Add Context::parent_viewport_id_of

[rustbasic]

• Closes ViewportInfo.parent doesn't always store any information. #4216

fix : ViewportInfo.parent doesn't always store any information.

and

addition ViewportInfo.this

[emilk]

https://rust-lang.github.io/api-guidelines/naming.html#getter-names-follow-rust-convention-c-getter

Suggested change

	pub(crate) fn get_parent_viewport_id(&self, viewport_id: ViewportId) -> ViewportId {
	pub(crate) fn parent_viewport_id_of(&self, viewport_id: ViewportId) -> ViewportId {

[rustbasic]

https://rust-lang.github.io/api-guidelines/naming.html#getter-names-follow-rust-convention-c-getter

what do you want?

parent_viewport_id_of() ? (you're writed here)
viewport_parent_id_of() ? (you're writed title)

[emilk]

This is unused?

I think everywhere we have a ViewportInfo we have a ViewportId for it as the key

[rustbasic]

This is used.
parent_viewport_id() returns the parent of the last viewport_id, making it difficult to use unless it's inside a crate.

[rustbasic]

This is unused?

I think everywhere we have a ViewportInfo we have a ViewportId for it as the key

no. There are places where viewport_id is missing. It's hard to explain.

[emilk]

Try to explain and/or make this a ids: ViewportIdPair which is set in a constructor, instead of sometimes being None.

[rustbasic]

Try to explain and/or make this a ids: ViewportIdPair which is set in a constructor, instead of sometimes being None.

There are parts where this is absolutely necessary, and users will be able to easily access it. (In fact, this may not be easy for beginners to access.)
This is absolutely necessary, as there are cases where there is currently no way to determine the viewport_id.
Without this, every time you create a viewport, you would have to save the viewport_id somewhere and take care of it.

[emilk]

Then add ids: ViewportIdPair to ViewportInfo (and remove the Default bound on it), so users can depend on the ids

[rustbasic]

Try to explain and/or make this a ids: ViewportIdPair which is set in a constructor, instead of sometimes being None.

If you don't save the viewport_id when creating a viewport, the current window sometimes doesn't know what the current viewport_id is. This is difficult to explain. Currently the viewport_id is unknown, so how can I find the parent_id? This is a different case from examples/demo_viewports.
last viewport_id may not be the current viewport.

[rustbasic]

Then add ids: ViewportIdPair to ViewportInfo (and remove the Default bound on it), so users can depend on the ids

info.this is absolutely necessary.
If info.this is present, info.parent does not need to be present.
info.parent pre-existed and could not work.

[emilk]

Suggested change

	pub this: Option<ViewportId>,
	pub this: ViewportId,

[emilk]

If we should store the ViewportId in this struct, we should force users to initialize it to the correct thing when they create it via a ViewportInfo::new, otherwise it will be wrong.

Suggested change

	#[derive(Clone, Debug, Default, PartialEq)]
	#[derive(Clone, Debug, PartialEq)]