Instantiable

Include file:

OverlayUnidraw/indexmixins.h

When a tree of graphical components is saved to disk (translated to ASCII), the graphic states are output first as 'gs' records, to allow for replicated graphic states to appear only once in a file. When reading these documents back in, the istream constructor of OverlayIdrawComp (and other top-level components) uses this mixin to manage a table of graphic states, building it up as each 'gs' record is read, and accessing entries for each ":gs id" field found in subsequent records.