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Optimized Blurhash #235
Description
I am looking at using Blurhash to get very small but nice blurred image previews : https://blurha.sh
The algorithm is quite simple and defined here: https://github.com/woltapp/blurhash/blob/master/Algorithm.md
There is a Ruby native Blurhash implementation, and it works fine using something like this:
image = Vips::Image.new_from_file(path)
Blurhash.encode(image.width, image.height, image.to_a.flatten)
Unfortunately this involves creating a huge array with all pixels and this is quite slow.
Do you think there is a way to have a more efficient implementation using Vips directly? I would be happy to have pointers, I am not really familiar with the low-level VIPS functions and if they can be used for this to avoid doing the computation using Ruby.
Thanks :)
Activity
Nakilon commentedon May 10, 2020
While it's still not the "using Vips directly", try resizing the image to 100x100 and see if it works enough well for you:
jcupitt commentedon May 11, 2020
I think the DCT would probably need to be implemented in C or C++. Let's tag this as an enhacement.
jcupitt commentedon May 11, 2020
... an enhancement on libvips, I mean
renchap commentedon May 11, 2020
@Nakilon Thanks for the suggestion, I am already doing a resize before calculating the blurhash to reduce the number of ruby allocations, but I think it can be even faster and memory-efficient :)
@jcupitt Ok, I was not sure it could be done, if vips gets primitives to do this it would be awesome!