Byte array to some sort of Java/Scala image. Performance considerations

Question

I am writing an FTP server that receives images and then resizes and uploads them.

My current process (pseudocode) is as follows:

val imagesAsBytes: Array[Byte] = ...
val bufferedImage: BufferedImage = ImageIO.read(new ByteArrayInputStream(bytes))
uploadImage(bufferedImage)

That's the gist of it. I've left out the resizing because it's not important. Essentially, I serialise the Array[Byte] into a BufferedImage using the ImageIO module, and then resize it.

I have done some profiling, and I've noticed that creating a BufferedImage using ImageIO is horribly slow.

If I just upload the Array[Byte], I can achieve about 4x the throughput, than if I actually try and convert it to a BufferedImage. The reason I can't just upload the Array[Byte], is that I do need to resize the image. I am not tied to BufferedImage, it's just my first attempt.

Does anyone know of some ideas I can use to speed this up? Is there a better format I should be using over BufferedImage?

I've already considered pushing resizing out to a separate microservice and perform it asynchronously, but it's not an option for the first release.

Edit: I have reviewed this question, and am aware of this: ImageIO.setUseCache(false)

Answer 1

I would suggest looking at more actively supported library (last release 4.0 at Feb 2020) like scrimage. Under the hood it uses java.awt.*. At least in case of any issues you will be able to address them and get them resolved, moreover using more "scalish" API.

Hope it helps.