TXFALayoutEngine.Create

Unit: HPDFXFALayout

constructor Create(ADoc: TXFADocument; APageW, APageH: Double;
  AWarnings: TStringList; AMeasureText: TXFAMeasureTextFunc = nil;
  AResolveText: TXFAResolveLayoutTextFunc = nil; AMaxFieldItems: Integer = 0;
  AMaxLayoutOperations: Integer = 200000;
  AResolveProperty: TXFAResolveInstanceProperty = nil;
  AResolveScope: TXFAResolveInstanceScope = nil);

Trailing optional resolvers add per-instance properties and repeat-parent binding whilst nil keeps existing callers working; the layout engine stays independent of HPDFDoc

See Dynamic XFA Instance Presentation for binding and selector rules, supported event syntax, budget defaults, transactional publication, persistence, painting and compatibility boundaries