Reasons:
- This API has been confused with the min size of the widget, resulting
in badly laid out applications.
- The EO API was not very nice (Range is about numbers, the Gfx size
hint in a part is really ugly).
While I understand the value of this API and how it can be used in
scalable applications, it is in fact not absolutely necessary.
Alternatively to that span size, the widget min size can already be
defined from the application side, or the widget can simply be expanded
to fill in its parent.
This can obviously be reinstated later if the need arises for EO. For
now, keep this feature as legacy-only.
Also prefix with widget.
I want to rename this as child rather than sub. It's inconsistent with
the other parent/child hierarchies. Anyway the various hierarchies are
confusing, so let's keep this name :)
Ref T5363
Some names have not been changed, hopefully making a distinction
between legacy APIs and internal code (elm_layout_blah) and valid EO
usages.
This means many internal functions are still elm_layout_ as their
sole purpose is to support the legacy API.
Ref T5315
elm_layout_sizing_eval() marks an object as requiring recalc.
Unfortunately, it's been massively abused by various widgets into
actually doing the calc, or the min calc. So we end up with one API
that has 3 different definitions depending on the widget type:
1. Mark as requiring recalc (correct, respects doc, elm_layout)
2. Calculate min size and other size hints
3. Actually do some geometry modification
I believe we need to clarify these 3 requirements into 3 very clear
and specific APIs in elementary. Right now we have similar functions
in evas for 1 (evas_object_smart_changed) and 3 (smart_calculate).
But their exact definition also isn't necessarily what we want for
elementary.
Another clear problem is that layout_eval does not do any calculation
(in theory), so the "eval" word is a bit of a stretch here.
Once we're sure about the exact API we want, we can add this back to
EO and make it work across our EO widgets. For now let's just keep
the legacy API, and its EO overrides, as is.
Ref T5315