image-rs
High compile times for `moxcms` crate
The moxcms dependency introduced in 0.25.8 seems to have excessively large compile times. It is adding 25s to my build time, and it's dependency pxfm is adding another 10s. This is compared to the 19s for image itself (which already seems like a lot to me)
These are single-core times, so the overall affect on my build time is not as bad due to paralellism. And these are also the build times when my machine is under load from building other Rust crates at the same time (as part of the same build). But still, this is a lot!
Could this dependency (and it's associated functionality) be made optional?
In functionality it is similar to the situation of idna/url. We can not make it outright optional, it would greatly impede work on color fidelity of read and write and working on images if you're preparing them for such.
In particular there are still quite many cases to be fixed, we're completely blocked from supporting many modern codec (variants) without the proper conversion functionality. Anything HDR and wide-gamut related needs at least most of the transfer functions and points. Technically we are unlikely to rely on the full ICC functionality like look-up table functions but that does not allow us to drop the crate without replacement.
We are however aware of some of the causes of build times, #2585. This will take a bit to work out and a new major version. What system target are you compiling on? We might be able to make some parts opt-in and error on unsupported functionality but it's really hard to say how to make that work without causing a lot of unexpected Err returns.
