Conversions between CoreGraphics and Kurbo types

[waywardmonkeys]

This is an optional feature, not enabled by default.

[waywardmonkeys]

This is most usable when it is able to use From impls, so having it here in the kurbo crate is easiest to use.

This is still missing support for various types.

It might be that the features should change so that they're objc2-core-foundation for the core types (affine, point, rect, size, vec) and objc2-core-graphics for the things like line caps, joins, paths, etc. There should also be support for UIBezierPath and NSBezierPath (which are 2 other crates).

[waywardmonkeys]

@xStrom What might be the best way to handle a feature that only works on a subset of platforms?

[xStrom]

To solve this at the CI level we would have to use cargo-hack for everything, including testing. However, I think we should solve this at a different level because being able to use --all-features locally for development is very nice.

What I think we should do is make this feature a NOP on other platforms. Then --all-features will continue working and no changes will be needed to CI either.

[xStrom]

Suggested change

	[dependencies.objc2-core-foundation]
	version = "0.3.1"
	optional = true
	default-features = false
	features = ["CFCGTypes"]
	[dependencies.objc2-core-graphics]
	version = "0.3.1"
	optional = true
	default-features = false
	features = ["CGPath"]
	[target.'cfg(target_vendor = "apple")'.dependencies.objc2-core-foundation]
	version = "0.3.1"
	optional = true
	default-features = false
	features = ["CFCGTypes"]
	[target.'cfg(target_vendor = "apple")'.dependencies.objc2-core-graphics]
	version = "0.3.1"
	optional = true
	default-features = false
	features = ["CGPath"]

[xStrom]

Suggested change

	#[cfg(feature = "objc2-core-graphics")]
	mod interop_objc2_core_graphics;
	#[cfg(all(target_vendor = "apple", feature = "objc2-core-graphics"))]
	mod interop_objc2_core_graphics;