Enhanced Metafile Record Structure
At the beginning of every enhanced metafile record is an EMR structure, which contains two members. The first member, iType, identifies the record type ¾ that is, the GDI function whose parameters are contained in the record. Because the structures are variable in length, the other member, nSize, contains the size of the record. Immediately following the nSize member are the remaining parameters, if any, of the GDI function.