EaseFunction svg graphs in doc

[SpecificProtagonist]

Objective

The docs of EaseFunction don't visualize the different functions, requiring you to check out the Bevy repo and running the easing_function example.

Solution

• Add tool to generate suitable svg graphs. This only needs to be re-run when adding new ease functions.
• works with all themes
• also add missing easing functions to example.

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Showcase

[bushrat011899]

I think this is a good idea. The documentation becomes massively more approachable when it's more than just type definitions; examples, tables, figures, all make it much nicer.

I do have a concern around needing to maintain this tool separately to bevy_math. Perhaps it would be worth trying to refactor this into a proc-macro? Especially considering we're using the doc attribute to just include the SVG string in the documentation anyway.

[SpecificProtagonist]

Perhaps it would be worth trying to refactor this into a proc-macro?

I like this idea, my only concern would be whether this would affect build time.

[bushrat011899]

I like this idea, my only concern would be whether this would affect build time.

Could use cfg_attr(doc, ...) to make the macro only run when building documentation?

[SpecificProtagonist]

Will do! I'm assuming the doc would be a feature enabled on docs.rs? Or is there a way to find out if it's getting build by rustdoc?

[bushrat011899]

Will do! I'm assuming the doc would be a feature enabled on docs.rs? Or is there a way to find out if it's getting build by rustdoc?

https://doc.rust-lang.org/rustdoc/advanced-features.html

doc is a built-in config set by rust-doc when it builds documentation. So if you do:

#[cfg_attr(doc, my_special_macro(...))]

It'll only include my_specual_macro when building documentation.

[bushrat011899]

After some experimentation, I don't think it'll be possible to use a proc-macro to generate the graphs. It'd require a cyclic dependency between the macro crate and bevy_math, which is forbidden outside of dev-dependencies.