img-hash VS fast_image_resize

I absolutely loved all the crates available that made my life very simple in many cases. I used (among others) the slint ui framework, kamadak-exif, img_hash, fast_image_resize and rawloader.

I'm using default img_hash algorithm - Gradient. It is also possible to use with this library different algorithms - https://github.com/abonander/img_hash/blob/master/src/alg/mod.rs#L20-L81

Unfortunately mostly useless for professional applications.

It fails the most simple test from [0] in the online demo[1]. ImageMagic also has a page about this[2]. I.e. also try the 'city lights' test with the online demo to see it fail for the same reason.

The issue is that if you write code that deals with color you must understand color spaces and gamma. A non-linearly encoded color can't be plugged into any of the math you use to manipulate images and get meaningful results.

Almost all code I come across in the Rust ecosystem (or elsewhere no less) treats color as linear. But color incoming from image files that are not RAW, EXR or some TIF variant is almost /never/ linear.

The reason is that it is written by people who are (often very skilled) software developers but lack any basic understanding of color science.

And then it often takes convicing the maintainers first and the yonx before it is fixed. I'm speaking from multiple experiences here.

For example, the fast image resize crate[3] addressed the resp. issue I filed last Dec.[4] less than a week ago. From the crate being released in the wild to it adding an option to treat color correct almost 1.5 years passed.

This is not the same as forcing crate users to treat color correct btw. The crate added a function that calls a closure but a user who do not understand color science may not grok why this is needed and not use it.

I guess I'm saying there is also often an 'UX' issue that perpetuates the problem to the user side of the API after the crate itself addressed it somehow.

That said, there are some very good crates that abstract the resp. parts away to address the issue. E.g. [5].

[0] http://www.ericbrasseur.org/gamma.html?i=1#explanation

[1] https://silvia-odwyer.github.io/photon/demo.html

[2] https://legacy.imagemagick.org/Usage/resize/#resize_colorspa...

[3] https://docs.rs/fast_image_resize

[4] https://github.com/Cykooz/fast_image_resize/issues/3

[5] https://docs.rs/colstodian

I absolutely loved all the crates available that made my life very simple in many cases. I used (among others) the slint ui framework, kamadak-exif, img_hash, fast_image_resize and rawloader.