Comparisons

The following are comparison of images created using conventional image resizing techniques, such as using the Graphics.drawImage method and Image.getScaledInstance method, along with resizing using Thumbnailator.

Image Quality and Rendering Speed

Graphics.drawImage	Graphics.drawImage using bilinear interpolation	Graphics.drawImage using bicubic interpolation	Image.getScaledInstance using Image.SCALE_DEFAULT	Image.getScaledInstance using Image.SCALE_SMOOTH	Thumbnailator
0 ms	0 ms	5 ms	422 ms	771 ms	94 ms
0 ms	5 ms	5 ms	677 ms	1161 ms	235 ms

• The thumbnail of the photograph in the first row was created from a 2112 pixel by 2816 pixel JPEG image.

• The thumbnail of the image of the gradient in the second row was created from a 3000 pixel by 3000 pixel PNG image.

• Times listed is the amount of time that each technique took to resize the image. The time is an average over three runs (using System.currentTimeMillis), measured on a Core 2 Duo system running Java 6 Update 21 on Windows XP.

Code

The following are the relevant sections of code used to generate the above images.

Graphics.drawImage

BufferedImage thumbnail = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
		
Graphics2D g = thumbnail.createGraphics();
g.drawImage(originalImage, 0, 0, WIDTH, HEIGHT, null);
g.dispose();

Graphics.drawImage using bilinear interpolation

BufferedImage thumbnail = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
		
Graphics2D g = thumbnail.createGraphics();
g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g.drawImage(originalImage, 0, 0, WIDTH, HEIGHT, null);
g.dispose();

Graphics.drawImage using bicubic interpolation

BufferedImage thumbnail = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
		
Graphics2D g = thumbnail.createGraphics();
g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g.drawImage(originalImage, 0, 0, WIDTH, HEIGHT, null);
g.dispose();

Image.getScaledInstance using Image.SCALE_DEFAULT

BufferedImage thumbnail = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
		
Graphics2D g = thumbnail.createGraphics();
g.drawImage(originalImage.getScaledInstance(WIDTH, HEIGHT, Image.SCALE_DEFAULT), 0, 0, WIDTH, HEIGHT, null);
g.dispose();

Image.getScaledInstance using Image.SCALE_SMOOTH

BufferedImage thumbnail = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
		
Graphics2D g = thumbnail.createGraphics();
g.drawImage(originalImage.getScaledInstance(WIDTH, HEIGHT, Image.SCALE_SMOOTH), 0, 0, WIDTH, HEIGHT, null);
g.dispose();

Thumbnailator

BufferedImage thumbnail = Thumbnails.of(originalImage)
        .size(WIDTH, HEIGHT)
        .asBufferedImage();