Add public methods to access clip path

[tomcur]

This adds public getters for clip path to non-LayoutCtx contexts, and also to WidgetState as it seems relevant for painting.

The motivation is to remove private field accesses from Widget::get_child_at_pos as mentioned in
#565 (comment).

This leaves one private field access, namely WidgetState::is_stashed. As per the docs of WidgetState ("widgets will generally not interact with it directly"), that field perhaps should not be publicly accessible from WidgetState, but then it should be accessible from WidgetRef.

[tomcur]

Private WidgetState::is_stashed is accessed here

xilem/masonry/src/widget/widget.rs

Line 214 in 67f0043

if !child.state().is_stashed

child is a WidgetRef. Perhaps WidgetRef can allow access to the underlying QueryCtx, and we add the stashed getter on QueryCtx.

[Philipp-M]

Yeah probably doesn't hurt to expose this, LGTM.
I expect though that this is very much in flux, a clip path just being Rect seems... limited.

[tomcur]

I'll leave the question of how to expose stashed state for a later PR.

I expect though that this is very much in flux, a clip path just being Rect seems... limited.

Right, iirc clip is intended to become generalized to arbitrary shapes, but it requires an efficient way in Kurbo to do so (maybe just an enum for the most common shapes?).

Edit, for reference:

xilem/masonry/src/widget/widget_state.rs

Lines 75 to 78 in 1fe790a

	// TODO - Use general Shape
	// Currently Kurbo doesn't really provide a type that lets us
	// efficiently hold an arbitrary shape.
	pub(crate) clip: Option<Rect>,