thumbnail and write to an OutputStream
OutputStream os = ...;
                
Thumbnails.of("large-picture.jpg")
        .size(200, 200)
        .outputFormat("png")
        .toOutputStream(os);
In this example, an image from the file large-picture.jpg is resized to a maximum dimension of 200 x 200 (maintaining the aspect ratio of the original image) and writes the that to the specified OutputStream as a PNG image.

Creating fixed-size thumbnails
BufferedImage originalImage = ImageIO.read(new File("original.png"));

BufferedImage thumbnail = Thumbnails.of(originalImage)
        .size(200, 200)
        .asBufferedImage();
The above code takes an image in originalImage and creates a 200 pixel by 200 pixel thumbnail using and stores the result in thumbnail.

Scaling an image by a given factor
BufferedImage originalImage = ImageIO.read(new File("original.png"));

BufferedImage thumbnail = Thumbnails.of(originalImage)
        .scale(0.25f)
        .asBufferedImage();
The above code takes the image in originalImage and creates a thumbnail that is 25% of the original image, and uses the default scaling technique in order to make the thumbnail which is stored in thumbnail.

Rotating an image when creating a thumbnail
BufferedImage originalImage = ImageIO.read(new File("original.jpg"));

BufferedImage thumbnail = Thumbnails.of(originalImage)
        .size(200, 200)
        .rotate(90)
        .asBufferedImage();
The above code takes the original image and creates a thumbnail which is rotated clockwise by 90 degrees.

Creating a thumbnail with a watermark
BufferedImage originalImage = ImageIO.read(new File("original.jpg"));
BufferedImage watermarkImage = ImageIO.read(new File("watermark.png"));

BufferedImage thumbnail = Thumbnails.of(originalImage)
        .size(200, 200)
        .watermark(Positions.BOTTOM_RIGHT, watermarkImage, 0.5f)
        .asBufferedImage();
As shown, a watermark can be added to an thumbnail by calling the watermark method.