Returns Readonly<
Ref<
{ height: number; left: number; top: number; width: number },
{ height: number; left: number; top: number; width: number },
>,
>
A readonly reactive ref containing the current viewer rectangle, or
a zero rectangle when no provider is available.
Returns the reactive rectangle of the current viewer subtree.
This function reads the rectangle previously registered by provideViewerRect. It is intended for floating panels, overlays, and other layout-aware descendants that need to align themselves to the current viewer host element.
When no provider exists in the current component tree, the function returns a shared readonly zero rectangle as a safe fallback. That behavior keeps the API easy to consume in optional or test-only contexts without forcing every caller to guard for
undefined.