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linebender / kurbo

A Rust library for manipulating curves
Apache License 2.0
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Support for no-alloc #327

Closed jneem closed 10 months ago

jneem commented 12 months ago

A surprising amount of useful kurbo code doesn't require allocation (which is really only used for BezPath and its dependents). This adds a feature for turning off allocation support altogether.

Note that this change might break anyone who uses kurbo with default-features = false.

xStrom commented 11 months ago

There was a tiny bit of discussion about this PR during office hours and a question that came up was the use case. I'm relaying that here to help move this forward.

Could you describe your use case a bit where no-alloc is beneficial? No need for a massive rationale, but because this does add a bit of complexity to the code and testing, it would be useful to have a bit more specifics about the benefits.

For extra context @longmathemagician pointed out in Zulip that dynamic allocation is disallowed in aerospace (DO-178B) but also automotive (MISRA C / ISO 26262) and functional safety applications (IEC 61508).

jneem commented 11 months ago

Ah, sorry, I replied on the zulip before seeing this comment. I'm using kurbo on an esp32c3 device, using esp-hal which doesn't support alloc out-of-the-box. It's quite possible that this is too niche to be worth supporting upstream, in which case I'm quite happy to maintain my own patchset.

jneem commented 10 months ago

I've done some more experimentation, and I think I'm better off switching to euclid and lyon_geom for the embedded part. They already have no-alloc (and f32) support, and the conversions aren't too painful.