Java convert image format with low memory footprint

Question

I'm writing a Web application that let user upload images in several formats (e.g. png,jpg,bmp). After the image has been uploaded the system should convert it to "png" and scale it to a predefined resolution.

To convert the image I use the handy method:

javax.imageio.ImageIO.write(im, type, baos);

Here's where the problem start. The first argument of Image javax.imageio.ImageIO.write is a RenderedImage. The Java Doc states that the only known implementation is BufferedImage.

I try to find a way to convert a java.awt.Image to a BufferedImage, but it doesn't seems possible. However, it is possible to draw an image on a BufferedImage.

The problem is that creating a new BufferedImage each time is very memory expensive. I can start creating a pool of BufferedImage but I'm looking for clever/news ideas.

score 5 · Answer 1 · answered Mar 06 '12 at 14:28

5

Try Thumbnailator library: http://code.google.com/p/thumbnailator/

Example code:

Thumbnails.of("large-picture.jpg")
        .scale(1.0)
        .outputFormat("png")
        .toOutputStream(os);

Library offers also much more like scaling, sizing, cropping, rotating, watermarking etc.

answered Mar 06 '12 at 14:28

muras

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This is a good library, but it also uses BufferedImage. Are there approaches that don't use BufferedImage? – user2910265 Nov 23 '16 at 23:13

score 1 · Answer 2 · edited May 23 '17 at 12:33

1

There's a bunch of Java libraries and SO posts about this. Did you check them out?

edited May 23 '17 at 12:33

Community

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answered Aug 31 '10 at 21:28

The Alchemist

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No, I didn't check them. Do you have any recommendation for this problem. I mean, converting images with low memory footprint – Dani Cricco Aug 31 '10 at 21:33
No, sorry, I haven't used any of them so I can't recommend anything. You can probably find some results on Google or whereever, but your best bet is to just try them yourself. – The Alchemist Aug 31 '10 at 22:33

score 1 · Answer 3 · answered Aug 31 '10 at 21:33

1

You could reuse one buffered image over and over again, using subimage to size appropriately when it's time to use the ImageIO.write method

answered Aug 31 '10 at 21:33

I82Much

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Ahap, that was the original idea (as the question describes) – Dani Cricco Aug 31 '10 at 21:35

score 0 · Answer 4 · answered Aug 31 '10 at 21:13

You could look at the implementation of BufferedImage and implement your own (A file-based implementation perhaps?). These classes are generally pretty straight-forward to read, often 50-70% comments and clearly written.

They give out the sources, why not make use of 'em?

score 0 · Answer 5 · answered Aug 31 '10 at 21:41

0

Launch a native converter like netpbm or imagemagick.

answered Aug 31 '10 at 21:41

Thorbjørn Ravn Andersen

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Java convert image format with low memory footprint

5 Answers5