Compuprint 4247-Z03 Programmer Manual - Manual (Page 107)

Control, or Write Bar Code (block) Control commands in the data stream indicates that the printed page
contains individual blocks of image, graphics, or bar code data for positioning on the page. These
commands cause a state transition to occur to an appropriate page block state. In the block state, the
printer establishes the initial conditions and processes the block of data onto the page. Receiving an End
command in a page block state terminates that state and returns processing back to the page state.
Figure 8 shows the relationship between the home state, page state, and block states.
Overlay State
Overlay state is the operating state that stores data in the printer. The printer enters the overlay state from
the home state as a result of receiving a Begin Overlay command.
A parameter in the Begin Overlay command provides an identifier for later references to this overlay. The
printer saves the currently active Logical Page Descriptor value, the Load Font Equivalence value, and the
Load Equivalence value as part of the stored overlay definition.
The same commands that the printer uses in the page state are also valid while in the overlay state.
Figure 9 on page 88 shows the relationship between the home state, overlay state, and block states.
Figure 8. The Relationship between Home State, Page State, and Block States
Chapter 3. Intelligent Printer Data Stream 87