Keeps one of MAIDR's fields readable on the page it is drawn in (see
keepFieldReadable), measured before it is painted. The floor checks the
field on its own when it gains or loses focus and when the page may have
changed its colours; this hook adds the checks only its component knows to
ask for.
When high contrast mode or its colours change, after
HighContrastService has painted or restored the chart's backdrop: the
service subscribes to the setting before the settings view model does,
and React commits the re-render this hook asks for only after both have
run.
When step changes, which catches braille up with a change the floor
does not watch for -- a class on an element between the body and the
chart, say -- on the reader's next step; review takes no steps while it
is open.
Like every check, these measure the field only where something the floor
reads has changed (see keepFieldReadable), and change nothing on the page
where nothing has. Whatever the floor throws is logged, never thrown on:
keeping the field readable must not cost the reader the chart.
Parameters
ref: RefObject<HTMLElement|null>
The field
step: object
The field's state from the store, a new object on every
update its view model dispatches, which is every step the reader takes
(a step can leave the field's text and caret as they were, from the
chart's starting place onto its first point)
Keeps one of MAIDR's fields readable on the page it is drawn in (see
keepFieldReadable), measured before it is painted. The floor checks the field on its own when it gains or loses focus and when the page may have changed its colours; this hook adds the checks only its component knows to ask for.HighContrastServicehas painted or restored the chart's backdrop: the service subscribes to the setting before the settings view model does, and React commits the re-render this hook asks for only after both have run.stepchanges, which catches braille up with a change the floor does not watch for -- a class on an element between the body and the chart, say -- on the reader's next step; review takes no steps while it is open.Like every check, these measure the field only where something the floor reads has changed (see
keepFieldReadable), and change nothing on the page where nothing has. Whatever the floor throws is logged, never thrown on: keeping the field readable must not cost the reader the chart.