XFA Overflow Targets

Flowed subforms, tables, leaders, breaks and now overflow targets complete the flowed-layout pipeline: <overflow target="ContinueHere"/> routes content that no longer fits the current content area into the named target subform's rectangle

Intrinsic measurement

Layout applies minW, minH, maxW and maxH constraints to measured leaves and growable containers, then propagates the resulting intrinsic dimensions through flowed parents

Growable text fields measure the actual bound data value through the configured text measurement callback rather than template placeholder text

Explicit empty values remain empty, calculated values are evaluated once and shared by measurement and emission, and repeated rows measure against their own bound instance

Text continuation

An eligible growable textEdit without a fixed height can split at a measured character boundary across the remaining content-area chain and later pages

Each continuation carries its exact text fragment, receives a unique AcroForm name and is emitted read-only so editing one fragment cannot invalidate the pagination contract

Splitting is atomic and limited to 1 MiB of text, 1024 fragments and 32768 measurements; exceeding any limit preserves the original placement path without publishing partial fragments

Intrinsic extents are cached by node, binding context, width and font constraints under one global measurement budget, whilst synthetic continuation names are allocated only after reserving every real output field name

Rich text, non-text objects, fixed-height fields, keep-intact content and single objects with leader, trailer or named overflow targets retain their existing whole-item or target placement behaviour

Continuation placement

When an item overflows, the target reference resolves against laid-out items by name (the same normalisation as leaders and trailers: path, # and $ prefixes strip to the last segment). Continuation items stack from the target's top with a small inset, preserving internal offsets, until the target rectangle fills; a target smaller than one item, a full target or an unresolvable name falls back to the normal content-area chain with a warning

Interaction with leaders and trailers

Trailer adornments still emit at the bottom of the overflowing area before the move, and leader adornments re-emit when the fallback area chain is used; the target route itself is a direct placement, so leaders apply only on the fallback path